Nickel(II) carbonate describes one or a mixture of

inorganic compounds 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 ...

containing

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 ...

and

carbonate A carbonate is a salt of carbonic acid (H2CO3), characterized by the presence of the carbonate ion, a polyatomic ion with the formula . The word ''carbonate'' may also refer to a carbonate ester, an organic compound containing the carbonate ...

. From the industrial perspective, the most important nickel carbonate is basic nickel carbonate with the formula Ni₄CO₃(OH)₆(H₂O)₄. Simpler carbonates, ones more likely encountered in the laboratory, are NiCO₃ and its hexahydrate. All are

paramagnetic Paramagnetism is a form of magnetism whereby some materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field. In contrast with this behavior, ...

green solids containing Ni²⁺ cations. The basic carbonate is an intermediate in the hydrometallurgical purification of nickel from its ores and is used in electroplating of nickel.

Structure and reactions

NiCO₃ adopts a structure like calcite, consisting of nickel in an

octahedral coordination geometry In chemistry, octahedral molecular geometry, also called square bipyramidal, describes the shape of compounds with six atoms or groups of atoms or ligands symmetrically arranged around a central atom, defining the vertices of an octahedron. The oc ...

. Nickel carbonates are hydrolyzed upon contact with aqueous acids to give solutions containing the ion i(H₂O)₆sup>2+, liberating water and

carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...

in the process. Calcining (heating to drive off CO₂ and water) of these carbonates gives

nickel oxide Nickel oxide may refer to: * Nickel(II) oxide, NiO, green, well-characterised oxide * Nickel(III) oxide Nickel (III) oxide is the inorganic compound In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydr ...

: :NiCO₃ → NiO + CO₂ The nature of the resulting oxide depends on the nature of the precursor. The oxide obtained from the basic carbonate is often most useful for

catalysis Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

. Basic nickel carbonate can be made by treating solutions of

nickel sulfate Nickel(II) sulfate, or just nickel sulfate, usually refers to the inorganic compound with the formula NiSO4(H2O)6. This highly soluble blue green coloured salt is a common source of the Ni2+ ion for electroplating. Approximately 40,000 tonnes ...

with sodium carbonate: :4 Ni²⁺ + CO₃²⁻ + 6 OH⁻ + 4 H₂O → Ni₄CO₃(OH)₆(H₂O)₄ The hydrated carbonate has been prepared by electrolytic oxidation of nickel in the presence of carbon dioxide: :Ni + O + CO₂ + 6 H₂O → NiCO₃(H₂O)₄

Uses

Nickel carbonates are used in some ceramic applications and as precursors to

catalyst Catalysis () is the process of increasing the rate of a chemical reaction by adding a substance known as a catalyst (). Catalysts are not consumed in the reaction and remain unchanged after it. If the reaction is rapid and the catalyst recyc ...

Natural occurrence

The natural nickel carbonate is known as

gaspéite Gaspéite, a very rare nickel carbonate mineral, with the formula , is named for the place it was first described, in the Gaspé Peninsula, Québec, Canada. Gaspéite is the nickel rich member of the calcite group. A solid solution series exis ...

- a rare mineral. Basic Ni carbonates also have some natural representatives.

Safety

It is moderately toxic and causes low irritation. Avoid prolonged contact.

References

{{Nickel compounds Carbonates Nickel compounds IARC Group 1 carcinogens