Nickel oxide hydroxide is the

inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemi ...

with the chemical formula NiO(OH). It is a black solid that is insoluble in all solvents but attacked by base and acid. It is a component of the nickel-metal hydride battery and of the

nickel–iron battery The nickel–iron battery (NiFe battery) is a rechargeable battery having nickel(III) oxide-hydroxide positive plates and iron negative plates, with an electrolyte of potassium hydroxide. The active materials are held in nickel-plated steel tub ...

Related materials

Nickel(III) oxides are often poorly characterized and are assumed to be

nonstoichiometric compounds In chemistry, non-stoichiometric compounds are chemical compounds, almost always solid inorganic compounds, having elemental composition whose proportions cannot be represented by a ratio of small natural numbers (i.e. an empirical formula); ...

. Nickel(III) oxide (Ni₂O₃) has not been verified crystallographically. For applications in organic chemistry, nickel oxides or peroxides are generated in situ and lack crystallographic characterization. For example, "nickel peroxide" ( CAS# 12035-36-8) is also closely related to or even identical with NiO(OH).

Synthesis and structure

Its layered structure resembles that of the brucite polymorph of

nickel(II) hydroxide Nickel(II) hydroxide is the inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a su ...

, but with half as many hydrogens. The oxidation state of nickel is 3+. It can be prepared by the reaction of nickel(II) hydroxide with aqueous

potassium hydroxide Potassium hydroxide is an inorganic compound with the formula K OH, and is commonly called caustic potash. Along with sodium hydroxide (NaOH), KOH is a prototypical strong base. It has many industrial and niche applications, most of which expl ...

and

bromine Bromine is a chemical element with the symbol Br and atomic number 35. It is the third-lightest element in group 17 of the periodic table (halogens) and is a volatile red-brown liquid at room temperature that evaporates readily to form a simil ...

as the oxidant: : 2 Ni(OH)₂ + 2 KOH + Br₂ → 2 KBr + 2 H₂O + 2 NiOOH

Use in organic chemistry

Nickel(III) oxides catalyze the oxidation of

benzyl alcohol Benzyl alcohol is an aromatic alcohol with the formula C6H5CH2OH. The benzyl group is often abbreviated "Bn" (not to be confused with "Bz" which is used for benzoyl), thus benzyl alcohol is denoted as BnOH. Benzyl alcohol is a colorless liqui ...

benzoic acid Benzoic acid is a white (or colorless) solid organic compound with the formula , whose structure consists of a benzene ring () with a carboxyl () substituent. It is the simplest aromatic carboxylic acid. The name is derived from gum benzoin, w ...

using bleach:''An Efficient and Practical System for the Catalytic Oxidation of Alcohols, Aldehydes, and ,-Unsaturated Carboxylic Acids'' Joseph M. Grill, James W. Ogle, and Stephen A. Miller J. Org. Chem.; 2006; 71(25) pp 9291 - 9296; (Article) : Similarly it catalyzes the double oxidation of 3-butenoic acid to

fumaric acid Fumaric acid is an organic compound with the formula HO2CCH=CHCO2H. A white solid, fumaric acid occurs widely in nature. It has a fruit-like taste and has been used as a food additive. Its E number is E297. The salts and esters are known as fum ...

: :

References

Inorganic compounds Catalysts Electrochemistry Nickel compounds Non-stoichiometric compounds Transition metal oxides {{electrochem-stub