1,4-Benzoquinone

1,4-Benzoquinone
Names
	Preferred IUPAC name Cyclohexa-2,5-diene-1,4-dione
	Other names 1,4-Benzoquinone; Benzoquinone; p-Benzoquinone; p-Quinone
Identifiers
CAS Number	106-51-4 ;
3D model (JSmol)	Interactive image; Interactive image;
Beilstein Reference	773967
ChEBI	CHEBI:16509 ;
ChEMBL	ChEMBL8320 ;
ChemSpider	4489 ;
ECHA InfoCard	100.003.097
EC Number	203-405-2;
Gmelin Reference	2741
IUPHAR/BPS	6307;
KEGG	C00472 ;
PubChem CID	4650;
RTECS number	DK2625000;
UNII	3T006GV98U ;
UN number	2587
CompTox Dashboard (EPA)	DTXSID6020145 ;
	InChI InChI=1S/C6H4O2/c7-5-1-2-6(8)4-3-5/h1-4H Key: AZQWKYJCGOJGHM-UHFFFAOYSA-N ; InChI=1/C6H4O2/c7-5-1-2-6(8)4-3-5/h1-4H Key: AZQWKYJCGOJGHM-UHFFFAOYAR;
	SMILES O=C\1\C=C/C(=O)/C=C/1; C1=CC(=O)C=CC1=O;
Properties
Chemical formula	C6H4O2
Molar mass	108.096 g·mol−1
Appearance	Yellow solid
Odor	Acrid, chlorine-like
Density	1.318 g/cm3 at 20 °C
Melting point	115 °C (239 °F; 388 K)
Boiling point	Sublimes
Solubility in water	11 g/L (18 °C)
Solubility	Slightly soluble in petroleum ether; soluble in acetone; 10% in ethanol, benzene, diethyl ether
Vapor pressure	0.1 mmHg (25 °C)
Magnetic susceptibility (χ)	−38.4·10−6 cm3/mol
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	Toxic
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H301, H315, H319, H331, H335, H400
Precautionary statements	P261, P264, P270, P271, P273, P280, P301+P310, P302+P352, P304+P340, P305+P351+P338, P311, P312, P321, P330, P332+P313, P337+P313, P362, P391, P403+P233, P405, P501
Flash point	38 to 93 °C; 100 to 200 °F; 311 to 366 K
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	296 mg/kg (mammal, subcutaneous); 93.8 mg/kg (mouse, subcutaneous); 8.5 mg/kg (mouse, IP); 5.6 mg/kg (rat); 130 mg/kg (rat, oral); 25 mg/kg (rat, IV)
	NIOSH (US health exposure limits):
PEL (Permissible)	TWA 0.4 mg/m3 (0.1 ppm)
REL (Recommended)	TWA 0.4 mg/m3 (0.1 ppm)
IDLH (Immediate danger)	100 mg/m3
Related compounds
Related compounds	1,2-Benzoquinone
	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

1,4-Benzoquinone, commonly known as para-quinone, is a chemical compound with the formula C₆H₄O₂. In a pure state, it forms bright-yellow crystals with a characteristic irritating odor, resembling that of chlorine, bleach, and hot plastic or formaldehyde. This six-membered ring compound is the oxidized derivative of 1,4-hydroquinone. The molecule is multifunctional: it exhibits properties of a ketone, being able to form oximes; an oxidant, forming the dihydroxy derivative; and an alkene, undergoing addition reactions, especially those typical for α,β-unsaturated ketones. 1,4-Benzoquinone is sensitive toward both strong mineral acids and alkali, which cause condensation and decomposition of the compound.