Sulfur molecular structure

Although non-exhaustive, this review shows that a large variety of new difunc-tionalized mixed phosphorus and sulfur molecular structures have been described during the last ten years. It also demonstrates that such compounds are powerful synthetic tools or building blocks and, in some cases, molecules (or precursors of more complex molecules) with potential biological activities. 

Another boron sulfide, of stoichiometry BS2, can be made by heating B2S3 and sulfur to 300°C under very carefully defined conditions. It is a colourless, moisture-sensitive material with a porphine-like molecular structure, BgSig, as shown in Fig. 6.29b. An alternative route to BgSie involves the reaction of dibromotrithiadiborolane with trithiocarbonic acid in an H2S generator in dilute CS2 solution ... 

The analysis of phosphates and phosphonates is a considerably complex task due to the great variety of possible molecular structures. Phosphorus-containing anionics are nearly always available as mixtures dependent on the kind of synthesis carried out. For analytical separation the total amount of phosphorus in the molecule has to be ascertained. Thus, the organic and inorganic phosphorus is transformed to orthophosphoric acid by oxidation. The fusion of the substance is performed by the addition of 2 ml of concentrated sulfuric acid to — 100 mg of the substance. The black residue is then oxidized by a mixture of nitric acid and perchloric acid. The resulting orthophosphate can be determined at 8000 K by atom emission spectroscopy. The thermally excited phosphorus atoms emit a characteristic line at a wavelength of 178.23 nm. The extensity of the radiation is used for quantitative determination of the phosphorus content. 

In nickel and palladium dithiobenzoato complexes, four-membered chelate rings are formed (366), whereas, in the corresponding phenyl-dithio acetates [M2(S2CCH2Ph)4], the dithio ligands act as bridging groups between the two metal atoms, with the formation of binuclear units (367). The molecular structure of the latter compounds shows that each metal atom is coordinated to four sulfur atoms and to the other metal atoms in a square-pyramidal geometry. Other evidence for... 

Extensive quantum chemical calculations have been reported for sulfur-rich compounds in the past two decades. These calculations were used to investigate molecular structures and spectroscopic properties, as well as to understand the nature chemical bonding and reaction mechanism. Many high-level ab initio calculations were used for interpretation of experimental data and for providing accurate predictions of molecular structures and thermochemical data where no reliable experimental values are available. In recent years, density functional calculations have been extensively tested and used on many first- and second-row compounds. These proven DFT methods look promising for larger systems because for their computational efficiency. 

Keywords Sulfur hydrides Molecular structures Reactivity Spectra Acidities Application... 

Keywords Sulfur chains Molecular structures Radical anions Spectra Redox reactions... 

The infrared and Raman spectra of SgO [78] reflect the molecular structure. The SO stretching vibration gives rise to very strong IR absorptions at 1133 cm (CS2 solution) and at 1104 cm (CsCl disc) but to a weak Raman line at 1080 cm (all at 25 C). Since SgO is a strong oxidant, KBr discs should not be used (formation of sulfur bromides). The Raman hnes in the... 

Conrad O, Jansen C, Krebs B (1998) Boron - Sulfur and Boron - Selenium compounds -From unique molecular structural principles to novel polymeric materials. Angew Chem IntEd37 3208-3218... 

During this process the atomic charges for the adsorbed molecules were taken from a Mulliken analysis of a DZP basis set Hartree Fock calculation (using CADPAC on the MOPAC (PM3) optimized molecular structure. Table 3 gives the cation charges for the sulfoxide group and C2 for each cation. In both cases the sulfur and transferred proton are positively charged but at sulfur the... 

The molecular structure of the complex [Ni([9]aneN2S)2]2+ reveals a center of symmetry, i.e., the sulfurs are placed trans to each other, which leads to a coordination geometry that is... 

Figure 9 Molecular structure of a compound containing four zinc atoms bridged by a central sulfur.511...

At present, the problems in thiepin chemistry awaiting solution are (i) how to construct the thiepin skeleton under mild reaction conditions, (ii) what are the structural effects on thermal stability of thiepin, (iii) whether the thianorcaradiene is an intermediate of sulfur extrusion reaction or not, (iv) what is the molecular structure of the thiepin (planar or nonplanar), (v) what is the antiaromaticity of the thiepin ring. 

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