Nitrides nitrogen anions

Structurally characterized since 1970 and the structure of the eighth (S4N3 ) has been redetermined recently b) the first binary sulfur-nitrogen anion, S N " was isolated in 1975 and its structure was reported a year later c) the novel sulfur nitride, SjNg, was first identified in 1978 and d) although tetrasulfur dinitride, S N, has been known since 1897, the structure was not unequivocally determined until 1981... 

N , also known as nitride or the nitrogen anion. By gaining three electrons, nitrogen, which is in Group VA, assumes a full octet, like neon. 

As was pointed out by Yuan (1977) there is a distinct difference between the rare earth nitrides and the other pnictides because of the smallness of the nitrogen anion. In the nitrides the Ln-Ln distances are practically the same as in the trivalent metals. Therefore, direct exchange ( 1) will dominate here the superexchange ( 2) via the anions. Many of the rare earth nitrides are indeed ferromagnetic at low temperatures. 

Structures of the lanthanide nitridoborates appear as layered structures with approximate hexagonal arrangements of metal atoms, and typical coordination preferences of anions. As in many metal nitrides, the nitride ion prefers an octahedral environment such as in lanthanum nitride (LaN). As a terminal constituent of a BNx anion, the nitrogen atom prefers a six-fold environment, such as B-N Lns, where Ln atoms form a square pyramid around N. Boron is typically surrounded by a trigonal prismatic arrangement of lanthanide atoms, as in many metal borides (Fig. 8.10). All known structures of lanthanide nitridoborates compromise these coordination patterns. 

No, the editor didn t know what this name meant either.) It means salts of the triva-lent anions of Group V, restricted in [1] to arsenides, antimonides and bismuthides and prepared by reaction of sodium pnictides with anhydrous halides of transition and lanthanide metals. This violently exothermic reaction may initiate as low as 25°C. Avoidance of hydrated halides is cautioned since these are likely to react uncontrollably on mixing. Another paper includes a similar reaction of phosphides, initiated by grinding [2], Nitrides are reported made from the thermally initiated reaction of sodium azide with metal halides, a very large sealed ampoule is counselled to contain the nitrogen [3],... 

It should be noted that the results for the formic acid decomposition donor reaction have no bearing for ammonia synthesis. On the contrary, if that synthesis is indeed governed by nitrogen chemisorption forming a nitride anion, it should behave like an acceptor reaction. Consistent with this view, the apparent activation energy is increased from 10 kcal/mole for the simply promoted catalyst (iron on alumina) to 13-15 kcal/mole by addition of K20. Despite the fact that it retards the reaction, potassium is added to stabilize industrial synthesis catalysts. It has been shown that potassium addition stabilizes the disorder equilibrium of alumina and thus retards its self-diffusion. This, in turn, increases the resistance of the iron/alumina catalyst system to sintering and loss of active surface during use. 

Zirconium metal (mp 1855°C 15°C), like titanium, is hard and corrosion resistant, resembling stainless steel in appearance. It is made by the Kroll process (Section 17-A-l). Hafnium metal (mp 2222°C 30°C) is similar. Like titanium, these metals are fairly resistant to acids, and they are best dissolved in HF where the formation of anionic fluoro complexes is important in the stabilization of the solutions. Zirconium will burn in air at high temperatures, reacting more rapidly with nitrogen than with oxygen, to give a mixture of nitride, oxide, and oxide nitride (Zr2ON2). 

The detailed electronic structures of monatomic ions may be deduced starting from the structures of the corresponding neutral atoms (presented in Chapter 4). Monatomic anions have simply added sufficient electrons to the outermost p subshell to complete that subshell. The + rule can be used to deduce the structure of the ion as well as that of the neutral atom. For example, the electronic configuration of the nitride ion (the anion of nitrogen) is deduced, starting with the configuration of nitrogen ... 

In covalent azides, the pseudohalogen azide RN3 has an angular structure as in HN3. Triazidoborazine [H3N3B3(N3)3] and other boron azides, for example, salts of the tetraazidoborate ion B(N3 (4 have been considered as boron nitride precursors (see Boron-Nitrogen Compounds). The M(Ns)3 azido complexes of the other group 13 elements (Al, Ga, In, Tl) and their M(N3)4 tetraazido anions are all known. They and their derivatives are also used as precursors for the nitrides. 

Lithium is the only alkali metal that reacts with gaseous nitrogen to form a nitride salt containing the N3- anion ... 

Nitride salt a compound containing the N3- anion. (18.2) Nitrogen cycle the conversion of N2 to nitrogen-containing compounds, followed by the return of nitrogen gas to the atmosphere by natural decay processes. (19.2)... 

Nitrogen exists in three anionic forms, (nitride), N3 (azide), and Nitrides of... 

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