Terbium(III,IV) oxide, occasionally called tetraterbium heptaoxide, has the formula Tb4O7.
T 1262 (OTTO) Terbium oxide, 99% Cas 12037-01-3 - used in the preparation of other terbium compounds. Terbium forms three other major oxides: Tb2O3, TbO2, and Tb6O11.