SYNTHESIS AND STRUCTURE OF SR2VN3 AND BA2VN3, 2 NEW NITRIDOVANADATES

Two new ternary nitrides, Sr2VN3 and Ba2VN3, have been synthesized by the solid state reaction of Sr2N or Ba3N2 with VN in sealed stainless steel crucibles and characterized by powder X-ray diffraction. Sr2VN3 crystallizes in the space group C2/c (a 5.71036(9) Angstrom, b = 10.9521(2) Angstrom, c = 12.2881(2) Angstrom, beta = 90.986(1)degrees, Z = 8) and is isostructural with Sr2TaN3. Ba2VN3 crystallizes in the space group Cmca (a 5.8614(4) Angstrom, b = 11.4682(7) Angstrom, c = 12.9121(9) Angstrom, Z = 8) and is isostructural with Rb2TiO3. In each structure vanadium (V) is coordinated to nitrogen in distorted tetrahedra, forming infinite one-dimensional chains of [VN3](4-) units running parallel to a. The strontium and barium atoms in these A(2)VN(3) materials (A = Sr, Ba) are coordinated to seven nitrogens. These materials are the first reported group II ternary nitrides to contain V-5+.