RARE EARTH METAL-METAL HALIDE SYSTEMS .12. THULIUM-THULIUM(3) CHLORIDE SYSTEM . THULIUM(2) CHLORIDE AND A SERIES OF INTERMEDIATE PHASES

Thermal analysis, equilibration, and X-ray data are reported for the condensed TmCl3-Tm system. Thulium(II) chloride melts congruently at 718 ± 3 °C and is isostructural with DyCl2 and YbCl2 with a0 = 6.55, b0 = 6.68, c0 = 6.93 A ̊, all ± 0.02 A ̊. The dichloride dissolves in water to give a short-lived, bordeaux-red color. Thermal analysis data give evidence for the presence of about nine intermediate compounds between TmCl2.04 and about TmCl2.12. Their apparent peritectic interconversions at 662 °-585 °C are rapid on both heating and cooling, and a close relationship between these and the parent TmCl2 structure is indicated by their powder patterns. The compounds may be considered as the ordered phases which derive from a hypothetical nonstoichiometric region. © 1969.