The phase equilibria in the Er2S3-In2S3-Ga2S3 quasi-ternary system at 770 K and the properties of the intermediate compounds

The quasi-ternary systems Er2S3-In2S3-Ga2S3 was investigated by X-ray method, the isothermal section of the system at 770 K was constructed. Using X-ray structure analysis the crystal structures of the new compounds Ga2.78In3.88Y3.35S15 (I) Ga2.98In2.66Er4.37S15 (II) Ga3.37In1.26Tm5.37S15 (III), Ga3.46In1.58Yb4.96S15 (IV) were calculated. They crystallize in the space group C2/m with lattice parameters: a = 23.4104(6) angstrom, b = 3.81242(12) angstrom, c = 12.5460(4) angstrom, beta = 90.775(3)degrees (I); a = 23.5181(17) angstrom, b = 3.8064(3) angstrom, c = 12.5592(9) angstrom, beta = 90.954 degrees (II); a = 23.5474(8) angstrom, b = 3.78634(15) angstrom, c = 12.5164(4) angstrom, beta = 90.988(3)degrees (III), a = 23.4427(7) angstrom, b = 3.77641(8) angstrom, c = 12.4970(3) angstrom, beta = 90.970 degrees (IV). The photoluminescent spectra of the (Ga54.59In44.66Er0.75)(2)S-300 single crystal were investigated. With the decreasing of the temperature fill 300, 250, 200, 150 K the intensity of the photoluminescent spectra decreases. The position and shape of the spectra do not change according to the temperature decreasing. The maximum of the photoluminescent spectra (0.81 eV) corresponds to the transitions (4)->(13/2) -> (4)I(15/2 )in the f-shell of Er3+ ions.