Nickel(II) carbonate

Nickel(II) carbonate

Names
IUPAC name Nickel(II) carbonate
Other names Nickelous carbonate
Identifiers
CAS Number	3333-67-3 N 29863-10-3 (Ni4CO3(OH)6(H2O)4) N
3D model (JSmol)	Interactive image
ChemSpider	17701 Y
ECHA InfoCard	100.020.063
EC Number	222-068-2
PubChem CID	18746
RTECS number	QR6200000
UN number	3288
CompTox Dashboard (EPA)	DTXSID201333983 DTXSID3025708, DTXSID201333983
InChI InChI=1S/CH2O3.Ni/c2-1(3)4;/h(H2,2,3,4);/q;+2/p-2 Y Key: ZULUUIKRFGGGTL-UHFFFAOYSA-L Y InChI=1/CH2O3.Ni/c2-1(3)4;/h(H2,2,3,4);/q;+2/p-2 Key: ZULUUIKRFGGGTL-NUQVWONBAN
SMILES [Ni+2].[O-]C([O-])=O
Properties
Chemical formula	NiCO3
Molar mass	118.7
Appearance	light green powder
Density	4.39 g/cm3
Melting point	205 °C (401 °F; 478 K) decomposes
Solubility in water	0.0093 g/100ml
Solubility product (Ksp)	6.6·10−9
Structure
Crystal structure	rhombohedral
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H302, H312, H315, H317, H319, H332, H334, H335, H350
Precautionary statements	P201, P261, P280, P305+P351+P338, P308+P313
NFPA 704 (fire diamond)	2 0 0
Lethal dose or concentration (LD, LC):
LD50 (median dose)	840 mg/kg
Safety data sheet (SDS)	ICSC 0927
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is YN ?) Infobox references

Nickel(II) carbonate describes one or a mixture of inorganic compounds containing nickel and carbonate. From the industrial perspective, an 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 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.

Preparation

The hexahydrate NiCO₃•6H₂O is claimed to form upon electrolysis of nickel metal under an atmosphere of carbon dioxide. Green and yellow forms of anhydrous NiCO₃ form when aqueous nickel chloride solutions are heated under high pressures of carbon dioxide.

Structure and reactions

NiCO₃ adopts a structure like calcite, consisting of nickel in an octahedral coordination geometry. A pentahydrate has also been characterized by X-ray crystallography. Also known as the mineral hellyerite, the solid consists of [Ni₂(CO₃)₂(H₂O)₈] subunits with an extra water of hydration.

Nickel carbonates are hydrolyzed upon contact with aqueous acids to give solutions containing the ion [Ni(H₂O)₆]²⁺, liberating water and carbon dioxide in the process. Calcining (heating to drive off CO₂ and water) of these carbonates gives nickel(II) oxide:

${\ce {NiCO3 -> NiO + CO2}}$

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.

Basic nickel carbonate can be made by treating solutions of nickel sulfate with sodium carbonate:

${\ce {4 Ni^2+ + CO3^2- + 6 OH- + 4 H2O -> Ni4CO3(OH)6(H2O)4}}$

The hydrated carbonate has been prepared by electrolytic oxidation of nickel in the presence of carbon dioxide:

${\ce {Ni + O + CO2 + 6 H2O -> NiCO3(H2O)4}}$

Uses

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

Natural occurrence

The natural nickel carbonate is hellyerite, mentioned above. Basic Ni carbonates also have some natural representatives.