geometrical isomerism

geometrical isomerism [¦jē·ə¦me·trə·kəl ī′sä·mə‚riz·əm]

(physical chemistry)

The phenomenon in which isomers contain atoms attached to each other in the same order and with the same bonds but with different spatial, or geometrical, relationships; the explicit geometry imposed upon a molecule by, say, a double bond between carbon atoms makes possible the existence of these isomers.