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51-408: In inorganic chemistry , the sulfuryl group is a functional group consisting of a sulfur atom covalently bound to two oxygen atoms ( S(=O) 2 X 2 ). It occurs in compounds such as sulfuryl chloride , SO 2 Cl 2 and sulfuryl fluoride , SO 2 F 2 . In organic chemistry , this group is found in sulfones ( RSO 2 R′ ) and sulfonyl halides ( RSO 2 X ), where it

102-760: A molecule and a solid. By definition, these compounds occur in nature, but the subfield includes anthropogenic species, such as pollutants (e.g., methylmercury ) and drugs (e.g., Cisplatin ). The field, which incorporates many aspects of biochemistry, includes many kinds of compounds, e.g., the phosphates in DNA, and also metal complexes containing ligands that range from biological macromolecules, commonly peptides , to ill-defined species such as humic acid , and to water (e.g., coordinated to gadolinium complexes employed for MRI ). Traditionally bioinorganic chemistry focuses on electron- and energy-transfer in proteins relevant to respiration. Medicinal inorganic chemistry includes

153-545: A range of bonding properties. Some are ionic compounds , consisting of very simple cations and anions joined by ionic bonding . Examples of salts (which are ionic compounds) are magnesium chloride MgCl 2 , which consists of magnesium cations Mg and chloride anions Cl ; or sodium hydroxide NaOH, which consists of sodium cations Na and hydroxide anions OH . Some inorganic compounds are highly covalent, such as sulfur dioxide and iron pentacarbonyl . Many inorganic compounds feature polar covalent bonding, which

204-507: A special category because organic ligands are often sensitive to hydrolysis or oxidation, necessitating that organometallic chemistry employs more specialized preparative methods than was traditional in Werner-type complexes. Synthetic methodology, especially the ability to manipulate complexes in solvents of low coordinating power, enabled the exploration of very weakly coordinating ligands such as hydrocarbons, H 2 , and N 2 . Because

255-578: A β-hydride elimination reaction also occurs periodically: Polymerization reactions of alkenes with solid titanium-based catalysts occur at special titanium centers located on the exterior of the catalyst crystallites. Some titanium atoms in these crystallites react with organoaluminum cocatalysts with the formation of Ti–C bonds. The polymerization reaction of alkenes occurs similarly to the reactions in metallocene catalysts: The two chain termination reactions occur quite rarely in Ziegler–Natta catalysis and

306-600: Is ammonium nitrate , used for fertilization. The ammonia is produced through the Haber process . Nitric acid is prepared from the ammonia by oxidation. Another large-scale inorganic material is portland cement . Inorganic compounds are used as catalysts such as vanadium(V) oxide for the oxidation of sulfur dioxide and titanium(III) chloride for the polymerization of alkenes . Many inorganic compounds are used as reagents in organic chemistry such as lithium aluminium hydride . Descriptive inorganic chemistry focuses on

357-427: Is microporous spheres of amorphous silica with a diameter of 30–40 mm. During the catalyst synthesis, both the titanium compounds and MgCl 2 are packed into the silica pores. All these catalysts are activated with organoaluminum compounds such as Al(C 2 H 5 ) 3 . All modern supported Ziegler–Natta catalysts designed for polymerization of propylene and higher 1-alkenes are prepared with TiCl 4 as

408-552: Is "self-exchange", which involves the degenerate reaction between an oxidant and a reductant. For example, permanganate and its one-electron reduced relative manganate exchange one electron: Coordinated ligands display reactivity distinct from the free ligands. For example, the acidity of the ammonia ligands in [Co(NH 3 ) 6 ] is elevated relative to NH 3 itself. Alkenes bound to metal cations are reactive toward nucleophiles whereas alkenes normally are not. The large and industrially important area of catalysis hinges on

459-621: Is a catalyst used in the synthesis of polymers of 1-alkenes ( alpha-olefins ). Two broad classes of Ziegler–Natta catalysts are employed, distinguished by their solubility: Ziegler–Natta catalysts are used to polymerize terminal alkenes (ethylene and alkenes with the vinyl double bond): The 1963 Nobel Prize in Chemistry was awarded to German Karl Ziegler , for his discovery of first titanium-based catalysts, and Italian Giulio Natta , for using them to prepare stereoregular polymers from propylene . Ziegler–Natta catalysts have been used in

510-475: Is a form of bonding intermediate between covalent and ionic bonding. This description applies to many oxides , carbonates , and halides . Many inorganic compounds are characterized by high melting points . Some salts (e.g., NaCl ) are very soluble in water. When one reactant contains hydrogen atoms , a reaction can take place by exchanging protons in acid-base chemistry . In a more general definition, any chemical species capable of binding to electron pairs

561-399: Is a metal from the groups 3–13, as well as the trans - lanthanides and trans - actinides , but from a certain perspective, all chemical compounds can be described as coordination complexes. The stereochemistry of coordination complexes can be quite rich, as hinted at by Werner's separation of two enantiomers of [Co((OH) 2 Co(NH 3 ) 4 ) 3 ] , an early demonstration that chirality

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612-565: Is called a Lewis acid ; conversely any molecule that tends to donate an electron pair is referred to as a Lewis base . As a refinement of acid-base interactions, the HSAB theory takes into account polarizability and size of ions. Subdivisions of inorganic chemistry are numerous, but include: Inorganic chemistry is a highly practical area of science. Traditionally, the scale of a nation's economy could be evaluated by their productivity of sulfuric acid . An important man-made inorganic compound

663-689: Is called the sulfonyl group. Greenwood, Norman N. ; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann . ISBN   978-0-08-037941-8 . Inorganic chemistry Many inorganic compounds are found in nature as minerals . Soil may contain iron sulfide as pyrite or calcium sulfate as gypsum . Inorganic compounds are also found multitasking as biomolecules : as electrolytes ( sodium chloride ), in energy storage ( ATP ) or in construction (the polyphosphate backbone in DNA ). Inorganic compounds exhibit

714-551: Is illustrated in the picture on the left with polypropylene. Stereoregular poly(1-alkene) can be isotactic or syndiotactic depending on the relative orientation of the alkyl groups in polymer chains consisting of units −[CH 2 −CHR]−, like the CH 3 groups in the figure. In the isotactic polymers, all stereogenic centers CHR share the same configuration. The stereogenic centers in syndiotactic polymers alternate their relative configuration. A polymer that lacks any regular arrangement in

765-546: Is not inherent to organic compounds. A topical theme within this specialization is supramolecular coordination chemistry. Coordination compounds show a rich diversity of structures, varying from tetrahedral for titanium (e.g., TiCl 4 ) to square planar for some nickel complexes to octahedral for coordination complexes of cobalt. A range of transition metals can be found in biologically important compounds, such as iron in hemoglobin. These species feature elements from groups I, II, III, IV, V, VI, VII, 0 (excluding hydrogen) of

816-440: Is relatively small because the requirements to the respective catalysts differ widely. Commercial catalysts are supported by being bound to a solid with a high surface area. Both TiCl 4 and TiCl 3 give active catalysts. The support in the majority of the catalysts is MgCl 2 . A third component of most catalysts is a carrier, a material that determines the size and the shape of catalyst particles. The preferred carrier

867-587: Is the Born–Haber cycle , which is used for assessing the energies of elementary processes such as electron affinity , some of which cannot be observed directly. An important aspect of inorganic chemistry focuses on reaction pathways, i.e. reaction mechanisms . The mechanisms of main group compounds of groups 13–18 are usually discussed in the context of organic chemistry (organic compounds are main group compounds, after all). Elements heavier than C, N, O, and F often form compounds with more electrons than predicted by

918-548: Is the kinetic lability of the complex illustrated by the exchange of free and bound water in the prototypical complexes [M(H 2 O) 6 ] : The rates of water exchange varies by 20 orders of magnitude across the periodic table, with lanthanide complexes at one extreme and Ir(III) species being the slowest. Redox reactions are prevalent for the transition elements. Two classes of redox reaction are considered: atom-transfer reactions, such as oxidative addition/reductive elimination, and electron-transfer . A fundamental redox reaction

969-474: Is transformed into a metallocenium ion Cp 2 + Zr CH 3 , which is ion-paired to some derivative(s) of MAO. A polymer molecule grows by numerous insertion reactions of C=C bonds of 1-alkene molecules into the Zr–C bond in the ion: Many thousands of alkene insertion reactions occur at each active center resulting in the formation of long polymer chains attached to the center. The Cossee–Arlman mechanism describes

1020-410: The octet rule , as explained in the article on hypervalent molecules. The mechanisms of their reactions differ from organic compounds for this reason. Elements lighter than carbon ( B , Be , Li ) as well as Al and Mg often form electron-deficient structures that are electronically akin to carbocations . Such electron-deficient species tend to react via associative pathways. The chemistry of

1071-403: The structures of main group compounds, such as an explanation for why NH 3 is pyramidal whereas ClF 3 is T-shaped. For the transition metals, crystal field theory allows one to understand the magnetism of many simple complexes, such as why [Fe (CN) 6 ] has only one unpaired electron, whereas [Fe (H 2 O) 6 ] has five. A particularly powerful qualitative approach to assessing

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1122-452: The 1960s, BASF developed a gas-phase, mechanically-stirred polymerization process for making polypropylene . In that process, the particle bed in the reactor was either not fluidized or not fully fluidized. In 1968, the first gas-phase fluidized-bed polymerization process, the Unipol process, was commercialized by Union Carbide to produce polyethylene. In the mid-1980s, the Unipol process

1173-430: The ability of metals to modify the reactivity of organic ligands. Homogeneous catalysis occurs in solution and heterogeneous catalysis occurs when gaseous or dissolved substrates interact with surfaces of solids. Traditionally homogeneous catalysis is considered part of organometallic chemistry and heterogeneous catalysis is discussed in the context of surface science , a subfield of solid state chemistry. But

1224-454: The active ingredient and MgCl 2 as a support. Another component of all such catalysts is an organic modifier, usually an ester of an aromatic diacid or a diether . The modifiers react both with inorganic ingredients of the solid catalysts as well as with organoaluminum cocatalysts. These catalysts polymerize propylene and other 1-alkenes to highly crystalline isotactic polymers. A second class of Ziegler–Natta catalysts are soluble in

1275-411: The alkylaluminium compounds are pyrophoric . The catalysts, therefore, are always prepared and handled under an inert atmosphere. The structure of active centers in Ziegler–Natta catalysts is well established only for metallocene catalysts. An idealized and simplified metallocene complex Cp 2 ZrCl 2 represents a typical precatalyst. It is unreactive toward alkenes. The dihalide reacts with MAO and

1326-484: The area. Clusters occur in "pure" inorganic systems, organometallic chemistry, main group chemistry, and bioinorganic chemistry. The distinction between very large clusters and bulk solids is increasingly blurred. This interface is the chemical basis of nanoscience or nanotechnology and specifically arise from the study of quantum size effects in cadmium selenide clusters. Thus, large clusters can be described as an array of bound atoms intermediate in character between

1377-417: The basic inorganic chemical principles are the same. Transition metals, almost uniquely, react with small molecules such as CO, H 2 , O 2 , and C 2 H 4 . The industrial significance of these feedstocks drives the active area of catalysis. Ligands can also undergo ligand transfer reactions such as transmetalation . Because of the diverse range of elements and the correspondingly diverse properties of

1428-564: The bonding and structure. The magnetism of inorganic compounds can be comlex. For example, most copper(II) compounds are paramagnetic but Cu 2 (OAc) 4 (H 2 O) 2 is almost diamagnetic below room temperature. The explanation is due to magnetic coupling between pairs of Cu(II) sites in the acetate. Inorganic chemistry has greatly benefited from qualitative theories. Such theories are easier to learn as they require little background in quantum theory. Within main group compounds, VSEPR theory powerfully predicts, or at least rationalizes,

1479-576: The classification of compounds based on their properties. Partly the classification focuses on the position in the periodic table of the heaviest element (the element with the highest atomic weight) in the compound, partly by grouping compounds by their structural similarities Classical coordination compounds feature metals bound to " lone pairs " of electrons residing on the main group atoms of ligands such as H 2 O, NH 3 , Cl , and CN . In modern coordination compounds almost all organic and inorganic compounds can be used as ligands. The "metal" usually

1530-492: The commercial manufacture of various polyolefins since 1956. As of 2010, the total volume of plastics, elastomers, and rubbers produced from alkenes with these and related (especially Phillips) catalysts worldwide exceeds 100 million tonnes. Together, these polymers represent the largest-volume commodity plastics as well as the largest-volume commodity chemicals in the world. In the early 1950s workers at Phillips Petroleum discovered that chromium catalysts are highly effective for

1581-495: The development of fully amorphous copolymers. The fluidized-bed process remains one of the two most widely used processes for producing polypropylene . Natta first used polymerization catalysts based on titanium chlorides to polymerize propylene and other 1-alkenes. He discovered that these polymers are crystalline materials and ascribed their crystallinity to a special feature of the polymer structure called stereoregularity . The concept of stereoregularity in polymer chains

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1632-579: The entirety of which can be evacuated to 0.001 mm Hg or less. Compounds are condensed using liquid nitrogen (b.p. 78K) or other cryogens . Solids are typically prepared using tube furnaces, the reactants and products being sealed in containers, often made of fused silica (amorphous SiO 2 ) but sometimes more specialized materials such as welded Ta tubes or Pt "boats". Products and reactants are transported between temperature zones to drive reactions. Ziegler-Natta process A Ziegler–Natta catalyst , named after Karl Ziegler and Giulio Natta ,

1683-580: The fullerenes, buckytubes and binary carbon oxides. Noble gas compounds include several derivatives of xenon and krypton . Usually, organometallic compounds are considered to contain the M-C-H group. The metal (M) in these species can either be a main group element or a transition metal. Operationally, the definition of an organometallic compound is more relaxed to include also highly lipophilic complexes such as metal carbonyls and even metal alkoxides . Organometallic compounds are mainly considered

1734-535: The growth of stereospecific polymers. This mechanism states that the polymer grows through alkene coordination at a vacant site at the titanium atom, which is followed by insertion of the C=C bond into the Ti−C bond at the active center. On occasion, the polymer chain is disengaged from the active centers in the chain termination reaction. Several pathways exist for termination: Another type of chain termination reaction called

1785-465: The laboratory. Inorganic synthetic methods can be classified roughly according to the volatility or solubility of the component reactants. Soluble inorganic compounds are prepared using methods of organic synthesis . For metal-containing compounds that are reactive toward air, Schlenk line and glove box techniques are followed. Volatile compounds and gases are manipulated in "vacuum manifolds" consisting of glass piping interconnected through valves,

1836-416: The language to describe the shapes of molecules according to their point group symmetry . Group theory also enables factoring and simplification of theoretical calculations. Spectroscopic features are analyzed and described with respect to the symmetry properties of the, inter alia , vibrational or electronic states. Knowledge of the symmetry properties of the ground and excited states allows one to predict

1887-471: The lanthanides mirrors many aspects of chemistry seen for aluminium. Transition metal and main group compounds often react differently. The important role of d-orbitals in bonding strongly influences the pathways and rates of ligand substitution and dissociation. These themes are covered in articles on coordination chemistry and ligand . Both associative and dissociative pathways are observed. An overarching aspect of mechanistic transition metal chemistry

1938-414: The ligands are petrochemicals in some sense, the area of organometallic chemistry has greatly benefited from its relevance to industry. Clusters can be found in all classes of chemical compounds . According to the commonly accepted definition, a cluster consists minimally of a triangular set of atoms that are directly bonded to each other. But metal–metal bonded dimetallic complexes are highly relevant to

1989-712: The low-temperature polymerization of ethylene, which launched major industrial technologies culminating in the Phillips catalyst . A few years later, Ziegler discovered that a combination of titanium tetrachloride (TiCl 4 ) and diethylaluminium chloride (Al(C 2 H 5 ) 2 Cl) gave comparable activities for the production of polyethylene. Natta used crystalline α-TiCl 3 in combination with Al(C 2 H 5 ) 3 to produce first isotactic polypropylene . Usually Ziegler catalysts refer to titanium -based systems for conversions of ethylene and Ziegler–Natta catalysts refer to systems for conversions of propylene . Also, in

2040-561: The metal-based orbitals transform identically for WF 6 and W(CO) 6 , but the energies and populations of these orbitals differ significantly. A similar relationship exists CO 2 and molecular beryllium difluoride . An alternative quantitative approach to inorganic chemistry focuses on energies of reactions. This approach is highly traditional and empirical , but it is also useful. Broad concepts that are couched in thermodynamic terms include redox potential , acidity , phase changes. A classic concept in inorganic thermodynamics

2091-430: The numbers and intensities of absorptions in vibrational and electronic spectra. A classic application of group theory is the prediction of the number of C–O vibrations in substituted metal carbonyl complexes. The most common applications of symmetry to spectroscopy involve vibrational and electronic spectra. Group theory highlights commonalities and differences in the bonding of otherwise disparate species. For example,

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2142-421: The organic ligands are derivatives of cyclopentadienyl . In some complexes, the two cyclopentadiene (Cp) rings are linked with bridges, like −CH 2 −CH 2 − or >SiPh 2 . Depending on the type of their cyclopentadienyl ligands, for example by using an ansa -bridge , metallocene catalysts can produce either isotactic or syndiotactic polymers of propylene and other 1-alkenes. Ziegler–Natta catalysts of

2193-505: The periodic table. Due to their often similar reactivity, the elements in group 3 ( Sc , Y , and La ) and group 12 ( Zn , Cd , and Hg ) are also generally included, and the lanthanides and actinides are sometimes included as well. Main group compounds have been known since the beginnings of chemistry, e.g., elemental sulfur and the distillable white phosphorus . Experiments on oxygen, O 2 , by Lavoisier and Priestley not only identified an important diatomic gas, but opened

2244-533: The position of its alkyl substituents (R) is called atactic. Both isotactic and syndiotactic polypropylene are crystalline, whereas atactic polypropylene, which can also be prepared with special Ziegler–Natta catalysts, is amorphous. The stereoregularity of the polymer is determined by the catalyst used to prepare it. The first and dominant class of titanium-based catalysts (and some vanadium -based catalysts) for alkene polymerization can be roughly subdivided into two subclasses: The overlap between these two subclasses

2295-447: The reaction medium. Traditionally such homogeneous catalysts were derived from metallocenes , but the structures of active catalysts have been significantly broadened to include nitrogen-based ligands. These catalysts are metallocenes together with a cocatalyst, typically MAO, −[O−Al(CH 3 )] n −. The idealized metallocene catalysts have the composition Cp 2 MCl 2 (M = Ti, Zr , Hf ) such as titanocene dichloride . Typically,

2346-675: The resulting derivatives, inorganic chemistry is closely associated with many methods of analysis. Older methods tended to examine bulk properties such as the electrical conductivity of solutions, melting points , solubility , and acidity . With the advent of quantum theory and the corresponding expansion of electronic apparatus, new tools have been introduced to probe the electronic properties of inorganic molecules and solids. Often these measurements provide insights relevant to theoretical models. Commonly encountered techniques are: Although some inorganic species can be obtained in pure form from nature, most are synthesized in chemical plants and in

2397-494: The structure and reactivity begins with classifying molecules according to electron counting , focusing on the numbers of valence electrons , usually at the central atom in a molecule. A construct in chemistry is molecular symmetry , as embodied in Group theory . Inorganic compounds display a particularly diverse symmetries, so it is logical that Group Theory is intimately associated with inorganic chemistry. Group theory provides

2448-726: The study of both non-essential and essential elements with applications to diagnosis and therapies. This important area focuses on structure , bonding, and the physical properties of materials. In practice, solid state inorganic chemistry uses techniques such as crystallography to gain an understanding of the properties that result from collective interactions between the subunits of the solid. Included in solid state chemistry are metals and their alloys or intermetallic derivatives. Related fields are condensed matter physics , mineralogy , and materials science . In contrast to most organic compounds , many inorganic compounds are magnetic and/or colored. These properties provide information on

2499-436: The third class, non-metallocene catalysts, use a variety of complexes of various metals, ranging from scandium to lanthanoid and actinoid metals, and a large variety of ligands containing oxygen (O 2 ), nitrogen (N 2 ), phosphorus (P), and sulfur (S). The complexes are activated using MAO, as is done for metallocene catalysts. Most Ziegler–Natta catalysts and all the alkylaluminium cocatalysts are unstable in air, and

2550-713: The way for describing compounds and reactions according to stoichiometric ratios. The discovery of a practical synthesis of ammonia using iron catalysts by Carl Bosch and Fritz Haber in the early 1900s deeply impacted mankind, demonstrating the significance of inorganic chemical synthesis. Typical main group compounds are SiO 2 , SnCl 4 , and N 2 O. Many main group compounds can also be classed as "organometallic", as they contain organic groups, e.g., B( CH 3 ) 3 ). Main group compounds also occur in nature, e.g., phosphate in DNA , and therefore may be classed as bioinorganic. Conversely, organic compounds lacking (many) hydrogen ligands can be classed as "inorganic", such as

2601-435: Was further extended to produce polypropylene . In the 1970s, magnesium chloride (MgCl 2 ) was discovered to greatly enhance the activity of the titanium-based catalysts. These catalysts were so active that the removal of unwanted amorphous polymer and residual titanium from the product (so-called deashing) was no longer necessary, enabling the commercialization of linear low-density polyethylene (LLDPE) resins and allowed

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