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 Ni
4CO
3(OH)
6(H
2O)
4. Simpler carbonates, ones more likely encountered in the laboratory, are NiCO
3 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 Ni
2+ 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
NiCO
3 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
2O)6">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 CO
2 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 ...
:
:NiCO
3 → NiO + CO
2
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 Ni
2+ + CO
32− + 6 OH
− + 4 H
2O → Ni
4CO
3(OH)
6(H
2O)
4
The hydrated carbonate has been prepared by electrolytic oxidation of nickel in the presence of carbon dioxide:
:Ni + O + CO
2 + 6 H
2O → NiCO
3(H
2O)
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 ...
s.
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