Barium carbonate

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Barium carbonate
Barium carbonate sample on watch glass.jpg
Sample of barium carbonate
Names
IUPAC name
Barium carbonate
Other names
Witherite
Properties
BaCO3
Molar mass 197.34 g/mol
Appearance White solid
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)
0.0016 g/100 ml (8.8 °C)
0.0022 g/100 ml (18 °C)
0.0024 g/100 ml (20 °C)
0.0024 g/100 ml (24.2 °C)
Solubility Reacts with acids
Insoluble in organic solvents
Vapor pressure ~0 mmHg
Thermochemistry
112 kJ/mol
-1,219 kJ/mol
Hazards
Safety data sheet Sigma-Aldrich
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
418 mg/kg (rat, oral)
Related compounds
Related compounds
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).
Infobox references

Barium carbonate is an insoluble barium salt of carbonic acid with the formula BaCO3, even less soluble than barium sulfate. Unlike BaSO4, barium carbonate reacts with acids and can serve as precursor to any barium salt.

Properties

Chemical

Heat causes it to decompose, liberating carbon dioxide and turning into the oxide BaO.

BaCO3 → BaO + CO2

It reacts with all acids, resulting in barium salts and carbon dioxide. This makes it a useful precursor to all barium compounds.

BaCO3 + HX → BaX2 + H2O + CO2

Physical

Barium carbonate is a white chalk-like powder, insoluble in water and virtually all solvents, though it dissolves in acids, releasing carbon dioxide.

When heated to 811 °C, it undergoes polymorphic transformation and starting from 1,360-1,450 °C it decomposes to release carbon dioxide. Barium carbonate is quite dense, 4.286 g/cm3

Availability

Barium carbonate is sold by chemical suppliers. Some rat poisons may contain barium carbonate.

Occasionally, pottery stores may sell barium carbonate.

It also occurs naturally as the mineral witherite.

Preparation

Barium carbonate is prepared from barium sulfate by lengthy boiling under reflux with sodium carbonate. This reaction is sometimes called the Curie reaction, because Marie Curie prepared radium carbonate the same way.

BaSO4 + Na2CO3 → BaCO3 + Na2SO4

The reaction is very slow and takes a long time to completion.

Projects

Handling

Safety

Barium carbonate is safe to handle, unless ingested. Upon ingestion, it is acutely poisonous, as it reacts with gastric acid to form barium chloride which is soluble in water. In the event of accidental ingestion, immediately consume a soluble sulfate solution, like aqueous magnesium sulfate.

Storage

It can be stored anywhere and in anything. But places that may have acidic vapors are best avoided.

Disposal

To neutralize barium carbonate, use sulfuric acid. The resulting inert barium sulfate can be dumped anywhere.

References

Relevant Sciencemadness threads