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50-415: The first 6 medals were awarded and presented May 8, 1963, by NASA Associate Director Dr. Robert Seamons to Paul J. Balfe, John A. Gordon, Larry J. Hough, Curtis C. Lyon, Charles L. Manes and Lynn B. Rowe. On November 9, 1962, NASA pilot Jack B. McKay was test flying an X-15 when it experienced engine failure. An emergency landing was made at Mud Lake, Nevada, where the aircraft flipped on its back. As part of

100-513: A base , a proton acceptor. Ammonia is moderately basic; a 1.0  M aqueous solution has a pH of 11.6, and if a strong acid is added to such a solution until the solution is neutral ( pH = 7 ), 99.4% of the ammonia molecules are protonated . Temperature and salinity also affect the proportion of ammonium [NH 4 ] . The latter has the shape of a regular tetrahedron and is isoelectronic with methane . The ammonia molecule readily undergoes nitrogen inversion at room temperature;

150-484: A vapour pressure of less than 1 bar even at 25 °C (77 °F). However, few oxyanion salts with other cations dissolve. Liquid ammonia will dissolve all of the alkali metals and other electropositive metals such as Ca , Sr , Ba , Eu and Yb (also Mg using an electrolytic process ). At low concentrations (<0.06 mol/L), deep blue solutions are formed: these contain metal cations and solvated electrons , free electrons that are surrounded by

200-444: A cage of ammonia molecules. These solutions are strong reducing agents. At higher concentrations, the solutions are metallic in appearance and in electrical conductivity. At low temperatures, the two types of solution can coexist as immiscible phases. The range of thermodynamic stability of liquid ammonia solutions is very narrow, as the potential for oxidation to dinitrogen, E ° ( N 2 + 6 [NH 4 ] + 6 e ⇌ 8 NH 3 ),

250-415: A cloud of ammonium chloride , which seems to appear 'out of nothing' as the salt aerosol forms where the two diffusing clouds of reagents meet between the two bottles. The salts produced by the action of ammonia on acids are known as the ammonium salts and all contain the ammonium ion ( [NH 4 ] ). Although ammonia is well known as a weak base, it can also act as an extremely weak acid. It

300-550: A colourless liquid , which boils at −33.1 °C (−27.58 °F), and freezes to colourless crystals at −77.7 °C (−107.86 °F). Little data is available at very high temperatures and pressures, but the liquid-vapor critical point occurs at 405 K and 11.35 MPa. The crystal symmetry is cubic, Pearson symbol cP16, space group P2 1 3 No.198, lattice constant 0.5125  nm . Liquid ammonia possesses strong ionising powers reflecting its high ε of 22 at −35 °C (−31 °F). Liquid ammonia has

350-406: A far lower temperature than would be possible with water alone. Substances containing ammonia, or those that are similar to it, are called ammoniacal . Ammonia is a colourless gas with a characteristically pungent smell . It is lighter than air , its density being 0.589 times that of air . It is easily liquefied due to the strong hydrogen bonding between molecules. Gaseous ammonia turns to

400-407: A fuel for thermal power production. The flammable range of ammonia in dry air is 15.15–27.35% and in 100% relative humidity air is 15.95–26.55%. For studying the kinetics of ammonia combustion, knowledge of a detailed reliable reaction mechanism is required, but this has been challenging to obtain. Ammonia is a direct or indirect precursor to most manufactured nitrogen-containing compounds . It

450-452: A laboratorial setting, gaseous ammonia can be detected by using concentrated hydrochloric acid or gaseous hydrogen chloride. A dense white fume (which is ammonium chloride vapor) arises from the reaction between ammonia and HCl(g). Ammoniacal nitrogen (NH 3 –N) is a measure commonly used for testing the quantity of ammonium ions, derived naturally from ammonia, and returned to ammonia via organic processes, in water or waste liquids. It

500-432: A pale yellowish-green flame. Ignition occurs when chlorine is passed into ammonia, forming nitrogen and hydrogen chloride ; if chlorine is present in excess, then the highly explosive nitrogen trichloride ( NCl 3 ) is also formed. The combustion of ammonia to form nitrogen and water is exothermic : The standard enthalpy change of combustion , Δ H ° c , expressed per mole of ammonia and with condensation of

550-559: A total of eight electrons, or four electron pairs that are arranged tetrahedrally . Three of these electron pairs are used as bond pairs, which leaves one lone pair of electrons. The lone pair repels more strongly than bond pairs; therefore, the bond angle is not 109.5°, as expected for a regular tetrahedral arrangement, but 106.8°. This shape gives the molecule a dipole moment and makes it polar . The molecule's polarity, and especially its ability to form hydrogen bonds , makes ammonia highly miscible with water. The lone pair makes ammonia

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600-438: A useful analogy is an umbrella turning itself inside out in a strong wind. The energy barrier to this inversion is 24.7 kJ/mol, and the resonance frequency is 23.79  GHz , corresponding to microwave radiation of a wavelength of 1.260 cm. The absorption at this frequency was the first microwave spectrum to be observed and was used in the first maser . One of the most characteristic properties of ammonia

650-465: A very high standard enthalpy change of vapourization (23.5  kJ/mol ; for comparison, water 's is 40.65 kJ/mol, methane 8.19 kJ/mol and phosphine 14.6 kJ/mol) and can be transported in pressurized or refrigerated vessels; however, at standard temperature and pressure liquid anhydrous ammonia will vaporize. Ammonia readily dissolves in water. In an aqueous solution, it can be expelled by boiling. The aqueous solution of ammonia

700-497: Is basic , and may be described as aqueous ammonia or ammonium hydroxide . The maximum concentration of ammonia in water (a saturated solution ) has a specific gravity of 0.880 and is often known as '.880 ammonia'. Liquid ammonia is a widely studied nonaqueous ionising solvent. Its most conspicuous property is its ability to dissolve alkali metals to form highly coloured, electrically conductive solutions containing solvated electrons . Apart from these remarkable solutions, much of

750-814: Is a protic substance and is capable of formation of amides (which contain the NH − 2 ion). For example, lithium dissolves in liquid ammonia to give a blue solution ( solvated electron ) of lithium amide : Like water, liquid ammonia undergoes molecular autoionisation to form its acid and base conjugates : Ammonia often functions as a weak base , so it has some buffering ability. Shifts in pH will cause more or fewer ammonium cations ( NH + 4 ) and amide anions ( NH − 2 ) to be present in solution . At standard pressure and temperature, Ammonia does not burn readily or sustain combustion , except under narrow fuel-to-air mixtures of 15–28% ammonia by volume in air. When mixed with oxygen , it burns with

800-406: Is a colourless gas with a distinctive pungent smell. Biologically, it is a common nitrogenous waste , and it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to fertilisers . Around 70% of ammonia produced industrially is used to make fertilisers in various forms and composition, such as urea and diammonium phosphate . Ammonia in pure form

850-402: Is a measure used mainly for quantifying values in waste treatment and water purification systems, as well as a measure of the health of natural and man-made water reserves. It is measured in units of mg/L ( milligram per litre ). The ancient Greek historian Herodotus mentioned that there were outcrops of salt in an area of Libya that was inhabited by a people called the 'Ammonians' (now

900-404: Is a rare naturally occurring mineral composed of ammonium chloride , NH 4 Cl. It forms colorless, white, or yellow-brown crystals in the isometric-hexoctahedral class. It has very poor cleavage and is brittle to conchoidal fracture . It is quite soft, with a Mohs hardness of 1.5 to 2, and it has a low specific gravity of 1.5. It is water-soluble. Salammoniac is also the archaic name for

950-568: Is about 10 . Liquid ammonia is an ionising solvent, although less so than water, and dissolves a range of ionic compounds, including many nitrates , nitrites , cyanides , thiocyanates , metal cyclopentadienyl complexes and metal bis(trimethylsilyl)amides . Most ammonium salts are soluble and act as acids in liquid ammonia solutions. The solubility of halide salts increases from fluoride to iodide . A saturated solution of ammonium nitrate ( Divers' solution , named after Edward Divers ) contains 0.83 mol solute per mole of ammonia and has

1000-415: Is also applied directly into the soil. Ammonia, either directly or indirectly, is also a building block for the synthesis of many chemicals. Ammonia occurs in nature and has been detected in the interstellar medium. In many countries, it is classified as an extremely hazardous substance . Ammonia is produced biologically in a process called nitrogen fixation , but even more is generated industrially by

1050-437: Is an irritant and irritation increases with concentration; the permissible exposure limit is 25  ppm , and lethal above 500 ppm by volume. Higher concentrations are hardly detected by conventional detectors, the type of detector is chosen according to the sensitivity required (e.g. semiconductor, catalytic, electrochemical). Holographic sensors have been proposed for detecting concentrations up to 12.5% in volume. In

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1100-403: Is formed. Pentavalent ammonia is known as λ -amine, nitrogen pentahydride decomposes spontaneously into trivalent ammonia (λ -amine) and hydrogen gas at normal conditions. This substance was once investigated as a possible solid rocket fuel in 1966. Ammonia is also used to make the following compounds: Ammonia is a ligand forming metal ammine complexes . For historical reasons, ammonia

1150-400: Is found around volcanic fumaroles , guano deposits and burning coal seams. Associated minerals include sodium alum , native sulfur and other fumarole minerals . Notable occurrences include Tajikistan ; Mount Vesuvius , Italy ; and Parícutin , Michoacan , Mexico. It is commonly used to clean the soldering iron in the soldering of stained-glass windows. In jewellery-making and

1200-508: Is found throughout the Solar System on Mars , Jupiter , Saturn , Uranus , Neptune , and Pluto , among other places: on smaller, icy bodies such as Pluto, ammonia can act as a geologically important antifreeze, as a mixture of water and ammonia can have a melting point as low as −100 °C (−148 °F; 173 K) if the ammonia concentration is high enough and thus allow such bodies to retain internal oceans and active geology at

1250-587: Is generated via the Ostwald process by oxidation of ammonia with air over a platinum catalyst at 700–850 °C (1,292–1,562 °F), ≈9 atm. Nitric oxide and nitrogen dioxide are intermediate in this conversion: Nitric acid is used for the production of fertilisers , explosives , and many organonitrogen compounds. The hydrogen in ammonia is susceptible to replacement by a myriad substituents. Ammonia gas reacts with metallic sodium to give sodamide , NaNH 2 . With chlorine, monochloramine

1300-519: Is its basicity . Ammonia is considered to be a weak base. It combines with acids to form ammonium salts ; thus, with hydrochloric acid it forms ammonium chloride (sal ammoniac); with nitric acid , ammonium nitrate , etc. Perfectly dry ammonia gas will not combine with perfectly dry hydrogen chloride gas; moisture is necessary to bring about the reaction. As a demonstration experiment under air with ambient moisture, opened bottles of concentrated ammonia and hydrochloric acid solutions produce

1350-637: Is likely to have been common sea salt . Nevertheless, that salt ultimately gave ammonia and ammonium compounds their name. The first attested reference to sal ammoniac as ammonium chloride is in the Pseudo-Geber work De inventione veritatis , where a preparation of sal ammoniac is given in the chapter De Salis armoniaci præparatione , salis armoniaci being a common name in the Middle Ages for sal ammoniac. It typically forms as encrustations formed by sublimation around volcanic vents and

1400-440: Is named ammine in the nomenclature of coordination compounds . One notable ammine complex is cisplatin ( Pt(NH 3 ) 2 Cl 2 , a widely used anticancer drug. Ammine complexes of chromium (III) formed the basis of Alfred Werner 's revolutionary theory on the structure of coordination compounds. Werner noted only two isomers ( fac - and mer -) of the complex [CrCl 3 (NH 3 ) 3 ] could be formed, and concluded

1450-584: Is not known whether the term is equivalent to the more modern sal ammoniac (ammonium chloride). The fermentation of urine by bacteria produces a solution of ammonia ; hence fermented urine was used in Classical Antiquity to wash cloth and clothing, to remove hair from hides in preparation for tanning, to serve as a mordant in dying cloth, and to remove rust from iron. It was also used by ancient dentists to wash teeth. Salammoniac Salammoniac , also sal ammoniac or salmiac ,

1500-404: Is only +0.04 V. In practice, both oxidation to dinitrogen and reduction to dihydrogen are slow. This is particularly true of reducing solutions: the solutions of the alkali metals mentioned above are stable for several days, slowly decomposing to the metal amide and dihydrogen. Most studies involving liquid ammonia solutions are done in reducing conditions; although oxidation of liquid ammonia

1550-543: Is the precursor to nitric acid, which is the source for most N-substituted aromatic compounds. Amines can be formed by the reaction of ammonia with alkyl halides or, more commonly, with alcohols : Its ring-opening reaction with ethylene oxide give ethanolamine , diethanolamine , and triethanolamine . Amides can be prepared by the reaction of ammonia with carboxylic acid and their derivatives. For example, ammonia reacts with formic acid (HCOOH) to yield formamide ( HCONH 2 ) when heated. Acyl chlorides are

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1600-438: Is usually slow, there is still a risk of explosion, particularly if transition metal ions are present as possible catalysts. The ammonia molecule has a trigonal pyramidal shape, as predicted by the valence shell electron pair repulsion theory (VSEPR theory) with an experimentally determined bond angle of 106.7°. The central nitrogen atom has five outer electrons with an additional electron from each hydrogen atom. This gives

1650-461: Is very difficult in the absence of a catalyst (such as platinum gauze or warm chromium(III) oxide ), due to the relatively low heat of combustion , a lower laminar burning velocity, high auto-ignition temperature , high heat of vapourization , and a narrow flammability range . However, recent studies have shown that efficient and stable combustion of ammonia can be achieved using swirl combustors, thereby rekindling research interest in ammonia as

1700-450: The Haber process . The process helped revolutionize agriculture by providing cheap fertilizers. The global industrial production of ammonia in 2021 was 235 million tonnes. Industrial ammonia is transported by road in tankers , by rail in tank wagons , by sea in gas carriers , or in cylinders . Ammonia boils at −33.34 °C (−28.012 °F) at a pressure of one atmosphere , but

1750-717: The Michoud Assembly Facility were awarded this medal for protecting the facility from flooding due to Hurricane Katrina in 2005. John V. Becker, "The X-15 Program in Retrospect," 3rd Eugen Sänger Memorial Lecture, Bonn, Germany, Dec. 4–5, 1968, copy in the NASA Dryden Historical Reference Collection. Bradley E. Rowe, A Personal Interview with a Hero. Telephone conversation with Retired Colonel Lynn B. Rowe, USAF, November 17, 2017. This article related to

1800-509: The National Aeronautics and Space Administration is a stub . You can help Misplaced Pages by expanding it . This article related to orders , decorations , and medals is a stub . You can help Misplaced Pages by expanding it . Ammonia#Fuel Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the formula N H 3 . A stable binary hydride and the simplest pnictogen hydride , ammonia

1850-477: The Siwa oasis in northwestern Egypt, where salt lakes still exist). The Greek geographer Strabo also mentioned the salt from this region. However, the ancient authors Dioscorides , Apicius , Arrian , Synesius , and Aëtius of Amida described this salt as forming clear crystals that could be used for cooking and that were essentially rock salt . Hammoniacus sal appears in the writings of Pliny , although it

1900-443: The addition of Nessler's solution , which gives a distinct yellow colouration in the presence of the slightest trace of ammonia or ammonium salts. The amount of ammonia in ammonium salts can be estimated quantitatively by distillation of the salts with sodium (NaOH) or potassium hydroxide (KOH), the ammonia evolved being absorbed in a known volume of standard sulfuric acid and the excess of acid then determined volumetrically ; or

1950-443: The ammonia may be absorbed in hydrochloric acid and the ammonium chloride so formed precipitated as ammonium hexachloroplatinate , [NH 4 ] 2 [PtCl 6 ] . Sulfur sticks are burnt to detect small leaks in industrial ammonia refrigeration systems. Larger quantities can be detected by warming the salts with a caustic alkali or with quicklime , when the characteristic smell of ammonia will be at once apparent. Ammonia

2000-611: The chemical compound ammonium chloride. Pliny , in Book XXXI of his Natural History , refers to a salt produced in the Roman province of Cyrenaica named hammoniacum , so called because of its proximity to the nearby Temple of Jupiter Amun ( Greek Ἄμμων Ammon ). However, the description Pliny gives of the salt does not conform to the properties of ammonium chloride. According to Herbert Hoover's commentary in his English translation of Georgius Agricola's De re metallica , it

2050-490: The chemistry in liquid ammonia can be classified by analogy with related reactions in aqueous solutions . Comparison of the physical properties of NH 3 with those of water shows NH 3 has the lower melting point, boiling point, density, viscosity , dielectric constant and electrical conductivity . These differences are attributed at least in part to the weaker hydrogen bonding in NH 3 . The ionic self- dissociation constant of liquid NH 3 at −50 °C

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2100-511: The ligands must be arranged around the metal ion at the vertices of an octahedron . Ammonia forms 1:1 adducts with a variety of Lewis acids such as I 2 , phenol , and Al(CH 3 ) 3 . Ammonia is a hard base (HSAB theory) and its E & C parameters are E B = 2.31 and C B = 2.04. Its relative donor strength toward a series of acids, versus other Lewis bases, can be illustrated by C-B plots . Ammonia and ammonium salts can be readily detected, in very minute traces, by

2150-479: The liquid can often be handled in the laboratory without external cooling. Household ammonia or ammonium hydroxide is a solution of ammonia in water. Pliny , in Book XXXI of his Natural History , refers to a salt named hammoniacum , so called because of the proximity of its source to the Temple of Jupiter Amun ( Greek Ἄμμων Ammon ) in the Roman province of Cyrenaica . However, the description Pliny gives of

2200-476: The mineral or, better, its synthetic counterpart, also serves for the production of cooling baths as well as in dyeing and leather tanning . Salammoniac (as ammonium chloride) was the electrolyte in Leclanché cells , a forerunner of the dry battery ; a carbon rod and a zinc rod or cylinder formed the electrodes. It was also brought into pharmacopeias by Islamic physicians for medicinal purposes. In

2250-474: The most reactive, but the ammonia must be present in at least a twofold excess to neutralise the hydrogen chloride formed. Esters and anhydrides also react with ammonia to form amides. Ammonium salts of carboxylic acids can be dehydrated to amides by heating to 150–200 °C as long as no thermally sensitive groups are present. Other organonitrogen compounds include alprazolam , ethanolamine , ethyl carbamate and hexamethylenetetramine . Nitric acid

2300-406: The past in bakery products to give cookies or biscuits their crisp texture, but the application of food grade baking ammonia ( ammonium carbonate or (NH 4 ) 2 CO 3 ) is generally being substituted with the creation of modern baking powder or baking soda ( sodium bicarbonate ). Salammoniac is used in salmiac liquorice , for instance salty liquorice or salmiak pastilles . In addition,

2350-438: The refining of precious metals, potassium carbonate is added to gold and silver in a borax -coated crucible to purify iron or steel filings that may have contaminated the scrap. It is then air-cooled and remelted with a one-to-one mixture of powdered charcoal and salammoniac to yield a sturdy ingot of the respective metal or alloy in the case of sterling silver (7.5% copper) or karated gold . Salammoniac has also been used in

2400-538: The rescue crew, these 6 men worked to free McKay in the presence of lethal concentrations of unjettisoned anhydrous ammonia fuel , saving McKay's life. Exceptional Bravery Medals were awarded in 1969 to NASA engineers Bill B. McClure and Charles J. "Jack" Beverlin, who prevented the collapse and explosion of an Atlas rocket at great risk to their own lives. A feature on Mars was later named after them. Medals were also awarded to Herbert W. Grandy in 1970, and to Paul D. Sebesta in 1974. Subsequently, thirty eight workers at

2450-600: The salt does not conform to the properties of ammonium chloride . According to Herbert Hoover 's commentary in his English translation of Georgius Agricola 's De re metallica , it is likely to have been common sea salt. In any case, that salt ultimately gave ammonia and ammonium compounds their name. Traces of ammonia/ammonium are found in rainwater. Ammonium chloride ( sal ammoniac ), and ammonium sulfate are found in volcanic districts. Crystals of ammonium bicarbonate have been found in Patagonia guano . Ammonia

2500-488: The water formed, is −382.81 kJ/mol. Dinitrogen is the thermodynamic product of combustion : all nitrogen oxides are unstable with respect to N 2 and O 2 , which is the principle behind the catalytic converter . Nitrogen oxides can be formed as kinetic products in the presence of appropriate catalysts , a reaction of great industrial importance in the production of nitric acid : A subsequent reaction leads to NO 2 : The combustion of ammonia in air

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