A polymorph of tetrakis(acetonitrile-κN)copper(I) tetrafluoridoborate

A P2(1)2(1)2(1) polymorph of the title compound, [Cu(CH(3)CN)(4)]BF(4), is reported. The crystal structure is very similar to the structure of the Pna2(1) polymorph reported by Jones & Crespo [Acta Cryst. (1998), C54, 18-20]. The anions and one of the three independent cations occupy similar positions in both polymorphs. Two of the four symmetry-related positions of the other two cations are also identical in the two polymorphs, and the other two positions are related by mirror symmetry. The crystal used for the structure determination contained a volume fraction of 0.088 (7) of the Pna2(1) polymorph.