Synthesis of Main Group Polycations in Molten and Pseudo‐Molten GaBr 3 Media

The prospects of synthesizing polycationic species using GaBr 3 in benzene solution at room temperature have been investigated. The salts Bi 8 [GaBr 4 ] 2 , Sb 8 [GaBr 4 ] 2 and Te 4 [Ga 2 Br 7 ] 2 have been isolated and characterized. The first two compounds are isotypic with Sb 8 [GaCl 4 ] 2 , crystallize in the space group Pna 2 1 , and feature square anti ‐prismatic E 8 2+ polycations (E = Sb, Bi). Unit‐cell parameters for Bi 8 [GaBr 4 ] 2 are a = 18.3014(10) Å, b = 10.3391(6) Å and c = 13.5763(7) Å, and for Sb 8 [GaBr 4 ] 2 ; a = 18.096(2) Å, b = 10.1572(9) Å and c = 13.2168(10) Å. Te 4 [Ga 2 Br 7 ] 2 crystallizes in the space group P 2 1 / c with a = 10.1600(9) Å, b = 10.8314(9) Å, c = 13.8922(10) Å and β = 99.182(7)°, and features a square‐planar Te 4 2+ polycation. The compound Bi 5 [GaBr 4 ] 3 has been synthesized from molten GaBr 3 and characterized by using powder diffractometry in space group Fm ‐3 c ; a = 17.6263(8) Å. The structure model for this compound suggests the included Bi 5 3+ cations to be practically freely oriented within its cavities in the solid phase. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)