Title: Sodium Metasilicate
CAS Registry Number: 6834-92-0
Molecular Formula: Na2O3Si
Molecular Weight: 122.06
Percent Composition: Na 37.67%, O 39.32%, Si 23.01%
Line Formula: Na2SiO3
Literature References: Usually prepared from sand (SiO2) and soda ash (Na2CO3) by fusion: Schwarz, Z. Anorg. Allg. Chem. 126, 62 (1923); Faith, Keyes & Clark's Industrial Chemicals, F. A. Lowenheim, M. K. Moran, Eds. (Wiley-Interscience, New York, 4th ed., 1975) pp 755-761. Review: Gmelins, Sodium (8th ed. supplement) 21, pp 1474-1478 (1967).
Properties: Usually obtained as a glass; also orthorhombic crystals. d 2.614. mp 1089°. nD25 (glass) 1.520. Specific heat (20°): 0.217. Heat of formation: -371.2 kcal/mol. Heat of soln (cryst) -7.45 kcal/mol. Heat of fusion: 10.3 kcal/mol. Sol in cold water, hydrolyzed by hot water. Insol in alcohol, acids, salt solns.
Melting point: mp 1089°
Index of refraction: nD25 (glass) 1.520
Density: d 2.614
Derivative Type: Nonahydrate
Properties: Efflorescent, orthorhombic bipyramidal platelets, mp 48° in water of crystn. Heat of hydration: -24.15 kcal/mol.
Melting point: mp 48°
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