Фазовая диаграмма системы Cu-Se

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Cu-Se (Copper-Selenium) D.J. Chakrabarti and D.E. Laughlin The equilibrium phases of the Cu-Se system at 1 atm are (1) the liquid, L, which exhibits two miscibility gaps-one at Cu-rich composition, between the liquids L1 and L2 above 1100 C, and the other at Se-rich compositions, between the liquids L2 and L3 above 523 C; (2) the fcc terminal solid solution, (Cu), with restricted solubility of Se amounting to 0.009 at.% at 900 C; (3) the rhombohedral terminal solid solution, (Se), with presumably negligible solubility of Cu; (4) the monoclinic Cu2Se compound (aCu2Se), stable up to 123 с 15 C; (5) the fcc high temperature modification of Cu2Se ( bCu2-xSe), stable between 123 с 15 and 1130 C at stoichiometry (x = 0) and with a broad homogeneity range extending on the Se side to form a defect compound; (6) the tetragonal stoichiometric compound Cu3Se2, stable up to 112 C; (7) the hexagonal stoichiometric compound CuSe (aCuSe), stable up to 51 C; (8) the orthorhombic modification of the CuSe compound (bCuSe), stable between 51 and 120 C; (9) the hexagonal high-temperature modification of the CuSe compound (gCuSe), stable between 120 and 377 C; and (10) the orthorhombic stoichiometric compound CuSe2, stable up to 332 C. The assessed phase diagram is based primarily on the work of [Hansen], [66Hey], [75Bab], and [75Mur]. The wide variety of properties manifested by the chalcogenides is evident in the Cu-Se system, where one of the compounds, cuprous selenide containing excess Se, Cu2-xSe, is a p-type extrinsic semiconductor, and the dichalcogenide, CuSe2, is a superconductor at low temperatures. At least three of the compounds in the Cu-Se system occur as minerals in nature-berzelianite, Cu2-xSe, umangite, Cu3Se2, and klockmannite, aCuSe. The fourth naturally occurring mineral, athabaskite (Cu5Se4), has not been synthesized in the laboratory and apparently does not exist as an equilibrium phase. 66Hey: R.D. Heyding, Can. J. Chem., 44(10), 1233-1236 (1966). 75Bab: A.A. Babitsyna, T.A. Emelyanova, M.A. Chernitsyna, and V.T. Kalinnikov, Zh. Neorg. Khim., 20(11) 3093-3096 (1975) in Russian; TR: Russ. J. Inorg. Chem. 20(11) 1711-1713 (1975). 75Mur: R.M. Murray and R.D. Heyding, Can. J. Chem., 53(6), 878-887 (1975). Published in Bull. Alloy Phase Diagrams, 2(3), Dec 1981. Complete evaluation contains 4 figures, 17 tables, and 58 references. Special Points of the Cu-Se System