Methylcyclopentadiene

Methylcyclopentadiene
	Left to right: 2-methyl-1,3-cyclopentadiene; 1-methyl-1,3-cyclopentadiene; 5-methyl-1,3-cyclopentadiene
Names
	Other names Cp′; MeCp
Identifiers
CAS Number	unspec: 96-38-8 ; 1-methyl: 96-39-9 ; 2-methyl: 3727-31-9 ; 5-methyl: 26519-91-5 ;
3D model (JSmol)	1-methyl: Interactive image; 2-methyl: Interactive image; 5-methyl: Interactive image;
ChemSpider	1-methyl: 60141; 2-methyl: 121669; 5-methyl: 23802;
ECHA InfoCard	100.043.400
EC Number	1-methyl: 247-724-5;
PubChem CID	1-methyl: 66775; 2-methyl: 138026; 5-methyl: 25512;
UNII	1-methyl: K4O53GR393; 5-methyl: X1DWO24VEA;
UN number	1993
CompTox Dashboard (EPA)	1-methyl: DTXSID0067216; 2-methyl: DTXSID10190729; 5-methyl: DTXSID7048035;
	InChI 1-methyl: InChI=1S/C6H8/c1-6-4-2-3-5-6/h2-4H,5H2,1H3 Key: NFWSQSCIDYBUOU-UHFFFAOYSA-N ; 2-methyl: InChI=1S/C6H8/c1-6-4-2-3-5-6/h2,4-5H,3H2,1H3 Key: AHQZRFBZJSCKAV-UHFFFAOYSA-N; 5-methyl: InChI=1S/C6H8/c1-6-4-2-3-5-6/h2-6H,1H3 Key: QVRBGKYLLCLCHL-UHFFFAOYSA-N;
	SMILES 1-methyl: C\1=C\C=C(\C)C/1; 2-methyl: C\1=C\C(\C)=CC/1; 5-methyl: C\1=C\C=CC/1(\C);
Properties
Chemical formula	C6H8
Molar mass	80.130 g·mol−1
Hazards
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H226, H350, H410
Precautionary statements	P201, P202, P210, P233, P240, P241, P242, P243, P273, P280, P281, P303+P361+P353, P308+P313, P370+P378, P391, P403+P235, P405, P501
	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

Methylcyclopentadiene is any of three isomeric cyclic dialkenes with the formula C₅MeH₅ (Me = CH₃). These isomers are the organic precursor to the methylcyclopentadienyl ligand (C₅H₄Me, often denoted as Cp′), commonly found in organometallic chemistry.

As with cyclopentadiene, methylcyclopentadiene is prepared by thermal cracking of its Diels–Alder dimer, followed by distillation for removal of cyclopentadiene, a common impurity.