Nomenclature
CAS number: 7758-97-6
Chromic acid (H
2CrO
4) lead (2+) salt
(1:1); Chrome yellow; Cologne yellow; King's yellow; Leipzig yellow; Paris yellow; C.I. Pigment Yellow 34; lead chromium oxide (PbCrO
4); plumbous chromate; C.I. 77600.
CrO
4Pb; mol wt 323.19.
Cr 16.09%, O 19.80%, Pb 64.11%.
PbCrO
4.
Description and references
Occurs in nature as the minerals crocoite, phoenicochroite. Ref: Colour Index vol. 4 (3rd ed., 1971) p 4677. Evaluation of carcinogenic
risk: IARC Monographs 23, 205-324 (1980); ibid. 49, 49-256 (1990). Review of environmental exposure and bioavailability:
D. Waldron, Am. Ink Maker 72, 50-60 (1994); of toxicology and human exposure: Toxicological Profile for Lead (PB99-166704,
1999) 640 pp.
Properties
Yellow or orange-yellow powder. d 6.3. mp 844°. It is one of the most insol salts
(0.2 mg/l H2O). Insol in acetic acid. Sol in solns of
fixed alkali hydroxides, in dil HNO3.Caution
Chromium hexavalent compounds are
listed as known human carcinogens: Report
on Carcinogens, Eleventh Edition (PB2005-104914, 2004)
p III-63.Use
Pigment for paints and inks; in oil and water colors;
printing fabrics, decorating china and porcelain; in chemical analysis
of organic substances; in traffic paints.