SYNTHESIS AND STRUCTURE OF LI3BA2TAN4

A new quaternary nitride, L3Ba2TaN4, has been synthesized from Li, Ba and Ta metals under flowing N2 at high temperature. The structure, as determined by single crystal X-ray diffraction techniques, is monoclinic, space group C2/c, Z = 4, with lattice parameters a = 11.294(2) angstrom, b = 5.678(1) angstrom, c = 11.350(2) angstrom, and beta = 121.407(7)degrees. Refinement based upon F2 yielded R2 = 0.052 and wR2 = 0.074 (for comparison, a refinement based upon F yielded R1 = 0.032). The Ta and one of the two independent Li ions are tetrahedrally coordinated by N anions; the Li tetrahedra are distorted. By sharing edges, the Ta and Li tetrahedra form chains which are linked together by the remaining Li ions to form the three-dimensional structure.