1,2-Dimethylcyclopropane

{{Expand Greek|topic=sci|date=March 2010}}

{{chembox

| Verifiedfields = changed

| Watchedfields = changed

| verifiedrevid = 477203928

| ImageFile=CC1CC1C.svg

| ImageFile1=Dimethylcyclopropane.png

| ImageCaption1 = cis (left) and (S,S)-trans (right) isomers

| PIN=1,2-Dimethylcyclopropane

| OtherNames=

|Section1={{Chembox Identifiers

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| ChemSpiderID = 92890

| InChI = 1/C5H10/c1-4-3-5(4)2/h4-5H,3H2,1-2H3

| InChIKey = VKJLDXGFBJBTRQ-UHFFFAOYAK

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChI = 1S/C5H10/c1-4-3-5(4)2/h4-5H,3H2,1-2H3

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

| StdInChIKey = VKJLDXGFBJBTRQ-UHFFFAOYSA-N

| CASNo_Ref = {{cascite|correct|CAS}}

| CASNo=2511-95-7

| PubChem=102832

| SMILES=CC1CC1C

| RTECS=

}}

|Section2={{Chembox Properties

| C=5 | H=10

| Appearance=

| Density= cis: 0.6889 g/cm³
trans: 0.6648 g/cm³

| MeltingPt= cis: -140 °C
trans: -149.6 °C

| BoilingPt= cis: 37 °C
trans: 28.2 °C

| RefractIndex= cis: 1.3829 (20 °C)
trans: 1.3713 (20 °C)

| Solubility=

| pKa =

| pKb =

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|Section3={{Chembox Hazards

| MainHazards=

| FlashPt=

| AutoignitionPt =

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|Section8={{Chembox Related

| OtherCompounds = cyclopropane, cyclopentane

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1,2-Dimethylcyclopropane is a cycloalkane consisting of a cyclopropane ring substituted with two methyl groups attached to adjacent carbon atoms.{{Cite web |last=PubChem |title=1,2-Dimethylcyclopropane |url=https://pubchem.ncbi.nlm.nih.gov/compound/102832 |access-date=2022-11-15 |website=pubchem.ncbi.nlm.nih.gov |language=en}} It has three stereoisomers, one cis-isomer and a pair of trans-enantiomers, which differ depending on the orientation of the two methyl groups. As with other cyclopropanes, ring tension results in a relatively unstable compound.

1,2-Dimethylcyclopropane is 1 of 10 structural isomers (cycloalkanes and aliphatic alkenes) which share the general formula of C5H10, the others being cyclopentane, methylcyclobutane, 1,1-dimethylcyclopropane, ethylcyclopropane, 1-pentene, 2-pentene, 2-methyl-1-butene, 3-methyl-1-butene, and 2-methyl-2-butene.