DUAL BEHAVIOR OF ACETONITRILE IN A NEW CADMIUM CYANIDE CLATHRATE: CRYSTAL STRUCTURE OF Cd(CH3CN)2Cd(CN)4·2CH3CN

We report a new crystal structure of the title clathrate containing tetrahedral and octahedral Cd atoms in a ratio of 1:1. The preparation of the compound is similar to that of the cristobalite-like clathrate Cd(CN)2·G, where all Cd atoms are tetrahedral. The new inclusion compound crystallizes in the monoclinic space group C2/c, a = 12.337(4), b = 11.964(3), c = 13.594(3) Å, β = 108.60(2)°, Z = 4, R = 0.034 for 1631 reflections. The three-dimensional host framework is built of alternate linkages between the tetrahedral Cd atom of the tetracyanocadmate and the octahedral Cd atom similar to that of the Hofmann-Td and the en-Td types. In the new clathrate dual behavior of acetonitrile, one as a unidentate ligand in the three-dimensional host framework and the other as the guest in the cage-like cavity, has been demonstrated.