Tetrahydroxy-1,4-benzoquinone

Tetrahydroxy-1,4-benzoquinone
Names
	Preferred IUPAC name 2,3,5,6-Tetrahydroxycyclohexa-2,5-diene-1,4-dione
	Other names Tetroquinone
Identifiers
CAS Number	319-89-1 ;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:137472;
ChEMBL	ChEMBL1329029;
ChemSpider	5231 ;
ECHA InfoCard	100.005.706
EC Number	206-275-5;
KEGG	D06096;
PubChem CID	5424;
UNII	U7L4P6H0SU ;
CompTox Dashboard (EPA)	DTXSID9045897 ;
	InChI InChI=1S/C6H4O6/c7-1-2(8)4(10)6(12)5(11)3(1)9/h7-8,11-12H Key: DGQOCLATAPFASR-UHFFFAOYSA-N;
	SMILES O=C(C(O)=C1O)C(O)=C(O)C1=O;
Properties
Chemical formula	C6H4O6
Molar mass	172.092 g·mol−1
Appearance	Blue-black crystals
Density	2.609 g/cm3
Boiling point	370.6 °C (699.1 °F; 643.8 K) at 760 mmHg
Solubility in water	Slightly soluble in cold water
Hazards
	GHS labelling:
Pictograms
Signal word	Warning
Hazard statements	H315, H319, H335
Precautionary statements	P261, P264, P271, P280, P302+P352, P304+P340, P305+P351+P338, P312, P321, P332+P313, P337+P313, P362, P403+P233, P405, P501
Flash point	192.1 °C (377.8 °F; 465.2 K)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Tetrahydroxy-1,4-benzoquinone, also called tetrahydroxy-p-benzoquinone, tetrahydroxybenzoquinone, or tetrahydroxyquinone (THBQ, THQ), is an organic compound with formula C₆O₂(OH)₄. Its molecular structure consists of a cyclohexadiene ring with four hydroxyl groups and two ketone groups in opposite (para) positions.

The compound gives a light red solution in water, and crystallizes as the glistening bluish-black (but non-conducting) dihydrate C₆O₂(OH)₄·2H₂O.

The compound can be synthesized from glyoxal or from myo-inositol, a natural compound widely present in plants. THBQ forms an adduct with 4,4′-bipyridine in a 2:3 ratio.