Fig. 2. MEPs of the unsaturated P(v) electrophiles 10–15. Both transparent and filled maps of the same structures are shown. The CHELPG charges of the reaction site, with hydrogen(s) summed into the terminal carbon, are written in black. The most positive MEP values (in kcal mol⁻¹) found on the edges of the isodensity surface (0.0004 a.u.) are written in blue.