|Jmol-3D images||Image 1|
|Molar mass||144.48 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)|
|Solubility in water||insoluble|
|Solubility||soluble in acid
very slightly soluble in ammonium hydroxide
|Refractive index (nD)||2.529|
|Crystal structure||Hexagonal, Cubic|
|Std enthalpy of
|EU classification||Carc. Cat. 2
Muta. Cat. 3
Repr. Cat. 3
Dangerous for the environment (N)
|R-phrases||R45, R22, R48/23/25, R62, R63, R68, R50/53|
|S-phrases||S53, S45, S61|
|LD50||7080 mg/kg (rat, oral)|
|Other anions||Cadmium oxide
|Other cations||Zinc sulfide
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
|(what is: / ?)|
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.
Cadmium sulfide can be prepared by the precipitation from soluble cadmium(II) salts with sulfide ion and this has been used in the past 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 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.
Routes to thin films of CdS
Thin films of CdS are 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:
- Cd2+ + H2O + (NH2)2CS + 2 NH3 → CdS + (NH2)2CO + 2 NH4+
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: Many other methods have been used to deposit these thin films, for example (note: there is a large body of research in this area and only representative references are given):
- Cd(CH3)2 + Et2S → CdS + CH3CH3 + C4H10
Other methods include
- Sol gel techniques
- Electrochemical deposition
- Spraying with precursor cadmium salt, sulfur compound and dopant
- Screen printing using a slurry containing dispersed CdS
- CdS + 2 HCl → CdCl2 + H2S
When sulfide solutions containing dispersed CdS particles are irradiated with light hydrogen gas is generated:
- H2S → H2 + S ΔHf = +9.4 kcal/mol
- Production of an electron hole pair
- CdS + hν → e− + hole+
- Reaction of electron
- 2e− + 2H2O → H2 + 2OH−
- Reaction of hole
- 2hole+ + S2− → S
Structure and physical properties
Cadmium sulfide has, like zinc sulfide, two crystal forms; the more stable hexagonal wurtzite structure (found in the mineral Greenockite) and the cubic zinc blende structure (found in the mineral Hawleyite). In both of these forms the cadmium and sulfur atoms are four coordinate. There is also a high pressure form with the NaCl rock salt structure.
- the conductivity increases when irradiated with light (leading to uses as a photoresistor)
- when combined with a p-type semiconductor it forms the core component of a photovoltaic (solar) cell and a CdS/Cu2S solar cell was one of the first efficient cells to be reported (1954)
- when doped with for example Cu+ ("activator") and Al3+ ("coactivator") CdS luminesces under electron beam excitation (cathodoluminescence) and is used as phosphor
- both polymorphs are piezoelectric and the hexagonal is also pyroelectric
- CdS crystal can act as a solid state laser
CdS is predominantly used as a pigment. About 2000 tons are produced annually.
In thin-film form, CdS can be combined with other layers for use in certain types of solar cells. CdS was also one of the first semiconductor materials to be used for thin-film transistors (TFTs). However interest in compound semiconductors for TFTs largely waned after the emergence of amorphous silicon technology in the late 1970s. Thin films of Cadmium Sulfide can be piezoelectric and have been used as transducers which can operate at frequencies in the GHz region.
CdS is known as cadmium yellow (CI pigment yellow 37). By adding varying amounts of selenium as selenide, it is possible to obtain a range of colors, for example CI pigment orange 20 and CI pigment red 108.
Synthetic cadmium pigments based on cadmium sulfide are valued for their good thermal stability, light and weather fastness, chemical resistance and high opacity. (but with problems of biocompatibility when used as colors in tattoos). The general commercial availability of cadmium sulfide from the 1840s led to its adoption by artists, notably Van Gogh, Monet (in his London series and other works) and Matisse (Bathers by a river 1916–1919). The presence of cadmium in paints has been used to detect forgeries in paintings alleged to have been produced prior to the 19th century. CdS is used as pigment in plastics.
- Lide, David R. (1998). Handbook of Chemistry and Physics (87 ed.). Boca Raton, FL: CRC Press. pp. 4–67; 1363. ISBN 0-8493-0594-2.
- Zumdahl, Steven S. (2009). Chemical Principles 6th Ed. Houghton Mifflin Company. p. A21. ISBN 0-618-94690-X.
- Egon Wiberg, Arnold Frederick Holleman (2001) Inorganic Chemistry, Elsevier ISBN 0-12-352651-5
- Fred Ibbotson (2007), The Chemical Analysis of Steel-Works' Materials,Read Books, ISBN 1-4067-8113-4
- Paul Klocek (1991), Handbook of Infrared Optical Materials, CRC Press ISBN 0-8247-8468-5
- Hugh MacDonald Smith (2002). High Performance Pigments. Wiley-VCH. ISBN 3-527-30204-2.
- Oladeji, I.O.; Chow, L. (1997). "Optimization of Chemical Bath Deposited Cadmium Sulfide". J. Electrochem. Soc. 144: 7.
- Uda, H; Yonezawa, H; Ohtsubo, Y; Kosaka, M; Sonomura, H (2003). "Thin CdS films prepared by metalorganic chemical vapor deposition". Solar Energy Materials and Solar Cells 75 (1–2): 219. doi:10.1016/S0927-0248(02)00163-0.
- Reisfeld, R (2002). "Nanosized semiconductor particles in glasses prepared by the sol–gel method: their optical properties and potential uses". Journal of Alloys and Compounds 341 (1–2): 56. doi:10.1016/S0925-8388(02)00059-2.
- Moon, B; Lee, J; Jung, H (2006). "Comparative studies of the properties of CdS films deposited on different substrates by R.F. sputtering". Thin Solid Films. 511-512: 299. doi:10.1016/j.tsf.2005.11.080.
- Goto, F; Shirai, Katsunori; Ichimura, Masaya (1998). "Defect reduction in electrochemically deposited CdS thin films by annealing in O2". Solar Energy Materials and Solar Cells 50 (1–4): 147. doi:10.1016/S0927-0248(97)00136-0.
- U.S. Patent 4,086,101 Photovoltaic cells, J.F. Jordan, C.M. Lampkin Issue date: April 25, 1978
- U.S. Patent 3,208,022, High performance photoresistor, Y.T. Sihvonen, issue date: September 21, 1965
- Wanrooij, P. H. P.; Agarwal, U. S.; Meuldijk, J.; Kasteren, J. M. N. van; Lemstra, P. J. (2006). "Extraction of CdS pigment from waste polyethylene". Journal of Applied Polymer Science 100 (2): 1024. doi:10.1002/app.22962.
- Mario Schiavello (1985) Photoelectrochemistry, Photocatalysis, and Photoreactors: Fundamentals and Developments Springer ISBN 90-277-1946-2
- D. Lincot, Gary Hodes Chemical Solution Deposition of Semiconducting and Non-Metallic Films: Proceedings of the International Symposium The Electrochemical Society, 2006 ISBN 1-56677-433-0
- Wells A.F. (1984) Structural Inorganic Chemistry 5th edition Oxford Science Publications ISBN 0-19-855370-6
- Antonio Luque, Steven Hegedus, (2003), Handbook of Photovoltaic Science and Engineering John Wiley and Sons ISBN 0-471-49196-9
- Reynolds, D.; Leies, G.; Antes, L.; Marburger, R. (1954). "Photovoltaic Effect in Cadmium Sulfide". Physical Review 96 (2): 533. doi:10.1103/PhysRev.96.533.
- C. Fouassier,(1994), Luminescence in Encyclopedia of Inorganic Chemistry, John Wiley & Sons ISBN 0-471-93620-0
- Minkus, Wilfred (1965). "Temperature Dependence of the Pyroelectric Effect in Cadmium Sulfide". Physical Review 138 (4A): A1277. doi:10.1103/PhysRev.138.A1277.
- Smith, Roland (1957). "Low-Field Electroluminescence in Insulating Crystals of Cadmium Sulfide". Physical Review 105 (3): 900. doi:10.1103/PhysRev.105.900.
- Akimov, Yu A; Burov, A A; Drozhbin, Yu A; Kovalenko, V A; Kozlov, S E; Kryukova, I V; Rodichenko, G V; Stepanov, B M; Yakovlev, V A (1972). "KGP-2: AN ELECTRON-BEAM-PUMPED CADMIUM SULFIDE LASER". Soviet Journal of Quantum Electronics 2 (3): 284. doi:10.1070/QE1972v002n03ABEH004443.
- Agarwal, Ritesh; Barrelet, Carl J.; Lieber, Charles M. (2005). "Lasing in Single Cadmium Sulfide Nanowire Optical Cavities". Nano Letters 5 (5): 917–20. doi:10.1021/nl050440u. PMID 15884894.
- Karl-Heinz Schulte-Schrepping, Magnus Piscator "Cadmium and Cadmium Compounds" in Ullmann's Encyclopedia of Industrial Chemistry, 2007 Wiley-VCH, Weinheim. doi:10.1002/14356007.a04 499.
- H. Zhao et al, "The effect of impurities on the doping and VOC of CdTe/CdS thin film solar cells", Thin Solid Films, Vol. 517, No. 7 (2009) pp. 2365-2369,  doi:10.1016/j.tsf.2008.11.041
- P.K. Weimar, "The TFT a new thin-film transistor", Proc. IRE, Vol. 50, No. 6 (1962) pp. 1462-1469,  doi:10.1109/JRPROC.1962.288190
- R. M. Christie 2001 Colour Chemistry, p. 155 Royal Society of Chemistry ISBN 0-85404-573-2
- Bjornberg, A (Sep 1963). "Reactions to light in yellow tattoos from cadmium sulfide". Arch Dermatol 88: 267–71. PMID 14043617.
- Sidney Perkowitz, 1998, Empire of Light: A History of Discovery in Science and Art Joseph Henry Press, ISBN 0-309-06556-9
- W. Stanley Taft, James W. Mayer, Richard Newman, Peter Kuniholm, Dusan Stulik (2000) The Science of Paintings, Springer, ISBN 0-387-98722-3
- Larry L. Barton 1995 Sulfate reducing bacteria, Springer, ISBN 0-306-44857-2
- Sweeney, Rozamond Y.; Mao, Chuanbin; Gao, Xiaoxia; Burt, Justin L.; Belcher, Angela M.; Georgiou, George; Iverson, Brent L. (2004). "Bacterial Biosynthesis of Cadmium Sulfide Nanocrystals". Chemistry & Biology 11 (11): 1553–9. doi:10.1016/j.chembiol.2004.08.022. PMID 15556006.
- Cadmium(II) sulphide information at Webelements
- IARC Monograph: "Cadmium and Cadmium Compounds" Last access November 2005.
- International Chemical Safety Card 0404
- National Pollutant Inventory - Cadmium and compounds
-  Report by the Academy of Medical Sciences to the Chief Scientific Adviser, Ministry of Defence on the zinc cadmium sulphide dispersion trials undertaken in the United Kingdom between 1953 and 1964.