Agent Name

Sodium metasilicate nonahydrate

CAS Number




Major Category



Silicic acid (H2SiO3), disodium salt, nonahydrate; [ChemIDplus] Disodium metasilicate nonahydrate; [Sigma-Aldrich MSDS] UN3253


Metals, Inorganic Compounds


Efflorescent solid; [Merck Index] Hygroscopic solid; [Sigma-Aldrich MSDS]


Used as a starting material for zeolites and silica catalysts, as an adhesive and binder, corrosion inhibitor, penetrating sealant, fireproofing agent (wood, paper, and fabric), detergent booster, and shell coating material to preserve eggs; Also used in cements, drilling fluids, and waste water treatment; [Merck Index] Alkali metal silicates are used as starting materials for products like silicas and zeolites, in detergents and cleaners, and pulp and paper production; Also used to a lesser extent in soil stabilization and sealing, adhesives and binders (construction materials, paperboard and cardboard, ceramic binders, refractories, welding rods, and foundry molds and cores), surface coatings (titanium dioxide production, paints for masonry and glass, and spray coatings for tunnel construction and mining), water treatment (corrosion protection), enhanced oil recovery, and textile processing (bleach and dye stabilizing); [Reference #1]


Corrosive to moistened rabbit skin; Sodium metasilicate was not sensitizing in a local lymph node assay study of mice; Similar uses and adverse effects are expected from the hydrous and anhydrous forms (Sodium metasilicate pentahydrate, Sodium metasilicate nonahydrate, Sodium metasilicate, Sodium silicate, and Potassium silicate). One case of occupational contact urticaria reported from sodium silicate; [Reference #1] Causes burns; Inhalation may cause corrosive injuries to upper respiratory tract; [Sigma-Aldrich MSDS] See "Sodium metasilicate."

Reference Link

OECD SIDS: Soluble Silicates - 2004

Exposure Assessment
Explanatory Notes

The Guide in the Emergency Response Guidebook is for "Disodium trioxosilicate."

Adverse Effects

Skin Burns

Links to Other NLM Databases
Toxicity Information


Chemical Information

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Related Information in HazMap

Industrial Processes with risk of exposure: