5687. Magnesium Silicates

Description and references

Several varieties of magnesium silicate are known. See also asbestos, talc.

Derivative

Magnesium metasilicate.

Nomenclature

CAS number: 13776-74-4
MgSiO3; mol wt 100.39.
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.

Derivative

Magnesium orthosilicate.

Nomenclature

CAS number: 10034-94-3
Mg2SiO4; mol wt 140.69.
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.

Derivative

Magnesium trisilicate.

Nomenclature

CAS number: 14987-04-3
Magnesium mesotrisilicate; Magnosil (Polfa); Petimin; Trisomin (Lilly).
Mg2Si3O8; mol wt 260.86.
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

Magnesium trisilicate pentahydrate.

Nomenclature

Sellagen.

Derivative

Serpentine (mineral).
Mg3O7Si2; mol wt 241.08.
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).

Therapeutic Category

Trisilicate as antacid.

Therapeutic Category (Veterinary)

Trisilicate as antacid; gastric sedative.

Keywords

Antacid