• Metal complexes that differ only in which ligands are adjacent to one another ( cis ) or directly across from one another ( trans ) in the coordination sphere of the metal are called geometrical isomers . (libretexts.org)
  • Examples of geometrical isomerism (cis-trans isomerism) include isomeric 2-butenes (cis-2-butene and trans-2-butene), maleic acid (cis-butenedioic acid) and fumaric acid (trans-butenedioic acid), cis-9-octadecenoic acid (oleic acid) and trans-9-octadecenoic acid (elaidic acid), etc. (adidarwinian.com)
  • Pentane exists as three isomers: n-pentane (often called simply "pentane"), isopentane (2-methylbutane) and neopentane (dimethylpropane). (wikipedia.org)