What is "chirality"

n. The phenomenon, in chemistry, physics and mathematics, in which objects are mirror images of each other, but are not identical.

Chirality (handedness) is a property of asymmetry.

Chirality may also refer to:

• Chirality (chemistry), a property of molecules having a non-superimposable mirror image
• Chirality (electromagnetism), an electromagnetic propagation in chiral media
• Chirality (mathematics), the property of a figure not being identical to its mirror image
• Chirality (physics), when a phenomenon is not identical to its mirror image
• Chirality (journal), an academic journal dealing with chiral chemistry
• Chirality (manga)

In geometry, a figure is chiral (and said to have chirality) if it is not identical to its mirror image, or, more precisely, if it cannot be mapped to its mirror image by rotations and translations alone. An object that is not chiral is said to be achiral. In 3 dimensions, not all achiral objects have a mirror plane. For example, a 3-dimensional object with inversion centre as its only nontrivial symmetry operation is achiral but has no mirror plane.

A chiral object and its mirror image are said to be enantiomorphs. The word chirality is derived from the Greek (cheir), the hand, the most familiar chiral object; the word enantiomorph stems from the Greek (enantios) 'opposite' + (morphe) 'form'. A non-chiral figure is called achiral or amphichiral.

Chirality is a geometric property of some molecules and ions. A chiral molecule/ion is non-superposable on its mirror image. The presence of an asymmetric carbon center is one of several structural features that induce chirality in organic and inorganic molecules. The term chirality is derived from the Greek word for hand, χειρ (kheir).

The mirror images of a chiral molecule/ion are called enantiomers or optical isomers. Individual enantiomers are often designated as either " right-" or "left-handed". Chirality is an essential consideration when discussing the stereochemistry in inorganic chemistry and organic chemistry. The concept is of great practical importance because most biomolecules and pharmaceuticals are chiral.

Chiral molecules and ions are described by various ways of designating their ″absolute configuration″ which codifies either the entity's geometry or its ability to rotate plane-polarized light, a common technique in studying chirality. Various naming conventions used to describe a given chiral entity's absolute configuration are explained here.

A chiral phenomenon is one that is not identical to its mirror image (see the article on mathematical chirality). The spin of a particle may be used to define a handedness, or helicity, for that particle, which, in the case of a massless particle, is the same as chirality. A symmetry transformation between the two is called parity. Invariance under parity by a Dirac fermion is called chiral symmetry.

An experiment on the weak decay of cobalt-60 nuclei carried out by Chien-Shiung Wu and collaborators in 1957 demonstrated that parity is not a symmetry of the universe.

is a 4-volume yuri manga series written and illustrated by author Satoshi Urushihara. The manga was originally serialized in Comic NORA in 1995, and later published in three bound volumes, which was re-released into two bound volumes in 2003. In 1997 Chirality was licensed for released in North America by Central Park Media. It was originally published as 18 issues between March 1997 and August 1998, as well as being released into four bound volumes from 1997 to 2000. The art was also flipped so that it would read left to right which was not an uncommon practice for manga released in Western Hemisphere at the time.

Chirality is a peer-reviewed scientific journal covering chiral chemistry in relation with physiology.

300px|thumb|The direction of current flow and induced magnetic flux follow a "handness" relationship

The term chiral describes an object, especially a molecule, which has or produces a non-superposable mirror image of itself. In chemistry, such a molecule is called an enantiomer or is said to exhibit chirality or enantiomerism. The term "chiral" comes from the Greek word for the human hand, which itself exhibits such non-superimposeability of the left hand precisely over the right. Due to the opposition of the fingers and thumbs, no matter how the two hands are oriented, it is impossible for both hands to exactly coincide. Helices, chiral characteristics (properties), chiral media, order, and symmetry all relate to the concept of left- and right-handedness.

Chirality is a property of asymmetry important in several branches of science. The word chirality is derived from the Greek, χειρ (kheir), "hand", a familiar chiral object.

An object or a system is chiral if it is distinguishable from its mirror image; that is, it cannot be superposed onto it. Conversely, a mirror image of an achiral object, such as a sphere, cannot be distinguished from the object. A chiral object and its mirror image are called enantiomorphs (Greek opposite forms) or, when referring to molecules, enantiomers. A non-chiral object is called achiral (sometimes also amphichiral) and can be superposed on its mirror image. If the object is non-chiral and is imagined as being colored blue and its mirror image is imagined as colored yellow, then by a series of rotations and translations the two can be superposed producing green with none of the original colors remaining.

The term was first used by Lord Kelvin in 1893 in the second Robert Boyle Lecture at the Oxford University Junior Scientific Club which was published in 1894:

Human hands are perhaps the most universally recognized example of chirality. The left hand is a non-superimposable mirror image of the right hand; no matter how the two hands are oriented, it is impossible for all the major features of both hands to coincide across all axes. This difference in symmetry becomes obvious if someone attempts to shake the right hand of a person using their left hand, or if a left-handed glove is placed on a right hand. In mathematics, chirality is the property of a figure that is not identical to its mirror image.