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Cadmium sulfide

Cadmium sulfide
3D model of the structure of hawleyite
3D model of the structure of greenockite
Cadmium sulfide.jpg
Names
Other names
Cadmium(II) sulfide,
Greenockite
Hawleyite
Identifiers
1306-23-6 YesY
3D model (Jmol) Interactive image
ChemSpider 7969586 YesY
ECHA InfoCard 100.013.771
EC Number 215-147-8
PubChem 14783
RTECS number EV3150000
UNII 057EZR4Z7Q YesY
UN number 2570
Properties
CdS
Molar mass 144.47 g·mol−1
Appearance Yellow-orange to brown solid.
Density 4.826 g/cm3, solid.
Melting point 1,750 °C (3,180 °F; 2,020 K) 10 MPa
Boiling point 980 °C (1,800 °F; 1,250 K) (sublimation)
insoluble
Solubility soluble in acid
very slightly soluble in ammonium hydroxide
-50.0·10−6 cm3/mol
2.529
Structure
Hexagonal, Cubic
Thermochemistry
65 J·mol−1·K−1
−162 kJ·mol−1
Hazards
Safety data sheet ICSC 0404
Carc. Cat. 2
Muta. Cat. 3
Repr. Cat. 3
Toxic (T)
Dangerous for the environment (N)
R-phrases R45, R22, R48/23/25, R62, R63, R68, R50/53
S-phrases S53, S45, S61
NFPA 704
Flammability code 0: Will not burn. E.g., water 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
Flash point Non-flammable
Lethal dose or concentration (LD, LC):
LD50 (median dose)
7080 mg/kg (rat, oral)
US health exposure limits (NIOSH):
PEL (Permissible)
[1910.1027] TWA 0.005 mg/m3 (as Cd)
REL (Recommended)
Ca
IDLH (Immediate danger)
Ca [9 mg/m3 (as Cd)]
Related compounds
Other anions
Cadmium oxide
Cadmium selenide
Other cations
Zinc sulfide
Mercury sulfide
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
YesY  (what is YesYN ?)
Infobox references

Cadmium sulfide is the inorganic compound with the formula CdS. Cadmium sulfide is a yellow solid. It occurs in nature with two different crystal structures as the rare minerals greenockite and hawleyite, but is more prevalent as an impurity substituent in the similarly structured zinc ores sphalerite and wurtzite, which are the major economic sources of cadmium. As a compound that is easy to isolate and purify, it is the principal source of cadmium for all commercial applications. Its vivid yellow color led to its adoption as a pigment for the yellow paint "cadmium yellow" in the 18th century.

Cadmium sulfide can be prepared by the precipitation from soluble cadmium(II) salts with sulfide ion. This reaction has been used for gravimetric analysis and qualitative inorganic analysis.
The preparative route and the subsequent treatment of the product, affects the polymorphic form that is produced (i.e., cubic vs hexagonal). It has been asserted that chemical precipitation methods result in the cubic zincblende form.

Pigment production usually involves the precipitation of CdS, the washing of the solid precipitate to remove soluble cadmium salts followed by calcination (roasting) to convert it to the hexagonal form followed by milling to produce a powder. When cadmium sulfide selenides are required the CdSe is co-precipitated with CdS and the cadmium sulfoselenide is created during the calcination step.

Cadmium sulfide is sometimes associated with sulfate reducing bacteria.

Special methods are used to produce films of CdS as components in some photoresistors and solar cells. In the chemical bath deposition method, thin films of CdS have been prepared using thiourea as the source of sulfide anions and an ammonium buffer solution to control pH:

Cadmium sulfide can be produced using metalorganic vapour phase epitaxy and MOCVD techniques. This process requies volatile cadmium and sulfur precursors. A common example is the reaction of dimethylcadmium with diethyl sulfide:


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