Nomenclature
CAS number: 513-77-9
Carbonic acid barium salt (1:1).
CBaO
3; mol wt 197.34.
C 6.09%, Ba 69.59%, O 24.32%.
BaCO
3.
Description and references
Occurs in nature as the mineral witherite. Prepn: Gmelins, Barium (8th ed) 30, 301-303 (1932) and supplement, 186-188,
461-466 (1960). Manuf: Faith, Keyes &
Clark's Industrial Chemicals, F. A. Lowenheim, M. K. Moran,
Eds. (Wiley-Interscience, New York, 4th ed., 1975) pp 121-125. Thermal
transition from orthorhombic to hexagonal phase: C. M. Earnest, Themochim. Acta 137, 365 (1989).
Prepn of submicron particles by high gravity technique: C. Y. Tai et al., Chem. Eng. Sci. 61, 7479 (2006). Polymer-controlled crystallization:
T. Wang et al., Angew. Chem.
Int. Ed. 45, 4451 (2006).
Properties
White, heavy powder. Poisonous. d (witherite) 4.2865. Orthorhombic (γ), hexagonal (β), and cubic (α) polymorphs exist.
Orthorhombic phase occurs under ambient conditions; transition to
hexagonal phase occurs at ≈810°; cubic at ≈976°; dec into BaO and
CO2 at ≈1300°. Almost insol in water, 0.024 g/l. Slightly
sol (1:1000) in CO2-water; sol in dil HCl, HNO3 or acetic acid; also sol in soln NH4Cl or NH4NO3.Caution
Potential symptoms of overexposure
are excessive salivation, vomiting, severe abdominal pain, violent
diarrhea; increased blood pressure; tinnitis, giddiness, vertigo;
muscle twitching, convulsions, paralysis; dilated pupils; confusion,
somnolence; cardiac arrest; death due to respiratory failure. See Clinical Toxicology of Commercial
Products, R. E. Gosselin et al., Eds. (Williams
& Wilkins, Baltimore, 5th ed., 1984) Section III, pp 61-63.Use
Rat poison; in brick, glass, oil-drilling muds,
ceramics, paints, enamels, marble substitutes, rubber; manuf of ceramics,
photographic paper, barium salts, electrodes, optical glasses, electronic
and magnetic materials; analytical reagent in the prepn of barium
standard solutions.