What is a nitride?

The simplest definition would be a compound that contains nitrogen as an anion. This is different from something like gallium nitrate where the anion is a polyatomic negative species that contains a nitrogen atom. Two of our compounds, Sr₄GaN₃O and Ca₆[Cr₂Cr₆]H, contain two anions but these are still considered to be nitrides as the two anions are separate from each other i.e. there is no bonding between the two. The former a oxy-nitride and the latter a nitride-hydride. Often people talk about ternary and quaternary nitrides. These are simply nitrides that contain two or three other elements such as Sr₇GeN₆ and Li₄Ca₁₃Ge₆N₆. Nitrides with more than just two elements (binary nitrides) can also be grouped into the term multinary nitrides.

Many new ternary nitrides have been prepared in the last few years, such as:

BaCuN, Ba₁₆Cu₁₃N₁₅, Ca₄BaCu₂N₄, Ag₈Ca₁₉N₇, Sr₃GaN₃, Ca₃Ga₂N₄, Sr₆GaN₅, Sr₄GaN₃O, LiSrGaN₂, Zr₃Mo₂Ga₃N, Nb₃NiGa₂N, Ca₇GeN₆, Sr₇GeN₆, Sr₈Ge₂N₅, Li₄Ca₁₃Ge₆N₆, Li₄Ca₁₃Ge₂N₆, Sr₃MgGeN₄, Ce₂Nb₃N₅, Eu₄TaMgN₅, Ca₉V₄N₁₂, Ca₆[Cr₂N₆]H, Ca₄[Cr₂N₆], Sr₂NiN₂, Sr₃₉Co₁₂N₃₁, Ca₁₁N₆(CN)₂, Ca₄N₂(CN₂), (Li,Mn)₂N, Ca₂InN

The range and surprising stoichiometry of these compounds demonstrates the interesting nature of solid state chemistry. Who could predict that Ba₁₆Cu₁₃N₁₅ would exist, what structure it would have if it did and why it has such an unusual elemental ratio?

We also continue to persue research into gallium nitride, GaN, which has promise in every digital application. We are able to grow this from a sodium melt at relatively low temperatures and pressures.