The crystal structure of zinc diborate ZnB4O7

Abstract

Zinc diborate crystallizes in the orth0rhombic system, space group Pbca, with eight formula units in a cell of dimensions a= 13"714_+0"005, b=8"091 _+0.005 and c=8.631 _+0.005 A. The calculated density is 3"07 g.cm-3, and all atoms are in general positions. The structure of ZnB407 has been solved by three-dimensional Fourier syntheses. The positional and isotropic thermal parameters were refined by the least-squares method based on 530 observed reflexions. The final conventional R index is 0.067. The structure consists of BO3 triangles and BO4 tetrahedra sharing a common vertex. Each zinc atom is surrounded by four close oxygen atoms, arranged in an irregular tetrahedron.