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In chemistry, a racemic mixture or racemate (/ r eɪ ˈ s iː m eɪ t, r ə-, ˈ r æ s ɪ m eɪ t / [1]) is one that has equal amounts of left- and right-handed enantiomers of a chiral molecule or salt. Racemic mixtures are rare in nature, but many compounds are produced industrially as racemates.
Racemic crystal structure of Rv1738 from Mycobacterium tuberculosis produced by racemic protein crystallography. Racemic crystallography is a technique used in structural biology where crystals of a protein molecule are developed from an equimolar mixture of an L-protein molecule of natural chirality and its D-protein mirror image.
A homogeneous mixture of the two enantiomers in equal parts is said to be racemic, and it usually differs chemically and physically from the pure enantiomers. Chiral molecules will usually have a stereogenic element from which chirality arises. The most common type of stereogenic element is a stereogenic center, or stereocenter.
The science that tries to reconstruct phylogenetic trees and thus discover clades is called phylogenetics or cladistics, the latter term coined by Ernst Mayr (1965), derived from "clade". The results of phylogenetic/cladistic analyses are tree-shaped diagrams called cladograms ; they, and all their branches, are phylogenetic hypotheses.
Deterministic mechanisms for the production of non-racemic mixtures from racemic starting materials include: asymmetric physical laws, such as the electroweak interaction (via cosmic rays [15]) or asymmetric environments, such as those caused by circularly polarized light, quartz crystals, or the Earth's rotation, β-Radiolysis or the ...
The parent of this category can be found in the page on Racemic mixtures. Pages in category "Racemic mixtures" The following 14 pages are in this category, out of 14 total.
Racemic acid does not occur naturally in grape juice, although L-tartaric acid does. Tartaric acid's sodium-ammonium salt is unusual among racemic mixtures in that during crystallization it can separate out into two kinds of crystals, each composed of one isomer, and whose macroscopic crystalline shapes are mirror images of each other.
If neither approach is favored, then these two ways occur equally, yielding a racemic mixture of enantiomers if the reaction takes place at a stereocenter. [9] This is illustrated below in the S N 1 reaction of S-3-chloro-3-methylhexane with an iodide ion, which yields a racemic mixture of 3-iodo-3-methylhexane: