(CuI)P4Se4: An adduct of polymeric P4Se4 with CuI

Pure yellow (CuI)P4Se4 was prepared by reaction of stoichiometric amounts o f CuI, red P, and gray Se in evacuated silica ampoules. The crystal structu re was determined from single crystals at room temperature. (CuI)P4Se4 crys tallizes in the orthorhombic system, space group Cmca with a = 14.770 (1) A ngstrom, b = 12.029 (1) Angstrom, c = 12.449 (1) Angstrom, V = 2211.9(6) An gstrom(3), and Z = 8. The structure refinement converged to R = 0.0190 (wR = 0.0272) for 1020 independent reflections and 51 parameters. A prominent f eature of the crystal structure are neutral polymeric P4Se4 strands which a re connected by copper iodide. These strands consist of norbornane analogou s P4Se3 cages which are linked by selenium bridges. The polymers are achira l since a mirror plane exists perpendicular to the strands. The single poly mers are connected by [Cu2I2] units to form layers. These layers are stacke d along the b axis and are connected by van der Waals-interactions only Ram an spectra of (CuI)P4Se4, differ significantly from Raman spectra of (CuI)( 3)P4Se4 and catena-(P4Se4)(x).