Barium CarbonateEdit
Barium carbonate (BaCO3) is an inorganic salt of barium and carbonate that appears as a white, odorless solid. In industry and science it serves principally as a convenient formal source of Ba2+ for the synthesis of other barium compounds, and as a flux and opacifier in glassmaking and ceramics. In nature the mineral form is known as witherite, a primary natural source of BaCO3. Because it is relatively insoluble in water, BaCO3 tends to be less immediately reactive in environmental and biological contexts than many other barium salts, though dissolution in acidic environments can release toxic Ba2+ ions.
Chemical properties
- Composition and appearance: BaCO3 is a white crystalline solid that is insoluble in water under standard conditions.
- Solubility: The compound is sparingly soluble in water; its dissolution is markedly favored by acidic media, where BaCO3 reacts with protons to yield Ba2+ and CO2.
- Reactions: BaCO3 readily reacts with acids to give soluble barium salts, carbon dioxide, and water. For example, with a mineral acid the general reaction is BaCO3 + 2H+ → Ba2+ + CO2 + H2O.
- Thermal behavior: On heating to sufficiently high temperatures, BaCO3 decomposes to yield BaO and CO2.
- Stability and uses as a precursor: Because of its stability and ease of conversion to other barium species, BaCO3 is a common starting material for laboratory syntheses and industrial processes that require Ba2+.
Occurrence and production
- Natural occurrence: BaCO3 occurs as the mineral witherite, which is the natural form of barium carbonate.
- Industrial production: In industry, BaCO3 can be produced by processing baryte ore (BaSO4) and related materials to convert sulfate units into carbonate units, or by precipitating BaCO3 from solutions of soluble barium salts using carbonate sources. The carbonate form is a convenient intermediate for preparing BaO and Ba(OH)2, and for making a wide range of other barium salts used in electronics, pigments, and catalysis.
- Related materials: BaCO3 is often discussed alongside other inorganic carbonates and barium compounds such as Barite (BaSO4) as an important part of the wider family of barium chemistry, and alongside the mineral Witherite as its natural form.
Uses
- Glass and ceramics: BaCO3 functions as a flux and opacifier in glassmaking and ceramic glazes, helping to lower melting temperatures and influence optical properties.
- Precursor to other barium compounds: It is a convenient feedstock for producing BaO and Ba(OH)2, which in turn participate in a range of industrial applications, including metal finishing, stabilization, and certain chemical syntheses.
- Analytical and preparative chemistry: In qualitative and quantitative inorganic analysis, BaCO3 and related barium salts serve as sources of Ba2+ for precipitating sulfates or for standardization in various titrations and syntheses.
- Sulfate chemistry and imaging precursors: Although BaSO4 is the more famous barium compound used as a radiographic contrast agent, BaCO3 can be converted to BaSO4 or used in laboratories as a starting material for related barium salts employed in signaling or imaging contexts.
Safety and handling
- Toxicology: Insolubility in water offers some practical safety advantages, but soluble barium salts are highly toxic if ingested or inhaled. BaCO3 should be handled with standard laboratory safety practices to avoid inhalation of dust and accidental ingestion.
- Practical handling: BaCO3 dust is irritating to the respiratory tract; it should be stored and handled to minimize dispersion and exposure, especially in environments where acidic or corrosive vapors are present, since acid exposure can mobilize toxic Ba2+ ions.
- Environmental considerations: As with many inorganic salts, Ba2+ release is regulated in many jurisdictions to prevent ecological and health impacts, and proper disposal or containment protocols are followed in industrial settings.