Comparison of flow-controlled calcium and barium carbonate precipitation patterns.

See more Barium products. Barium (atomic symbol: Ba, atomic number: 56) is a Block S, Group 2, Period 6 element with an atomic weight of 137.27. The number of electrons in each of barium's shells is [2, 8, 18, 18, 8, 2] and its electron configuration is [Xe] 6s². Barium is a member of the alkaline-earth metals. The barium atom has a radius of 222 pm and a Van der Waals radius of 268 pm. Barium was discovered by Carl Wilhelm Scheele in 1772 and first isolated by Humphry Davy in 1808. In its elemental form, barium is a soft, silvery-gray metal. Industrial applications for barium include acting as a "getter," or unwanted gas remover, for vacuum tubes, and as an additive to steel and cast iron. Barium is also alloyed with silicon and aluminum in load-bearing alloys. The main commercial source of barium is the mineral barite (BaSO₄); it does not occur naturally as a free element . The name barium is derived from the Greek word "barys," meaning heavy.

See more Calcium products. Calcium (atomic symbol: Ca, atomic number: 20) is a Block S, Group 2, Period 4 element with an atomic weight of 40.078. The number of electrons in each of Calcium's shells is [2, 8, 8, 2] and its electron configuration is [Ar]4s². The calcium atom has a radius of 197 pm and a Van der Waals radius of 231 pm. Calcium was discovered and first isolated by Sir Humphrey Davy in 1808. It is the fifth most abundant element in the earth's crust and can be found in minerals such as dolomite, gypsum, plagioclases, amphiboles, pyroxenes and garnets. In its elemental form, calcium has a dull gray-silver appearance. Calcium is a reactive, soft metal that is a member of the alkaline earth elements. It frequently serves as an alloying agent for other metals like aluminum and beryllium, and industrial materials like cement and mortar are composed of calcium compounds like calcium carbonate. It is also an biologically essential substance found in teeth, bones, and shells. The name "calcium" originates from the Latin word "calics," meaning lime.