Transition metal-chalcogen systems viii: The CrTe phase diagram

Abstract

The CrTe phase diagram was investigated in the composition range 30–100 at.% Te using differential thermal analysis and powder diffraction methods. Six NiAs-related phases were characterized between 52.4 and 62 at.% Te. Two of them, hexagonal Cr 1− x Te (52.4–53.5 at.% Te) and monoclinic Cr 3Te 4-h (53.5–59.3 at.% Te), are high temperature phases. At lower temperatures monoclinic Cr 3Te 4-l (56.4–59.2 at.% Te) and trigonal Cr 2Te 3 (59.5–60.0 at.% Te) are stable. Two phases, monoclinic Cr 5Te 8-m (59.6–61.5 at.% Te) and trigonal Cr 5Te 8-tr (61.5–62.0 at.% Te), were found on the tellurium-rich side of this phase system. At 75 at.% Te monoclinic CrTe 3, a novel polytelluride, is formed in a peritectic reaction at 753 K. There are also indications of the formation of another tellurium-rich phase at about 70 at.% Te and 734 K.