Cation silicates

Natural isotope variations in chlorine isotope ratios might be expected due to both the mass difference between Cl and Cl as well as to variations in coordination of chlorine in the vapor, aqueous and solid phases. Schauble et al. (2003) calculated equilibrium fractionation factors for some geochemically important species. They showed that the magnitude of fractionations systematically varies with the oxidation state of Cl, but also depends on the oxidation state of elements to which Cl is bound with greater fractionations for 2+ cations than for 1+ cations. Silicates are predicted to be enriched compared to coexisting brines and organic molecules are enriched to dissolved Cl. ... 

Belov, N. V., Crystal Chemistry of Large-Cation Silicates, pp. 34-36, Consultants Bureau, N. Y., Academy of Science Press, Moscow, 1961. 

The phenomenon of increased hardness occurs principally in minerals of sheet and chain structures, which link together through the cations (silicates and aluminosilicates, as well as hydrated sheet minerals, such as glauconite, melilite and gypsum—M ranging from 0 to about 1.25), and also in minerals of skeletal structures (borates, phosphates, sulphates, nitrates, carbonates, such as calcite, dolomite and others—Ah from 0 to about 1.15). For this reason, the hardness analysis of minerals with weak bonds demands consideration of the fact that just as the basic crystallo-chemical factors, so is hardness influenced by the form of domains (component parts of structures) in all anisodesmic minerals of chain, sheet or skeletal structure. Depending on the form of domain (and also according... 

Surface treatment of clays The surface treatment of the nanoadditives helps establish an interface with the polymer matrix and hence enhance the compatibility and/or the miscibility of the nanoadditive with the polymer matrix. In terms of the cationic silicate clay, such as MMT, the interface is... 

Based on the above observations, we suggest the mechanism shown in Scheme 10-1. Transmetallation of a pentacoordinate silicate with R-PdL -X proceeds in a way so that R-PdL -X can coordinate to the Si atom of the coordinatively unsaturated silicate to give a coordinatively saturated hexacoordinate silicate. Interaction of the bivalent palladium with the C= C bond followed by C-Pd bond formation would produce a /S-cationic silicate... 

By means of Si NMR spectroscopy, it is established that the distribution of silicate anions in alkaline silicate solutions is a moderate function of base composition. At a fixed SiC concentration and silicate ratio, the proportion of Si present in oligomeric and cage-like structures increases in progressing from Li to Cs hydroxide. This trend is ascribed to cation-silicate anion pairing and to a higher selectivity for ion pairing by large silicate anions as cation size increases. 

W. Eitcl, ed., Silicate Science, Vols. I-V, Academic Press W. A. Deer, R. A. Howie and J, Zussman, Rock Forming Minerals, Vols. I-V, Longmans N. V- Belov, Crystal Chemistry of Large Cation Silicates, Consultants Bureau, 1963 A. A. Hodgson, Fibrous Silicates, Royal Inst. Clicm. (London), Lecture Scries No. 4, 1964. 

In some sources, the enthalpies of formation or the Gibbs energies of oxide compounds with several cations (silicates, aluminates etc.) are reported in terms of the reactions of formation from the constituent oxides. In such cases the data have been corrected with respect to the corresponding basic data of the constituent oxides presented in this work. 

Among a small group of silicates that can be obtained from aqueous solutions at room temperatuiTe and normal pressure are silicates with complex cations. Silicates with chelate complexes of transition metals were first obtained by V. Molchanov and N.Pri-khid ko at the Institute of Silicate Chemistry (jl,). Silicates with alkylammonium cations were prepared in aqueous solutions by S. Glixelli and T. Krokowski ( ) and D. Hoebbel and W, Wieker (3),... 

Rare-earth silicate compounds form a chapter in the chemistry of large-cation silicates. With RE + ionic radii ranging from 0.85 to 1.28 A, the crystal structures consist of isolated (Si04) tetrahedra or groups of (SigOv) and (SigOio) Rare-earth cations show six- to tenfold oxygen coordination. 

Ilyukhin, V.V. and Belov, N.V. (1962) "The crystal structure of rubidium di (meta) fiuoroberyllate (Rb Be2Fs) and its relationship to silicate sheet stmcture with [Si20s] units" in N.V. Belov (ed.). Crystal Chemistry of Large-Cations silicates. Consultant Bureau, New-Yoik, pp. 154-162. 

Belov, N.V. (1959). "Crystal Chemistry of Large Cation Silicates. Consuitants Bureau New York. 

The structure of apatite-type mixed cation rare earth germanates is similar to that described for mixed cation silicate apatites. The structure is capacious toward isomorphic substitutions and preserves itself in various substitutions, in the cation as well as in the anion structure (Cockbain and Smith, 1965 Ito, 1968 Fedorov et al., 1982). 

PBT is a good material for the automobile industry. Lor instance it can be used for wheel covers, components of door handles, and distributor caps because of its chemical resistance, thermal stability, and hydrolytic stability.The hydrophobicity of the organically modified MMT and the polar interactions between the ammonium cations, silicate layers, and the PBT itself are critical to hybrid formation. As it possesses the proper hydrophobicity and compatibility with PBT, Cloisite lOA can be intercalated and partially exfoliated in a PBT matrix. Cloisite SOB, on the other hand, can only form intercalated nanocomposites with PBT, due to the strong interactions between the ammonium cation and silicate layers. Linally, PBT/Cloisite 6A systems exhibit the... 

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