Skip to main content
Chemistry LibreTexts

Steric Hindrance

  • Page ID
    42957
  • \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)

    Steric hindrance at a given atom in a molecule is the congestion caused by the physical presence of the surrounding ligands, which may slow down or prevent reactions at the atom.

    eg. 1:

    sterichindrance1.png

    In 1, the carbonyl carbon is bonded to two hydrogen atoms. In 2, it is bonded to a hydrogen atom and a methyl group. Since the methyl group is larger than the hydrogen atom, steric hindrance is greater at the carbonyl carbon in 2 than that in 1.

    eg. 2:

    sterichindrance2.png

    In 1, the nitrogen atom is bonded to three hydrogen atoms; in 2, it is bonded to three methyl groups. A methyl group is larger than a hydrogen atom. Thus, the steric hindrance at the nitrogen atom in 2 is greater than that in 1.

    eg. 3:

    sterichindrance3.png

    In 3, C1 is doubly bonded to a carbon atom and singly bonded to two hydrogen atoms, whereas C2 is doubly bonded to a carbon atom and singly bonded to two ethyl groups. An ethyl group is larger than a hydrogen atom. Thus, the steric hindrance at C2 is greater than that at C1.


    This page titled Steric Hindrance is shared under a All Rights Reserved (used with permission) license and was authored, remixed, and/or curated by Gamini Gunawardena via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request.

    • Was this article helpful?