Die Kristallstruktur von Tetraphenylarsonium-tetrabromooxotechnetat(V), (Ph4As)TcOBr4

The Crystal Structure of Tetraphenylarsonium-tetrabromooxotechnetate(V), (Ph₄As)TcOBr₄ (Ph₄As)TcOBr₄ has been prepared from (Bu₄N)TcO₄, HBr and (Ph₄As)Br. The crystal structure of the complex has been determined by X-ray diffraction using MoKα radiation. The crystals are tetragonal, space group P 4/n with a = 1276.6(1) pm, c = 803.2(1) pm, Z = 2. The refinement based on 1595 reflexes converged to R = 0.034. The structure consists of discrete TcOBr₄^? anions and Ph₄As⁺ cations. The technetium is coordinated in a square pyramidal environment. A C_4v symmetry was derived for the complex anion. With this, it is isomorphous to the other structurally studied (Ph₄As)TcYX₄ complexes (Y = O, N; X = Cl, Br). The Tc = O length is 161.3(9) pm with Tc? Br 246.0(1) pm