Oxatriquinacene

Oxatriquinacene is an organic cation with formula C
₉H
₉O⁺
. It is an oxonium ion, with a tricoordinated oxygen atom with +1 charge connected to carbons 1,4, and 7 of a cyclononatriene ring, forming three fused pentagonal cycles. The compound may possess weak tris-homoaromatic character.

Oxatriquinacene

Names
Preferred IUPAC name (2as,4as,6as)-4a,6a-Dihydro-2a1λ4-oxacyclopenta[cd]pentalen-2a1(2aH)-ylium
Identifiers
CAS Number	1056450-16-8
3D model (JSmol)	Interactive image
ChemSpider	32675183
PubChem CID	66553020
CompTox Dashboard (EPA)	DTXSID001027148
InChI InChI=1S/C9H9O/c1-2-8-5-6-9-4-3-7(1)10(8)9/h1-9H/q+1/t7-,8+,9- Key: YQBOZXASCNTXGC-AYMMMOKOSA-N InChI=1/C9H9O/c1-2-8-5-6-9-4-3-7(1)10(8)9/h1-9H/q+1/t7-,8+,9- Key: YQBOZXASCNTXGC-AYMMMOKOBA
SMILES C1=C[C@@H]2[O+]3[C@H]1C=C[C@@H]3C=C2
Properties
Chemical formula	C9H9O
Molar mass	133.167
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

Oxatriquinacene has remarkable stability compared to other oxonium cations, although not as extreme as that of the similar oxatriquinane. It reacts with water, but can be dissolved in acetonitrile. It is of interest as a possible precursor to oxaacepentalene, a hypothetical neutral aromatic species.^[1]

Oxatriquinacene was obtained in 2008 by Mascal and coworkers, through a variant of the synthesis that led them to oxatriquinane.^[1][2][3]

See also

• Triethyloxonium tetrafluoroborate
• Brookhart's acid
• Pyrylium salt