The crystal structure and molecular structures of twinned [Cr(NH3)6] [Ni(H2O)6]Cl5 . 1/2(NH4Cl): A new complex bimetallic compound

The complex bimetallic salt crystallizes in the space group Fd3 with a = 20.440(2) Å and Z = 16. The crystal and molecular structures have been determined from single crystal data, despite a systematic twinning (RF = 0.037, RI = 0.041 for 1065 reflections). The spatial arrangement consists in discrete [Cr(NH3)6]3+, [Ni(H2O)6]2+, Cl−, and NH+4 ions, held together by ionic forces and by a network of hydrogen bonds. Both chromium and nickel ions are in octahedral sites. Structural correlations with related compounds are examined.This work was partially supported by Grant MAT88-176 from the Comision Interministerial de Ciencia y Tecnologia and by a grant from the Spanish-French Committee for Scientific Cooperation. One of us (M.C.M.) is grateful for the receipt of a NATO Postdoctoral Fellowship and for finantial support given by the CNRS (France).Peer Reviewe