What characterizes a dative (co-ordinate) bond?

A dative (or coordinate) bond is specifically characterized by one atom providing both of the electrons needed to form the bond. This type of bond occurs when a lone pair of electrons from one atom is shared with another atom that has an empty orbital, allowing them to bond together. This is distinct from a regular covalent bond, where each atom contributes one electron to the bond.

In the context of molecular formation, a dative bond is commonly found in complex ions or certain molecular structures, such as ammonium ion (NH₄⁺), where nitrogen donates its lone pair to bond with a hydrogen ion (H⁺). This explains why the answer correctly identifies that one atom provides both electrons for forming the bond, highlighting the unique contribution of the atom donating the lone pair. Understanding this concept helps distinguish dative bonds from other types of bonding interactions in chemistry.