Silicates metasilicates

Sodium silicates (metasilicate, water glass, solids and solution)... 

Fig. 1. Examples of stmctures for silicates (a) monomer where is present (b) metasilicates where is present and (c) branched-ring...

Magnetite is unstable relative to ferrous metasilicate (FeSi03) and so, under certain high-silica BW conditions, ferrous metasilicate may form in preference to magnetite. Iron silicate scales are exceedingly insoluble and adherent. 

Addition of suitable builders, such as sodium silicates or sodium tripolyphosphate, could increase the detergency of soap-LSDA blend even further. A systematic investigation of three-component systems, soap-LSDA builder, showed that a detergency maximum could be attained which corresponded to a certain fixed ratio of components. Maximum detergency corresponded to an approximate composition of 75% soap, 10% MES, and 15% metasilicate. The tests were carried out at 50°C and at 300 ppm water hardness which is well above that of U.S. municipal water supplies. The principle of detergency potentiation of soap by an LSDA and builder was always evident, even when using other artificially soiled cloths, such as those supplied by U.S. Testing Co. or Testfabrics Inc. 

The silicates which will occur are orthosilicates, R++2Si04, metasilicates, R++Si03, etc. This is verified by observation no basic silicates of such cations are known, although many normal silicates such as forsterite Mg2Si04, etc., exist. 

C09-0139. Describe the bonding differences among silica, silicate minerals, and metasilicate minerals. 

Note carefully the sequence of intermediate reactions that have occurred, as depicted in this diagram. We see that the first solid state reaction involves formation of the orthosilicate. But this is very quickly transformed into meta- and pyro-sllicates. However, it is the metasilicate which predominates as the solid state reaction reaches its maturity. Finally, it predominates over all other forms of silicate present. 

Chain silicates, consisting of connected metasilicate units, (SiOg) " (Q ), and of an open structure. Wollastonite Ca(SiOg) reacted completely with poly(acrylic add), but the cement was much affected by water. 

Separate silicate rings [(Sio3)n]2n- metasilicates or cyclosilicates 1 3 (0.33) ... 

The product of the fusion of silica with sodium carbonate, sodium silicate (strictly called sodium poly trioxosilicate but usually metasilicate), dissolves in water to give a clear, viscous solution known as waterglass . It hydrolyses slowly and silica is precipitated. Besides the metasilicate, other silicates of sodium are known, e.g. the poly-tetroxosilicate (orthosilicate), Na4Si04. Only the silicates of the alkali metals are soluble in water. Other silicates, many of which occur naturally, are insoluble, and in these substances the polysilicate anions can have highly complicated structures, all of which are constructed from a unit of one silicon and four oxygen atoms arranged tetrahedrally (cf. the structure of silica). Some of these contain aluminium (the aluminatesilicates) and some have import ant properties and uses. 

ATH used in flame-retardant compounds precipitated silicates micas, wollastonite or calcium metasilicate barium sulphate, used for its opacity to X-rays and high density litho-pone quartz used in flour form. 

Magnesium forms an array of silicates having varying structures. Such a wide variety of silicates include metasilicate, orthosilicate, pyrosilicate, polysilicates, and a number of complex silicates, such as asbestos and talc in combination with other metal ions. Many such silicates occur in nature either as complex silicates or as discrete magnesium silicate. Some important magnesium silicates are listed below ... 

There is an interesting analogy between cyclosiloxanes and the cyclic metasilicates [Si 03 ] " n = 3-6), e.g. (Me2SiO)3 (10.42) and [SisOg] " (10.43) the methyl groups in the dimethylsiloxanes are replaced by the formally iso-electronic in the silicates. Cyclic metasilicates occur naturally in certain minerals. For example, the trimer (n = 3) is found in CasSisOg (a-wollastonite), whereas the hexamer (n = 6) is a constituent of Be3Al2Si60ig (beryl). 

Chain metasilicates or ino -silicates Chains or ribbons of [Si04] tetrahedra sharing two oxygen atoms Jadeite, NaAl(Si2Ofi) Wollastonite, Ca3(Si309) Tremolite, Ca2Mg5(Si40,)2(OH)2... 

Although the metasilicates, disilicates, and other silicates in which tetrahedron corners are shared are very stable, the corresponding compounds of phosphorus and sulfur are unstable. The explanation of... 

Gafac RE-610 4.0 Rhodaterge SMC 3.0 Sodium Metasilicate Pentahydrate 10.0 Sodium Silicate 5.0 Water 78... 

Polymeric chain, band- and sheet silicate structures have been discussed previously (page 742), and it should not be surprising to learn that cyclic silicate anions, such as [Si3Oy]ft and [Si601B]l2 (Fig. 16.28) are known. These anions are sometimes referred to as metasilicates in line with the older system of nomenclature, which assigned vrtlto to the most fully hydrated species [as in orthosilicic acid." Si(QH)J and metu to the acid (and anion) from which one mole of water has been removed [either in fact or formally for example, "metasilicic acid," OSi(OH)2]. 

Zeolite A 30.0 Sodium metasilicate pentahydrate 5.0 Magnesium silicate 1.0 Sodium perborate tetrahydrate 25.0 Tetraacetylethylenediamine (TAED) 3.0 Sodium carbonate 15.0 Carboxymethyl cellulose 1.5 Sodium sulphate light, enzymes to 100... 

Simple Silicates. The most important simple silicate glass-ceramics are based on lithium metasilicate [10102-24-6], Li SiO, lithium disilicate... 

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