Cadmium sulfate

Chemical compound From Wikipedia, the free encyclopedia

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: the octahydrate (3CdSO4·8H2O) and the anhydrous salt (CdSO4). All salts are colourless and highly soluble in water.

Quick facts Names, Identifiers ...
Cadmium sulfate
Cadmium sulfate
Cadmium sulfate
Names
IUPAC name
Cadmium(II) sulfate
Other names
Sulfuric acid, cadmium salt (1:1),
Identifiers
3D model (JSmol)
ChEBI
ChemSpider
ECHA InfoCard 100.030.288 Edit this at Wikidata
EC Number
  • 233-331-6
8295
RTECS number
  • EV2700000
UNII
UN number 2570
  • InChI=1S/Cd.H2O4S/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+2;/p-2 checkY
    Key: QCUOBSQYDGUHHT-UHFFFAOYSA-L checkY
  • InChI=1/Cd.H2O4S/c;1-5(2,3)4/h;(H2,1,2,3,4)/q+2;/p-2
    Key: QCUOBSQYDGUHHT-NUQVWONBAG
  • [Cd+2].[O-]S([O-])(=O)=O
Properties
  • 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
  • 1,000 °C (1,830 °F; 1,270 K) (anhydrous)
  • 105 °C (221 °F; 378 K) (monohydrate, decomposes)
  • 40 °C (104 °F; 313 K) (octahydrate, decomposes)
Boiling point (decomposes to basic sulfate and then oxide)[quantify]
    • anhydrous:
    • 75 g/100 mL (0 °C (32 °F; 273 K))
    • 76.4 g/100 mL (25 °C (77 °F; 298 K))
    • 58.4 g/100 mL (99 °C (210 °F; 372 K))
    • monohydrate:
    • 76.7 g/100 mL (25 °C (77 °F; 298 K))
    • octahydrate:
    • very soluble
Solubility in methanol slightly soluble
Solubility in ethyl acetate slightly soluble
−59.2×10−6 cm3/mol
1.565
Viscosity
  • 2.41 mPa·s (20 °C (68 °F; 293 K))
  • 1.49 mPa·s (40 °C (104 °F; 313 K))
Structure
  • orthorhombic (anhydrous)
  • monoclinic (mono & octahydrate)
Thermochemistry
123 J⋅mol−1·K-1[2]
−935 kJ⋅mol−1[2]
Hazards[3]
GHS labelling:
GHS06: ToxicGHS08: Health hazardGHS09: Environmental hazard
Danger
H301, H330, H340, H350, H360, H372, H410
P201, P202, P260, P264, P270, P271, P273, P280, P284, P301+P310+P330, P304+P340+P310, P308+P313, P403+P233, P405, P501
NFPA 704 (fire diamond)
[4]
NFPA 704 four-colored diamondHealth 3: Short exposure could cause serious temporary or residual injury. E.g. chlorine gasFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability 1: Normally stable, but can become unstable at elevated temperatures and pressures. E.g. calciumSpecial hazards (white): no code
3
1
1
  • 0.01 mg/m3 (total dust)
  • 0.002 mg/m3 (respirable dust)
(TWA)
Lethal dose or concentration (LD, LC):
107 mg/kg (oral, rat, analgous compound)
0.75 mg/L (goldfish, analgous compound)
NIOSH (US health exposure limits):[5]
PEL (Permissible)
 TWA 0.005 mg/m3 (as Cd)
REL (Recommended)
 TWA 0.005 mg/m3 (as Cd)
IDLH (Immediate danger)
 9 mg/m3 (as Cd)
Safety data sheet (SDS)
  • Fisher Scientific[4]
  • Sigma-Aldrich[3]
Related compounds
Other anions
Other cations
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Preparation

Cadmium sulfate hydrate can be prepared by the reaction of cadmium metal or its oxide or hydroxide with dilute sulfuric acid:[citation needed]

CdO + H2SO4 → CdSO4 + H2O
Cd + H2SO4 → CdSO4 + H2

The anhydrous material can be prepared using sodium persulfate:[citation needed]

Cd + Na2S2O8 → CdSO4 + Na2SO4

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 as well as a pigment in fluorescent screens.[citation needed]

Structure

Portion of structure of CdSO4 illustrating the distorted tetrahedral geometry at Cd (dark blue spheres).[6]

X-ray crystallography shows that CdSO4·H2O is a typical coordination polymer. Each Cd2+ center has octahedral coordination geometry, being surrounded by four oxygen centers provided by four sulfate ligands and two oxygen centers from the bridging water ligands.[7]

Occurrence

Cadmium sulfates occur as the following rare minerals drobecite (CdSO4·4H2O),[contradictory] voudourisite (monohydrate), and lazaridisite (the octahydrate).[citation needed]

Safety

Cadmium sulfate (along with cadmium and its compounds) are classified as group 1 (human carcinogens) by IARC and have been identified as causing lung and prostate cancer as well as mutagenic effects in humans.[8]

References

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