A co-ordinate bond is a type of alternative covalent bond formed when an electron pair from a single atom is shared. The same atom provides both shared electrons. It’s also known as a dipolar bond or a dative bond.
Example of co-ordinate bond
In ammonium ion, ammonia has a lone pair of electrons present on N atom, so nitrogen shares the lone pair of electrons with the fourth hydrogen atom and a co-ordinate bond is formed between them.