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 Ga_2.78In_3.88Y_3.35S₁₅ (I), Ga_2.98In_2.66Er_4.37S₁₅ (II), Ga_3.37In_1.26Tm_5.37S₁₅ (III), Ga_3.46In_1.58Yb_4.96S₁₅ (IV) were calculated. They crystallize in the space group C2/m with lattice parameters: a ​= ​23.4104(6) Å, b ​= ​3.81242(12) Å, c ​= ​12.5460(4) Å, β ​= ​90.775(3)° (I); a ​= ​23.5181(17) Å, b ​= ​3.8064(3) Å, c ​= ​12.5592(9) Å, β ​= ​90.954° (II); a ​= ​23.5474(8) Å, b ​= ​3.78634(15) Å, c ​= ​12.5164(4) Å, β ​= ​90.988(3)° (III), a ​= ​23.4427(7) Å, b ​= ​3.77641(8) Å, c ​= ​12.4970(3) Å, β ​= ​90.970° (IV). The photoluminescent spectra of the (Ga_54.59In_44.66Er_0.75)₂S₃₀₀ single crystal were investigated. With the decreasing of the temperature till 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 ⁴І_13/2 ​→ ​⁴I_15/2 in the f-shell of Er³⁺ ions.

用X射线法研究了准三元体系Er ₂ S ₃ -In ₂ S ₃ -Ga ₂ S ₃，构造了系统在770 K的等温截面。使用X射线结构分析，新化合物的晶体结构Ga _2.78 In _3.88 Y _3.35 S ₁₅（I），Ga _2.98 In _2.66 Er _4.37 S ₁₅（II），Ga _3.37 In _1.26 Tm _5.37 S ₁₅（III），Ga _3.46在_1.58 Yb计算得出_4.96 S ₁₅（IV）。它们在晶格参数为C2 / m的空间群中结晶：a = 23.4104（6）Å，b = 3.81242（12）Å，c = 12.5460（4）Å，β= 90.775（3 ）°（I）；a等于23.5181（17）Å，b等于3.8064（3）Å，c = 12.5592（9）Å，β= 90.954°（II）; a = 23.5474（8）Å，b = 3.8634（15）Å，c = 12.5164（4）Å，β= 90.988（3）°（III），a = 23.4427（7） ）Å，b = 3.7641（8）Å，c = 12.4970（3）Å，β= 90.970°（IV）。（Ga _54.59 In _44.66 Er _0.75）₂ S ₃₀₀的光致发光光谱研究了单晶。随着温度降低直至300、250、200、150 K，光致发光光谱的强度降低。光谱的位置和形状不会随温度降低而变化。中的过渡的最大光致发光光谱（0.81 eV）的对应的⁴ І _13/2  → ⁴我_15/2在铒的f壳³⁺离子。