A generic hydrogen bond. X-H is the hydrogen bond donor (shown in red) and A is the hydrogen bond acceptor. The hydrogen bond is indicated by -------.
In this hydrogen bond between water and ammonia, water is the hydrogen bond donor (shown in red) and ammonia is the hydrogen bond acceptor.
In this hydrogen bond between water and ammonia, ammonia is the hydrogen bond donor (shown in red) and water is the hydrogen bond acceptor.