Crystal structure and magnetic properties of CuSb2O4
The crystal structure of a copper antimonite (CuSb2O 4) was determined from X-ray powder diffraction data. The structure was solved by simulated annealing in direct space using the Rietveld method. The compound crystallizes in tetragonal symmetry and space group P4 2 bc (106); unit cell parameters a = b = 8.76033(5) Å, c = 5.79786(4) Å, Z = 4, V = 444.947(5) Å3 and density (calc.) = 5.539 g cm -3. The CuO6 polyhedra are strongly elongated due to Jahn-Teller distortion in a [2+2+2] coordination arrangement, i.e. there are two long axial Cu-O1 bonds of 2.447(13) Å and in the equatorial plane there are two intermediate Cu-O2 bonds of 2.07(3) Å and two short Cu-O2 bonds of 1.88(2) Å. The SbO3 pyramidal arrangement is almost regular with Sb-O1 bonds of 1.97(2) Å (2x) and Sb-O2 of 1.959(5) Å. The experimentally obtained Raman spectrum is consistent with values obtained from theoretical modelling studies. The magnetic behaviour of this new compound suggests that it belongs to the class of S = 1/2 Heisenberg chain systems.