Nickel manganese oxides, or nickel manganates, are

spinel Spinel () is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula in the cubic crystal system. Its name comes from the Latin word , which means ''spine'' in reference to its pointed crystals. Properties S ...

structure compounds of

Nickel Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is a hard and ductile transition metal. Pure nickel is chemically reactive but large pieces are slow to ...

Manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...

and

Oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as wel ...

of the form: Some common forms are Ni₂MnO₄, NiMn₂O₄, and Ni_1.5Mn_1.5O₄ They are most commonly formulated for use in thin film resistors and thermistors. The resistivity and temperature coefficient can be accurately controlled in the manufacturing process. In nickel-metal hydride batteries the addition of manganese oxide provides for formation of spinel structure nickel manganates in various oxidation states, with higher conductivity and charge capacity than nickel hydroxides alone. Magnetic properties of nickel manganates. Although nickel manganates exhibit ferromagnetic behaviour at low temperatures, they have a paramagnetic behavior at room temperature. The magnetic behavior depends on the cation distribution and spin alignment among them. In nickel manganates, the Ni²⁺ and Mn⁴⁺ ions have a strong preference for occupying octrahedral sites instead of tetrahedral sites. Mn²⁺ ion is in tretrahedral sites and Mn³⁺ ion can be in both sites. Also, these compounds has been studied as electrodes for supercapacitors and as photocatalyst taking advantage of the Change in the oxidation state of the Mn catios.

References

{{reflist Transition metal oxides Manganese compounds Nickel compounds