Linked from
The 9 pages that link to Oxide ion, each with the reason it gives.
Metal oxideBroader topic: It is the oxygen-containing ion in common ionic metal oxides.
Barium oxideRelated: Each formula unit pairs one oxide ion with one barium ion.
Potassium oxideBroader topic: Each oxide ion balances the charge of two potassium ions in K₂O.
Iron(II,III) oxideRelated: Oxide ions balance the positive charges of both iron states in Fe₃O₄.
Manganese(II) oxideRelated: Oxide ions balance Mn²⁺ charges in the compound's formula and lattice.