Is barium sulfate soluble in nitric acid

Barium sulfate

Barium sulfate, BaSO4, colorless, rhombic crystals; D. 4.50 g cm-3. At 1148 ° C, B. changes into a monoclinic form, above 1400 ° C it breaks down into barium oxide, sulfur dioxide and oxygen: BaSO4 → BaO + SO2 + 1/2 O2. B. is very sparingly soluble in water and therefore non-toxic (solubility product KL. = 1.08 10-10 at 25 ° C; this corresponds to a solubility of 0.24 mg B. in 100 g water). It therefore falls when mixing SO42--Ions and Ba2+-Ions-containing solutions always appear as a fine crystalline precipitate. This reaction is used for both quantitative and qualitative determination of Ba2+ used, as is the technical production of B. In conc. Sulfuric acid is readily soluble in B., since the complex acid H2[Ba (SO4)2] forms. B. occurs naturally as barite (barite). Because of his chem. and thermal resistance, B. under the names permanent white, barite white or blanc fixe serves as a pigment and solvent. Since these colorants have little opacity, they are usually used in a mixture with zinc sulfide. B. serves as a filler (photo paper, plastics) and is added to the concrete during the construction of nuclear reactors, because this absorbs the radioactive radiation very well. For the same reason, it is used in medicine as an X-ray contrast medium.