THE SYSTEMS CUCL-MIICL2 (M = MN, CD) - CRYSTAL-STRUCTURES OF CU2MNCL4AND GAMMA-CUCL

The phase relationships of the quasibinary systems CuCl-M(II)Cl2 (M(II ) = Mn, Cd) were studied by high-temperature X-rav methods and differe nce thermal analyses (DTA). Four phases have been established: CdCl2-t ype M1-x(II)Cu2xCl2 and alpha-CuI-type Cu1-y(I)Mo.5y(II)Cl solid solut ions (above 361 and 321-degrees-C, respectively), and beta- and gamma- CuCl with negligible solubility for M(II). The phase widths of the Cd containing compounds are 0 < x < 0.35 at 25-degrees-C, 0 < x < 0.6 at 315-degrees-C, and 0 < y < 0.4 at 420-degrees-C, those of the manganes e compounds are similar, The crystal structures of alpha-CuI-type Cu2M nCl4 at 400-degrees-C and of Mn0.84Cu0.32Cl2 and gamma-CuCl both at 60 -degrees-C were determined by means of neutron powder diffraction. The structures were refined by Rietveld's method to final R(I) = 1.7, 6.0 , and 2.5%, respectively. The hitherto unknown high-temperature alpha- polymorph of CuCl can be stabilized by Mn(II) and Cd(II). The alpha-Cu I-type solid solutions are fast Cu+ ion conductors with conductivities of sigma > 10(-1) OMEGA-1 cm-1 above 350-degrees-C.