Jeff Betzler, age 13, of Longview, Wash., for his question:
HOW IS BARIUM USED?
Barium is a soft, heavy, silver colored metal element. The metal itself has very few uses outside the laboratory, but it can be combined easily with many other chemicals to form compounds that have important industrial uses.
Doctors use a barium compound called barium sulfate in X ray examinations of a patients digestive system. The barium sulfate absorbs X rays to show an outline of the intestines on the developed film.
Barium sulfate and zinc sulfide combine to form a compound called lithopone. This is a white coloring matter that is used in paint.
The compound called barium carbonate is used in the manufacture of ceramics and special glass and also to purify certain chemical solutions. It is also an ingredient in clay slurries or watery muds used in drilling oil wells.
Chemical manufacturers also often use barium carbonate as a raw material when making other barium compounds. Barium carbonate is poisonous and so is any barium compound that dissolves in water.
Barium oxide and barium hydroxide are used in motor oil detergents. Barium nitrate makes signal flares burn with a green flame. Barium ferrite is used to make magnets.
Barium is never found in a pure state because it combines so easily with other elements. Pure barium is obtained by passing an electric current through a fused or melted barium compound, such as barium chloride.
A piece of barium metal quickly reacts with oxygen and water vapor in the air to form barium oxide. It must be stored under kerosene to keep it pure.
Barium is found most often as barium sulfate in the mineral barite, or heavy spar, and also as barium carbonate in witherite.
Most barite produced in the United States is mined in Arkansas, Georgia, Missouri and Nevada. The world's leading barite producers are the United States, Mexico and West Germany.
The chemical symbol for barium is Ba. Barium's atomic number. is 56 and its atomic weight is 137.33.
Barium melts at 1337 degrees Fahrenheit, or 725 degrees Centigrade and it boils at 2084 degrees Fahrenheit or 1140 degrees Centigrade.
Barium was first isolated in 1808 by an English chemist named Sir Humphrey Davy. Davy rose to fame as the inventor of the miner's safety lamp. The Davy lamp, perfected in 1815, greatly reduced the risks of coal mine explosions.
Davy was also the first person to isolate the chemical elements sodium and potassium. He did this by passing an electric current through the fused hydroxides of these elements.
In addition to being the first to isolate barium, he was also first to isolate calcium, magnesium and strontium.