 In such asymmetric cases, the substituent angles' half angles, , are averaged and then doubled to find the total cone angle, "θ".In the case of diphosphines, the of the backbone is approximated as half the chelate bite angle, assuming a bite angle of 74°, 85°, and 90° for diphosphines with methylene, ethylene, and propylene backbones, respectively.The Manz cone angle is often easier to compute than the Tolman cone angle