SYNTHESIS, CRYSTAL-STRUCTURE AND MAGNETIS M OF SODIUM TETRACHLOROTITANATE(II), NA2TICL4

Na2TiCl4 is obtained as single crystals by metallothermic reduction of TiCl3 with sodium (525-degrees-C, 90 d, Ta container). Pure powder sa mples may be prepared by synproportionation of TiCl3 with Ti in the pr esence of NaCl (950-520-degrees-C, 21 d). The structure refinement fro m four-circle diffractometer data confirms that Na2TiCl4 is isotypic w ith Sr2PbO4 (orthorhombic, space group Pbam (No. 55), Z = 2 a = 694.2( 1), b = 1 198.9(2), c = 385.6(1) pm, R = 0.055, R(w) = 0,038). Ti2+ is surrounded by a distorted octahedron of Cl-. The octahedra are connec ted via common edges to chains, 1infinity[TiCl2/1Cl4/2]2-, that run in the [001] direction. Magnetic susceptibility data were recorded in th e 2 to 300 K temperature range at various field strengths. The interpr etation of the data was carried out with the aid of crystal-field calc ulations taking magnetic interactions into account. The non-Curie beha viour of the reciprocal magnetic susceptibility of Ti2+ in Na2TiCl4 is due to the influence of spin-obit coupling.