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Greek meaning of word
A '''chiral molecule''' is a molecule that cannot be superimposed on its mirror image. Chiral molecules are optically active in the sense that they rotate the plane of [[polarized light]].
A '''chiral molecule''' is a [[molecule]] that cannot be superimposed on its mirror image, i.e. it is an object which is not identical with its mirror image, it does not have the center plane of [[symmetry]], but it may have a rotational symmetry axis. The relationship between an object and its image is similar to the relationship between the left and right hand. Chiral molecules are optically active in the sense that they rotate the plane of [[polarized light]].
An atom containing carbon forms optical isomers if one or more of the carbon atoms is bonded to four different species.
An [[atom]] containing [[carbon]] forms ''optical isomers'' if one or more of the carbon atoms is bonded to four different species.
The definition of chirality as property of optically active compounds of molecules was in fact introduced by [[Pasteur]] who however originally used a term ''dissymmetry'' instead. The word ''chirality'' is derived from greek ''chiros'' meaning 'hand'. According to Whyte the term chirality was coined by [[lord Kelvin]] who used it for the first time in the [[physics]] at the turn of the 20th century. Its introduction into [[organic chemistry]] is attributed to Cahn, Ingold and Prelog.<ref>{{cite web |author=Otakar Červinka |title=Chiralita a pojmy s ní související (Chirality and associated terms) |publisher=Chem. Listy |volume=93 |pages=294 - 305 |year=1999|url=http://www.chemicke-listy.cz/docs/full/1999_05_294-305.pdf |accessdate=December 3, 2013|language=Czech}}</ref>
==Louis Pasteur==
==Louis Pasteur==
<blockquote>
<blockquote>
In isomeric bodies, the elements and the proportions in which they are combined are the same, only the arrangement of the atoms is differetn... We know, on the one hand, that the molecular arrangements of the two tartaric acids are asymmetric, and on the other hand, that these arrangements are absolutely identical, excepting that they exhibit asymmetry in opposite directions. Are atoms of the dextro acid grouped in the form of a right-handed spiral, or are they placed at the apex of an irregular tetrahedron, or are they disposed according to this or that asymmetric arrangement? We do not know.<ref>From pasteur's lecture to the Societe Chimique de Paris in 1883, quoted in DuBos, R. (1976) Louis Pasteur: Free Lance of Science, p. 95, Charles Scribner's Sons, New York.</ref>
In isomeric bodies, the elements and the proportions in which they are combined are the same, only the arrangement of the atoms is different... We know, on the one hand, that the molecular arrangements of the two tartaric acids are asymmetric, and on the other hand, that these arrangements are absolutely identical, excepting that they exhibit asymmetry in opposite directions. Are atoms of the dextro acid grouped in the form of a right-handed spiral, or are they placed at the apex of an irregular tetrahedron, or are they disposed according to this or that asymmetric arrangement? We do not know.<ref>From Pasteur's lecture to the Societe Chimique de Paris in 1883, quoted in DuBos, R. (1976) Louis Pasteur: Free Lance of Science, p. 95, Charles Scribner's Sons, New York.</ref>
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