▁alk ene ▁bond : ▁ 1 4 6 ▁pm ). ▁ ▁St ability ▁due ▁to ▁cy clic ▁del ocal ization ▁of ▁the ▁six ▁electrons ▁of ▁cy clo prop ane ' s ▁three ▁C - C ▁ σ ▁b onds ▁was ▁given ▁by ▁Michael ▁J . ▁S . ▁D ew ar ▁as ▁an ▁explanation ▁of ▁the ▁only ▁slightly ▁greater ▁stra in ▁of ▁cy clo prop ane ▁(" only " ▁ 2 7 . 6   k cal / m ol ) ▁as ▁compared ▁to ▁cy c lob ut ane ▁( 2 6 . 2   k cal / m ol ) ▁with ▁cy clo hex ane ▁as ▁reference ▁with ▁E str = 0   k cal / m ol . ▁This ▁stabil ization ▁is ▁referred ▁to ▁as ▁ σ ▁a rom atic ity , ▁in ▁contrast ▁to ▁the ▁usual ▁ π ▁a rom atic ity , ▁that , ▁for ▁example , ▁is ▁a ▁highly ▁stabil izing ▁effect ▁in ▁ben z ene . ▁Other ▁studies ▁do ▁not ▁support ▁the ▁role ▁of ▁ σ - ar om atic ity ▁in ▁cy clo prop ane ▁and ▁the ▁existence ▁of ▁an ▁induced ▁ring ▁current ; ▁such ▁studies ▁provide ▁an ▁alternative ▁explanation ▁for ▁the ▁ener get ic ▁stabil ization ▁and ▁ab normal ▁magnetic ▁behaviour ▁of ▁cy clo prop ane . ▁ ▁Syn thesis ▁Cy clo prop ane ▁was ▁first ▁produced ▁via ▁a ▁W urt z ▁coupling , ▁in ▁which ▁▁ 1 , 3 - d ib rom op rop ane ▁was ▁cycl ised ▁using ▁sod ium . ▁The ▁yield