C5H4
# C5H4

The molecular formula $C_5H_4$ (molar mass: 64.09 g/mol, exact mass: 64.0313 u) may refer to:

* 3-Ethynylcycloprop-1-ene
* 1,4-Pentadiyne
* Penta-1,2-dien-4-yne
* Spiropentadiene, or bowtiediene
