What is Cadmium

Cadmium (pronounced as KAD-mee-əm) is a naturally-occurring shiny metal denoted by the chemical symbol Cd. Although a non-radioactive element, it is poisonous, causing cancer and prenatal defects, therefore having limited uses. It has eight naturally-existing isotopes of which only Cd-110, Cd-111, and Cd-112 have a stable half-life.

Where is Cadmium Found on Earth

Greenockite and sphalerite are the important natural sources of the metal. On a commercial scale, it is extracted in the vapor form as a by-product of zinc refining.

History

Origin of its Name: It is derived from the Latin word ‘cadmia’ that stands for the mineral calamine.

Who Discovered it: A German chemist called Friedrich Stromeyer

When and Where was Cadmium Discovered

In the early 1800s, zinc oxide was produced by some apothecaries at Hanover in Germany by heating zinc carbonate (cadmia). However, the compound was not pure white but discolored. Later, in 1817 Stromeyer from Gottingen University after a thorough analysis inferred that the discoloration could be due to an unknown element. So he extracted it as a brown oxide and then heated with lampblack to produce a blue-grey metal sample, named as cadmium. While at Halle, Karl Meissner, a German-American physicist, and at Berlin, Karl Karsten, another German scientist worked on the same problem and declared their findings the following year ^[1].

Identification
Atomic number	48 [1]
CAS number	7440-43-9 [1]
Position in the periodic table [1]	Group	Period	Block
	12	5	d

Properties and Characteristics of Cadmium

General Properties
Relative atomic mass	112.414  [1]
Atomic mass/weight	112.414 atomic mass units [4]
Molar mass	112.4110 g/mole [5]
Physical Properties
Color/appearance	Silver with a bluish tinge [1]
Luster	Metallic [6]
Melting point/freezing point	321.069°C (609.924°F) [1]
Boiling point	767°C (1413°F)  [1]
Density	8.69 g/cm3 [1]
State of matter at normal room temperature (solid/liquid/gas)	Solid [1]
Specific Heat	0.230274 J/(g-°C) [7]
Chemical Properties
Oxidation state/Oxidation number		(+1), +2 [1]

Atomic Data of Cadmium (Element 48)

What is Cadmium Used for

• Since cadmium has high corrosion resistance, it’s used in plating bolts, fasteners, and also airplane parts and oil platforms made from stainless steel ^[1].
• Rechargeable batteries made by combining nickel and cadmium have a longer storage life and low internal resistance ^{[1, 9]}.
• Helium-cadmium lasers have an excellent beam quality making them useful in spectroscopy, exposing holography, microlithography, and 3-D stereolithography ^[10].
• As Cd is a good absorber of neutrons, it is used in control rods of nuclear reactors for conducting atomic fission ^[1].
• Silver alloyed with the element forms low-melting solder used for joining pipes, electrical components, and other metallic equipment ^[2].

Does it Have Any Toxic Effects

Inhalation of high levels of cadmium dust over a short duration of time can cause several health hazards like lung and kidney damage as a result of poisoning. Also, its accidental ingestion can directly affect the liver and kidneys. ^[12]

Interesting Facts

• In the past, Cd was used as phosphor coating in cathode ray tubes of color television sets as well as a component in orange, yellow, and red pigments ^[1].
• It is a soft metal that can be easily cut with a knife ^[11].

Cadmium Price

The pure form of the metal may cost somewhere between $6 and $7 per gram.

References
1. http://www.rsc.org/periodic-table/element/48/cadmium
2. https://education.jlab.org/itselemental/ele048.html
3. https://pubchem.ncbi.nlm.nih.gov/compound/cadmium
4. http://hobart.k12.in.us/ksms/PeriodicTable/cadmium.htm
5. https://www.webqc.org/molecular-weight-of-cadmium.html
6. http://webmineral.com/data/Cadmium.shtml#.Wx5FO0iFPIU
7. https://www.engineersedge.com/materials/specific_heat_capacity_of_metals_13259.htm
8. https://study.com/academy/answer/how-many-valence-electrons-does-cadmium-have.html
9. http://www.bodine.com/downloads/docs/Ni-Cad_Battery_Advantages.Article.L0000024.pdf
10. https://www.globalspec.com/learnmore/optical_components_optics/lasers/helium_cadmium_hecd_lasers
11. https://www.thoughtco.com/cadmium-element-facts-606511
12. https://www.osha.gov/SLTC/cadmium/healtheffects.html