Magnesium nitride chemistry

Experiments in the system RE-Mg-N (RE=La, Ce, Gd) have been done to explore the possible synthesis of nitrides using Mg as reactive melt and to extend the number of known nitride compounds containing Mg. Since these experimen ts produce only binary nitrides, we explored the use of mixed Na/Mg melts a nd discovered the quarternary nitrides BaMg3.33Nb0.67N4 (1), BaMg3.33Ta0.67 N4 (2) and Eu4TaMgN5 (3), which were characterized by single crystal struct ure analysis. The BaMg3.33M0.67N4 compounds are isotypic to UCr4C4 [R.K. Be hrens, W. Jeitschko, Monotsh. Chem, 118 (1987) 43-50] (filled MoNi4 type [D . Harker, J. Chem. Phys. 12 (1944) 315-317]) and crystallize in the space g roup I4/m (#87) with the lattice parameters a=856.40(12) and c =353.90(7) p m for (1), and a=859.61(8) and c=354.21(5) for (2). (3) crystallizes in a n ew structure type in the acentric orthorhombic space group Pna2, (#33) with the lattice parameters a=1265.5(3), b=1015.9(2) and c=691.5(1) pm. (C) 200 1 Elsevier Science B.V. All rights reserved.