O ▁is ▁ 6 s - domin ated , ▁and ▁the ▁L UM O ▁is ▁ 6 p - domin ated . ▁The ▁N BO s ▁are ▁of ▁the ▁ 6 s ▁l one ▁pair ▁and ▁vac ant ▁ 6 p ▁orb ital ▁respectively . ▁ ▁The ▁P b – C ▁bond ▁distance ▁was ▁found ▁to ▁be ▁ 2 . 3 0 3   Å ▁and ▁the ▁C – P b – C ▁angle ▁ 1 0 5 . 7 ° . ▁Not with standing ▁the ▁different ▁levels ▁of ▁theory , ▁the ▁larger ▁bond ▁angle ▁for ▁( C 6 H 5 ) 2 P b ▁compared ▁to ▁ ▁can ▁be ▁rational ized ▁by ▁the ▁greater ▁rep ulsion ▁between ▁the ▁ster ically ▁bulk ier ▁phen yl ▁groups ▁relative ▁to ▁m eth yl ▁groups . ▁ ▁At oms ▁in ▁mole cules ▁( A IM ) ▁topology ▁analysis ▁revealed ▁critical ▁points ▁in ▁( C 6 H 5 ) 2 P b , ▁and ▁is ▁consistent ▁with ▁the ▁literature . ▁ ▁Pl um by len es ▁occur ▁as ▁re active ▁inter medi ates ▁in ▁the ▁formation ▁of ▁t etra val ent ▁pl um ban es ▁( R 4 P b ). ▁Although ▁the ▁in ert ▁pair ▁effect ▁suggests ▁the ▁div al ent ▁state ▁should ▁be ▁therm od ynam ically ▁more ▁stable ▁than ▁the ▁t etra val ent ▁state , ▁in ▁the ▁absence ▁of ▁stabil izing ▁subst itu ents , ▁pl um by len es ▁are ▁sensitive ▁to ▁heat ▁and ▁light , ▁and ▁tend ▁to ▁under go ▁polym