Cadmium sulfate

From Sciencemadness Wiki
Jump to: navigation, search
Cadmium sulfate
Cadmium sulfate octahydrate bottle sample.jpg
Cadmium sulfate octahydrate
Names
IUPAC name
Cadmium(II) sulfate
Other names
Cadmium monosulfate
Cadmium sulphate
Properties
CdSO4 (anhydrous)
CdSO4·H2O (monohydrate)
CdSO4·4H2O (tetrahydrate)
3CdSO4·8H2O (octahydrate)
Molar mass 208.47 g/mol (anhydrous)
226.490 g/mol (monohydrate)
769.546 g/mol (octahydrate)
Appearance White hygroscopic solid
Odor Odorless
Density 4.691 g/cm3 (anhydrous)
3.790 g/cm3 (monohydrate)
3.080 g/cm3 (octahydrate)
Melting point 1000 (anhydrous) (decomposes)
105 °C (monohydrate) (decomposes)
40 °C (octahydrate) (decomposes)
Boiling point Decomposes
anhydrous:
75.0 g/100 mL (0 °C)
76.4 g/100 mL (25 °C)
58.4 g/100 mL (99 °C)
monohydrate:
76.7 g/100 mL (25 °C)
octahydrate:
very soluble
Solubility Slightly soluble in methanol, ethyl acetate
Insoluble in ethanol, toluene, xylene
Thermochemistry
123 J·mol−1·K−1
−935 kJ·mol−1
Hazards
Safety data sheet Sigma-Aldrich
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
280 mg/kg (oral, rat)
Related compounds
Related compounds
Zinc sulfate
Mercury(II) sulfate
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Cadmium sulfate is the chemical compound with the chemical formula CdSO4. While it exists in anhydrous form, it's generally encountered as octahydrate (3CdSO4·8H2O).

Cadmium sulfate can be found in nature as the rare mineral drobecite (CdSO4·4H2O). It is also a component of the rare mineral niedermayrite, which is hydrated copper cadmium sulfate hydroxide.

Properties

Chemical

Cadmium sulfate can be substituted by a more reactive metal, such as aluminium to aluminium sulfate:

3 CdSO4 + 2 Al → 3 Cd + Al2(SO4)3

Physical

Cadmium sulfate is a colorless, hygroscopic odorless salt, very soluble in water. It exists as mono-, tetra- and octahydrated form.

Availability

Cadmium sulfate can be purchased from chemical suppliers.

It can be found in nature in the rare minerals drobecite and niedermayrite.

Due to its toxicity, its sale may be restricted in many places.

Preparation

Cadmium sulfate can be prepared by dissolving cadmium oxide into sulfuric acid.

CdO + H2SO4 → CdSO4 + H2O

Using cadmium metal is not recommended, as a layer of cadmium sulfate forms on the surface of the metal which slows its dissolution.

Anhydrous cadmium sulfate can be made by reacting sodium persulfate with cadmium metal.

Cd + Na2S2O8 → CdSO4 + Na2SO4

Projects

  • Electroplate cadmium metal
  • Make a Weston cell
  • Make cadmium sulfide

Handling

Safety

Being a soluble cadmium compound, it is very toxic and highly carcinogenic. Wear proper protection when handling it. Always wear gloves!

Storage

Cadmium sulfate should be stored in closed plastic or glass bottles, in a hazardous chemical cabinet. If the annhydrous form is desired, it should be stored in air-tight containers.

Disposal

Cadmium should be converted into insoluble form, like cadmium sulfide and taken to hazardous disposal centers.

References

Relevant Sciencemadness threads