PREPARATION AND CRYSTAL-STRUCTURE INVESTIGATION OF SR2CO(SEO3)(3)

The structure of hydrothermally synthesized Sr2Co(SeO3)(3) was determi ned using single-crystal X-ray diffraction data up to sin theta/lambda =0.81 Angstrom(-1) (triclinic; space group, <P(1)over bar>; a=7.326(2) Angstrom, b=7.605(2) Angstrom, c=8.734(2) Angstrom, alpha=103.19(1)de grees, beta=105.50(1)degrees, gamma=95.52(1)degrees; Z=2; R(w)=0.032 f or 2973 unique reflections with F-o> 3 sigma(F-o)). Sr2Co(SeO3)(3) for ms a three-dimensional network structure composed of SrO8, CoO6, and S eO3 polyhedra. Sr-O distances range from 2.513 to 2.846 Angstrom (Sr1) and from 2.530 to 2.991 Angstrom (Sr2), and Co-O distances from 2.048 to 2.256 Angstrom; Se-O bond lengths within three crystallographicall y different selenite groups were determined between 1.666 and 1.715 An gstrom. Sr2Co(SeO3)(3) is isotypic with the corresponding copper compo und, although in Sr2Cu(SeO3)(3) the environment of the Cu(II) atoms is strongly Jahn-Teller distorted to a tetragonal pyramidal [4+1] coordi nation with only weak interaction to a sixth oxygen ligand.