Sodium chromate

Sodium chromate
Names
	IUPAC name Sodium chromate
	Other names Chromic acid, (Na2CrO4), disodium salt; Chromium disodium oxide; Rachromate
Identifiers
CAS Number	7775-11-3 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:78671 ;
ChemSpider	22896;
ECHA InfoCard	100.028.990
EC Number	231-889-5;
PubChem CID	24488;
RTECS number	GB2955000;
UNII	6A49BO6K4M ;
UN number	3288
CompTox Dashboard (EPA)	DTXSID7032056 ;
	InChI InChI=1S/Cr.2Na.4O/q;2+1;;;2-1;
	SMILES [O-][Cr](=O)(=O)[O-].[Na+].[Na+];
Properties
Chemical formula	Na2CrO4
Molar mass	161.97 g/mol
Appearance	yellow crystals
Odor	odorless
Density	2.698 g/cm3
Melting point	792 °C (1,458 °F; 1,065 K) (anhydrous) ; 20 °C (decahydrate)
Solubility in water	31.8 g/100 mL (0 °C) ; 84.5 g/100 mL (25 °C) ; 126.7 g/100 mL (100 °C)
Solubility	slightly soluble in ethanol
Solubility in methanol	0.344 g/100 mL (25 °C)
Magnetic susceptibility (χ)	+55.0·10−6 cm3/mol
Structure
Crystal structure	orthorhombic (hexagonal above 413 °C)
Thermochemistry
Heat capacity (C)	142.1 J/mol K
Std molar; entropy (S⦵298)	174.5 J/mol K
Std enthalpy of; formation (ΔfH⦵298)	−1329 kJ/mol
Gibbs free energy (ΔfG⦵)	-1232 kJ/mol
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H301, H312, H314, H317, H330, H334, H340, H350, H360, H372, H410
Precautionary statements	P201, P202, P260, P261, P264, P270, P271, P272, P273, P280, P281, P284, P285, P301+P310, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P304+P341, P305+P351+P338, P308+P313, P310, P312, P314, P320, P321, P322, P330, P333+P313, P342+P311, P363, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)	3 0 OX
Flash point	Non-flammable
Safety data sheet (SDS)	ICSC 1370
Related compounds
Other anions	Sodium dichromate; Sodium molybdate; Sodium tungstate
Other cations	Potassium chromate; Calcium chromate; Barium chromate
	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

Sodium chromate is the inorganic compound with the formula Na₂CrO₄. It exists as a yellow hygroscopic solid, which can form tetra-, hexa-, and decahydrates. It is an intermediate in the extraction of chromium from its ores.

Names


IUPAC name Sodium chromate
Other names Chromic acid, (Na₂CrO₄), disodium salt Chromium disodium oxide Rachromate
Identifiers
CAS Number	7775-11-3^Y
3D model (JSmol)	Interactive image
ChEBI	CHEBI:78671^Y
ChemSpider	22896
ECHA InfoCard	100.028.990
EC Number	231-889-5
PubChem CID	24488
RTECS number	GB2955000
UNII	6A49BO6K4M^Y
UN number	3288
CompTox Dashboard (EPA)	DTXSID7032056
InChI InChI=1S/Cr.2Na.4O/q;2+1;;;2-1
SMILES [O-][Cr](=O)(=O)[O-].[Na+].[Na+]
Properties
Chemical formula	Na₂CrO₄
Molar mass	161.97 g/mol
Appearance	yellow crystals
Odor	odorless
Density	2.698 g/cm³
Melting point	792 °C (1,458 °F; 1,065 K) (anhydrous) 20 °C (decahydrate)
Solubility in water	31.8 g/100 mL (0 °C) 84.5 g/100 mL (25 °C) 126.7 g/100 mL (100 °C)
Solubility	slightly soluble in ethanol
Solubility in methanol	0.344 g/100 mL (25 °C)
Magnetic susceptibility (χ)	+55.0·10⁻⁶ cm³/mol
Structure
Crystal structure	orthorhombic (hexagonal above 413 °C)
Thermochemistry
Heat capacity (C)	142.1 J/mol K
Std molar entropy (S^⦵₂₉₈)	174.5 J/mol K
Std enthalpy of formation (Δ_fH^⦵₂₉₈)	−1329 kJ/mol
Gibbs free energy (Δ_fG^⦵)	-1232 kJ/mol
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H301, H312, H314, H317, H330, H334, H340, H350, H360, H372, H410
Precautionary statements	P201, P202, P260, P261, P264, P270, P271, P272, P273, P280, P281, P284, P285, P301+P310, P301+P330+P331, P302+P352, P303+P361+P353, P304+P340, P304+P341, P305+P351+P338, P308+P313, P310, P312, P314, P320, P321, P322, P330, P333+P313, P342+P311, P363, P391, P403+P233, P405, P501
NFPA 704 (fire diamond)	3 0 OX
Flash point	Non-flammable
Safety data sheet (SDS)	ICSC 1370
Related compounds
Other anions	Sodium dichromate Sodium molybdate Sodium tungstate
Other cations	Potassium chromate Calcium chromate Barium chromate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is ^YN ?) Infobox references