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  2. Descriptor (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Descriptor_(Chemistry)

    See: E-Z notation Violet leaf aldehyde, systematic name (E,Z)-nona-2,6-dienal, is a compound having one (E)- and one (Z)-configured double bond. The descriptors (E) (from German entgegen, 'opposite') and (Z) (from German zusammen, 'together') are used to provide a distinct description of the substitution pattern for alkenes, cumulenes or other double bond systems such as oximes.

  3. Globally Harmonized System of Classification and Labelling of ...

    en.wikipedia.org/wiki/Globally_Harmonized_System...

    The pictogram for harmful substances of the Globally Harmonized System of Classification and Labelling of Chemicals.. The Globally Harmonized System of Classification and Labelling of Chemicals (GHS) is an internationally agreed-upon standard managed by the United Nations that was set up to replace the assortment of hazardous material classification and labelling schemes previously used around ...

  4. CPK coloring - Wikipedia

    en.wikipedia.org/wiki/CPK_coloring

    Several of the CPK colors refer mnemonically to colors of the pure elements or notable compound. For example, hydrogen is a colorless gas, carbon as charcoal, graphite or coke is black, sulfur powder is yellow, chlorine is a greenish gas, bromine is a dark red liquid, iodine in ether is violet, amorphous phosphorus is red, rust is dark orange-red, etc.

  5. Absolute configuration - Wikipedia

    en.wikipedia.org/wiki/Absolute_configuration

    If the arrangement is clockwise, it is the D form. As usual, if the molecule itself is oriented differently, for example, with H towards the viewer, the pattern may be reversed. The L form is the usual one found in natural proteins. For most amino acids, the L form corresponds to an S absolute stereochemistry, but is R instead for certain side ...

  6. Simplified Molecular Input Line Entry System - Wikipedia

    en.wikipedia.org/wiki/Simplified_Molecular_Input...

    The terms "canonical" and "isomeric" can lead to some confusion when applied to SMILES. The terms describe different attributes of SMILES strings and are not mutually exclusive. Typically, a number of equally valid SMILES strings can be written for a molecule. For example, CCO, OCC and C(O)C all specify the structure of ethanol. Algorithms have ...

  7. Chemical nomenclature - Wikipedia

    en.wikipedia.org/wiki/Chemical_nomenclature

    Because the S 2− anion has a subscript of 2 in the formula (giving a 4− charge), the compound must be balanced with a 4+ charge on the Pb cation (lead can form cations with a 4+ or a 2+ charge). Thus, the compound is made of one Pb 4+ cation to every two S 2− anions, the compound is balanced, and its name is written as lead(IV) sulfide.

  8. Isotopic labeling - Wikipedia

    en.wikipedia.org/wiki/Isotopic_labeling

    A carbon-13 label was used to determine the mechanism in the 1,2- to 1,3-didehydrobenzene conversion of the phenyl substituted aryne precursor 1 to acenaphthylene. [3]An isotopic tracer, (also "isotopic marker" or "isotopic label"), is used in chemistry and biochemistry to help understand chemical reactions and interactions.

  9. Glossary of chemistry terms - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_chemistry_terms

    Also acid ionization constant or acidity constant. A quantitative measure of the strength of an acid in solution expressed as an equilibrium constant for a chemical dissociation reaction in the context of acid-base reactions. It is often given as its base-10 cologarithm, p K a. acid–base extraction A chemical reaction in which chemical species are separated from other acids and bases. acid ...