Calcium chromate

Structural formula
General
Surname	Calcium chromate
other names	Pigment yellow 33; Calcium chrome yellow; Steinbühl's yellow; Calcium chromate;
Molecular formula	CaCrO 4
Brief description	yellow powder or crystals
External identifiers / databases
EC number	237-366-8
ECHA InfoCard	100,033,955
PubChem	26264
Wikidata	Q905723
properties
Molar mass	156.07 g mol −1
Physical state	firmly
density	3.12 g cm −3
Melting point	1020 ° C (decomposition)
solubility	little in water; practically insoluble in ethanol;
safety instructions
H and P phrases	H: 350-302-410
	P: ?
	As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

Calcium chromate is a chemical compound from the group of chromates with the empirical formula CaCrO ₄ . It is in the form of a yellow crystalline powder, the color of which depends on the water of crystallization. It is usually in the form of a dihydrate .

properties

Calcium chromate is a strong oxidizing agent ; it reacts violently with reducing agents such as B. boron , metals and organic substances. As an anhydrate it is poorly soluble, but as a dihydrate it is soluble in water.

Calcium chromate crystallizes tetragonally in the zirconium type. Here, distorted CrO readily form ₄ - tetrahedra , which are isolated from each other, but edge-sharing between chains CaO ₈ - dodecahedron connect. Gaps in the crystal structure that can be occupied by water molecules remain free.

use

Calcium chromate is used as a pigment, anti-corrosion agent and as a depolarizer in batteries.

safety instructions

Calcium chromate is classified as a category 2 carcinogen.

Individual evidence

↑ ^a ^b ^c ^d Entry on calcium chromate in the GESTIS substance database of the IFA , accessed on February 21, 2017(JavaScript required) .
^ ^A ^b William M. Haynes: CRC Handbook of Chemistry and Physics, 97th Edition . CRC Press, 2016, ISBN 978-1-4987-5429-3 , pp. 105 ( limited preview in Google Book search).
↑ Entry on calcium chromate in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on December 15, 2019. Manufacturers or distributors can expand the harmonized classification and labeling .
↑ Gabriele Weber, Klaus-Jürgen Range: The crystal structure of calcium chromate (VI), CaCrO ₄ / The Crystal Structure of calcium chromate (VI), CaCrO ₄ . In: Zeitschrift für Naturforschung B. 51, 1996, p. 751, doi : 10.1515 / znb-1996-0523 .
^ Department of Health - Testing Status of Agents at NTP: Calcium chromate 10827-V , accessed November 18, 2014.

[GESTIS-1] Entry on calcium chromate in the GESTIS substance database of the IFA , accessed on February 21, 2017(JavaScript required) .

[William_M._Haynes-2] A ^b William M. Haynes: CRC Handbook of Chemistry and Physics, 97th Edition . CRC Press, 2016, ISBN 978-1-4987-5429-3 , pp. 105 ( limited preview in Google Book search).

[CLP_100.033.955-3] Entry on calcium chromate in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on December 15, 2019. Manufacturers or distributors can expand the harmonized classification and labeling .

[Weber-4] Gabriele Weber, Klaus-Jürgen Range: The crystal structure of calcium chromate (VI), CaCrO ₄ / The Crystal Structure of calcium chromate (VI), CaCrO ₄ . In: Zeitschrift für Naturforschung B. 51, 1996, p. 751, doi : 10.1515 / znb-1996-0523 .

[5] Department of Health - Testing Status of Agents at NTP: Calcium chromate 10827-V , accessed November 18, 2014.