Synthesis and crystal structure of a noncentrosymmetric form of potassium strontium monovanadate KSrVO4

Transparent single crystals of KSrVO4 were grown at 1500 degrees C by the d irect melt and slow cooling technique. X-ray crystallography has shown that this compound crystallizes in the orthorhombic system with the space group P2(1)2(1)2(1) (No. 9). The lattice parameters are a = 5.865, b = 7.491, c = 10.021 Angstrom, and Z = 4. The structure is isotypical with beta-K2SO4, hut with a different space group. It can be regarded as made of independent [VO4](3-) tetrahedra arranged in such way as to delimit large cavities whe re Sr2+ and K+ are located in eight- and ninefold coordination spheres, res pectively. The mean interatomic distances K-O, Sr-O, and V-O are equal to 2 .952, 2.645, and 1.720 Angstrom, respectively. (C) 2000 Elsevier Science Lt d. All rights reserved.