Crystal Chemistry of Ternary and Quaternary Transition Metal Nitrides

Nitrides are fascinating materials. Although the air we breathe is 78% nitrogen, essentially 100% of the land we walk upon are made of oxides. It would take an encyclopaedia to review oxide crystal chemistry, on the other hand we can present here a comprehensive review of ternary and quaternary solid state nitrides. In the ternary and quaternary solid state nitrides (IA,IIA)-M-N, unusual low valence M⁺ were found for copper, nickel, cobalt, iron and manganese, and various MN_n transition metal-nitrogen coordination polyhedra with CN=2(linear), 3(trigonal-planar), 4(tetrahedral and square planar), 5(square pyramidal), and 6(octahedral and trigonal prismatic) and different fashions of connection make nitrides an important family of inorganic solid state materials. A suitable classification is made on the basis of the correlation between coordination numbers (CN), the connection fashions and oxidation states of the anionic principal structures.