pentacarbon dioxide

{{short description|Chemical compound}}

{{chembox

|Verifiedfields = changed

|verifiedrevid = 464197772

|ImageFile = Pentacarbon dioxide.svg

|ImageSize = 220px

|ImageAlt = Full structural formula of pentacarbon dioxide

|ImageFile1 = Pentacarbon dioxide 3D spacefill.png

|ImageFile2 = File:Pentacarbon dioxide 3D ball.png

|ImageSize1 = 220px

|ImageAlt1 = Space-filling model of the pentacarbon dioxide molecule

|IUPACName = penta-1,2,3,4-tetraene-1,5-dione

|Section1 = {{Chembox Identifiers

|ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

|ChemSpiderID = 454765

|InChI = 1/C5O2/c6-4-2-1-3-5-7

|InChIKey = BKMBQDLZBSCFGV-UHFFFAOYAJ

|StdInChI_Ref = {{stdinchicite|correct|chemspider}}

|StdInChI = 1S/C5O2/c6-4-2-1-3-5-7

|StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

|StdInChIKey = BKMBQDLZBSCFGV-UHFFFAOYSA-N

|CASNo_Ref = {{cascite|changed|??}}

|CASNo=51799-36-1

|PubChem=521350

|SMILES=O=C=C=C=C=C=O

}}

|Section2 = {{Chembox Properties

|Formula=C₅O₂

|MolarMass=92.05 g/mol

}}

}}

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 2,4,6-tris(diazo)cyclohexane-1,3,5-trione (C₆N₆O₃).{{cite journal | title = C₅O₂ (1,2,3,4-Pentatetraene-1,5-dione), a New Oxide of Carbon |author1=Maier, G. |author2=Reisenauer, H. P. |author3=Schäfer, U. |author4=Balli, H. | journal = Angewandte Chemie International Edition | year = 1988 | volume = 27 | issue = 4 | pages = 566–568 | doi = 10.1002/anie.198805661}}{{cite book | author = Eastwood, F. W. | year = 1997 | chapter = Gas Phase Pyrolytic Methods for the Preparation of Carbon-Hydrogen and Carbon-Hydrogen-Oxygen Compounds | editor = Vallée, Y. | title = Gas Phase Reactions in Organic Synthesis | publisher = CRC Press | isbn = 90-5699-081-0}}{{rp|97}} Diazo transfer can produce the latter compound from phloroglucinol. It is stable at room temperature in solution. The pure compound is stable up to −90 °C, at which point it polymerizes.{{rp|100}}