Chalcogenides and Related Compounds

Table 4.5. A selection of Si chemical shifts for chalcogenides and related compounds, in ppm with respect to TMS.

Density functional theory has been used to calculate the P-E bond energies and orbital populations of trimethylphosphine chalcogenides and related compounds. The results indicate that Me3P=CH2 has a 7i-bond order of 0.5. The equilibrium acidities in DMSO solution and gas-phase homolytic bond dissociation energies of tributylphosphonium ylide precursors have also been determined. ... 

W° Chalcogenides with CO Ligands and Related Compounds 4.8.83.1 Complexes containing tellurium and selenium... 

A-heterocyclic germylenes and related compounds 04CCR(248)411. Supramolecular compounds of cucurbituril and chalcogenide cluster aquocom-plexes of molybdenum and tungsten 03IZV987. 

In terms deriving from the Ramsey approach, a review of chemical shifts in chalcogenide and pnictide semiconductors in terms of Harrison s BOM and related approaches has been given [130]. The Ramsey approach has also been used to explain chemical shifts in III-V compounds [131], and specifically 113Cd shifts in Cd chalcogenides [132]. 

Obrien P, Nomura R (1995) Single-Molecule Precursor Chemistry for the Deposition of Chalcogenide(S or Se)-Containing Compound Semiconductors by Mocvd and Related Methods. Journal of Materials Chemistry 5(11), 1761-1773... 

Five aspects of the preparation of solids can be distinguished (i) preparation of a series of compounds in order to investigate a specific property, as exemplified by a series of perovskite oxides to examine their electrical properties or by a series of spinel ferrites to screen their magnetic properties (ii) preparation of unknown members of a structurally related class of solids to extend (or extrapolate) structure-property relations, as exemplified by the synthesis of layered chalcogenides and their intercalates or derivatives of TTF-TCNQ to study their superconductivity (iii) synthesis of a new class of compounds (e.g. sialons, (Si, Al)3(0, N)4, or doped polyacetylenes), with novel structural properties (iv) preparation of known solids of prescribed specifications (crystallinity, shape, purity, etc.) as in the case of crystals of Si, III-V compounds and... 

The platinum metal chalcogenides in general are easier to prepare than the corresponding oxides. Whereas special conditions of temperature and pressure are required to prepare many of the oxides, the platinum metals react most readily with S, Se, and Te. A number of additional differences concerning the chemistry of the chalcogenides and the oxides are summarized as follows The metal—sulfur (selenium, tellurium) bond has considerably more covalent character than the metal-oxygen bond and, therefore, there are important differences in the structure types of the compounds formed. Whereas there may be considerable similarity between oxides and fluorides, the structural chemistry of the sulfides tends to be more closely related to that of the chlorides. The latter compounds... 

Wn Chalcogenides with CO Ligands and the Related Compounds 4.8.63.1 Complexes containing phosphine ligands... 

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