Pentoxide may refer to:
Antimony pentoxide, Sb2O5 Arsenic pentoxide, As2O5 Carbon pentoxide, CO5 Dinitrogen pentoxide, N2O5 Iodine pentoxide, I2O5 Niobium pentoxide, Nb2O5 Phosphorus pentoxide, P4O10 Tantalum pentoxide, Ta2O5 Tungsten pentoxide, W18O49