Salts, complex mixed

Copper quinolinolate (oxine copper) is the chelate of divalent copper and 8-hydroxyquinoline and shares most of its market with copper naphthenate, which is a complex copper salt of mixed naphthenic acids. The principal uses are in wood treatments and some military textiles, where the green color is not objectionable. Copper naphthenate has an odor but is cheaper than oxine. Both copper naphthenate and 2inc naphthenate have performed well in environment tests, with exposure to soil above-ground, as well as concrete (33). 

PbO PbO H2O, for example, may be formed by boiling suspensions of lead oxide and lead sulfate in water. In addition, complex mixed salts, such as white lead, 2PbC02 Pb(OH)2, are readily formed. 

Sometimes it so happens that crystals of a new salt are formed when solutions of two simple salts are mixed and the mixed solution is evaporated. The salt thus obtained is a distinct chemical substance in the solid state as well as in solution. In aqueous solution, it does not dissociate into all the simple ions of the salts it is obtained from, but yields complex ions along with the simple ions. Such a salt is known as a complex salt. A characteristic feature of complex salts is that in these the constituents retain their separate entities both in the solid state and in solution. Potassium ferrocynide, K4Fe(CN)6, is a complex salt and is obtained on mixing the solution of a ferrous salt with an excess of potassium cyanide solution. From its composition [Fe(CN)2,4 KCN], it appears to be a mixture of ferrous cyanide and potassium cyanide in the ratio of 1 4, and is thus taken to be an ordinary double salt. This representation of the compound is, however, not satisfactory since it responds neither to tests for Fe2+ ions nor to those for CN ions but does respond to tests for K+ ions and tetravalent Fe(CN)Jj ions. The ionization reaction of the complex salt cited in the present example can be represented as ... 

Explosions sometimes resulted on opening sealed tubes in which complex mixed chloride salts of this compound had been prepared. There is no obvious source of pressure in the reaction mixture of tungsten hexachloride, sodium and aluminium chlorides and aluminium metal. 

Figure 3 Crystal structure of a magnesium salt of mixed half-sandwich chloroyttraVchloromagnesacarborane complex. Reproduced by permission of the American Chemical Society from Organometallics 1998, 17, 3196.

Coprecipitation of the metals is usually achieved from an aqueous solution of nitrates upon addition of anions such as carbonates, citrates, or oxalates (10)(24-27). First reports in this field have underlined the necessity to neutralize the pH of the solution in order to obtain complete precipitation of barium or strontium. Also, oxalate or citrate ligands may bind to two different cations. This should allow a better mixing at a microscopic level. However, care should be taken since some cations such as Y or La may precipitate as double salt complexes with alkaline ions that have been added to the solution as hydroxides in order to control the pH (24). 

When multicomponent alkoxide solutions, or a single alkoxide and a soluble inorganic salt, are mixed, a multicomponent alkoxide may result. In this way, such complex oxides such as the YBCO superconductor (cf. Section 6.1.2.4) can be formed. Sol-gel processing can also be used to coat fibers for composites and to form ceramics with very fine pore sizes called xerogels. A xerogel commonly contains 50-70% porosity, a pore size of 1-50 nm, and a specific surface area exceeding 100 m /g. 

SALTS OF MIXED PLATINUM-TETRARHODIUM CLUSTER COMPLEXES... 

Salts of Mixed Platinum-Tetrarhodium Cluster Complexes 373... 

Crystallographic studies of the bis oxalates of chromium(III) are not abundant. However, the structure of both tarns904 and cis905 isomers has been confirmed crystallographically. Potassium tams-bis(oxalato)diaquachromate(III) is monoclinic (space group P2/c) the oxalates are strictly coplanar. The crystal structure of the complex salt [Cr(en)2(ox)][Cr(en)(ox)2] has been determined 905 this red salt is obtained as an intermediate in the preparation of salts of mixed ethylenediamine/oxalate chromium(III) complexes. The structure consists of discrete complex ions linked by H bonding to water molecules and neighbouring ions. 

For tridentate amino acids with three non-equivalent donor atoms such as L-aspartic acid or L-cysteine, the isomers possible are illustrated below (252-254). There have been a number of reports of the preparation of L-aspartic acid complexes.1180,1181,1182. In the earlier work the isomers were not identified, however in the later study, the complexes were tentatively identified by comparison of their spectroscopic properties with those of the corresponding cobalt(III) complexes.1183 The order of elution of the complexes on HPLC was also similar to that observed for the corresponding cobalt(III) complexes. Mixed complexes containing l- or D-aspartate and L-histidine were also prepared.1182 A crystal structure of one salt obtained from this kind of system, bis(L-histidinato-0,Ar,Ar )chromium(III) nitrate, has been determined.1184... 

Enhanced acidity solids including Brpnsted and Lewis acid-modified metal oxides and mixed oxides, as well as metal salts complexed with Lewis acids. 

Thiophilic separation Complex mix mode All antibodies High amount of salts... 

Searles Lake. Searles Lake is a large evaporite deposit about 78 km square and 46 rn deep. It contains a complex mixed salt system that includes trona along with potassium, boron, and other salts (23,24). North American Chemical Company recovers soda ash (1.0 x 10° t/yr) from the lake by carbonating and cooling the brine to crystallize sodium bicarbonate (25). The bicarbonate is filtered and calcined to light soda ash which is densified by conversion to the monohydrate followed by calcining. The procedure results in a dense ash with properties equivalent to Wyoming trona derived ash. 

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