Bildung von Nitridokomplexen durch Ammonolyse von Metallhalogeniden mit NH4 +. Synthese und Struktur von (NH4)3Nb2NBr10, (NH4)3Ta2NI10 und (NH4)3W2NBr10 / Formation of Nitrido Complexes by Ammonolysis of Metal Halides with NH4 +. Synthesis and Structure of (NH4)3Nb2NBr10, (NH4)3Ta2NI10 and (NH4)3W2NBr10

Abstract

The reaction of WCl6 or ReCl5 with NH4Cl in a sealed glas ampoule between 350 and 400 °C yields the hexachlorometallates(IV ) (NH4)2MCl6. MoCl5 forms (NH4)2MoC16 at 275 °C, whereas at 420 °C (NH4)3Mo2C19 is obtained. The salts (NH4)2MC16 crystallize in the K2PtCl6 type structure. NbBr5, WBr6 and Tal5 undergo ammonolysis reactions with NH4 + forming the nitrido complexes M2NX10 3- with a symmetrical nitrido bridge M = N = M . The com plexes have the point symmetry D4h. (NH4)3Nb2NBr10 crystallizes in the tetragonal space group P4/mnc with a = 727.8, c = 1932.9 pm and Z = 2. For (NH4)3Ta2NI10 a partially disordered structure in the tetragonal space group I4/mmm was observed. The lattice constants are a - 162.5, c - 1990.2 pm, Z = 2. (NH4)3W2NBr10 was obtained in the form of an am orphous powder. The vibrational spectra of the nitrido com plexes are assigned and discussed