Complexes thio complex

Other mononuclear complexes include the tetrahedral [Mo(NMe2)r] and the octahedral Li2[Mo(N Me2)6].2thfi hut recent interest in the chemistry of the M" ion has eentred on the trinuclear 0x0 and thio complexes of Mo and W, particularly the former. They are of three main types. The first may be conceptually based on the [M3O11I unit found in the aquo ions [.M304(H209] (M = Mo. W). It contains a... 

Reed and Spycher (1985) pointed out based on thermochemical calculations that gold does not precipitate due to boiling because pH increases by boiling, leading to an increase in gold solubility due to gold-thio complexes. They indicated that acidification... 

Seward, T.M. (1973) Thio complexes of gold and the transport of gold in hydrothermal solutions. Geochim. Cosmochim. Acta, 37, 379-399. 

This reaction means that higher /hjS causes higher concentration of Au(HS)2 as well as higher fo. Higher fujS, /ss and /o, of back-arc hydrothermal fluids can explain higher Au, Hg, As and Sb who.se dominant dissolved species are probably thio complexes. 

All reported cases of CD antimony sulphide involve the trisulphide, Sb2S3. Sb2S3 is soluble in hydroxide to give antimonates and in excess sulphide to give thio-complexes. The latter is not a problem in CD since free sulphide, if it exists, does so in a very low concentration and is rapidly taken up to precipitate Sb2S3. However, the solubility in alkaline solutions limits the pH of the deposition solutions. Sb2S3 exists in two forms so-called amorphous Sb2S3, which varies in color from... 

The principal oxidation states involved in the rather few thiourea (thio) complexes which have been studied are II, III and (as the osmyl complex) VI. In no case is the mode of bonding properly established. In view of the uncertainty surrounding some of these species we consider both unsubstituted and substituted complexes together, using the apparent oxidation state for classification purposes. 

Organometallic Cp MoOS(CH2SiMe3) was prepared in 1989 by Faller and Ma (182) by the reaction of the dioxo analogue with H2S. Under similar conditions the methyl derivative produced Cp MoO(S2)(Me), which was readily oxidized to stable Cp MoO(S20)(Me). The formation of the disulfido complex highlights the reactivity of nascent Mo=S bonds. Satisfactory structural characterization of the oxo-thio-complex has not been achieved. 

Dioxo and Oxo-Thio Complexes and their Conjugate Acids 454... 

Oxo complexes continue to dominate high-valent Mo chemistry. Previous reviews by Stiefel1,2 and Nugent and Mayer14 provide essential background to this section, which describes molybdate and related species, then trioxo-, dioxo-, mono-oxo, and oxo-thio complexes in that order. 

Arsenic (As, at. wt. 74.92) occurs in its compounds in the oxidation states -III (arsine, AsHa), III (arsenite), and V (arsenate). Arsenic (IE and V) are amphoteric, but with much more acidic than basic character. The sulphides are characteristically capable of yielding soluble complexes (thio-salts). Arsenic(V) forms heteropoly acids. 

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