Cyclobutanetetrone, also called tetraoxocyclobutane, is an organic compound with formula C<sub>4</sub>O<sub>4</sub> or (CO)<sub>4</sub>, the fourfold ketone of cyclobutane. It would be an oxide of carbon, indeed a tetramer of carbon monoxide.
The compound seems to be thermodynamically unstable. , it had yet to be synthesized in significant amounts but may have transient existence as detected by mass spectrometry.
Cyclobutanetetrone can be viewed as the neutral counterpart of the squarate anion , which is stable and has been known at least since 1959.
The compound octahydroxycyclobutane or cyclobutaneoctaol (C(OH)<sub>2</sub>)<sub>4</sub> may be referred to in the literature as "hydrated tetraoxocyclobutane".