The correct option is D Coordinate bond, Nitrogen, Boron
∙ In covalent bond each of the two bonded atoms contribute one electron to form the bond.
∙ However, in some compounds, the formation of a covalent bond between two atoms takes place by the sharing
of two electrons, both of which comes from only one of the combining atoms. This bond is called Coordinate covalent bond.
bond.
∙ The atom which provides the electron pair is called donor atom while the other atom which accepts the electron pair is called acceptor atom.
∙ In NH3BF3 molecule a coordinate bond is present between nitrogen and boron atom. Here, Nitrogen is the donar atom while boron is the acceptor atom.