8579. Sodium Arsenate, Dibasic

Nomenclature

CAS number: 7778-43-0
Arsenic acid (H3AsO4) sodium salt (1:2); disodium arsenate.
AsHNa2O4; mol wt 185.91.
As 40.30%, H 0.54%, Na 24.73%, O 34.42%.
Na2HAsO4.

Description and references

Toxicity study: Franke, Moxon, J. Pharmacol. Exp. Ther. 58, 454 (1936). Review of toxicology and human exposure: Toxicological Profile for Arsenic (PB2000-108021, 2000) 468 pp.

Properties

Powder. Poisonous. Very sol in water; slightly sol in alcohol.

Derivative

Heptahydrate.

Nomenclature

CAS number: 10048-95-0
AsHNa2O4.7H2O; mol wt 312.01.
As 24.01%, H 4.85%, Na 14.74%, O 56.41%.

Properties

Odorless crystals; effloresces in warm air. Poisonous, but less so than the arsenite. Loses 5 H2O (29%) at about 50°; becomes anhydr at 100°. At 150° or higher it is converted into pyroarsenate. d 1.87. mp 57° when rapidly heated. Sol in 1.3 parts water; sol in glycerol, slightly in alcohol. The aq soln is alkaline to litmus. LD75 i.p. in rats: 14-18 mg As/kg (Franke, Moxon).

Use

The technical grade, about 98% pure, is used in dyeing with Turkey-red oil and in printing fabrics; manuf of other arsenates. Source of soluble arsenic.