Barium carbonate

Names
Other names Witherite
Identifiers
CAS Number	513-77-9 Y
3D model (JSmol)	Interactive image Interactive image
ChEBI	CHEBI:190439
ChemSpider	10121 Y
ECHA InfoCard	100.007.426
EC Number	208-167-3
PubChem CID	10563
RTECS number	CQ8600000
UNII	6P669D8HQ8 Y
UN number	1564
CompTox Dashboard (EPA)	DTXSID1029623
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[1] 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)[1]
Solubility product (Ksp)	2.58·10−9
Solubility	decomposes in acid insoluble in methanol
Magnetic susceptibility (χ)	-58.9·10−6 cm3/mol
Refractive index (nD)	1.676
Structure
Crystal structure	orthorhombic
Thermochemistry
Heat capacity (C)	85.35 J/mol·K[1]
Std molar entropy (S⦵298)	112 J/mol·K[2]
Std enthalpy of formation (ΔfH⦵298)	-1219 kJ/mol[2]
Gibbs free energy (ΔfG⦵)	-1139 kJ/mol[1]
Hazards
GHS labelling:
Pictograms	[3]
Signal word	Warning
Hazard statements	H302[3]
NFPA 704 (fire diamond)	[4] 2 0 0
Flash point	Non-flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose)	418 mg/kg, oral (rat)
Safety data sheet (SDS)	ICSC 0777
Related compounds
Other cations	Beryllium carbonate Magnesium carbonate Calcium carbonate Strontium carbonate Radium carbonate
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

Barium carbonate is the inorganic compound with the formula BaCO₃. Like most alkaline earth metal carbonates, it is a white salt that is poorly soluble in water. It occurs as the mineral known as witherite. In a commercial sense, it is one of the most important barium compounds.^[5]

Preparation

Barium carbonate is made commercially from barium sulfide by treatment with sodium carbonate at 60 to 70 °C (soda ash method) or, more commonly carbon dioxide at 40 to 90 °C:

In the soda ash process, an aqueous solution of barium sulfide is treated with sodium carbonate:^[5]

BaS + H₂O + CO₂ → BaCO₃ + H₂S

Reactions

Barium carbonate reacts with acids such as hydrochloric acid to form soluble barium salts, such as barium chloride:

BaCO
₃ + 2 HCl → BaCl
₂ + CO
₂ + H
₂O

Pyrolysis of barium carbonate gives barium oxide.^[6]

Uses

It is mainly used to remove sulfate impurities from feedstock of the chlor-alkali process. Otherwise it is a common precursor to barium-containing compounds such as ferrites.^[5]

Other uses

Barium carbonate is widely used in the ceramics industry as an ingredient in glazes. It acts as a flux, a matting and crystallizing agent and combines with certain colouring oxides to produce unique colours not easily attainable by other means. Its use is somewhat controversial since it can leach from glazes into food and drink. To reduce toxicity concerns, it is often substituted with strontium carbonate, which behaves in a similar way in glazes but is of lower toxicity.

In the brick, tile, earthenware and pottery industries barium carbonate is added to clays to precipitate soluble salts (calcium sulfate and magnesium sulfate) that cause efflorescence.