Definition

1. Noun:
   • A compound that exists in forms having different arrangements of atoms but the same molecular weight: In chemistry, an isomer is one of two or more substances that have identical molecular formulas (the same number and types of atoms) but differ in the arrangement of these atoms within the molecule, leading to different physical and/or chemical properties.

Usage Examples

• Noun:
  • Glucose and fructose are isomers; they share the formula C₆H₁₂O₆ but have different structures.
  • The chemist studied the different isomers of the hydrocarbon to understand their reactivity.
  • Cis-trans isomerism is a common type of stereoisomerism.

Advanced Usage

• Structural Isomer: An isomer where the atoms are bonded together in a different order.
  • Butane and isobutane are structural isomers of C₄H₁₀.
• Stereoisomer: An isomer with the same atomic connectivity but a different spatial arrangement of atoms.
  • The drug's effectiveness depended on which stereoisomer was administered.
• To exist as isomers: Describes the property of a compound having isomeric forms.
  • This molecule can exist as several isomers.

Variants and Related Words

• Isomeric (adj): Relating to or exhibiting isomerism.
  • The two compounds showed isomeric differences.
• Isomerism (n): The phenomenon of the existence of isomers.
  • The lecture covered the principles of optical isomerism.
• Isomerize (v): To change from one isomer to another.
  • The compound can isomerize under heat.

Synonyms

• Structural analogue: A compound with a similar but not identical structure (a broader, less precise term).
• Congener: Often used for compounds of the same type or series, which may include isomers.

Related Phrases and Terms

• Geometric isomer: A type of stereoisomer (e.g., cis-trans isomers).
• Optical isomer: A stereoisomer that rotates plane-polarized light.
• Positional isomer: A type of structural isomer where a functional group is in a different position on the carbon chain.

Noun

1. a compound that exists in forms having different arrangements of atoms but the same molecular weight