Cadmium sulfate

Cadmium sulfate
IUPAC name Cadmium(II) sulfate
Other names Sulfuric acid, cadmium salt (1:1), Niedermayrite
Identifiers
CAS number	10124-36-4 Y,  7709-84-3 (monohydrate) 15244-35-9 (octahydrate)
ChemSpider	23335 Y
UNII	947UNF3Z6O Y
EC number	233-331-6
UN number	2570
ChEBI	CHEBI:50292 Y
RTECS number	EV2700000
Jmol-3D images	Image 1
SMILES [Cd+2].[O-]S([O-])(=O)=O
InChI InChI=1S/Cd.H2O4S/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+2;/p-2 Y Key: QCUOBSQYDGUHHT-UHFFFAOYSA-L Y InChI=1/Cd.H2O4S/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+2;/p-2 Key: QCUOBSQYDGUHHT-NUQVWONBAG
Properties
Molecular formula	CdSO4 CdSO4·H2O (monohydrate) 3CdSO4·8H2O (octahydrate)
Molar mass	208.47 g/mol (anhydrous) 226.490 g/mol (monohydrate) 769.546 g/mol (octahydrate)
Appearance	White hygroscopic solid
Density	4.691 g/cm3 (anhydrous) 3.79 g/cm3 (monohydrate) 3.08 g/cm3 (octahydrate)
Melting point	1000 °C (anhydrous) 105 °C (monohydrate) 40 °C (octahydrate)
Boiling point	(decomposes to basic sulfate and then oxide)
Solubility in water	anhydrous: 75 g/100 mL (0 °C) 76.4 g/100 mL (25 °C) 58.4 g/100 mL (99 °C) octahydrate: very soluble
Solubility	insoluble in ethanol
Structure
Crystal structure	orthorhombic (anhydrous) monoclinic (octahydrate)
Thermochemistry
Std enthalpy of formation ΔfHo298	−935 kJ·mol−1
Standard molar entropy So298	123 J·mol−1·K−1
Hazards
MSDS	[1]
EU Index	048-009-00-9
EU classification	Carc. Cat. 2 Muta. Cat. 2 Repr. Cat. 2 Very toxic (T+) Dangerous for the environment (N)
R-phrases	R45, R46, R60, R61, R25, R26, R48/23/25, R50/53
S-phrases	S53, S45, S60, S61
NFPA 704	1 3 0
LD50	280 mg/kg (oral, rat)
Related compounds
Other anions	Cadmium acetate, Cadmium chloride, Cadmium nitrate
Other cations	Zinc sulfate, Calcium sulfate, Magnesium sulfate
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Cadmium sulfate is the name of a series of related inorganic compounds with the formula CdSO₄.xH₂O. The most common form is the monohydrate CdSO₄.H₂O, but two other forms are known CdSO₄.8/3H₂O and the anhydrous salt (CdSO₄). All salts are colourless and highly soluble in water.

Preparation and occurrence

Cadmium sulfate octohydrate can be prepared by the reaction of cadmium metal or its oxide or hydroxide with dilute sulfuric acid:

CdO + H₂SO₄ → CdSO₄ + H₂O

Cd + H₂SO₄ → CdSO₄ + H₂

The anhydrous material is prepared using sodium persulfate:

Cd + Na₂S₂O₈ → CdSO₄ + Na₂SO₄

Cadmium sulfate is very rarely found naturally in from of a tetrahydrate mineral called drobecite and as a basic salt in the mineral Niedermayrite. It is used as a pigment.

Applications

Cadmium sulfate is used widely for the electroplating of cadmium in electronic circuits. It is also a precursor to cadmium-based pigment such as cadmium sulfide. It is also used for electrolyte in a Weston standard cell.