Cinemeccanica was created in 1920.

P= S + S + S + S

P= # + # + # + #

P= answer

M-I-S-S-I-S-S-I-P-P-I was created in 1916.

Among s-s,s-p,p-p

sigma P-P is strong enough because of greater overlapping.The bond strengths for sigma S-S is 1.0 ,for sigma S-P is 1.71 and for sigma P-P is 3.0. so sigma

P-P is stronger it means that it is more stable. But many books they have given that s-s overlapping is more than p-p overlapping .This is not true because due spherical shape of the s orbital the charge is symmetrically distributed and also small size there will not effective overlapping of orbitals as P-P overlapping .So P-P bond is stronger than S-S bond.