Pentacarbon dioxide

Names
IUPAC name penta-1,2,3,4-tetraene-1,5-dione
Identifiers
CAS Number	51799-36-1 N
3D model (JSmol)	Interactive image
ChemSpider	454765 Y
PubChem CID	521350
CompTox Dashboard (EPA)	DTXSID90334624
InChI InChI=1S/C5O2/c6-4-2-1-3-5-7 Y Key: BKMBQDLZBSCFGV-UHFFFAOYSA-N Y InChI=1/C5O2/c6-4-2-1-3-5-7 Key: BKMBQDLZBSCFGV-UHFFFAOYAJ
SMILES O=C=C=C=C=C=O
Properties
Chemical formula	C5O2
Molar mass	92.05 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Pentacarbon dioxide, officially penta-1,2,3,4-tetraene-1,5-dione, is an oxide of carbon (an oxocarbon) with formula C₅O₂ or O=C=C=C=C=C=O.

The compound was described in 1988 by Günter Maier and others, who obtained it by pyrolysis of cyclohexane-1,3,5-trione (phloroglucin, the tautomeric form of phloroglucinol).^[1] It has also been obtained by flash vapor pyrolysis of 2,4,6-tris(diazo)cyclohexane-1,3,5-trione (C₆N₆O₃).^[2]: 97 It is stable at room temperature in solution.^[1] The pure compound is stable up to −96 °C, at which point it polymerizes.^{[2][page needed]}