Dative bonding is defined as a covalent bond in which:

• A. The electrons being shared are supplied by both participating atoms.
• B. The electrons being shared are supplied by electrons from both participating atoms in equal amounts.
• C. The electrons being shared are supplied by only one of the participating atoms.
• D. The electrons being shared are supplied by the ions in an ionic bond.

Answer: (C)

Coordinate covalent bonds form when the electron pair being shared comes from one atom, typically a atom with a lone pair, and is donated to another atom that accepts it. The bond is still covalent because a pair of electrons is shared, but the source of that pair is a single atom rather than both contributing equally. This is why the correct description is that the electrons being shared are supplied by only one of the participating atoms. An example is ammonia donating its lone pair to boron in boron trifluoride to form a coordinate bond; after formation, the N–B linkage behaves like a normal covalent bond, even though the electron pair originated from nitrogen. The other descriptions either imply equal sharing from both atoms or involve ions in an ionic bond, which are not characteristic of dative bonding.