Hydrides nitrogen

Ammonia is an important industrial chemical used principally (over 80%) as fertilizers in various forms, and is employed in the production of many other compounds such as urea, nitric acid, and explosives. 

Diazene (or diimide) is a yellow crystalline compound that is unstable above 93 K. In the molecule, each N atom uses two sp2 hybrids for a bonding with the neighboring N and H atoms, and the lone pair occupies the remaining sp2 orbital. The molecule adopts the trans configuration  

Anhydrous NH2OH is a colorless, thermally unstable hygroscopic compound which is usually handled as an aqueous solution or in the form of its salts. Pure hydroxylamine melts at 305 K and has a very high dielectric constant (77.6-77.9). Aqueous solutions are less basic than either ammonia or hydrazine  

It is a reasonably strong Lewis base (electron donor), particularly towards transition metal ions, and forms an alkaline solution in water, often used in household cleaners. 

Liquid ammonia (Tb -33 °C) is one of the most widely used non-aqueous solvents. Alkali metals, for example, dissolve reversibly to give blue solutions, in contrast to their more familiar reactions with water. The blue colour is thought to arise from electrons solvated by ammonia molecules. The first observation of this reaction was by Sir Humphry Davy, who in November 1807 wrote in his laboratory notebook, when 8 grains of potassium were heated in ammoniacal gas it assumed a beautiful metallic appearance and gradually became a pure blue colour . B 

Ammonia is produced industrially by the Haber-Bosch process (see also the Industrial Inorganic Chemistry Case Study) which was discovered just before World War I in Germany. It was introduced at a time when naturally occurring sodium nitrate, NaNO, from Chile was the main raw material for the synthesis of fertilizers. The available nitrate deposits were insufficient to keep pace with demand, and the Haber-Bosch process undoubtedly helped to prevent mass starvation at the time. The completion of the first functioning ammonia plants by the chemical company BASF coincided with the start of the war, and they were also used to fuel the production of explosives for the German and Austro-Hungarian armies. 

The Haber-Bosch process involves direct combination of the elements N2(g) + 3H2(g) = 2NH3(g) AH = -92kJmol-  

At room temperature the reaction is very slow, which means industrial processes must operate at high temperature (400-450 °C) and high pressure (80-350 atm) and also require the presence of an iron catalyst. The fertilizers ammonium nitrate, NH4NO3, and ammonium sulfate, (NH4)2S04 are manufactured by treating ammonia with either nitric or sulfuric acid, respectively. 

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Synonyms Hydrazine anhydrous diamide diamine nitrogen hydride... 

The Commission on the Nomenclature of Inorganic Chemistry is currently producing a further volume of the Nomenclature of Inorganic Chemistry, which will deal with more specialised aspects of inorganic nomenclature not currently treated in the 1990 version. For example, one chapter will be devoted to the nomenclature of nitrogen hydrides, another to the nomenclature of iso- and heteropolyanions and yet another to techniques and recommendations for abbreviations of names, especially ligand names. These chapters are innovative but also codify a great deal of established practice. 

D. Reactivity of NP with other Nitrogen Hydrides NH2OH, NH3, and N3... 

The reductive NO chemistry will cover some new developments on the electrophilic reactions of bound nitrosyl with different nucleophiles, particularly the nitrogen hydrides (hydrazine, hydroxylamine, ammonia, azide) and trioxodinitrate, along with new density functional theoretical (DFT) calculations which have allowed to better understand the detailed mechanistic features of these long-studied addition reactions, including the one with OH-. The redox chemistry of other molecules relevant to biochemistry, such as O2, H2O2 and the thiolates (SR-) will also be presented. 

Table III also shows the values of the equilibrium constants, KVAp for the conversion of iron nitrosyl complexes into the corresponding nitro derivatives. Keq decreases downwards, meaning that the conversions are obtained at a lower pH for the complexes at the top of the table. Thus, NP can be fully converted into the nitro complex only at pHs greater than 10. The NO+ N02 conversion, together with the release of N02 from the coordination sphere, are key features in some enzymatic reactions leading to oxidation of nitrogen hydrides to nitrite (14). The above conversion and release must occur under physiological conditions with the hydroxylaminoreductase enzyme (HAO), in which the substrate is seemingly oxidized through two electron paths involving HNO and NO+ as intermediates. Evidently, the mechanistic requirements are closely related to the structure of the heme sites in HAO (69). No direct evidence of bound nitrite intermediates has been reported, however, and this was also the case for the reductive nitrosylation processes associated with ferri-heme chemistry (Fig. 4) (25).

Diazene (Diimide, N2H2) and Other Nitrogen Hydrides... 

A second nitrogen hydride of major importance is hydrazine (N2H4). The Lewis structure of hydrazine... 

FIGURE 8-24 Nitrogen Hydrides. Some multiple bonds are not shown. (Bond angles and distances are from A. F. Wells, Structural Inorganic Chemistry, 5th ed., Oxford University Press, New York, 1984.)... 

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