Three nitrogen groups are bound to this element in alternative coupling agents used in solid-phase peptide synthesis, such as B·O·P and Py·B·O·P. A method of activating a palladium zero catalyst for the Heck reaction involves acetate forming a bond with this element. Nickel complexes to ligands containing this element were used to develop the Tolman cone angle parameter. Berry (*) pseudo-rotation (-5[1])is classically exemplified by this element bound to five fluorine atoms. (10[1])Many courses incorrectly teach that oxygen (10[1])binds to this element in a betaine (“beta-een”) intermediate [emphasize] after a carbon-carbon bond forms in the Wittig reaction. (10[1])For 10 points, name this element that sits right below nitrogen on the periodic (10[1])table. ■END■ (10[1])