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🥼organic chemistry review

Penta-1,4-diyne

Written by the Fiveable Content Team • Last updated September 2025
Written by the Fiveable Content Team • Last updated September 2025

Definition

Penta-1,4-diyne is an organic compound with the molecular formula C₅H₄. It consists of a linear chain of five carbon atoms, with two triple bonds (alkynes) located at the 1st and 4th positions. This structural arrangement gives penta-1,4-diyne unique chemical and physical properties that are important in the context of naming alkynes.

5 Must Know Facts For Your Next Test

  1. The prefix 'penta-' indicates that the carbon chain has five carbon atoms.
  2. The positions of the triple bonds are specified by the numbers '1,4' to indicate that they are located at the 1st and 4th carbon atoms.
  3. Penta-1,4-diyne is a linear, acyclic alkyne with two triple bonds, which affects its physical and chemical properties.
  4. The systematic IUPAC name for penta-1,4-diyne is derived from the parent alkane 'pentane' and the presence of the two triple bonds.
  5. Penta-1,4-diyne is an important structural isomer of other pentadiyne compounds, which can have different physical and chemical properties.

Review Questions

  • Explain the significance of the prefix 'penta-' in the name 'penta-1,4-diyne'.
    • The prefix 'penta-' in the name 'penta-1,4-diyne' indicates that the compound has a carbon chain consisting of five carbon atoms. This information is crucial for correctly naming and identifying the structure of the alkyne, as the number of carbon atoms in the parent chain is a fundamental aspect of the IUPAC naming system for organic compounds.
  • Describe how the positions of the triple bonds in penta-1,4-diyne affect its structural and chemical properties.
    • The positions of the two triple bonds in penta-1,4-diyne, specifically at the 1st and 4th carbon atoms, are essential for determining its structural and chemical properties. This arrangement creates a linear, acyclic molecule with increased reactivity and altered physical properties compared to other structural isomers of pentadiyne. The positioning of the triple bonds also influences the compound's ability to participate in various organic reactions and its potential applications.
  • Analyze how the systematic IUPAC naming of penta-1,4-diyne relates to its underlying chemical structure and the broader principles of alkyne nomenclature.
    • The systematic IUPAC name 'penta-1,4-diyne' for this compound directly reflects its chemical structure and aligns with the general principles of alkyne nomenclature. The 'penta-' prefix denotes the five-carbon parent chain, while the '1,4' numbers specify the positions of the two triple bonds. This naming convention allows for the unambiguous identification of the compound's connectivity and facilitates the communication of its structural features within the context of organic chemistry.