Definition

1. Noun:
   • A type of molecular representation: A structural formula is a diagrammatic or symbolic representation of a chemical compound that shows the arrangement of atoms within a molecule and the bonds between them. It provides more detail than a simple molecular formula by illustrating the molecular structure.

Usage

• A structural formula is used in chemistry to convey the specific connectivity of atoms, which is crucial for understanding a compound's properties and reactions.
• It is distinct from a molecular formula (e.g., C₂H₆O for ethanol), which only indicates the number and type of atoms, not their arrangement.

Examples

• Noun:
  • The textbook showed the structural formula of benzene as a hexagon with a circle inside.
  • To understand why the two substances have different properties, you must compare their structural formulas.
  • The structural formula clearly indicates that the oxygen atom is bonded to a hydrogen atom and a carbon chain.

Advanced Usage

• "Condensed structural formula": A shorthand version of a structural formula that groups atoms together.
  • For simplicity, the condensed structural formula CH₃CH₂OH is often used instead of the full structural diagram for ethanol.
• "Lewis structure": A specific type of structural formula that shows all valence electrons as dots or lines representing bonds.
  • Drawing the Lewis structure is often the first step in determining the complete structural formula.

Variants and Related Words

• Molecular formula (n): A formula that gives the number of atoms of each element in a molecule but not the arrangement (e.g., C₆H₁₂O₆).
• Skeletal formula (n): A simplified structural formula where carbon atoms and their attached hydrogen atoms are implied by the vertices and ends of lines.
• Stereochemical formula (n): A structural formula that depicts the three-dimensional arrangement of atoms.

Synonyms

• Graphical formula: A synonym emphasizing the diagrammatic nature.
• Constitutional formula: A synonym emphasizing the depiction of atomic connectivity (constitution).

Related Phrases

• To draw a structural formula: The common verb used with this term.
  • The first step in the problem is to draw the structural formula of the compound.
• As shown in the structural formula: A phrase used to direct attention to the structural detail.
  • As shown in the structural formula, the double bond is located between the second and third carbon atoms.

Noun

1. an expanded molecular formula showing the arrangement of atoms within the molecule