Chromium(III) oxide

Chromium(III) oxide
Names
	Other names Chromium sesquioxide; Chromia; Chrome green; Eskolaite
Identifiers
CAS Number	1308-38-9 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:48242 ;
ChemSpider	451305 ;
ECHA InfoCard	100.013.783
EC Number	215-160-9;
Gmelin Reference	11116
PubChem CID	517277;
RTECS number	GB6475000;
UNII	X5Z09SU859 ;
UN number	3077
CompTox Dashboard (EPA)	DTXSID4043721 ;
	InChI InChI=1S/2Cr.3O Key: QDOXWKRWXJOMAK-UHFFFAOYSA-N ; InChI=1/2Cr.3O/rCr2O3/c3-1-5-2-4 Key: QDOXWKRWXJOMAK-LUXALHLMAR;
	SMILES O=[Cr]O[Cr]=O;
Properties
Chemical formula	Cr2O3
Molar mass	151.9904 g/mol
Appearance	light to dark green, fine crystals
Density	5.22 g/cm3
Melting point	2,435 °C (4,415 °F; 2,708 K)
Boiling point	4,000 °C (7,230 °F; 4,270 K)
Solubility in water	insoluble
Solubility in alcohol	insoluble in alcohol, acetone, acids
Magnetic susceptibility (χ)	+1960.0×10−6 cm3/mol
Refractive index (nD)	2.551
Structure
Crystal structure	Corundum
Space group	R3c (No. 167)
Lattice constant	a = 495 pm, c = 1358 pm
Thermochemistry
Std molar; entropy (S⦵298)	81 J·mol−1·K−1
Std enthalpy of; formation (ΔfH⦵298)	−1128 kJ·mol−1
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H317, H319, H360
Precautionary statements	P201, P202, P261, P264, P270, P272, P280, P281, P301+P312, P302+P352, P305+P351+P338, P308+P313, P321, P330, P333+P313, P337+P313, P363, P405, P501
	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). verify (what is ?) Infobox references

Chromium(III) oxide (or chromia) is an inorganic compound with the formula Cr
₂O
₃. It is one of the principal oxides of chromium and is used as a pigment. In nature, it occurs as the rare mineral eskolaite.

^ Abdullah, M. M.; Rajab, Fahd M.; Al-Abbas, Saleh M. (2014). "Structural and optical characterization of Cr2O3 nanostructures: Evaluation of its dielectric properties". AIP Advances. 4 (2). AIP Publishing: 027121. Bibcode:2014AIPA....4b7121A. doi:10.1063/1.4867012. ISSN 2158-3226.
^ ^a ^b ^c NIOSH Pocket Guide to Chemical Hazards. "#0141". National Institute for Occupational Safety and Health (NIOSH).

[1] Abdullah, M. M.; Rajab, Fahd M.; Al-Abbas, Saleh M. (2014). "Structural and optical characterization of Cr2O3 nanostructures: Evaluation of its dielectric properties". AIP Advances. 4 (2). AIP Publishing: 027121. Bibcode:2014AIPA....4b7121A. doi:10.1063/1.4867012. ISSN 2158-3226.

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

[1]

[2]

Names


Other names Chromium sesquioxide Chromia Chrome green Eskolaite
Identifiers
CAS Number	1308-38-9^Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:48242^Y
ChemSpider	451305^Y
ECHA InfoCard	100.013.783
EC Number	215-160-9
Gmelin Reference	11116
PubChem CID	517277
RTECS number	GB6475000
UNII	X5Z09SU859^Y
UN number	3077
CompTox Dashboard (EPA)	DTXSID4043721
InChI InChI=1S/2Cr.3O^Y Key: QDOXWKRWXJOMAK-UHFFFAOYSA-N^Y InChI=1/2Cr.3O/rCr2O3/c3-1-5-2-4 Key: QDOXWKRWXJOMAK-LUXALHLMAR
SMILES O=[Cr]O[Cr]=O
Properties
Chemical formula	Cr₂O₃
Molar mass	151.9904 g/mol
Appearance	light to dark green, fine crystals
Density	5.22 g/cm³
Melting point	2,435 °C (4,415 °F; 2,708 K)
Boiling point	4,000 °C (7,230 °F; 4,270 K)
Solubility in water	insoluble
Solubility in alcohol	insoluble in alcohol, acetone, acids
Magnetic susceptibility (χ)	+1960.0×10⁻⁶ cm³/mol
Refractive index (n_D)	2.551
Structure^[1]
Crystal structure	Corundum
Space group	R3c (No. 167)
Lattice constant	a = 495 pm, c = 1358 pm
Thermochemistry
Std molar entropy (S^⦵₂₉₈)	81 J·mol⁻¹·K⁻¹
Std enthalpy of formation (Δ_fH^⦵₂₉₈)	−1128 kJ·mol⁻¹
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H317, H319, H360
Precautionary statements	P201, P202, P261, P264, P270, P272, P280, P281, P301+P312, P302+P352, P305+P351+P338, P308+P313, P321, P330, P333+P313, P337+P313, P363, P405, P501
NIOSH (US health exposure limits):
PEL (Permissible)	TWA 1 mg/m³^[2]
REL (Recommended)	TWA 0.5 mg/m³^[2]
IDLH (Immediate danger)	250 mg/m³^[2]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Y verify (what is ^YN ?) Infobox references