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110-484: The district has the following sub-districts: This Iraq geographical location article is a stub . You can help Misplaced Pages by expanding it . This Iraqi Kurdistan geographical location article is a stub . You can help Misplaced Pages by expanding it . Geography of Iraq The geography of Iraq is diverse and falls into five main regions: the desert (west of the Euphrates ), Upper Mesopotamia (between

220-403: A base. This is also true of some compounds with ionic character, typically oxides or hydroxides of less-electropositive metals (so the compound also has significant covalent character), such as zinc oxide , aluminium hydroxide , aluminium oxide and lead(II) oxide . Electrostatic forces between particles are strongest when the charges are high, and the distance between the nuclei of the ions

330-679: A compound with no net electric charge (electrically neutral). The constituent ions are held together by electrostatic forces termed ionic bonds . The component ions in a salt can be either inorganic , such as chloride (Cl ), or organic , such as acetate ( CH 3 COO ). Each ion can be either monatomic (termed simple ion ), such as sodium (Na ) and chloride (Cl ) in sodium chloride , or polyatomic , such as ammonium ( NH 4 ) and carbonate ( CO 3 ) ions in ammonium carbonate . Salts containing basic ions hydroxide (OH ) or oxide (O ) are classified as bases , for example sodium hydroxide . Individual ions within

440-469: A day at the beginning and end of the season but for several days at other times. This wind is often accompanied by violent duststorms that may rise to heights of several thousand meters and close airports for brief periods. From mid-June to mid-September the prevailing wind, called the shamal , is from the north and northwest. It is a steady wind, absent only occasionally during this period. The very dry air brought by this shamal permits intensive sun heating of

550-415: A network with long-range crystalline order. Many other inorganic compounds were also found to have similar structural features. These compounds were soon described as being constituted of ions rather than neutral atoms , but proof of this hypothesis was not found until the mid-1920s, when X-ray reflection experiments (which detect the density of electrons), were performed. Principal contributors to

660-453: A paste and then heated to a temperature where the ions in neighboring reactants can diffuse together during the time the reactant mixture remains in the oven. Other synthetic routes use a solid precursor with the correct stoichiometric ratio of non-volatile ions, which is heated to drive off other species. In some reactions between highly reactive metals (usually from Group 1 or Group 2 ) and highly electronegative halogen gases, or water,

770-752: A peace settlement, problems of irrigation and flooding would receive top priority from the government. Iraqi coastal waters boast a living coral reef , covering an area of 28 km in the Persian Gulf , at the mouth of the Shatt al-Arab river ( 29°37′00″N 48°48′00″E  /  29.61667°N 48.80000°E  / 29.61667; 48.80000 ). The coral reef was discovered by joint Iraqi–German expeditions of scientific scuba divers carried out in September 2012 and in May 2013. Prior to its discovery, it

880-416: A potential energy well with minimum energy when the nuclei are separated by a specific equilibrium distance. If the electronic structure of the two interacting bodies is affected by the presence of one another, covalent interactions (non-ionic) also contribute to the overall energy of the compound formed. Salts are rarely purely ionic, i.e. held together only by electrostatic forces. The bonds between even

990-400: A reducing agent such as carbon) such that the metal ions gain electrons to become neutral atoms. According to the nomenclature recommended by IUPAC , salts are named according to their composition, not their structure. In the most simple case of a binary salt with no possible ambiguity about the charges and thus the stoichiometry , the common name is written using two words. The name of

1100-529: A role in determining the strength of the interactions and propensity to melt. Even when the local structure and bonding of an ionic solid is disrupted sufficiently to melt it, there are still strong long-range electrostatic forces of attraction holding the liquid together and preventing ions boiling to form a gas phase. This means that even room temperature ionic liquids have low vapour pressures, and require substantially higher temperatures to boil. Boiling points exhibit similar trends to melting points in terms of

1210-460: A salt usually have multiple near neighbours, so they are not considered to be part of molecules, but instead part of a continuous three-dimensional network. Salts usually form crystalline structures when solid. Salts composed of small ions typically have high melting and boiling points , and are hard and brittle . As solids they are almost always electrically insulating , but when melted or dissolved they become highly conductive , because

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1320-498: A shorter wavelength when they are involved in more covalent interactions. This occurs during hydration of metal ions, so colorless anhydrous salts with an anion absorbing in the infrared can become colorful in solution. Salts exist in many different colors , which arise either from their constituent anions, cations or solvates . For example: Some minerals are salts, some of which are soluble in water. Similarly, inorganic pigments tend not to be salts, because insolubility

1430-527: A variety of structures are commonly observed, and theoretically rationalized by Pauling's rules . In some cases, the anions take on a simple cubic packing and the resulting common structures observed are: Some ionic liquids , particularly with mixtures of anions or cations, can be cooled rapidly enough that there is not enough time for crystal nucleation to occur, so an ionic glass is formed (with no long-range order). Within any crystal, there will usually be some defects. To maintain electroneutrality of

1540-626: A wide variety of uses and applications. Many minerals are ionic. Humans have processed common salt (sodium chloride) for over 8000 years, using it first as a food seasoning and preservative, and now also in manufacturing, agriculture , water conditioning, for de-icing roads, and many other uses. Many salts are so widely used in society that they go by common names unrelated to their chemical identity. Examples of this include borax , calomel , milk of magnesia , muriatic acid , oil of vitriol , saltpeter , and slaked lime . Soluble salts can easily be dissolved to provide electrolyte solutions. This

1650-483: Is K). When one of the ions already has a multiplicative prefix within its name, the alternate multiplicative prefixes ( bis- , tris- , tetrakis- , ...) are used. For example, Ba(BrF 4 ) 2 is named barium bis(tetrafluoridobromate) . Compounds containing one or more elements which can exist in a variety of charge/ oxidation states will have a stoichiometry that depends on which oxidation states are present, to ensure overall neutrality. This can be indicated in

1760-578: Is a river delta interlaced by the channels of the two rivers and by irrigation canals. Intermittent lakes , fed by the rivers in flood, also characterize southeastern Iraq. A fairly large area (15,000 km or 5,800 sq mi) just above the confluence of the two rivers at Al Qurnah and extending east of the Tigris beyond the Iranian border is marshland, known as Hawr al Hammar , the result of centuries of flooding and inadequate drainage. Much of it

1870-429: Is a more sandy region with a covering of scrub vegetation. Elevation in the southern desert averages between 1,000 and 2,700 feet (300 and 820 metres). A height of 3,119 feet (951 metres) is reached at Mount 'Unayzah at the intersection of the borders of Jordan, Iraq and Saudi Arabia. The deep Wadi Al-Batin runs 45 miles (72 km) in a northeast–southwest direction through Al-Dibdibah. It has been recognized since 1913 as

1980-407: Is a simple way to control the concentration and ionic strength . The concentration of solutes affects many colligative properties , including increasing the osmotic pressure , and causing freezing-point depression and boiling-point elevation . Because the solutes are charged ions they also increase the electrical conductivity of the solution. The increased ionic strength reduces the thickness of

2090-590: Is a vast desert region covering some 64,900 square miles (168,000 square kilometres), almost two-fifths of the country. The western desert, an extension of the Syrian Desert, rises to elevations above 1,600 feet (490 metres). The southern desert is known as Al-Hajarah in the western part and as Al-Dibdibah in the east. Both deserts are part of the Arabian Desert. Al Hajarah has a complex topography of rocky desert, wadis, ridges, and depressions. Al-Dibdibah

2200-400: Is highest in polar solvents (such as water ) or ionic liquids , but tends to be low in nonpolar solvents (such as petrol / gasoline ). This contrast is principally because the resulting ion–dipole interactions are significantly stronger than ion-induced dipole interactions, so the heat of solution is higher. When the oppositely charged ions in the solid ionic lattice are surrounded by

2310-476: Is mainly a hot desert climate or a hot semi-arid climate to the northernmost part. Averages high temperatures are generally above 40 °C (104 °F) at low elevations during summer months (June, July and August) while averages low temperatures can drop to below 0 °C (32 °F) during the coldest month of the year during winter The all-time record high temperature in Iraq of 53.9 °C (129.0 °F)

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2420-535: Is named iron(2+) sulfate (with the 2+ charge on the Fe ions balancing the 2− charge on the sulfate ion), whereas Fe 2 (SO 4 ) 3 is named iron(3+) sulfate (because the two iron ions in each formula unit each have a charge of 3+, to balance the 2− on each of the three sulfate ions). Stock nomenclature , still in common use, writes the oxidation number in Roman numerals (... , −II, −I, 0, I, II, ...). So

2530-418: Is permanent marsh, but some parts dry out in early winter, and other parts become marshland only in years of great flood. Because the waters of the Tigris and Euphrates above their confluence are heavily silt - laden, irrigation and fairly frequent flooding deposit large quantities of silty loam in much of the delta area. Windborne silt contributes to the total deposit of sediments. It has been estimated that

2640-548: Is required for fastness. Some organic dyes are salts, but they are virtually insoluble in water. Salts can elicit all five basic tastes , e.g., salty ( sodium chloride ), sweet ( lead diacetate , which will cause lead poisoning if ingested), sour ( potassium bitartrate ), bitter ( magnesium sulfate ), and umami or savory ( monosodium glutamate ). Salts of strong acids and strong bases (" strong salts ") are non- volatile and often odorless, whereas salts of either weak acids or weak bases (" weak salts ") may smell like

2750-414: Is small. In such cases, the compounds generally have very high melting and boiling points and a low vapour pressure . Trends in melting points can be even better explained when the structure and ionic size ratio is taken into account. Above their melting point, salts melt and become molten salts (although some salts such as aluminium chloride and iron(III) chloride show molecule-like structures in

2860-551: Is the formation of an F-center , a free electron occupying an anion vacancy. When the compound has three or more ionic components, even more defect types are possible. All of these point defects can be generated via thermal vibrations and have an equilibrium concentration. Because they are energetically costly but entropically beneficial, they occur in greater concentration at higher temperatures. Once generated, these pairs of defects can diffuse mostly independently of one another, by hopping between lattice sites. This defect mobility

2970-421: Is the source of most transport phenomena within an ionic crystal, including diffusion and solid state ionic conductivity . When vacancies collide with interstitials (Frenkel), they can recombine and annihilate one another. Similarly, vacancies are removed when they reach the surface of the crystal (Schottky). Defects in the crystal structure generally expand the lattice parameters , reducing the overall density of

3080-411: Is the summation of the interaction of all sites with all other sites. For unpolarizable spherical ions, only the charges and distances are required to determine the electrostatic interaction energy. For any particular ideal crystal structure, all distances are geometrically related to the smallest internuclear distance. So for each possible crystal structure, the total electrostatic energy can be related to

3190-460: Is the urban area surrounding Baghdad . These " Baghdad Belts " can be described as the provinces adjacent to the Iraqi capital and can be divided into four quadrants: northeast, southeast, southwest, and northwest. Beginning in the north, the belts include the province of Saladin , clockwise to Baghdad province, Diyala in the northeast, Babil and Wasit in the southeast and around to Al Anbar in

3300-537: The Arabian Peninsula . The region, sparsely inhabited by pastoral Bedouins , consists of a wide stony plain interspersed with rare sandy stretches. A widely ramified pattern of wadis –watercourses that are dry most of the year–runs from the border to the Euphrates. Some wadis are over 400 km (250 mi) long and carry brief but torrential floods during the winter rains. Western and southern Iraq

3410-482: The Kapustinskii equation . Using an even simpler approximation of the ions as impenetrable hard spheres, the arrangement of anions in these systems are often related to close-packed arrangements of spheres, with the cations occupying tetrahedral or octahedral interstices . Depending on the stoichiometry of the salt, and the coordination (principally determined by the radius ratio ) of cations and anions,

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3520-597: The Karun River enters the Shatt al Arab from Iran, carrying large quantities of silt that present a continuous dredging problem in maintaining a channel for ocean-going vessels to reach the port at Basra. This problem has been superseded by a greater obstacle to river traffic, however, namely the presence of several sunken hulls that have been rusting in the Shatt al Arab since early in the Iran-Iraq war. The waters of

3630-462: The Nineveh Plains , Duhok , Zakho and Amedi , mainly consist of Mediterranean vegetation. The vegetation cyclically dries out and appear brown in the virtually arid summer and flourish in the wet winter. An alluvial plain begins north of Baghdad and extends to the Persian Gulf . Here the Tigris and Euphrates rivers lie above the level of the plain in many places, and the whole area

3740-580: The Zagros Mountains in northeastern Iraq there is permanent vegetation, such as oak trees, and date palms are found in the south. In 1922 British officials concluded the Treaty of Mohammara with Abd al Aziz ibn Abd ar Rahman Al Saud , who in 1932 formed the Kingdom of Saudi Arabia. The treaty provided the basic agreement for the boundary between the eventually independent nations. Also in 1922

3850-416: The anhydrous material. Molten salts will solidify on cooling to below their freezing point . This is sometimes used for the solid-state synthesis of complex salts from solid reactants, which are first melted together. In other cases, the solid reactants do not need to be melted, but instead can react through a solid-state reaction route . In this method, the reactants are repeatedly finely ground into

3960-405: The conjugate acid (e.g., acetates like acetic acid ( vinegar ) and cyanides like hydrogen cyanide ( almonds )) or the conjugate base (e.g., ammonium salts like ammonia ) of the component ions. That slow, partial decomposition is usually accelerated by the presence of water, since hydrolysis is the other half of the reversible reaction equation of formation of weak salts. Salts have long had

4070-580: The electrical double layer around colloidal particles, and therefore the stability of emulsions and suspensions . The chemical identity of the ions added is also important in many uses. For example, fluoride containing compounds are dissolved to supply fluoride ions for water fluoridation . Solid salts have long been used as paint pigments, and are resistant to organic solvents, but are sensitive to acidity or basicity. Since 1801 pyrotechnicians have described and widely used metal-containing salts as sources of colour in fireworks. Under intense heat,

4180-435: The electronegative halogens gases to salts. Salts form upon evaporation of their solutions . Once the solution is supersaturated and the solid compound nucleates. This process occurs widely in nature and is the means of formation of the evaporite minerals. Insoluble salts can be precipitated by mixing two solutions, one with the cation and one with the anion in it. Because all solutions are electrically neutral,

4290-627: The Euphrates continues to the Hindiya Barrage , which was constructed in 1914 to divert the river into the Hindiyah Channel; the present day Shatt al Hillah had been the main channel of the Euphrates before 1914. Below Al Kifl , the river follows two channels to As-Samawah , where it reappears as a single channel to join the Tigris at Al Qurnah . The Tigris also rises in Turkey but is significantly augmented by several rivers in Iraq,

4400-413: The Euphrates north of Hit , is known as Al Jazira (the island) and is part of a larger area that extends westward into Syria between the two rivers and into Turkey . Water in the area flows in deeply cut valleys, and irrigation is much more difficult than it is in the lower plain. The southwest areas of this zone are classified as desert or semi-desert. The northern parts, which include such places like

4510-1792: The Iraqis during the war to fix the border once and for all but Baghdad repeatedly demurred, claiming that the issue is a potentially divisive one that could inflame nationalist sentiment inside Iraq. Hence in 1988 it was likely that a solution would have to wait until the war ended. Area: total: 438,317 km (169,235 sq mi) land: 437,367 km (168,868 sq mi) water: 950 km (370 sq mi) Land boundaries: total: 3,809 km (2,367 mi) border countries: Iran 1,599 km (994 mi), Saudi Arabia 811 km (504 mi), Syria 599 km (372 mi), Turkey 367 km (228 mi), Kuwait 254 km (158 mi), Jordan 179 km (111 mi) Coastline: 58 km (36 mi) Maritime claims: territorial sea: 12  nmi (22.2 km; 13.8 mi) continental shelf: not specified Terrain: mostly broad plains; reedy marshes along Iranian border in south with large flooded areas; mountains along borders with Iran and Turkey Elevation extremes: lowest point: Persian Gulf 0 m highest point: Cheekah Dar 3,611 m (11,847 ft) Natural resources: petroleum, natural gas, phosphates, sulfur Land use: arable land: 7.89% permanent crops: 0.53% other: 91.58% (2012) Irrigated land: 35,250 km or 13,610 sq mi (2003) Total renewable water resources: 89.86 km or 21.56 cu mi (2011) Freshwater withdrawal (domestic/industrial/agricultural): total: 66 km /yr (7%/15%/79%) per capita: 2,616 m /yr (2000) While its proven oil reserves of 145 billion barrels (23.1 × 10 ^   m ) ranks Iraq fifth in

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4620-466: The Sea , Ozone Layer Protection signed, but not ratified: Environmental Modification 33°00′N 44°00′E  /  33.000°N 44.000°E  / 33.000; 44.000 Salt (chemistry) In chemistry , a salt or ionic compound is a chemical compound consisting of an assembly of positively charged ions ( cations ) and negatively charged ions ( anions ), which results in

4730-399: The Shatt al-Hayy well above the confluence of the two main channels at Al Qurnah. Both the Tigris and the Euphrates break into a number of channels in the marshland area, and the flow of the rivers is substantially reduced by the time they come together at Al Qurnah. Moreover. the swamps act as silt traps, and the Shatt al Arab is relatively silt free as it flows south. Below Basra , however,

4840-504: The Tigris and Euphrates are essential to the life of the country, but they sometimes threaten it. The rivers are at their lowest level in September and October and at flood in March, April, and May when they may carry forty times as much water as at low mark. Moreover, one season's flood may be ten or more times as great as that in another year. In 1954, for example, Baghdad was seriously threatened, and dikes protecting it were nearly topped by

4950-658: The anion and cation. This difference in electronegativities means that the charge separation, and resulting dipole moment, is maintained even when the ions are in contact (the excess electrons on the anions are not transferred or polarized to neutralize the cations). Although chemists classify idealized bond types as being ionic or covalent, the existence of additional types such as hydrogen bonds and metallic bonds , for example, has led some philosophers of science to suggest that alternative approaches to understanding bonding are required. This could be by applying quantum mechanics to calculate binding energies. The lattice energy

5060-511: The anions and net positive charge of the cations. There is also a small additional attractive force from van der Waals interactions which contributes only around 1–2% of the cohesive energy for small ions. When a pair of ions comes close enough for their outer electron shells (most simple ions have closed shells ) to overlap, a short-ranged repulsive force occurs, due to the Pauli exclusion principle . The balance between these forces leads to

5170-491: The area of arable land and limits the size of the community dependent on it, and it also usually results in large unsettled and uncultivated stretches between the villages. Fragmentary information suggests that most farmers in the alluvial plain tend to live in villages of over 100 persons. For example, in the mid-1970s a substantial number of the residents of Baqubah , the administrative center and major city of Diyala Governorate, were employed in agriculture. The Marsh Arabs of

5280-416: The arid areas of Iraq to the west and south, cities and large towns are almost invariably situated on watercourses, usually on the major rivers or their larger tributaries. In the south this dependence has had its disadvantages. Until the recent development of flood control, Baghdad and other cities were subject to the threat of inundation. Moreover, the dikes needed for protection have effectively prevented

5390-462: The atoms can be ionized by electron transfer , a process thermodynamically understood using the Born–Haber cycle . Salts are formed by salt-forming reactions Ions in salts are primarily held together by the electrostatic forces between the charge distribution of these bodies, and in particular, the ionic bond resulting from the long-ranged Coulomb attraction between the net negative charge of

5500-553: The borders of the countries. Through Algerian mediation, Iran and Iraq agreed in March 1975 to normalize their relations, and three months later they signed a treaty known as the Algiers Accord . The document defined the common border all along the Khawr Abd Allah (Shatt) River estuary as the thalweg . To compensate Iraq for the loss of what formerly had been regarded as its territory, pockets of territory along

5610-503: The boundary between western Kuwait and Iraq. The Euphrates originates in Turkey, is augmented by the Balikh and Khabur rivers in Syria, and enters Iraq in the northwest. Here it is fed only by the wadis of the western desert during the winter rains. It then winds through a gorge, which varies from two to 16 kilometers in width, until it flows out on the plain at Ar Ramadi . Beyond there

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5720-590: The cation (the unmodified element name for monatomic cations) comes first, followed by the name of the anion. For example, MgCl 2 is named magnesium chloride , and Na 2 SO 4 is named sodium sulfate ( SO 4 , sulfate , is an example of a polyatomic ion ). To obtain the empirical formula from these names, the stoichiometry can be deduced from the charges on the ions, and the requirement of overall charge neutrality. If there are multiple different cations and/or anions, multiplicative prefixes ( di- , tri- , tetra- , ...) are often required to indicate

5830-558: The compound is the result of a reaction between a strong acid and a weak base , the result is an acid salt . If it is the result of a reaction between a strong base and a weak acid , the result is a base salt . If it is the result of a reaction between a strong acid and a strong base, the result is a neutral salt. Weak acids reacted with weak bases can produce ionic compounds with both the conjugate base ion and conjugate acid ion, such as ammonium acetate . Some ions are classed as amphoteric , being able to react with either an acid or

5940-462: The constituent ions, or the hydrated form of the same compound. The anions in compounds with bonds with the most ionic character tend to be colorless (with an absorption band in the ultraviolet part of the spectrum). In compounds with less ionic character, their color deepens through yellow, orange, red, and black (as the absorption band shifts to longer wavelengths into the visible spectrum). The absorption band of simple cations shifts toward

6050-406: The counterions can be chosen to ensure that even when combined into a single solution they will remain soluble as spectator ions . If the solvent is water in either the evaporation or precipitation method of formation, in many cases the ionic crystal formed also includes water of crystallization , so the product is known as a hydrate , and can have very different chemical properties compared to

6160-861: The crystal. Defects also result in ions in distinctly different local environments, which causes them to experience a different crystal-field symmetry , especially in the case of different cations exchanging lattice sites. This results in a different splitting of d-electron orbitals , so that the optical absorption (and hence colour) can change with defect concentration. Ionic compounds containing hydrogen ions (H ) are classified as acids , and those containing electropositive cations and basic anions ions hydroxide (OH ) or oxide (O ) are classified as bases . Other ionic compounds are known as salts and can be formed by acid–base reactions . Salts that produce hydroxide ions when dissolved in water are called alkali salts , and salts that produce hydrogen ions when dissolved in water are called acid salts . If

6270-464: The crystals, defects that involve loss of a cation will be associated with loss of an anion, i.e. these defects come in pairs. Frenkel defects consist of a cation vacancy paired with a cation interstitial and can be generated anywhere in the bulk of the crystal, occurring most commonly in compounds with a low coordination number and cations that are much smaller than the anions. Schottky defects consist of one vacancy of each type, and are generated at

6380-424: The delta plains are built up at the rate of nearly twenty centimeters in a century. In some areas, major floods lead to the deposit in temporary lakes of as much as thirty centimeters of mud. The Tigris and Euphrates also carry large quantities of salts . These, too, are spread on the land by sometimes excessive irrigation and flooding. A high water table and poor surface and subsurface drainage tend to concentrate

6490-483: The development of a theoretical treatment of ionic crystal structures were Max Born , Fritz Haber , Alfred Landé , Erwin Madelung , Paul Peter Ewald , and Kazimierz Fajans . Born predicted crystal energies based on the assumption of ionic constituents, which showed good correspondence to thermochemical measurements, further supporting the assumption. Many metals such as the alkali metals react directly with

6600-521: The electrons in the metal ions or small molecules can be excited. These electrons later return to lower energy states, and release light with a colour spectrum characteristic of the species present. In chemical synthesis , salts are often used as precursors for high-temperature solid-state synthesis. Many metals are geologically most abundant as salts within ores . To obtain the elemental materials, these ores are processed by smelting or electrolysis , in which redox reactions occur (often with

6710-569: The electrostatic energy of unit charges at the nearest neighboring distance by a multiplicative constant called the Madelung constant that can be efficiently computed using an Ewald sum . When a reasonable form is assumed for the additional repulsive energy, the total lattice energy can be modelled using the Born–Landé equation , the Born–Mayer equation , or in the absence of structural information,

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6820-502: The examples given above would be named iron(II) sulfate and iron(III) sulfate respectively. For simple ions the ionic charge and the oxidation number are identical, but for polyatomic ions they often differ. For example, the uranyl(2+) ion, UO 2 , has uranium in an oxidation state of +6, so would be called a dioxouranium(VI) ion in Stock nomenclature. An even older naming system for metal cations, also still widely used, appended

6930-529: The expansion of the urban areas in some directions. The growth of Baghdad , for example, was restricted by dikes on its eastern edge. The diversion of water to the Milhat ath Tharthar and the construction of a canal transferring water from the Tigris north of Baghdad to the Diyala River have permitted the irrigation of land outside the limits of the dikes and the expansion of settlement. The climate of Iraq

7040-500: The farmer leaves his village to cultivate the fields outside it. The pattern holds for farming communities in the Kurdish highlands of the northeast as well as for those in the alluvial plain. The size of the settlement varies, generally with the volume of water available for household use and with the amount of land accessible to village dwellers. Sometimes, particularly in the lower Tigris and Euphrates valleys, soil salinity restricts

7150-399: The flooding Tigris. Since Syria built a dam on the Euphrates, the flow of water has been considerably diminished and flooding was no longer a problem in the mid-1980s. In 1988 Turkey was also constructing a dam on the Euphrates that would further restrict the water flow. Until the mid-twentieth century, most efforts to control the waters were primarily concerned with irrigation. Some attention

7260-535: The foothills and steppes; adequate soil and rainfall, however, make cultivation possible. Here, too, are the great oil fields near Mosul and Kirkuk. The northeast is the homeland of most Iraqi Kurds . The desert zone, an area lying west and southwest of the Euphrates River, is a part of the Syrian Desert and Arabian Desert , which covers sections of Syria , Jordan , and Saudi Arabia and most of

7370-467: The highlands in the north and northeast; and the alluvial plain through which the Tigris and Euphrates flow. Iraq's official statistical reports give the total land area as 438,446 km (169,285 sq mi), whereas a United States Department of State publication gives the area as 434,934 km (167,929 sq mi). The uplands region, between the Tigris north of Hamrin Mountains and

7480-651: The inhabited marsh areas east of An Kshatriya by drying up or diverting the feeder streams and rivers; a once sizable population of Shi'a Muslims, who have inhabited these areas for thousands of years, has been displaced; furthermore, the destruction of the natural habitat poses serious threats to the area's wildlife populations; inadequate supplies of potable water; development of Tigris-Euphrates Rivers system contingent upon agreements with upstream riparian Turkey; air and water pollution; soil degradation (desalination) and erosion; and desertification . Environment - international agreements: party to: Biodiversity , Law of

7590-445: The ions become completely mobile. For this reason, molten salts and solutions containing dissolved salts (e.g., sodium chloride in water) can be used as electrolytes . This conductivity gain upon dissolving or melting is sometimes used as a defining characteristic of salts. In some unusual salts: fast-ion conductors , and ionic glasses , one or more of the ionic components has a significant mobility, allowing conductivity even while

7700-469: The ions become mobile. Some salts have large cations, large anions, or both. In terms of their properties, such species often are more similar to organic compounds. In 1913 the structure of sodium chloride was determined by William Henry Bragg and William Lawrence Bragg . This revealed that there were six equidistant nearest-neighbours for each atom, demonstrating that the constituents were not arranged in molecules or finite aggregates, but instead as

7810-423: The land surface, but the breeze has some cooling effect. The combination of rain shortage and extreme heat makes much of Iraq a desert. Because of very high rates of evaporation, soil and plants rapidly lose the little moisture obtained from the rain, and vegetation could not survive without extensive irrigation. Some areas, however, although arid, do have natural vegetation in contrast to the desert. For example, in

7920-556: The levees' back-slope, and the coarse soils of the levees are easier to cultivate and permit better subsurface drainage. The height of the levees gives some protection against floods and the frost that often affect low-lying areas and may kill and/or damage winter crops. Above all, those living or cultivating on the crest of a levee have easy access to water for irrigation and household use in a dry, hot country. Although there are some isolated homesteads, most rural communities are nucleated settlements rather than dispersed farmsteads; that is,

8030-446: The liquid phase). Inorganic compounds with simple ions typically have small ions, and thus have high melting points, so are solids at room temperature. Some substances with larger ions, however, have a melting point below or near room temperature (often defined as up to 100 °C), and are termed ionic liquids . Ions in ionic liquids often have uneven charge distributions, or bulky substituents like hydrocarbon chains, which also play

8140-442: The marshes. Also, in early 1988, the marshes had become the refuge of deserters from the Iraqi army who attempted to maintain life in the fastness of the overgrown, desolate areas while hiding out from the authorities. These deserters in many instances have formed into large gangs that raid the marsh communities; this also has induced many of the marsh dwellers to abandon their villages. The war has also affected settlement patterns in

8250-399: The material as a whole remains solid. This is often highly temperature dependent, and may be the result of either a phase change or a high defect concentration. These materials are used in all solid-state supercapacitors , batteries , and fuel cells , and in various kinds of chemical sensors . The colour of a salt is often different from the colour of an aqueous solution containing

8360-427: The most electronegative / electropositive pairs such as those in caesium fluoride exhibit a small degree of covalency . Conversely, covalent bonds between unlike atoms often exhibit some charge separation and can be considered to have a partial ionic character. The circumstances under which a compound will have ionic or covalent character can typically be understood using Fajans' rules , which use only charges and

8470-728: The most important of which are the Khabur , the Great Zab , the Little Zab , and the Adhaim , all of which join the Tigris above Baghdad, and the Diyala , which joins it about thirty-six kilometers below the city. At the Kut Barrage much of the water is diverted into the Shatt al-Hayy , which was once the main channel of the Tigris. Water from the Tigris thus enters the Euphrates through

8580-424: The mountain border in the central sector of its common boundary with Iran were assigned to it. Nonetheless, in September 1980 Iraq went to war with Iran , citing among other complaints the fact that Iran had not turned over to it the land specified in the Algiers Accord . This problem has subsequently proved to be a stumbling block to a negotiated settlement of the ongoing conflict. In 1988 the boundary with Kuwait

8690-477: The mountains is more abundant and may reach 1,000 millimeters (39.4 in) a year in some places, but the terrain precludes extensive cultivation. Cultivation on nonirrigated land is limited essentially to the mountain valleys, foothills, and steppes , which have 300 millimeters (11.8 in) or more of rainfall annually. Even in this zone, however, only one crop a year can be grown, and shortages of rain have often led to crop failures. Mean minimum temperatures in

8800-440: The name by specifying either the oxidation state of the elements present, or the charge on the ions. Because of the risk of ambiguity in allocating oxidation states, IUPAC prefers direct indication of the ionic charge numbers. These are written as an arabic integer followed by the sign (... , 2−, 1−, 1+, 2+, ...) in parentheses directly after the name of the cation (without a space separating them). For example, FeSO 4

8910-455: The normal level. The searing summer heat only exists in low elevations in these countries while mountains and higher elevations know much more moderated summer temperatures. The summer months are marked by two kinds of wind phenomena. The southern and southeasterly sharqi , a dry, dusty wind with occasional gusts of 80 kilometers per hour (50 mph), occurs from April to early June and again from late September through November. It may last for

9020-405: The northern Kurdish areas. There, the struggle for a Kurdish state by guerrillas was rejected by the government as it steadily escalated violence against the local communities. Starting in 1984, the government launched a scorched-earth campaign to drive a wedge between the villagers and the guerrillas in the remote areas of two provinces of Kurdistan in which Kurdish guerrillas were active. In

9130-467: The opposite pole of a polar molecule, the solid ions are pulled out of the lattice and into the liquid. If the solvation energy exceeds the lattice energy , the negative net enthalpy change of solution provides a thermodynamic drive to remove ions from their positions in the crystal and dissolve in the liquid. In addition, the entropy change of solution is usually positive for most solid solutes like salts, which means that their solubility increases when

9240-671: The process whole villages were torched and subsequently bulldozed, which resulted in the Kurds flocking into the regional centers of Irbil and As Sulaymaniyah . Also as a "military precaution", the government has cleared a broad strip of territory in the Kurdish region along the Iranian border of all its inhabitants, hoping in this way to interdict the movement of Kurdish guerrillas back and forth between Iran and Iraq. The majority of Kurdish villages, however, remained intact in early 1988. In

9350-407: The relative compositions, and cations then anions are listed in alphabetical order. For example, KMgCl 3 is named magnesium potassium trichloride to distinguish it from K 2 MgCl 4 , magnesium dipotassium tetrachloride (note that in both the empirical formula and the written name, the cations appear in alphabetical order, but the order varies between them because the symbol for potassium

9460-612: The rural areas of the alluvial plain and in the lower Diyala region, settlement almost invariably clusters near the rivers, streams, and irrigation canals. The bases of the relationship between watercourse and settlement have been summarized by Robert McCormick Adams, director of the Oriental Institute of the University of Chicago . He notes that the levees laid down by streams and canals provide advantages for both settlement and agriculture. Surface water drains more easily on

9570-548: The salts near the surface of the soil. In general, the salinity of the soil increases from Baghdad south to the Persian Gulf and severely limits productivity in the region south of Al Amarah . The salinity is reflected in the large lake in central Iraq, southwest of Baghdad, known as Bahr al Milh (Sea of Salt). There are two other major lakes in the country to the north of Bahr al Milh: Buhayrat ath Tharthar and Buhayrat al Habbaniyah . Between Upper and Lower Mesopotamia

9680-448: The size of ions and strength of other interactions. When vapourized, the ions are still not freed of one another. For example, in the vapour phase sodium chloride exists as diatomic "molecules". Most salts are very brittle . Once they reach the limit of their strength, they cannot deform malleably , because the strict alignment of positive and negative ions must be maintained. Instead the material undergoes fracture via cleavage . As

9790-418: The sizes of each ion. According to these rules, compounds with the most ionic character will have large positive ions with a low charge, bonded to a small negative ion with a high charge. More generally HSAB theory can be applied, whereby the compounds with the most ionic character are those consisting of hard acids and hard bases: small, highly charged ions with a high difference in electronegativities between

9900-420: The sodium chloride structure (coordination number 6), and less again than those with a coordination number of 4. When simple salts dissolve , they dissociate into individual ions, which are solvated and dispersed throughout the resulting solution. Salts do not exist in solution. In contrast, molecular compounds, which includes most organic compounds, remain intact in solution. The solubility of salts

10010-790: The solvent, so certain patterns become apparent. For example, salts of sodium , potassium and ammonium are usually soluble in water. Notable exceptions include ammonium hexachloroplatinate and potassium cobaltinitrite . Most nitrates and many sulfates are water-soluble. Exceptions include barium sulfate , calcium sulfate (sparingly soluble), and lead(II) sulfate , where the 2+/2− pairing leads to high lattice energies. For similar reasons, most metal carbonates are not soluble in water. Some soluble carbonate salts are: sodium carbonate , potassium carbonate and ammonium carbonate . Salts are characteristically insulators . Although they contain charged atoms or clusters, these materials do not typically conduct electricity to any significant extent when

10120-415: The south usually live in small clusters of two or three houses kept above water by rushes that are constantly being replenished. Such clusters often are close together, but access from one to another is possible only by small boat. Here and there a few natural islands permit slightly larger clusters. Some of these people are primarily water buffalo herders and lead a semi- nomadic life. In the winter, when

10230-522: The southwest provinces along the borders with Saudi Arabia and Jordan and geographically belongs in the Arabian Peninsula . Most geographers, including those of the Iraqi government, discuss the country's geography in terms of four main zones or regions: the desert in the west and southwest; the rolling upland between the upper Tigris and Euphrates rivers (in Arabic the Dijla and Furat , respectively);

10340-403: The substance is solid. In order to conduct, the charged particles must be mobile rather than stationary in a crystal lattice . This is achieved to some degree at high temperatures when the defect concentration increases the ionic mobility and solid state ionic conductivity is observed. When the salts are dissolved in a liquid or are melted into a liquid , they can conduct electricity because

10450-422: The surfaces of a crystal, occurring most commonly in compounds with a high coordination number and when the anions and cations are of similar size. If the cations have multiple possible oxidation states , then it is possible for cation vacancies to compensate for electron deficiencies on cation sites with higher oxidation numbers, resulting in a non-stoichiometric compound . Another non-stoichiometric possibility

10560-399: The temperature increases. There are some unusual salts such as cerium(III) sulfate , where this entropy change is negative, due to extra order induced in the water upon solution, and the solubility decreases with temperature. The lattice energy , the cohesive forces between these ions within a solid, determines the solubility. The solubility is dependent on how well each ion interacts with

10670-413: The temperature is elevated (usually close to the melting point) a ductile–brittle transition occurs, and plastic flow becomes possible by the motion of dislocations . The compressibility of a salt is strongly determined by its structure, and in particular the coordination number . For example, halides with the caesium chloride structure (coordination number 8) are less compressible than those with

10780-461: The two parties agreed to the creation of the diamond-shaped Neutral Zone of approximately 7,500 km (2,900 sq mi) adjacent to the western tip of Kuwait in which neither Iraq nor Saudi Arabia would build dwellings or installations. Bedouins from either country could utilize the limited water and seasonal grazing resources of the zone. In April 1975, an agreement signed in Baghdad fixed

10890-413: The two solutions mixed must also contain counterions of the opposite charges. To ensure that these do not contaminate the precipitated salt, it is important to ensure they do not also precipitate. If the two solutions have hydrogen ions and hydroxide ions as the counterions, they will react with one another in what is called an acid–base reaction or a neutralization reaction to form water. Alternately

11000-590: The upper Tigris and Euphrates rivers), the northern highlands of Iraq, Lower Mesopotamia , and the alluvial plain extending from around Tikrit to the Persian Gulf . The mountains in the northeast are an extension of the alpine system that runs eastward from the Balkans through southern Turkey , northern Iraq, Iran , and Afghanistan , eventually reaching the Himalayas in Pakistan . The desert lies in

11110-411: The waters are at a low point, they build fairly large temporary villages. In the summer they move their herds out of the marshes to the river banks. The war has had its effect on the lives of these denizens of the marshes. With much of the fighting concentrated in their areas, they have either migrated to settled communities away from the marshes or have been forced by government decree to relocate within

11220-408: The west. The northeastern highlands begin just south of a line drawn from Mosul to Kirkuk and extend to the borders with Turkey and Iran . High ground, separated by broad, undulating steppes , gives way to mountains ranging from 1,000 to 3,611 meters (3,281 to 11,847 ft) near the Iranian and Turkish borders. Except for a few valleys, the mountain area proper is suitable only for grazing in

11330-499: The western desert. Such summer heat, even in a hot desert, is high and this can be easily explained by the very low elevations of deserts regions which experience these exceptionally searing high temperatures. In fact, the elevations of cities such as Baghdad or Basra are near the sea level (0 m) because deserts are located predominantly along the Persian Gulf . That is why some Gulf's countries like Iraq , Iran and Kuwait experience extreme heat during summer, even more extreme than

11440-475: The winter months from December through March. The remaining six months, particularly the hottest ones of June, July, and August, are extremely dry. Except in the north and northeast, mean annual rainfall ranges between 100 and 190 millimeters (3.9 and 7.5 in). Data available from stations in the foothills and steppes south and southwest of the mountains suggest mean annual rainfall between 320 and 570 millimeters (12.6 and 22.4 in) for that area. Rainfall in

11550-653: The winter range from near freezing (just before dawn) in the northern and northeastern foothills and the western desert to 2 and 4 to 5 °C (35.6 and 39.2 to 41.0 °F) in the alluvial plains of southern Iraq. They rise to a mean maximum of about 16 °C (60.8 °F) in the western desert and the northeast, and 17 °C (62.6 °F) in the south. In the summer mean minimum temperatures range from about 27 to 31 °C (80.6 to 87.8 °F) and rise to maxima between roughly 41 and 45 °C (105.8 and 113.0 °F). Temperatures sometimes fall below freezing and have fallen as low as −14 °C (6.8 °F) at Ar Rutbah in

11660-682: The world behind Iran , the United States Department of Energy estimates that up to 90 percent of the country remains unexplored. Unexplored regions of Iraq could yield an additional 100 billion barrels (16 × 10 ^  m ). Iraq's oil production costs are among the lowest in the world. However, only about 2,000 oil wells have been drilled in Iraq, compared to about 1 million wells in Texas alone. Natural hazards: dust storms, sandstorms, floods Environment - current issues: government water control projects have drained most of

11770-503: Was another outstanding problem. It was fixed in a 1913 treaty between the Ottoman Empire and British officials acting on behalf of Kuwait's ruling family , which in 1899 had ceded control over foreign affairs to Britain. The boundary was accepted by Iraq when it became independent in 1932, but in the 1960s and again in the mid-1970s, the Iraqi government advanced a claim to parts of Kuwait. Kuwait made several representations to

11880-466: Was believed that Iraq lacks coral reefs as the local turbid waters prevented the detection of the potential presence of local coral reefs. Iraqi corals were found to be adapted to one of the most extreme coral-bearing environments in the world, as the seawater temperature in this area ranges between 14 and 34 °C. The reef harbors several living stone corals, octocorals , ophiuroids and bivalves . There are also silica -containing demo-sponges. In

11990-410: Was given to problems of flood control and drainage before the revolution of July 14, 1958, but development plans in the 1960s and 1970s were increasingly devoted to these matters, as well as to irrigation projects on the upper reaches of the Tigris and Euphrates and the tributaries of the Tigris in the northeast. During the war, government officials stressed to foreign visitors that, with the conclusion of

12100-436: Was recorded near Basra on 22 July 2016. Most of the rainfall occurs from December through April and averages between 100 and 180 millimeters (3.9 and 7.1 in) annually. The mountainous region of northern Iraq receives appreciably more precipitation than the central or southern desert region, where they tend to have a Mediterranean climate . Roughly 90% of the annual rainfall occurs between November and April, most of it in

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