Cyclopentane has very little angle strain (the angles of a pentagon are 108º), but its eclipsing strain would be large (about 10 kcal/mol) if it remained planar. ... Rings larger than cyclopentane would have angle strain if they were planar.

What is the angle strain in cyclopropane?

Angle strain in cyclopropane arises from the circumstance that the C-C-C angle is forced to be 60 degrees (that of an equilateral triangle), about 49 degrees less than the ideal angle for the strongest C-C bond (the strain angle is ca. 49 degrees.

Why does cyclopentane have torsional strain?

There is some torsional strain in cyclopentane. The envelope conformation reduces torsional strain by placing some bonds in nearly staggered positions. However, other bonds are still almost fully eclipsed. Cyclopentane is not large enough to allow for steric strain to be created.