The crystal structure of copper metaborate, CuB2O4

Abstract

Copper metaborate crystallizes in the tetragonal system, space group l~2d, with twelve formula units in a cell of dimensions a = 11.484 4-_ 0.004 and c = 5.620 _+_ 0.004/~,. The calculated density is 4.02 g.cm -3. The structure of CuB204 has been determined by three-dimensional Fourier syntheses. The positional and isotropic thermal parameters were refined by least-squares analysis, yielding a final R value of 0.053. All boron atoms are tetrahedrally coordinated. The structure consists of BO4 tetrahedra sharing the four common oxygen atoms. Each copper atom is surrounded in a planar-square coordination by four oxygen atoms. All interatomic distances are of the usual order of magnitude.