Application of Dicyanohexasulfane for the Synthesis of cyclo-Nonasulfur. Crystal and Molecular Structures of S₆(CN)₂ and of α-S₉¹

Abstract

A novel synthesis for dichlorotetrasulfane is reported. Careful chlorination of cyclo-hexasulfur yields S(4)Cl(2) (besides S(2)Cl(2)), which is used to prepare S(6)(CN)(2) by reaction with Hg(SCN)(2). An X-ray diffraction analysis of S(6)(CN)(2) shows nonhelical chainlike molecules with the following molecular parameters: SS bond lengths 203.4-207.4 pm, SSS valence angles 104.95-105.96 degrees, SS torsion angles 81.2-94.5 degrees (motif: + + - - +). The chain-terminating SCN groups exhibit a parallel orientation within the molecules and are antiparallel in neighboring molecules. S(6)(CN)(2) reacts with titanocene pentasulfide to give S(9) and titanocene diisothiocyanate. alpha-S(9) was obtained as single crystals, the structure of which was determined by X-ray diffraction. The two independent molecules occupy sites of C(1) symmetry, but the molecular symmetry is approximately C(2), in agreement with predictions by density functional and ab-initio MO calculations. Molecular parameters: bond lengths 203.2-206.9 pm, valence angles 103.7-109.7 degrees, torsion angles 59.7-115.6 degrees (motif: + + - - + + - + -). The average SS bond lengths in S(6)(CN)(2) and alpha-S(9) agree with the single-bond value of 205 pm as observed in H(2)S(2) and in alpha-S(8).

Synthesis, Crystal, and Electronic Structure of Ba3Sb2Q7 (Q = S, Se)

“…This value is close to the sum of the corresponding Pauling single-bond radii of S (1.05 Å) [33] and similar to S-S distances in the crystal structures of different modifications of elemental sulfur: 2.03-2.08 Å. [34][35][36] The [S 2 ] 2-dumbbell is not a typical building block for compounds in the Ba-Sb-S system, but is present in barium polysulfides with S-S distances of 2.12 Å in BaS 2 [37] and 2.08 Å in BaS 3 , [38] as well as in the strontium antimony sulfide, Sr 6 Sb 6 S 17 , where the S-S distance is almost identical to the S-S distance found in Ba 3 Sb 2 S 7 . [30] In the crystal structure of Ba 3 Sb 2 S 7 the end member of the [S 2 ] 2-dumbbell is the S1 atom.…”

Das gelbe Element und seine erstaunliche Vielseitigkeit

“…Die Konzentration von S, ist in der von 122 "C abgeschreckten Schmelze sehr gering (0,2 %), erreicht in mittelschnell abgekiihlten SchmelZen ein Maximum (2,O -3 3 %) und ist in sehr langsam abgekuhlten Praparaten wieder sehr gering (0,2 -0,6 %) [ 9 den beiden benachbarten Schichten (oben und unten) im rechten Winkel zu denen der ersten Schicht (Typ 11). Diese beiden Typen unterscheiden sich in ihrem Rontgenbeugungsmuster, im Raman-Spektrum und in der thermischen Stabilitat.…”

Does the Interconversion of Polysulfur Compounds Proceed Via Hypervalent Intermediates?—An Ab Initio MO Study

“…Atom S3 bears a negative charge of À 0.58 and atoms S2 and H2 have positive charges of 0.32 respectively 0.23 units, which indicates that their interaction will be mainly ionic and only partly covalent in nature. The rather long S3´´´S2 distance of 260.6 pm supports this view, although the van der Waals distance of 350 pm [38] is still much larger. The S3´´´H2 distance amounts to 208.7 pm.…”