Preparation and structural characterisation of the trigonal nitridometalate Ba3MoN4

Abstract

The preparation and structural characterisation of a high temperature trigonal modification of Ba₃MoN₄ is described and compared to the previously reported orthorhombic form. The trigonal form was prepared by the reaction of barium nitride and molybdenum metal foil at 1393 K for 5 days in sealed stainless steel crucibles under argon. The structure is characterised by the presence of isolated [MoN₄]⁶⁻ tetrahedra which are stacked along the c axis. The structural analogies and differences between the two forms of Ba₃MoN₄ are discussed and their relationship to the AMoO₄ (A = Ca, Sr, Ba) compounds with the scheelite structure, which represents the family of oxides most structurally related to the Ba–Mo–N nitrides.