Barium carbonate

Barium carbonate

Names
Other names Witherite
Identifiers
CAS Number	513-77-9 Y
3D model (Jmol)	Interactive image Interactive image
ChemSpider	10121 Y
ECHA InfoCard	100.007.426
EC Number	208-167-3
PubChem	10563
RTECS number	CQ8600000
UNII	6P669D8HQ8 Y
UN number	1564
InChI InChI=1S/CH2O3.Ba/c2-1(3)4;/h(H2,2,3,4);/q;+2/p-2 Y Key: AYJRCSIUFZENHW-UHFFFAOYSA-L Y InChI=1/CH2O3.Ba/c2-1(3)4;/h(H2,2,3,4);/q;+2/p-2 Key: AYJRCSIUFZENHW-NUQVWONBAT
SMILES [Ba+2].[O-]C([O-])=O C(=O)([O-])[O-].[Ba+2]
Properties
Chemical formula	BaCO3
Molar mass	197.34 g/mol
Appearance	white crystals
Odor	odorless
Density	4.286 g/cm3
Melting point	811 °C (1,492 °F; 1,084 K) polymorphic transformation
Boiling point	1,450 °C (2,640 °F; 1,720 K) decomposes from 1360 °C
Solubility in water	16 mg/L (8.8°C) 22 mg/L (18 °C) 24 mg/L (20 °C) 24 mg/L (24.2 °C)
Solubility product (Ksp)	2.58·10−9
Solubility	decomposes in acid insoluble in ethanol
Magnetic susceptibility (χ)	-58.9·10−6 cm3/mol
Refractive index (nD)	1.676
Thermochemistry
Specific heat capacity (C)	85.35 J/mol·K
Std molar entropy (So298)	112 J/mol·K
Std enthalpy of formation (ΔfHo298)	-1219 kJ/mol
Gibbs free energy (ΔfG˚)	-1139 kJ/mol
Hazards
Safety data sheet	ICSC 0777
GHS pictograms
GHS signal word	Warning
GHS hazard statements	H302
EU classification (DSD)	Xn
R-phrases	R22
S-phrases	(S2), S24/25
NFPA 704	0 2 1
Flash point	Non-flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose)	418 mg/kg, oral (rat)
Related compounds
Other cations	Magnesium carbonate Calcium carbonate Strontium carbonate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
N  (what is YN ?)
Infobox references

Barium carbonate (BaCO₃), also known as witherite, is a chemical compound used in rat poison, bricks, ceramic glazes and cement.

Witherite crystallizes in the orthorhombic system. The crystals are invariably twinned together in groups of three, giving rise to pseudo-hexagonal forms somewhat resembling bipyramidal crystals of quartz, the faces are usually rough and striated horizontally. It transforms into an hexagonal phase at 1084 K that changes into a cubic phase at 1254 K.

The mineral is named after William Withering, who in 1784 recognized it to be chemically distinct from barytes. It occurs in veins of lead ore at Hexham in Northumberland, Alston in Cumbria, Anglezarke, near Chorley in Lancashire and a few other localities. Witherite is readily altered to barium sulfate by the action of water containing calcium sulfate in solution and crystals are therefore frequently encrusted with barytes. It is the chief source of barium salts and is mined in considerable amounts in Northumberland. It is used for the preparation of rat poison, in the manufacture of glass and porcelain, and formerly for refining sugar. It is also used for controlling the chromate to sulfate ratio in chromium electroplating baths.