Cadmium sulfate

From Wikipedia, the free encyclopedia
Jump to: navigation, search
Cadmium sulfate
Cd2+.svg Sulfat-Ion2.svg
Identifiers
CAS number 10124-36-4 YesY
7709-84-3 (monohydrate)
15244-35-9 (octahydrate)
ChemSpider 23335 YesY
UNII 947UNF3Z6O YesY
EC number 233-331-6
UN number 2570
ChEBI CHEBI:50292 YesY
RTECS number EV2700000
Jmol-3D images Image 1
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
Odor odorless
Density 4.691 g/cm3 (anhydrous)
3.79 g/cm3 (monohydrate)
3.08 g/cm3 (octahydrate)[1]
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)
monohydrate:
76.7 g/100 mL (25 °C)
octahydrate:
very soluble
Solubility slightly soluble in methanol, ethyl acetate
insoluble in ethanol
Refractive index (nD) 1.565
Structure
Crystal structure orthorhombic (anhydrous)
monoclinic (hepta & octahydrate)
Thermochemistry
Std molar
entropy
So298
123 J·mol−1·K−1[2]
Std enthalpy of
formation
ΔfHo298
−935 kJ·mol−1[2]
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
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g., canola oil Health code 3: Short exposure could cause serious temporary or residual injury. E.g., chlorine gas Reactivity code 0: Normally stable, even under fire exposure conditions, and is not reactive with water. E.g., liquid nitrogen Special hazards (white): no codeNFPA 704 four-colored diamond
LD50 280 mg/kg (oral, rat)
Related compounds
Other anions Cadmium acetate,
Cadmium chloride,
Cadmium nitrate
Other cations Zinc sulfate,
Calcium sulfate,
Magnesium sulfate
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
 YesY (verify) (what is: YesY/N?)
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[edit]

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 as the tetrahydrate mineral drobecite (CdSO4·4H2O) and as a basic salt in the mineral niedermayrite (Cu4Cd(SO4)2(OH)6·4H2O).

Applications[edit]

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 as well as a pigment in fluorescent screens.

References[edit]

  1. ^ Lide, David R., ed. (2006). CRC Handbook of Chemistry and Physics (87th ed.). Boca Raton, FL: CRC Press. ISBN 0-8493-0487-3. 
  2. ^ a b Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A21. ISBN 0-618-94690-X.