AsS2Cl—an Arsenic(v) Compound? Formation, Stability and Structure of gaseous AsSCl and AsS2Cl—a combined experimental and theoretical study

Abstract

By reaction of solid As 4 S 4 with gaseous Cl 2 at a temperature of 410 K gaseous AsSCl and AsS 2 Cl are formed. Unexpectedly in AsS 2 Cl the arsenic is not of formal oxidation state +V but +III: the molecular structure of AsS 2 Cl is arranged as a 1-chloro-dithia-arsirane and comprises an hitherto unknown AsS 2 three-membered ring. Thermodynamic data on AsSCl and AsS 2 Cl are obtained by mass spectrometry (MS). The experimental data are extended and confirmed by ab initio quantum chemical calculations (QC). The following values are given:

PS2Br and AsS2X (X = Br, I): similar molecules with completely different shapes – a combined experimental and theoretical study

“…These observations correspond in part to results of the As/S/Cl-system we have described earlier. 3 Whereas the existence of AsSX could be expected in principle as analogous gaseous molecules like AsOCl and PSCl were described earlier, 4 AsS 2 Cl was found not to be an arsenic(V) compound of C 2v symmetry, but to consist of arsenic(III) and a quite unusual three-membered As-S-S-ring structure.…”

“…A value Δ f H 0 (As 4 S 4,g ) = 14.4 ± 10 kJ mol −1 has been selected after evaluation of literature data as pointed out in a previous work. 3 Using the entropy data of As 4 S 4 (g), AsX 3 (g) and As 4 (g) given in the literature, 16 the calculated entropy value of AsSX(g) (Table 3) and the K p -value given above, one calculates the heat of reaction Δ r H 0 (3) (AsSBr: 992.4, AsSI: 993.7 kJ mol −1 ) and from this the heat of formation Δ f H 0 (AsSX) (AsSBr: 34.8; AsSI: 91.6 kJ mol −1 ). The heat capacities have not been taken into account during the calculations as the reaction temperature is not far from room temperaturethe error resulting from this approximation is negligible.…”

“…This procedure has proven to be valid for AsCl 3 , AsSCl and AsS 2 Cl before. 3 Theoretical thermochemical data on gaseous AsSX and AsS 2 X were obtained by means of the investigation of the following theoretical reactions in which only the thermochemical values of the novel compounds AsSX or AsS 2 X, respectively, are unknown:…”

Tungsten Borides: On the Reaction of Tungsten with Boron(III) Bromide

“…The reliability of the procedure to obtain the theoretical enthalpies of formation has been tested before; it is explained by WBr 4 (g):…”

“…The coefficients were determined using the mathematical program package MAPLE. [24] The reliability of the procedure to obtain the theoretical enthalpies of formation has been tested before; [25] it is explained by WBr 4 (g):…”