PREPARATION, PROPERTIES, AND CRYSTAL-STRUCTURE OF THE SOLID ELECTROLYTES CU2P3I2 AND AG2P3I2

The new compound Cu//2P//3I//2 is a diamagnetic semiconductor with a susceptibility of chi equals minus 193 multiplied by 10** minus **6 cm**3/ mole and a band gap of E//a equals 0. 72 ev. Its crystal structure is monoclinic, space group P2//1/c, with the lattice constants a equals 15. 343(2) A, b equals 12. 925(2) A, c equals 15. 260(2) A, beta equals 116. 38(1) degree , and Z equals 16 formula units per cell. Twinning wrongly suggests orthorhombic and tetragonal symmetry. The crystal structure was determined from single-crystal X-ray data and refined to a residual of R equals 0. 068 and 4330 independent structure factors and 197 variable parameters. The P atoms form tubes similar to those in the Hittorf modification of phosphorus. They are surrounded by Cu atoms on 15 equipoint positions with occupancies varying between 0. 15(1) and 0. 97(1).