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.^[2]

Preparation

Chromium(III) hydroxide is prepared by treating an aqueous solution of hydrated chromium trichloride with ammonia.^[3]

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:^[4] The following idealize 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.^[5]

Natural occurrence

Three chromium(III) oxide hydroxide (CrO(OH)) minerals are known: bracewellite, grimaldiite and guyanaite.^[6]^[7]^[8]^[9]

References

^ ^a ^b ^c NIOSH Pocket Guide to Chemical Hazards. "#0141". National Institute for Occupational Safety and Health (NIOSH).
^ 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.

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

[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.

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