The name is derived from the word chloros, which means yellow-green. Chlorum is a yellow-green gas which dissolves quite easily in water. It was discovered in 1774.
It is a highly corrosive gas, although slightly less aggressive than Fluor. We use it in substances such as bleach, stain removers and disinfectants (in swimming pools) and in various salts, plastics such as PVC and in insecticides.
Its biological properties are quite neutral: it is an element that regulates the electrolyte balance [like a mother who makes sure that everything stays in balance without asking anything for it in return].