ChemIDPlus/HSDB 14807-96-6 Chemical - National Toxicology Program

CAS Registry Number: 14807-96-6 (Talc)

http://ntp.niehs.nih.gov/go/23927

Selected information from two of the National Library of Medicine's databases: ChemIDPlus¹ and HSDB².

Structure

Chemical Structure for CAS Registry Number 14807-96-6 from NLM

Chemical Properties²

Property	Description
Color/Form	White to grayish-white, very fine crystalline powder Apple-green powder; luster pearly or greasy; feel greasy White powder. A layered, hydrated magnesium silicate Mono- or triclinic ... Pale-green to dark-green or greenish-gray; also white, silvery-white, grey, brownish; translucent; pearly, greasy or dull ... Commonly thin tabular crystals, up to 1 cm in width. Usually massive, fine-grained, compact; also as foliated or fibrous masses or in globular stellate groups
Odor	Odorless.
Taste	Tasteless
Boiling Point	None found
Melting Point	None found
Molecular Weight	Varies
Corrosivity	None found
Critical Temperature & Pressure	None found
Density/Specific Gravity	2.58-3.83
Disassociation Constants	None found
Heat of Combustion	None found
Heat of Vaporization	None found
log P (octanol-water)	None found
pH	None found
Solubilities	Insol in water, cold acids or in alkalies Sparingly soluble in acetone, slightly soluble in methanol and isopropyl acetate, very slightly soluble in ethanol, practically insoluble in octanol, and insoluble in water.
Spectral Properties	Index of refraction = 1.58
Surface Tension	None found
Vapor Density	None found
Vapor Pressure	None found
Relative Evaporation Rate	None found
Viscosity	None found
Other Properties	Unctuous, and adheres readily to the skin. Mohs hardness 1-1.5 (may be harder when impure) Crystals of talc are made up of stacks of ... double-sheet units held together by the weakest of chemical bonds - the Van der Waal's forces. ... they can be separated by slight forces, causing slippage of the individual sheets along a perfect cleavage direction in the basal plane. Relatively inert and nonreactive with conventional acids and bases. ... talc has Lewis acid sites on its surface and at elevated temperatures is a mild catalyst for oxidation, depolymerization, and cross-liking of polymers. ... Thermally stable up to 930 deg C, and loses its crystalline bound water (4.8%) between 930 and 970 deg C, leaving an enstatite (dehydrated magnesium silicate residue). Talc products are also characterized by their crystallinity or relative platiness. ... pH in water of 9.0 to 9.5 ... has Lewis acid sites on its surface and at elevated temperatures is a mild catalyst for oxidation, depolymerization, and cross-linking of polymers. Talc is used commercially because of its fragrance retention, luster, purity, softness, and whiteness. Other commercially important properties of talc are its chemical inertness, high dielectric strength, high thermal conductivity, low electrical conductivity, and oil and grease adsorption. Contains less than 1% crystalline silica

Uses²

Additive to clay in ceramic manufacture and paper coatings, for roofing materials. **PEER REVIEWED**
Carrier and diluent for insecticides; filler and pigment for paints and elastomers; additive in manufacture of refractories. **PEER REVIEWED**
Ceramics; cosmetics and pharmaceuticals; filler in rubber, paints, putty, plaster, oilcloth; abherent; slate pencils and crayons
Dusting powder, either alone or with starch or boric acid, for medicinal and toilet preparations; excipient and filler for pills, tablets and for dusting tablet molds; clarifying liquids by filtration. As pigment in paints, varnishes, rubber; filler for paper, rubber, soap; in fireproof and cold-water paints for wood, metal and stone; lubricating molds and machinery; glove and shoe powder; electric and heat insulator.
VET: Topically on vulva fold pyodermas of dogs as protectant.

Superlist Classes¹

Ceiling 20 mppcf;
Overall Carcinogenic Evaluation: Group 3
TWA 2 mg/m3; (Inhalable particulate matter containing no asbestos and < 1% crystalline silica); Not classifiable as a human carcinogen