Chromium(III) hydroxide

Chromium(III) hydroxide
Names
	IUPAC name Chromium(3+) hydroxide
Identifiers
CAS Number	1308-14-1 ;
3D model (JSmol)	ionic form: Interactive image; coordination form: Interactive image;
ChemSpider	145861;
ECHA InfoCard	100.013.781
PubChem CID	166720;
RTECS number	GB2670000;
UNII	DX3N9U5Q97 ;
CompTox Dashboard (EPA)	DTXSID0051651 ;
	InChI InChI=1S/Cr.3H2O/h;3*1H2 Key: LXMQZGGLHVSEBA-UHFFFAOYSA-N;
	SMILES ionic form: [OH-].[OH-].[OH-].[Cr+++]; coordination form: O[Cr](O)O;
Properties
Chemical formula	Cr(OH)3
Molar mass	103.017 g·mol−1
Appearance	green, gelatinous precipitate
Density	3.11 g/cm3
Solubility in water	insoluble
Hazards
	NIOSH (US health exposure limits):
PEL (Permissible)	TWA 1 mg/m3
REL (Recommended)	TWA 0.5 mg/m3
IDLH (Immediate danger)	250 mg/m3
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Chromium(III) hydroxide is a gelatinous green inorganic compound with the chemical formula Cr(OH)₃. It is a polymer with an undefined structure and low solubility. It is amphoteric, dissolving in both strong alkalis and strong acids.

Preparation

Chromium(III) hydroxide is prepared by treating an aqueous solution of hydrated chromium trichloride with ammonia.

It can also be prepared by treating an aqueous solution of chromium(III) nitrate with potassium hydroxide until the pH is within 7 to 8: The following idealized equation suffices:

Cr(NO₃)₃ + 3 KOH → Cr(OH)₃ + 3 KNO₃

Use

It is used as a pigment, as a mordant, and as a catalyst for organic reactions.

Natural occurrence

Three chromium(III) oxide hydroxide (CrO(OH)) minerals are known: bracewellite, grimaldiite and guyanaite.

References

1 2 3 "#0141". NIOSH Pocket Guide to Chemical Hazards. National Institute for Occupational Safety and Health.
↑ Rai, Dhanpat; Sass, Bruce M.; Moore, Dean A. "Chromium(III) hydrolysis constants and solubility of chromium(III) hydroxide" Inorganic Chemistry 1987, volume 26, pp. 345-9. doi:10.1021/ic00250a002
↑ F. Hein and S. Herzog (1963). "Chromium, Molybdenum, Tungsten, Uranium". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 2. NY, NY: Academic Press. p. 1345.
↑ Papassiopi, N.; Vaxevanidou, K.; Christou, C.; Karagianni, E.; Antipas, G. S. E. (2014-01-15). "Synthesis, characterization and stability of Cr(III) and Fe(III) hydroxides". Journal of Hazardous Materials. 264: 490–497. doi:10.1016/j.jhazmat.2013.09.058. ISSN 0304-3894.
↑ Holleman, Arnold F.; Wiberg, Egon; Wiberg, Nils (1985). "Chromium". Lehrbuch der Anorganischen Chemie (in German) (91–100 ed.). Walter de Gruyter. pp. 1081–1095. ISBN 3-11-007511-3.
↑ "Bracewellite".
↑ "Grimaldiite".
↑ "Guyanaite".
↑ "List of Minerals". 21 March 2011.

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[PGCH-1] 1 2 3 "#0141". NIOSH Pocket Guide to Chemical Hazards. National Institute for Occupational Safety and Health.

[2] Rai, Dhanpat; Sass, Bruce M.; Moore, Dean A. "Chromium(III) hydrolysis constants and solubility of chromium(III) hydroxide" Inorganic Chemistry 1987, volume 26, pp. 345-9. doi:10.1021/ic00250a002

[3] F. Hein and S. Herzog (1963). "Chromium, Molybdenum, Tungsten, Uranium". In G. Brauer (ed.). Handbook of Preparative Inorganic Chemistry, 2nd Ed. Vol. 2. NY, NY: Academic Press. p. 1345.

[4] Papassiopi, N.; Vaxevanidou, K.; Christou, C.; Karagianni, E.; Antipas, G. S. E. (2014-01-15). "Synthesis, characterization and stability of Cr(III) and Fe(III) hydroxides". Journal of Hazardous Materials. 264: 490–497. doi:10.1016/j.jhazmat.2013.09.058. ISSN 0304-3894.

[HollemanAF-5] Holleman, Arnold F.; Wiberg, Egon; Wiberg, Nils (1985). "Chromium". Lehrbuch der Anorganischen Chemie (in German) (91–100 ed.). Walter de Gruyter. pp. 1081–1095. ISBN 3-11-007511-3.

[6] "Bracewellite".

[7] "Grimaldiite".

[8] "Guyanaite".

[9] "List of Minerals". 21 March 2011.