Crystal Structure of Ca1.29Bi0.14VO4

The structure of a single crystal, grown by a slow cooling a melt of $Ca_{1.29}Bi_{0.14}VO_4$ composition, was analyzed. The crystals belong to the rhombohedral space group R3c and the dimensions of the unit cells are a = 10.848(1) ${\AA}$ , c = 38.048(6) ${\AA}$ , V = 3877.6(8) ${\AA}^3$ for the pale yellow crystal, and a = 10.857(1), c = 38.063(6) ${\AA}$ , V = 3885.6(8) ${\AA}^3$ for the yellow crystal, respectively. Unit cell dimensions of the crystal were larger than those of the host crystal, $Ca_3(VO_4)_2$ , owing to the Bi that replaced Ca in the unit cell. Ca in the unit cell formed six, eight and nine coordinated polyhedra with O atoms and Bi replacing Ca entered the eight or nine coordinated Ca sites with different crystallographic environments in the unit cell. All the V in the unit cell formed four coordinated tetrahedra with O atoms, however V-O bond lengths in the tetrahedra were different from one another.