Syntheses,Crystal Structures,and Properties of the Three Novel perselenoborates RbBSe-3,and TIBSe_3 with Polymeric Chain Anions

摘要

The perselenoborates RbBSe3 and CsBSe3 can be prepared from the metal selenides, amorphous boron, and selenium, in the case of TIBSe.3 directly from the elements. The solid-state reac-dons were carried out in evacuated carbon-coated silica tubes at high temperatures. Single-crystal X-ray data were used to deter-mine the crystal structures. Both alkali metal perselenoborates RhBSe3 and CsBSe3 crystallize in the monodinic space group P2,/c (RbBSe3: a = 7.279(2) A, b 12.385(3) A, c = 6.169(2) A, P = 105.67(3)0, Z = 4, Ri = 0.0373, and wR2(F2) = 0.1000;CsBS%: a = 7.570(2) A, b = 12.791(4) A, c = 6.171(2) A, p = 107.09(2)~, Z 4, Ri = 0.0332, and wR2(F2) = 0.0751), while the thallium perselenoborate TIBSe3 crystallizes in the acentric monoclinic space group Ia (alternative setting to Cc) with the lattice constants a = 6.166(2) A, b = 12.109(2) A, c= 7.031(2) A, fi = 113.88(3)0, Z= 4, Ri = 0.0423, and wR2(F2) = 0.1157. All three compounds contain polymeric ani-onic chains of composition (IIBSe3I[),2 formed by spirocydically fused nonplanar five-membered B2Se3 rings in which the boron atoms are in a tetrahedral BSe4 coordination. Vibrational spectra of the new compounds were measured and X-ray powder patterns are reported.