Barium is a soft, silvery metal that rapidly tarnishes in air and reacts with water. It is not an extensively used element, but it has several applications:
- Drilling fluids: Most barium is used in drilling fluids for oil and gas wells.
- Paint and glassmaking: Barium is used in paint and in glassmaking.
- Medical imaging: Barium sulfate is used to help diagnose diseases and other problems that affect the large intestine or the esophagus. The heavy barium blocks X-rays, causing the filled part of the digestive system to show up clearly on the X-ray picture or CT scan. Barium sulfate can be taken into our body because it is highly insoluble in water, and is eliminated completely from the digestive tract.
- Metallurgy: Barium is used in metallurgy, and its compounds are used in pyrotechnics, petroleum production, and radiology.
- Pigment in paints: Barium sulfate is used as a pigment in paints, where it is known as blanc fixe (i.e., “permanent white”) or as lithopone when mixed with zinc sulfide.
- Specialty glass: About 75 percent of all barium carbonate (BaCO3) goes into the manufacture of specialty glass, either to increase its refractive index or to provide radiation shielding in cathode-ray and television tubes. The carbonate also is used to make other barium chemicals, as a flux in ceramics, in the manufacture of ceramic permanent magnets for loudspeakers, and in the removal of sulfate from salt brines before they are fed into electrolytic cells (for the production of chlorine and alkali) .
- High-temperature superconductors: On heating, the carbonate forms barium oxide, BaO, which is employed in the preparation of cuprate-based high-temperature superconductors such as YBa2Cu3O7−x.
- Heat-treating baths: Barium chloride (BaCl2·2H2O), consisting of colourless crystals that are soluble in water, is used in heat-treating baths and in laboratories as a chemical reagent to precipitate soluble sulfates.
- Barium X-rays: Barium sulfate is used to help diagnose or find problems in the esophagus, stomach, and bowels. It is a radiographic contrast agent. Barium X-rays (also called upper and lower GI series) are used to diagnose abnormalities of the GI tract, such as tumors, ulcers, and other inflammatory conditions. Barium is a dry, white, chalky powder that is mixed with water to make barium liquid. Barium is an X-ray absorber and appears white on X-ray film. When instilled into the GI tract, barium coats the inside wall of the esophagus, stomach, large intestine, and/or small intestine so that the inside wall lining, size, shape, contour, and patency (openness) are visible on X-ray.
