Metal silicates

Table 11.1 Standard heats of formation of some metal silicates at room temperature (from metal oxides)...

It follows that since the addition of metal oxides has such a profound effect on the properties of liquid silicates such as the viscosity, that the Reynolds number of liquid silicates in metal-silicate liquid two-phase systems will influence the boundary layer thickness to a greater extent than in the liquid metals and alloys, mainly because of the higher viscosity of the silicate. 

You can find sodium silicate in the colorful Magic Rocks seen in gift shops at museums. The dry form is mixed with salts of various metals. When you drop them in water, the sodium is replaced by the metal. The resulting metallic silicate is not soluble in water, and it takes on a color characteristic of the metal (e.g., copper is blue). The metallic silicate is also a gel, so it expands and grows into colorful stalagmites in the water. 

If the standard free energy change associated with the metal silicate chlorination reaction is given by AG , then... 

A novel feature of the route is that it leads to monomeric and oligomeric alkyl silicates from metal silicates in good yield and with full or substantial siloxane framework preservation. Further, it leads to oligomeric organosiloxanes of intermediate molecular weight from alkyl silicates in good yield and with siloxane framework preservation. 

Silicates Metal ion(s) + silicate ion Granite (a metal silicate), used mostly for building... 

Andesite Making tools Complex metal silicates (about 60% silica) Compact and tough chips easily... 

Basalt Building Complex metal silicates (about 50% silica) Dark-colored, fine-grained... 

Jade Making jewelry and decorative objects Metal silicates Two varieties jadeite and nephrite... 

Adularia Metal Silicates Potassium aluminum silicate Varies... 

With the exception of metal-silicate equilibrium, (which is relevant to mantle-core segregation), igneous processes seem to be inefficient at fractionating Cu and Zn isotopes. 

Examples include silica, Si02, and various metal silicates. 

Marra, W.H. and Stinchfreld, ).C. (1955) Paper coating compositions comprising an adhesive, an alkali metal silicate and... 

Tardy Y. and Garrels R. M. (1977). Prediction of Gibbs energies of formation of compounds from the elements, II Monovalent and divalent metal silicates. Geochim. Cosmochim. Acta, 41 87-92. 

Essene E.J. and Fisher D.C. (1986) Lightning strike fusion extreme reduction and metal-silicate liquid immiscibility. Science 234, 189-193. 

Ganguly J. and Stimpfl M. (2000) Cation ordering in orthopyroxenes from two stony-iron meteorites implications for cooling rates and metal-silicate mixing. Geochim. Cosmo-chim. Acta 64, 1291-1297. 

Both lithium and barium salts reduce expansion based on alkali-silicate and alkali-carbonate swelling through the osmotic pressure development mechanisms. Two theories have been postulated [5, 11]. According to the first mechanism, soluble metal silicates, formed by the attack of alkali hydroxides on silica, are said to convert to insoluble lithium silicates in the presence of lithium salts. Consequently, less water is imbibed and this results... 

It is also worth mentioning that the constants for the metal silicate complexes tit very well into the relative order of ligand stability, even though they have been classified as uncertain data (see discussion below) because of... 

To some extent, the aqueous metal silicate complexes constitute an entire class of placeholders. There is ample evidence that silica forms strong complexes with several metals, but the stoichiometry of such complexes has not yet been established. Different speciation schemes have been proposed to interpret experimental data, for example, 1 2 complexes, chelates, or mixed hydroxide silicate complexes. Despite these ambiguities we decided to include several metal silicate complexes in the data base as guidelines for modellers. Should such complexes turn out to be of crucial importance in particular systems, additional experimental studies would be called for. 

The most obvious future data needs concern the missing, uncertain, and conflicting data identified above. Additional experimental investigations are needed in the case of Fe(III) and Zr(IV) carbonate complexation, and in the case of the Sn(IV)/Sn(II) and the Se(0)/Se(-II) redox couples. The molecular structure of metal silicate complexes needs clarification in order to remove ambiguities in the speciation scheme of these complexes. A rather challenging topic concerns the supposed transformation of crystalline tetra-valent actinide oxides, AnOz(cr), to solids with an amorphous surface layer as soon as the An4+ ion hydrolyses. The consequences of such... 

Preparation. Precipitated silica is formed from an alkaline metal silicate solution, such as sodium silicate in a ratio of approximately 2.5—3.3... 

Vitreous silica is susceptible to attack by alkaline solutions, especially at higher concentrations and temperatures. For 5% NaOH at 95°C, although crazing may be evident, surface corrosion is only 10 Jim after 24 h (87). For 45 wt % NaOH at 200°C, dissolution proceeds at 0.54 mm/h (88). The corrosion rates in other alkaline solutions are Us ted in Table 3. Alkaline-earth ions inhibit alkaline solution attack on vitreous silica. Their presence leads to the formation of hydrated metal silicate films which protect the glass surface (90). 

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