What Is Potassium Perchlorate?

Potassium perchlorate is a salt of perchloric acid, one of the strongest acids. Like other perchlorate salts, it is a strong oxidizing agent. Adding organic compounds creates a mixture that can potentially detonate, given the right conditions. A similar salt called ammonium perchlorate is even more explosive and enjoyed a long history of use as an oxidizing agent in shuttle booster rockets.

Uses and Properties

Potassium perchlorate does occur naturally in a few places, especially in potash ore. It's more common, however, as an industrial chemical, where it's used to make fireworks, explosives and rocket fuel. It also finds use in the manufacture of matches and in bleaching powders for processing wood pulp. It is water soluble, though less so than are many other potassium salts; at room temperature, it's an odorless white powder with a high melting point.

Chemistry

Potassium perchlorate is an ionic compound; the potassium ion has a +1 charge, while the perchlorate ion has a -1 charge, and the attractive force between the two ions holds them together in the solid form. The perchlorate ion has the chemical formula ClO4 with a net -1 charge. It is shaped like a tetrahedron with the chlorine atom at the center and the four oxygen atoms at the corners of the tetrahedron.

Oxidation

All four oxygen atoms are bonded to the chlorine. Oxygen has higher electronegativity, or affinity for electrons, than does chlorine, although chlorine is also quite electronegative, so the compound tends to react by transferring oxygen atoms to other compounds -- a process called oxidation. This tendency accounts for the explosive behavior of potassium perchlorate and similar salts when mixed with organic compounds or powdered aluminum, although the reaction may require heat or a catalyst to get it going.

Health

In the human body, potassium perchlorate can interfere with iodine uptake by the thyroid gland, potentially leading to hypothyroidism. This effect is so pronounced that, according to the FDA, perchlorate has actually been used to treat hyperthyroidism and diagnose disorders of iodine metabolism. In 2009, the Environmental Protection Agency released a health advisory recommending that levels of perchlorate in drinking water be kept at 15 parts per billion or less to minimize long-term exposure.