• A chemical element whose atomic number is 17. It is a dense and highly toxic greenish-yellow gas with a suffocating odor. It is an extremely powerful oxidizer, and is one of the most reactive elements. It has over 15 known isotopes, of which 2 are stable. Because of its activity, it does not occur uncombined in nature, although it is present in countless compounds. It has numerous applications, including its use in the preparation of chlorinated compounds used in electronics, such as carbon tetrachloride. It is a halogen, and its chemical symbol is CI.
  • chemical symbol CI

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