dative covalent bond,

自旋极化成键(spin-polarized bond):nabh3-中的na-b键 - 知乎
accept a pair of electrons to form a (dative) covalent bond 亲核
the boron–boron triple bond in nhc→b[triple bond, length as m
33 the dative-character of the nhc
33 the dative-character of the nhc