Melting point :−135 °C(lit.)
Boiling point :44-46 °C(lit.)
Density :0.771 g/mL at 25 °C(lit.)
vapor pressure :20.89 psi ( 55 °C)
refractive index :n20/D 1.421(lit.)
Flash point :<−30 °F
storage temp. :0-6°C
solubility :water: soluble0.535g/L at 25°C
form :Liquid
Specific Gravity :0.771
color :Colorless
Water Solubility :immiscible
Sensitive :Air Sensitive
BRN :635707
Henry's Law Constant :6.3 x 10^-2 atm?m³/mol at 25 °C (Hine and Mookerjee, 1975)
Stability :Stable. Highly flammable. Incompatible with strong oxidizing agents. Store cold.
InChIKey :LPIQUOYDBNQMRZ-UHFFFAOYSA-N
LogP :2.47 at 25℃
CAS DataBase Reference :142-29-0(CAS DataBase Reference)
NIST Chemistry Reference :Cyclopentene(142-29-0)
EPA Substance Registry System :Cyclopentene (142-29-0)

Symbol(GHS):
Signal word:	Danger
Hazard statements:	Code Hazard statements Hazard class Category Signal word Pictogram P-Codes H225 Highly Flammable liquid and vapour Flammable liquids Category 2 Danger P210,P233, P240, P241, P242, P243,P280, P303+ P361+P353, P370+P378,P403+P235, P501 H304 May be fatal if swallowed and enters airways Aspiration hazard Category 1 Danger H315 Causes skin irritation Skin corrosion/irritation Category 2 Warning P264, P280, P302+P352, P321,P332+P313, P362
Precautionary statements:	P210 Keep away from heat/sparks/open flames/hot surfaces. — No smoking. P233 Keep container tightly closed. P280 Wear protective gloves/protective clothing/eye protection/face protection. P301+P310 IF SWALLOWED: Immediately call a POISON CENTER or doctor/physician. P303+P361+P353 IF ON SKIN (or hair): Remove/Take off Immediately all contaminated clothing. Rinse SKIN with water/shower. P331 Do NOT induce vomiting.