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Etymology from Wiktionary, CC BY-SA 4.0.
Today it means: A theoretical organic molecule made of one carbon atom bonded to four different halogens: bromine, chlorine, fluorine, and iodine (CBrClFI₂). Because all four attached atoms are different, the molecule is chiral, meaning it has two mirror-image forms. It is mainly used as an example in stereochemistry and chirality studies. Full definition →