The most common compound of chlorine, sodium chloride, has been known since ancient times; however, around 1630, chlorine gas was obtained by the Belgian chemist and physician Jan Baptist van Helmont.
Senyawa klor yang paling umum adalah natrium klorida, yang telah dikenal sejak zaman purba; namun baru pada tahun 1630 gas klor diperoleh oleh kimiawan sekaligus fisikawan Belgia Jan Baptist van Helmont.