noun

• 1Chemistry
  Each of two or more compounds with the same formula but a different arrangement of atoms in the molecule and different properties.

  ‘However, several research groups have suggested cis isomers of lycopene are better absorbed than the all-trans form.’

  More example sentences

  • ‘Conjugated linoleic acid is a mixture of positional and geometric isomers of linoleic acid.’
  • ‘In 1907, he synthesized a pair of geometric isomers that confirmed his predictions.’
  • ‘There is evidence that tocopherol isomers differ from each other in their functional properties.’
  • ‘An aromatic molecule containing two nitro groups will have three positional isomers.’
  • ‘The plant material contains only the active isomers.’
• 2Physics
  Each of two or more atomic nuclei that have the same atomic number and the same mass number but different energy states.

  ‘Constitutional isomers are isomers that have different atomic connectivities.’

  More example sentences

  • ‘One form is called the (+) isomer because it rotates polarized light to the right, in a positive direction.’
  • ‘The article proclaimed the dawn of the age of atomic aircraft powered by hafnium-178 isomer reactors.’