physical isomerism

1 definition found

physical isomerism - Collaborative International Dictionary of English v.0.48 :

  Isomerism \I*som"er*ism\, n. (Chem.)
     The state, quality, or relation, of two or more isomeric
     substances.
     [1913 Webster]
  
     Physical isomerism (Chem.), a former term for optical  isomerism
        .
  
     optical isomerism (Chem.), the condition or relation of
        certain (isomeric) substances, which, while chemically
        identical (in that they have the same composition, the
        same molecular weights, and the same ultimate
        constitution), are yet physically different, as in their
        action on polarized light, as dextro- and l[ae]vo-tartaric
        acids, or the sugars galactose and glucose. In such
        compounds there is usually at least one unsymmetrical
        carbon atom and typically more than one. See
        Unsymmetrical.
        [1913 Webster +PJC]