Title: Magnesium Silicates
Literature References: Several varieties of magnesium silicate are known. See also asbestos, talc.
Derivative Type: Magnesium metasilicate
CAS Registry Number: 13776-74-4
Molecular Formula: MgSiO3
Molecular Weight: 100.39
Percent Composition: Mg 24.21%, Si 27.98%, O 47.81%
Properties: Occurs in nature as the minerals clinoenstatite, enstatite, protoenstatite. White monoclinic crystals, dec at 1557°. d425 3.192. Practically insol in water; very slightly sol in HF.
Density: d425 3.192
Derivative Type: Magnesium orthosilicate
CAS Registry Number: 10034-94-3
Molecular Formula: Mg2SiO4
Molecular Weight: 140.69
Percent Composition: Mg 34.55%, Si 19.96%, O 45.49%
Properties: Occurs in nature as the mineral forsterite. White orthorhombic crystals. mp 1910°; d 3.21. Practically insol in water.
Melting point: mp 1910°
Density: d 3.21
Derivative Type: Magnesium trisilicate
CAS Registry Number: 14987-04-3
Additional Names: Magnesium mesotrisilicate
Trademarks: Magnosil (Polfa); Petimin; Trisomin (Lilly)
Molecular Formula: Mg2Si3O8
Molecular Weight: 260.86
Percent Composition: Mg 18.63%, Si 32.30%, O 49.07%
Properties: Occurs in nature as the minerals meerschaum, parasepiolite, sepiolite. Prepd from sodium silicate and magnesium sulfate: Glass, Q. J. Pharm. Pharmacol. 9, 445 (1936); Uyeda, US 3272594 (1966 to Merck & Co.). Odorless, tasteless, slightly hygroscopic powder. Usually contains some water of hydration. Practically insol in water.
Derivative Type: Magnesium trisilicate pentahydrate
Derivative Type: Serpentine (mineral)
Molecular Formula: Mg3O7Si2
Molecular Weight: 241.08
Percent Composition: Mg 30.25%, O 46.46%, Si 23.30%
Properties: Occurs in nature as the dihydrate, (OH)4MgSi2O5; exists in two forms: antigorite, a platy variety, and chrysotile, a fibrous variety. The latter is the most common form of asbestos.
Use: An activated magnesium silicate, Florisil, a hard, porous, granular substance, is used in vitamin analysis, chromatography, antibiotic processing: Simons, US 2393625 (1946 to Floridin).
Therap-Cat: Trisilicate as antacid.
Therap-Cat-Vet: Trisilicate as antacid; gastric sedative.