Why doesn't Oxygen form coordinate covalent bonds?

Question

We know that an Oxygen atom has two lone pairs. Why doesn't oxygen then form coordinate covalent bonds using those since it has nothing to lose?

Answer 1

Oxygen very much does form bonds in which both electrons come from the oxygen atom. Examples include:

1. The $\ce{H3O^+}$ ion at the center of the solvated proton in aqueous acids, also available as salts of some of the strongest acids such as $\ce{(H3O)(ClO4)}$

2. Carbon monoxide, with its triple rather than double bond.

3. Ozone, in which the oxygen atoms form a bent chain and one of the three bonds must have both electrons coming from the middle atom. The resulting charge separation makes ozone one of the few one-element substances with a nonzero dipole moment.

Answer 2

The number of complex compounds that are surrounded by water molecules is quite big , a few examples of water being a ligand include [Cu(H₂O)₄]²⁺ or [Co(H₂O)₆]²⁺. Anyway oxygen is indeed less eager to donate its electrons because its electronegativity is considerably high, nitrogen for example works better as a ligand (actually the first complex compounds to be observed and classified were with NH₃ as ligands).But the examples where O donates his electrons can be found quite readily.