Growth of single crystals of fast-ion conducting binary and ternary copper and silver halides for neutron scattering

Abstract

We report the room temperature solution growth of single crystals of the halides Cul, CuBr, Ag 2 Hgl 4 and Cu 2 HgI 4 of sizes sufficient for single-crystal neutron diffraction studies. High quality Cul crystals to volumes of 9 mm 3 have been obtained by decomplexation reactions, exchange reactions and by evaporation of solutions. Growth of single crystals of CuBr to 10 mm 3 was successfully achieved by decomplexation of a HBr-CuBr solution upon diffusion through a gel. Crystals of Ag 2 HgI 4 , of several mm 3 in volume, larger than previously reported, have been produced by decomplexation of an HI solution. Both decomplexation and exchange reactions provided high quality single crystals of Cu 2 HgI 4 . A single crystal diffraction study of these ternary phases shows unambiguously that the room temperature phases are not isomorphic.