ADOLF BAEYER SAYS THAT THE NORMAL BOND ANGLE BETWEEEN CARBON CARBON ATOMS IS 109 DEGREES AND 28 MINUTES , BAYER STRAIN THEORY IS BASED ON THE FACT THAT ANY DEVIATION IN THE ANGLE BETWEEN C-C BOND WOULD RESULT IN STABILITY CHANGE THAT MEANS IF IT IS NEARER TO 109.28’ THERE WILL BE MORE STABILITY..
EX:-
C-C BOND ANGLE IN VARIOUS HYDROCARBONS RESULTING IN STABILITY VARIATION.
BOND ANGLE ANGLE STRAIN
CYCLOPROPANE : 60 24.44’
CYCLOBUTANE : 90 9.44’
CYCLOPENTANE : 108 0.44’
WE CAN SEE THAT CYCLOPENTANE BOND ANGLE IS MORE CLOSER TO 109.28’N AND CYCLOPROPANE IS FARTHER TO THAT, SO CYCLOPENTANE IS MORE STABLE THAN CYCLOPROPANE.