Phosphates, complexation

Since about 1968, triple superphosphate has been far outdistanced by diammonium phosphate as the principal phosphate fertilizer, both in the United States and worldwide. However, production of triple superphosphate is expected to persist at a moderate level for two reasons (/) at the location of a phosphoric acid—diammonium phosphate complex, production of triple superphosphate is a convenient way of using sludge acid that is too impure for diammonium phosphate production and (2) the absence of nitrogen in triple superphosphate makes it the preferred source of phosphoms for the no-nitrogen bulk-blend fertilizers that frequendy are prescribed for leguminous crops such as soy beans, alfalfa, and clover. 

Sohd uranium—phosphate complexes have been reported for the IV and VI oxidation states, as well as for compounds containing mixed oxidation states of U(IV) and U(VI). Only a few sohd state stmctures of U(IV) phosphates have been reported, including the metaphosphate U(P03)4, the pyrophosphate U(P202), and the orthophosphate, CaU(PO4)2. The crystal stmcture of orthorhombic CaU(POis similar to anhydrite (194). Compounds of the general formula MU2(PO4)3 have been reported for M = Li, Na, and K, but could not be obtained with the larger Rb and Cs ions (195). In the sohd state, uranium(IV) forms the triclinic metaphosphate, U(P03)4. Each uranium atom is eight-coordinate with square antiprismatic UOg units bridged by... 

Sodium Hypochlorite—Trisodium Phosphate Complex. Commercial crystalline trisodium phosphate (TSP) is a complex of the type (Na PO -xH20) NaY where n = 4 to 7, a = 11 or 12, and Y is a monovalent anion (see Phosphoric acids and phosphates). Chlorinated trisodium... 

Economic Aspects. Sodium hypochlorite—trisodium phosphate complex was commercialized in 1930. Chlorinated TSP is manufactured by Stauffer (a subsidiary of Rhc ne-Poulenc, Inc.). The consumption, steadily decreasing since 1980, dropped sharply in 1985 because of reduced use in dishwasher detergents. The estimated demand in 1987 was 37,360 t (220). In 1988 it sold for 0.32/lb ( 0.70/kg) for tmddoad quantities of 660 kg (300-lb) dmms. 

Ln(II) in LnFj Ln(II) were determined after samples dissolution in H PO in the presence of a titrated solution of NFI VO, which excess was titrated with the Fe(II) salt. It was found that dissolution of the materials based on CeF CeFj in H PO does not change the oxidation state of cerium, thus phosphate complexes of Ce(III, IV) can be used for quantitative spectrophotometric determination of cerium valence forms. The contents of Ln(II, III) in Ln S LnS may be counted from results of the determination of total sulfur (determined gravimetric ally in BaSO form) and sum of the reducers - S and Ln(II) (determined by iodometric method). 

Maltose phosphorylase proceeds via a single-displacement reaction that necessarily requires the formation of a ternary maltose E Pi (or glucose E glucose-l-phosphate) complex for any reaction to occur. Exchange reactions are a characteristic of enzymes that obey double-displacement mechanisms at some point in their catalysis. 

Chemical Name Tetracycline phosphate complex see tetracycline for chemical name Common Name —... 

Tu, A. J., Heller, M. J. Structure and Stability of Metal-Nucleoside Phosphate Complexes, in Metal Ions in Biological Systems Vol. 1 (ed. Sigel, H.), p. 1, Marcel Dekker, Inc. New York 1974... 

Transition metal dithio- and diseleno-phosphate complexes. J. R. Wasson, G. M. Woltermann and H. J. Stoklosa, Top. Curr. Chem., 1973,35,66-129 (428). 

Younis, H.M., Weber, G. Boyer, J.S. (1983). Activity and conformational changes in chloroplast coupling factor induced by ion binding Formation of a magnesium-enzyme-phosphate complex. Biochemistry, 22, 2505-12. 

The calcium phosphate method was first used in 1973 to introduce adenovirus DNA into mammalian cells [3]. DNA-Calcium-phosphate complexes are formed by mixing DNA in a phosphate buffer with calcium chloride. These complexes adhere to the cell membrane and enter the cytoplasm by endocytosis. Disadvantages of DEAE-dextran and calcium phosphate transfection are a certain level of cytotoxicity, a complicated transfection procedure, and the fact that not all cell types can be transfected using these methods. 

The niobium phosphate complex ( Pr0)4Nb[02P(0 Bu)2] 2 was produced by the reaction of Nb(0 Pr)5 with H0P(0)(0 Bu)2 in pentane [71]. Although crystals of sufficient quality for an X-ray crystallographic analysis were not obtained, spectroscopic evidence suggests that the phosphate ligands bridge the two Nb centers. 

The following examples describing the thermolytic behavior of di(ferf-butyl)phosphate complexes serve to demonstrate the utihty of the TMP approach for synthesis of various phosphate materials. 

We have noted earlier that aluminium is unusual in forming alumino-phosphate complexes in phosphoric acid solution which may be of a polymeric nature. Bearing in mind the analogies between aluminium phosphate and silica structures, it may well be that during cement formation an aluminium phosphate hydrogel is formed. Its character may be analogous to that of silica gel, where a structure is built up by the... 

Dental silicate cement liquids are concentrated aqueous solutions of orthophosphoric acid generally containing aluminium and zinc (Wilson, Kent Batchelor, 1968 Kent, Lewis Wilson, 1971a,b Wilson et al., 1972). The optimum orthophosphoric acid concentration is 48 to 55 % by mass (Wilson et al, 1970a), although higher concentrations are encountered. Aluminium is present as phosphate complexes and zinc as a simple ion (see Section 6.1.2). Examples are given in Table 6.6. 

All commercial examples of phosphoric add solutions used in these cements contain metal ions, whose role has been discussed in Section 6.1.2. In the case of the dental silicate cement, aluminium and zinc are the metals added to liquids of normal commerdal cements and have a significant effect on cement properties (Table 6.8) (Wilson, Kent Batchelor, 1968 Kent, Lewis Wilson, 1971a,b). Aluminium accelerates setting for it forms phosphate complexes and is the prindpal cation of the phosphatic matrix. Zinc retards setting for it serves to neutralize the addic liquid - it... 

The most important cation is aluminium. In the absence of fluoride, aluminium is present in solution as the Al(H20)e complex which hydrolyses to form complex multinuclear species such as [Al2(OH)2] and [A1i304(0H)24(H20)i2] + (Avcston, 1965 Waters Henty, 1977). There are also two kinds of phosphate complexes (Akitt, Greenwood Lester, 1971 O Neill et al., 1982) those based on the H3PO4 ligand, A1(H3P04) +... 

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