Magnesium carbonate

Magnesium carbonate
Names
	Other names Magnesite; Barringtonite (dihydrate); Nesequehonite (trihydrate); Lansfordite (pentahydrate)
Identifiers
CAS Number	546-93-0 (anhydrous) ; 17968-26-2 (monohydrate) ; 5145-48-2 (dihydrate) ; 14457-83-1 (trihydrate) ; 61042-72-6 (pentahydrate) ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:31793 ;
ChEMBL	ChEMBL1200736 ;
ChemSpider	10563 ;
ECHA InfoCard	100.008.106
E number	E504(i) (acidity regulators, ...)
PubChem CID	11029;
RTECS number	OM2470000;
UNII	0IHC698356 ; 0E53J927NA (monohydrate) ;
CompTox Dashboard (EPA)	DTXSID4049660 ;
	InChI InChI=1S/CH2O3.Mg/c2-1(3)4;/h(H2,2,3,4);/q;+2/p-2 Key: ZLNQQNXFFQJAID-UHFFFAOYSA-L ; InChI=1/CH2O3.Mg/c2-1(3)4;/h(H2,2,3,4);/q;+2/p-2 Key: ZLNQQNXFFQJAID-NUQVWONBAU;
	SMILES [Mg+2].[O-]C([O-])=O;
Properties
Chemical formula	MgCO3
Molar mass	84.3139 g/mol (anhydrous)
Appearance	Colourless crystals or white solid; Hygroscopic
Odor	Odorless
Density	2.958 g/cm3 (anhydrous) ; 2.825 g/cm3 (dihydrate) ; 1.837 g/cm3 (trihydrate) ; 1.73 g/cm3 (pentahydrate)
Melting point	350 °C (662 °F; 623 K) ; decomposes (anhydrous); 165 °C (329 °F; 438 K); (trihydrate)
Solubility in water	Anhydrous:; 0.0139 g/100 ml (25 °C); 0.0063 g/100 ml (100 °C)
Solubility product (Ksp)	10−7.8
Solubility	Soluble in acid, aqueous CO2 ; Insoluble in acetone, ammonia
Magnetic susceptibility (χ)	−32.4·10−6 cm3/mol
Refractive index (nD)	1.717 (anhydrous); 1.458 (dihydrate); 1.412 (trihydrate)
Structure
Crystal structure	Trigonal
Space group	R3c, No. 167
Thermochemistry
Heat capacity (C)	75.6 J/mol·K
Std molar; entropy (S⦵298)	65.7 J/mol·K
Std enthalpy of; formation (ΔfH⦵298)	−1113 kJ/mol
Gibbs free energy (ΔfG⦵)	−1029.3 kJ/mol
Pharmacology
ATC code	A02AA01 (WHO) A06AD01 (WHO)
Hazards
NFPA 704 (fire diamond)	1 0 0
Flash point	Non-flammable
	NIOSH (US health exposure limits):
PEL (Permissible)	TWA 15 mg/m3 (total); TWA 5 mg/m3 (resp);
Safety data sheet (SDS)	ICSC 0969
Related compounds
Other anions	Magnesium bicarbonate
Other cations	Beryllium carbonate; Calcium carbonate; Strontium carbonate; Barium carbonate; Radium carbonate
Related compounds	Artinite; Hydromagnesite; Dypingite
	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

Magnesium carbonate, Mg CO₃ (archaic name magnesia alba), is an inorganic salt that is a colourless or white solid. Several hydrated and basic forms of magnesium carbonate also exist as minerals.