The preparation of SeI₃SbF₆ and TeI₃SbF₆; the X-ray crystal structures of SBr₃AsF₆, SeI₃AsF₆, SeI₃SbF₆, and TeI₃SbF₆; some considerations of the energetics of the formation of SBr₃AsF₆ and SeI₃AsF₆

Abstract

Te13SbF6 (4) are reported and the quantitative preparation of the hitherto unknown 3 and 4 from SbF5 and the respectiye elements in SO2 are given. Crystal data are asfollows: 1, monoclinic, spacegroup P21/c, with a = 8.015(1) A, b = 9.342(1)A, c = 12.126(2), P = 97.81(1)", andZ = 4; 2, monoclinic, space group P21/c, with a = 8.380(2) 4, b = 10.237(1) 4, c = 12.524(1) A, P = 99.36(1)", and Z = 4; 3, monoclinic, space group P 2 , / c , with ci = 8.548(2) A, b = 10.297(6) A, c = 12.877(8) 6, P = 98.70(3)", and Z = 4; 4, monoclinic, space group P21/c, with a = 8.463(1) A, b = 10.676(2) A, c = 13.121(4) A, P = 100.05(1), and Z = 4.Compounds l , 2 , 3 , and 4 are isostructural and were refined to a final R values of 0.040,0.05 1,0.047, and 0.037, respectively. The structures of these salts consist of essentially discrete MX3+ cations and M1F6-anions (M = S, Se, Te; X = Br, I; M' = As, Sb) with some cation-anion interactions. The Se13+ bond distances and angles were essentially identical in both AsF6-and SbF6-salts (average Se-I distance and I-Se-I angle for AsF6-salt; 2.508(2) A, 102.4(1)" and for SbF6_ salt; 2.512(1) A, 102.3(1)"). Similarly the average Te-I bond distance and I-Te-I angle for Te13SbF6 were 2.666(1) A and 99.8(1)" which are essentially identical to those in the previously reported Te13AsF6. The average S-Br distance and Br-S-Br angle were 2.142(6) A and 103.4(2)" in SBr3AsF6. Estimates of the S-I bond distance and I-S-I bond angle in the as yet unknown S13M1F6 are made from the extrapolation of MX3+ data. The bond distances observed in the simple MX3+ cations (M = S, Se, Te; X = C1, Br, I) with anions of very low basicity are within 0.02 A of the corresponding distances calculated by the Schomaker-Stevenson equation. The observed and estimated bond distances in SBr3+, S13+, and Se13+ are significantly longer than the corresponding S-Br, S-I, and Se-I distances in S71+, S7Br+, and Se6II2+. This observation is used to support the thesis that the long intra-cationic halogen-chalcogen contacts in polychalcogen-halogen cations are weakly bonding, and responsible for the cluster-like nature of these cations. The heats of formation of 1 and 2 from their respective elements and AsF5 were estimated. On utilise cetteobservation pour supporter la thkse selon laquelle les contacts intra-ioniques halogknes-chalcog&nes, qui sont longs dans les cations polychalcogknes-halogknes, provoquent une liaisons faible qui est responsable du fait que ces cations sont pratiquement des agrkgats. On a tvaluk les chaleurs de formation des composks I et 2 h partir du AsFs et de leurs ClCments respectifs.[Traduit par la revue]

The preparation and characterization of SeCl3SbF6, improved syntheses of MCl3(As/Sb)F6 (M = S, Se), and the X-ray crystal structure determination of SeCl3AsF6 and a new phase of SBr3SbF6

“…The observed average Se+-Cl distance and C1-Se-discussed in ref. 10. T h e bond distances of the group 16 cations mirror the trends seen in the neutral group 15 trihalides (see Table 5), and are similar to the M-X distances calculated by the Schomaker-Stevenson equation given in ref.…”

“…T h e bond distances of the group 16 cations mirror the trends seen in the neutral group 15 trihalides (see Table 5), and are similar to the M-X distances calculated by the Schomaker-Stevenson equation given in ref. 10. The bond distances in the cations are shorter than the isoelectronic neutral group 15 trihalides, consistent with the smaller size of M' ( M = elements of group 16) relative to that of M' (M' = elements of group 15).…”

Quantum chemical modeling of the thermochemical characteristics and acidity of polynitroazole salts

“…the sum of anionic and cationic volumes). For MX salts (1:1), Bartlett's relationship is widely applicable to calculate enthalpies of formation [5][6][7][8][9][10][11][12]. The dependence of the lattice energy U POT of the M q X p salt from the molecular volume (V m ) can be expressed by the equation:…”

Preference of npπ−npπ Bonding (n = 3, 4) over Purely σ-Bonded Species in M42+ (M = S, Se): Geometries, Bonding, and Energetics of Several M42+ Isomers,

“…viewed as responsible for the anion-cation interaction in salts of M 4 2+ and in salts of mixed halogen-chalcogen cations, e.g., [EX 3 + ][MF 6 -] [E ) S, Se, Te; X ) F, Cl, Br, I (apart from SI 3 + ); M ) As, Sb], [51][52][53][54] which increases in strength as the group is descended.…”