P-Xylene

p-Xylene
	Skeletal formula
	Space-filling model
Names
	Preferred IUPAC name 1,4-Xylene
	Systematic IUPAC name 1,4-dimethylbenzene
	Other names p-Xylene, p-dimethylbenzene; p-xylol; 1,4-xylene; p-methyltoluene; paraxylene; chromar; scintillar; 4-methyltoluene; NSC 72419; or 1,4-dimethylbenzene.
Identifiers
CAS Number	106-42-3 ;
3D model (JSmol)	Interactive image;
Beilstein Reference	1901563
ChEBI	CHEBI:27417 ;
ChEMBL	ChEMBL31561 ;
ChemSpider	7521 ;
ECHA InfoCard	100.003.088
EC Number	203-396-5;
Gmelin Reference	2697
KEGG	C06756 ;
PubChem CID	7809;
RTECS number	ZE2625000;
UNII	6WAC1O477V ;
CompTox Dashboard (EPA)	DTXSID2021868 ;
	InChI InChI=1S/C8H10/c1-7-3-5-8(2)6-4-7/h3-6H,1-2H3 Key: URLKBWYHVLBVBO-UHFFFAOYSA-N ; InChI=1/C8H10/c1-7-3-5-8(2)6-4-7/h3-6H,1-2H3 Key: URLKBWYHVLBVBO-UHFFFAOYAE;
	SMILES CC1=CC=C(C)C=C1;
Properties
Chemical formula	C8H10
Molar mass	106.168 g·mol−1
Appearance	Colorless liquid
Odor	Aromatic
Density	0.861 g/mL
Melting point	13.2 °C (55.8 °F; 286.3 K)
Boiling point	138.35 °C (281.03 °F; 411.50 K)
Solubility in water	Insoluble
Solubility in ethanol	Very soluble
Solubility in diethyl ether	Very soluble
Vapor pressure	9 mmHg (20 °C)
Magnetic susceptibility (χ)	−76.78·10−6 cm3/mol
Refractive index (nD)	1.49582
Viscosity	0.7385 cP at 0 °C; 0.6475 cP at 20 °C
Dipole moment	0.00 D
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	Harmful or if swallowed. Vapor maybe toxic. Flammable liquid and vapor.
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H226, H302, H304, H312, H315, H319, H332, H335, H412
Precautionary statements	P210, P233, P240, P241, P242, P243, P261, P264, P271, P273, P280, P301+P310, P302+P352, P303+P361+P353, P304+P312, P304+P340, P305+P351+P338, P312, P321, P322, P331, P332+P313, P337+P313, P362, P363, P370+P378, P403+P233, P403+P235, P405, P501
NFPA 704 (fire diamond)	2 3 0
Flash point	27 °C (81 °F; 300 K)
Autoignition; temperature	528 °C (982 °F; 801 K)
Explosive limits	1.1%-7.0%
Threshold limit value (TLV)	100 ppm (TWA), 150 ppm (STEL)
	Lethal dose or concentration (LD, LC):
LD50 (median dose)	4300 mg/kg
LC50 (median concentration)	4550 ppm (rat, 4 hr)
LCLo (lowest published)	3401 ppm (mouse)
	NIOSH (US health exposure limits):
PEL (Permissible)	TWA 100 ppm (435 mg/m3)
REL (Recommended)	TWA 100 ppm (435 mg/m3) ST 150 ppm (655 mg/m3)
IDLH (Immediate danger)	900 ppm
Safety data sheet (SDS)	External MSDS
Related compounds
Related aromatic; hydrocarbons	benzene; toluene; o-xylene; m-xylene
Supplementary data page
	P-Xylene (data page)
	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

p-Xylene (para-xylene) is an aromatic hydrocarbon. It is one of the three isomers of dimethylbenzene known collectively as xylenes. The p- stands for para-, indicating that the two methyl groups in p-xylene occupy the diametrically opposite substituent positions 1 and 4. It is in the positions of the two methyl groups, their arene substitution pattern, that it differs from the other isomers, o-xylene and m-xylene. All have the same chemical formula C₆H₄(CH₃)₂. All xylene isomers are colorless and highly flammable. The odor threshold of p-xylene is 0.62 parts per million (ppm).