Manganese oxide is any of a variety of manganese oxides and hydroxides.^[1] These include

• Manganese(II) oxide, MnO
• Manganese(II,III) oxide, Mn₃O₄
• Manganese(III) oxide, Mn₂O₃
• Manganese dioxide, MnO₂
• Manganese(VI) oxide, MnO₃
• Manganese(VII) oxide, Mn₂O₇

Other manganese oxides include Mn₅O₈, Mn₇O₁₂ and Mn₇O₁₃.

It may refer more specifically to the following manganese minerals:

• Birnessite, (Na,Ca)_0.5(Mn^IV,Mn^III)₂O₄ · 1.5 H₂O
• Buserite, MnO₂·nH₂O
• Hausmannite, Mn^IIMn^III₂O₄
• Manganite, Mn^IIIO(OH)
• Manganosite, Mn^IIO
• Psilomelane, Ba(Mn^II)(Mn^IV)₈O₁₆(OH)₄, or (Ba,H₂O)₂Mn₅O₁₀
• Pyrolusite, Mn^IVO₂

Manganese may also form mixed oxides with other metals :

• Bixbyite, (Fe^III,Mn^III)₂O₃, a manganese(III) iron(III) oxide mineral
• Jacobsite, Mn^IIFe^III₂O₄, a manganese(II) iron(III) oxide mineral
• Columbite, (Fe^II,Mn^II)Nb₂O₆, a niobate of iron(II) and manganese(II)
• Tantalite, (Fe^II,Mn^II)Ta₂O₆, a tantalum(V) mineral group close to that of columbite
• Coltan, a mixture of columbite and tantalite series
• Galaxite, Mn^IIAl₂O₄, a spinel mineral
• Todorokite, (Na,Ca,K,Ba,Sr)
  _1-x(Mn,Mg,Al)
  ₆O
  ₁₂·3-4H
  ₂O, a rare complex hydrous manganese oxide mineral