What does chlorate mean?
Chlorate is a noun from chemistry referring to any salt or ester of chloric acid — a compound built around the negatively charged ion ClO₃⁻. The most commonly encountered examples are potassium chlorate and sodium chlorate, both powerful oxidizing agents. That oxidizing power gives chlorates their practical importance and their cautionary reputation: they supply oxygen readily, which makes them useful for bleaching paper pulp, killing weeds along railways, and fueling the vigorous reactions behind matches and fireworks, but also means they can intensify fires when mishandled. In speech and writing, chlorate belongs firmly to the technical register, appearing in chemical formulas, industrial safety documents, and regulatory texts rather than casual conversation. It is usually named after its paired cation, as in 'a solution of sodium chlorate.' Closely related terms include chloride, chlorite, and perchlorate, which differ only in the number of oxygen atoms bonded to chlorine, making careful spelling genuinely important in this family of words.
nounA chlorate is a salt or ester of chloric acid, containing the polyatomic ion ClO₃⁻; potassium chlorate and sodium chlorate are the most familiar examples. Chlorates are strong oxidizing agents used in bleaching, herbicides, matches, and pyrotechnics.
- Chemistry: any salt or ester of chloric acid containing the ClO₃⁻ anion.
- By extension: a specific compound such as potassium chlorate or sodium chlorate, named by its metal or cation.
"The match head contained a small amount of potassium chlorate, which released oxygen when struck."
"Sodium chlorate was once widely sprayed as a non-selective herbicide on railway tracks and industrial ground."
"When heated gently, potassium chlorate decomposes to release oxygen, a reaction long used to demonstrate gas evolution in classrooms."
Used when referring collectively to different chlorate compounds or multiple samples; often uncountable when discussing the substance class generally.
"Both chlorates were stored separately because of their oxidizing properties."
The same ion that whitens paper can launch fireworks — and in 19th-century chemistry labs it launched a few accidental explosions too.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of chlorate
Chlorate derives from chlorine, whose name comes from the Greek 'chloros,' meaning pale green or yellow-green, coined by Humphry Davy in the early 19th century for the greenish-yellow gas he identified. The '-ate' suffix follows standard chemical nomenclature for salts of oxyacids, so a chlorate is literally a salt of chloric acid. Its closest relatives are the other chlorine-oxygen compounds — chloride, chlorite, and perchlorate — all built on the same Greek root.
How chlorate is actually used
Chlorate is almost exclusively a technical term used in chemistry, industry, agriculture, and safety regulation. It appears chiefly in compound names naming its cation (potassium chlorate, sodium chlorate) and carries connotations of hazard and oxidizing power rather than everyday use.
Easily confused with chlorate
Perchlorates contain the ClO₄⁻ ion (one more oxygen than the ClO₃⁻ ion in chlorates) and come from perchloric acid rather than chloric acid.
Chlorites contain the ClO₂⁻ ion with one fewer oxygen than chlorates, and derive from chlorous acid.