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Sodium metasilicate is the chemical substance with formula Na 2 SiO 3, which is the main component of commercial sodium silicate solutions. It is an ionic compound consisting of sodium cations Na + and the polymeric metasilicate anions [– SiO 2− 3 –] n.
The standard can be compared visually to a suspension of bacteria in sterile saline or nutrient broth. If the bacterial suspension is too turbid, it can be diluted with more diluent. If the suspension is not turbid enough, more bacteria can be added. McFarland nephelometer standards:{2}
Idealized structure of sodium metasilicate. Metasilicates are silicates containing ions of empirical formula SiO 2− 3. Common stoichiometries include M I 2 SiO 3 and M II SiO 3. Metasilicates can be cyclic, usually the hexamer (SiO 3) 12− 6 or chains (SiO 3)n 2−. [1] Common compounds containing metasilicate anion are: Inosilicates
Antibiotic resistance tests: Bacteria are streaked on dishes with white disks, each impregnated with a different antibiotic. Clear rings, such as those on the left, show that bacteria have not grown—indicating that these bacteria are not resistant. The bacteria on the right are fully resistant to all but two of the seven antibiotics tested. [33]
To attempt to simplify and to stylize a very complex set of various reactions, the whole ASR reaction, after its complete evolution (ageing process) in the presence of sufficient Ca 2+ cations available in solution, could be compared to the pozzolanic reaction which would be catalysed by the undesirable presence of excessive concentrations of alkali hydroxides (NaOH and KOH) in the concrete.
Potassium silicate can be synthesized in the laboratory by treating silica with potassium hydroxide, according to this idealized equation: nSiO 2 + 2 KOH → K 2 O·nSiO 2 + H 2 O. These solutions are highly alkaline. Addition of acids causes the reformation of silica. K 2 SiO 3 adopts a chain or cyclic structures with interlinked SiO 2− 3 ...
Sodium silicate is also the technical and common name for a mixture of such compounds, chiefly the metasilicate, also called waterglass, water glass, or liquid glass. The product has a wide variety of uses, including the formulation of cements , coatings, passive fire protection , textile and lumber processing, manufacture of refractory ...
Sodium orthosilicate is the chemical compound with the molecular formula Na 4 SiO 4. It is one of the sodium silicates, specifically an orthosilicate, formally a salt of the unstable orthosilicic acid H 4 SiO 4. [2] [3] [4]