RATIONALE Sulfide systems are often used at high temperatures, when vaporization of the components is enabled. Sulfide ores are used as sources of various metals and nonmetals and gaseous sulfides, and sulfosalts may also play a role in the atmosphere chemistry of hot rocky exoplanets. To predict the existence and thermal stability of gaseous sulfides and sulfosalts it is important to know their thermodynamic characteristics. In this study the sulfosalt of indium and arsenic was obtained in the gaseous phase for the first time. METHODS High-temperature Knudsen effusion mass spectrometry was used to determine the partial pressures of vapor species over indium and arsenic sulfides. A molybdenum double two-temperature cell was used to create the conditions of coexistence of indium and arsenic sulfides. A theoretical study of gaseous As4 S4 and In2 AsS2 was performed using both B3LYP, M06, PBE0 and TPSSh hybrid DFT functionals and an ab initio wave function-based MP2(Full) method. RESULTS Gaseous In2 AsS2 has been identified during vaporization of In6 S7 and As2 S3 from the molybdenum double two-temperature cell. The structure and molecular parameters of gaseous In2 AsS2 were determined using quantum chemical calculations. Energetically favorable structures of gaseous In2 S, AsS, As4 S4 and In2 AsS2 were found and vibrational frequencies were evaluated in the harmonic approximation. The formation enthalpy of gaseous In2 AsS2 (186 ± 37 kJ mol-1 ) was derived as a result of measurements of the equilibrium constants of two independent gas-phase reactions. CONCLUSIONS The gaseous sulfosalt of indium and arsenic was obtained for the first time. The formation enthalpy of the In2 AsS2 (g) molecule at 298 K was evaluated both experimentally and theoretically. The thermal stability of the gaseous sulfosalt is less than that of the gaseous oxyacid salts.

中文翻译：

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气态铟砷亚硫酸盐的热化学研究。

理性硫化物系统通常在高温下使用，这时可以使组分汽化。硫化矿石被用作各种金属和非金属以及气态硫化物的来源，并且亚硫酸盐也可能在热岩石系外行星的大气化学中起作用。预测气态硫化物和亚硫酸盐的存在及其热稳定性，重要的是要了解它们的热力学特性。在这项研究中，首次在气相中获得了铟和砷的亚硫酸盐。方法采用高温克努森渗流质谱法测定铟和硫化砷上蒸气种类的分压。钼双双温电池用于创造铟和砷化硫共存的条件。使用B3LYP，M06，PBE0和TPSSh混合DFT功能以及基于从头算波函数的MP2（Full）方法对气态As4 S4和In2 AsS2进行了理论研究。结果在从钼双双温电池中汽化In6 S7和As2 S3的过程中已鉴定出气态In2 AsS2。气态In2 AsS2的结构和分子参数使用量子化学计算确定。发现了气态In2 S，AsS，As4 S4和In2 AsS2的能量上有利的结构，并以谐波近似法评估了振动频率。测量了两个独立气相反应的平衡常数，得出了气态In2 AsS2（186±37 kJ mol-1）的形成焓。结论首次获得了铟和砷的气态硫盐。通过实验和理论评估了In2 AsS2（g）分子在298 K时的形成焓。气态亚硫酸盐的热稳定性小于气态含氧盐的热稳定性。