Lanthanum nitride

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. 

Fig. 1. X-ray diffraction powder patterns of (a) tetragonal and (b) cubic lanthanum nitride (Kikkawa et al.

A similar solid-state metathesis (SSM) reaction, whereby lanthanum oxide was combined with calcium nitride as a nitriding agent, leading to lanthanum nitride and calcium oxide, had been previously described by Marchand and Lemarchand (1981) ... 

---