MetaSil Basic

Fig. 9. Gradient separation of the test mixture. Column RP Cs MetaSil Basic 250x4.6 mm I.D. 5 pm (Varian). Mobile phase A, acetonitrile B, water (1% acetic add/20 m M ammonium acetate) 0 min. 10% B, 10 min. 20% B, 25 min. 50% B.l-EEIM Br, 2- PMIM Br, 3- PEIM Br, 4-BMIM Cl, 5- BzMIM BF4,6-AMIM Cl, 7- EBzMIM Cl, 8- pMBzMIM Cl, 9-HMIM Q, 10-HEIM Cl, 11- HpMIM Cl. (Stepnowski et al., 2003).

Chain metasilicates Si03 formed by comersharing of Si04 tetrahedra arc particularly prevalent in nature and many important minerals have this basic structural unit (cf, polyphosphates, p, 528), Despite the apparent simplieily of their structure motif and stoichiometry considerable structural diversity is encountered because of the differing conformations that can be adopted by the linked tetrahedra. As a result, the repeat distance along the c -axis can be (1). 

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. 

Coesite. Coesite, the second most dense (3.01 g/cm3) phase of silica, was first prepared in the laboratory by heating a mixture of sodium metasilicate and diammoniiim hydrogen phosphate or another mineralizer at 500—800°C and 1.5—3.5 GPa (14,800—34,540 atm). Coesite has also been prepared by oxidation of silicon with silver carbonate under pressure (67). The structure is monodinic a0 = b0 = 717 pm, c0 = 1.238 pm, and 7 = 120°. There are 16 Si03 units per unit cell the space group is C2/c. Coesite persists as a basically stranded phase at atmospheric pressure and is a stable phase at... 

However, there is distinctly more complexity in the range of known compounds, and in the observed coordination polyhedra, in the crystalline silicates.250 There are only two basic silicates Mn2Si04, which occurs naturally (tephroite) and MnSi03 the metasilicate, which also occurs... 

In our studies, the nano-sized sihca was synthesized using cheap sodium orthosilicate and sodiirm metasihcate rather than expensive alkoxysilanes. An inverse microemulsion containing NP-5/NP-9 as surfactant and cylcohexane or petroleum ether as the oil was used to carry out the hydrolysis and condensation of sodium orthosilicate or metasilicate using an acidic medium [152, 153]. The spherical silica particles of size 10-20 nm were obtained in a system using cyclohexane as the oil and with sodium orthosihcate of 0.01-0.1 M [152]. The particle size increased as the concentration of sodium orthosihcate and the pH were increased. Sihca particles prepared in basic conditions were more uniform in size than those prepared in an acidic medium. But calcined sihca powders with larger specific areas (350-400 mVg) were obtained for those prepared in an acidic medium. 

Crystamet . [Crosfield Rhone-Poulenc Basic] Sodium metasilicate penta-hydrate for formulating specialty detergents and contributing buffering capacity and corrosion inhibition of soft metals and ceramic glazes. 

BSWL 202 EINECS 233-246-4 Lead metasilicate (PbSiOs) Lead monosilicate Lead silicate (PbSiOj) Lead silicon oxide (PbSiOa) Lead silicon trioxide Lead(2+) silicate. Basic silicate white lead white pigment acting as heat stabilizer for chlorinated polyethylene, chlorosulfonated polyethylene, PVC, and polyepi-chlorohydrin rust-... 

Rammelsberg (1875) thought that the basis of formula calculation is the relationship Si/R (in parentheses below) and not either ortho- or metasilicates. Thus normal silicates (by analogy with carbonates) of the type R SiO or RSiO or RSi O, of basic silicates of varied character ... 

The liquid chemical developers that have been in use in the IC industry are basic, aqueous solutions. The main two classes are the buffered metal-ion-containing (e.g., sodium metasilicate) and the metal-ion-free (MIF) developers (e.g., aqueous solutions of TMAH). Both classes of developers are typically formulated with additives such as surfactants to improve wetting.The buffered systems can be used at lower pH for the same normality, and thus offer better... 

Synonyms Basic lead white silicate Lead metasilicate... 

CAS 10099-76-0 11120-22-2 Synonyms Basic lead white silicate Lead metasilicate Empincal OaSi Pb Formula PbSiOa... 

When the drug load was very high, the solid dispersion could, however, exist as a viscous semisolid mass and may not be processable into tablets. Such materials may not also disperse in aqueous media and, therefore, may exhibit incomplete drug release. The issues were resolved by adsorbing the solid dispersion on a metasilicate (Neusilin US2). Further studies showed that the supersolubilization technology has general application in the development of solid dispersion systems for both basic and acidic drugs. 

Regarding environmental protection, the most important advantage of the use of aluminum acetate is that acetate can very easily escape as CO2 and H2O molecules. For industrial applications only the samples prepared in basic conditions should be taken into consideration. The same can be concluded about the application of the samples prepared from sodium metasilicate (water glass solution). The price gives some preference to sodium silicate over TEOS. 

Various basic compounds such as sodium hydroxide and sodium metasilicate also bring about vulcanization in these cases, cross-linking is accompanied by the liberation of alcohol which indicates the following type of reaction ... 

In the dimer, x = 2.346, 5(OH)= —0.33 and i5(Si)= +0.34. Condensation should not stop at this stage. Corner-sharing tetrahedi a tend to form rings and lead to oligomers with degrees of condensation between 3 and 8 [7], The cyclic tetramer is the most abundant species for pH between 11 and 12. These. species are the metasilicates. Within this pH range, equilibria are fast owing to the basic catalysis of oxolation. 

---