New mixed alkaline-earth nitridomolybdate(vi) nitride oxides with anion-ordered sub-structuresDedicated to Dr Marten G. Barker in memoriam.

Abstract

New molybdenum(VI) nitride oxides were synthesised by the reaction of strontium nitride and calcium nitride with molybdenum foil at high temperature in sealed stainless steel crucibles. The reactions yielded single crystalline products determined by X-ray diffraction to form complex structures in the triclinic space group P1(no. 2). The mixed alkaline earth compounds with composition Ca38Sr13[MoN4]12N8O3 and Ca36Sr15[MoN4]12N8O3 are isostructural with the quaternary nitride oxides Sr51[WN4]12N8O3 and Ca51[WN4]12N8O3. The structures contain isolated [MoN4](6-) tetrahedra, partially disordered alkaline earth cations and an ordered sublattice of N(3-) and O(2-) anions. Oxide anions are coordinated only to the alkaline earth metals. The title compounds are the first mixed alkaline earth metal nitride oxides.

20 New compounds and structures in the solid state

“…Chemical bonding analyses with the COHP method show the presence of significant covalent Ta-Ta interactions. 166 New molybdenum(VI) nitride oxides synthesised by the reaction of strontium nitride and calcium nitride in molybdenum foil have complex structures containing isolated [MoN 4 ] 62 tetrahedra, partially disordered alkaline earth cations and an ordered sublattice of N 32 167 Thermal ammonolysis of reactive precursors, prepared using the citrate complexation-calcination route, yields RWO 3 N oxynitrides [R = Nd and Pr], after thermal treatment. Both possess a scheelite-type tetragonal unit cell; neutron diffraction experiments performed on the Nd-phase did not provide evidence for any oxygen/nitrogen order within the scheelite anionic subnetwork (Fig.…”

11 Chromium, molybdenum and tungsten

“…181 New molybdenum(VI) nitride oxides were synthesised by the reaction of strontium nitride and calcium nitride with molybdenum foil at high temperature in sealed stainless steel crucibles. 182 The molybdenum bimetallic interstitial carbides Fe 3 Mo 3 C and Co 3 Mo 3 C have been synthesised by temperature-programmed reaction (TPR) between the molybdenum bimetallic interstitial nitrides Fe 3 Mo 3 N and Co 3 Mo 3 N and a flowing mixture of CH 4 and H 2 diluted in Ar. 183 These compounds were characterised by X-ray diffraction, laser Raman spectroscopy, elemental analysis, energy dispersive analysis of X rays, thermal analysis (in air), and scanning electron microscopy (field emission).…”