Synthesis and crystal structure of a new compound: CaGaBO4

A new compound CaGaBO4 was synthesized by solid state reaction at high temperature and its structure was solved by direct methods from X-ray powder diffraction data. The refinement was carried out using the Rietveld method, and the final refinement converged with Rp=10.2% and Rwp=14.5%. It crystallizes in the orthorhombic system with the space group Ccc2 and lattice parameters a=15.473(1) Å, b=8.2940(8) Å, c=5.8392(6) Å, and Z=8. The crystal structure of CaGaBO4 is formed by BO3-triangle groups, GaO4-tetrahedron groups that are linked to chains along the c-axis, and six-coordinated calcium groups, in which there is a channel of ∼5 Å in diameter along the c-axis. The XRD results show that no phase transition occurs between −173 and 227°C. The lattice parameters and expansion coefficients were calculated.