Cadmium

__**Cadmium:**__ Is an extremely toxic metal found in industrial workplaces particularly where ore is being processed or smelted. Cadmium is metal that is solid at room temperature, and is located in group 12 and period 5 of the periodic table.
 * Atomic number: 48
 * Atomic symbol: Cd
 * Melting Point: 321.07 degrees Celsius/609.93 degrees Fahrenheit
 * Boiling Point: 767 degrees Celsius/1413 degrees Fahrenheit
 * Atomic Weight: 112.411
 * Density: 8.69 grams per centimeter cubed

Harmful effects: Cadmium and its compounds are highly toxic. Characteristics: Cadmium is a soft, malleable, ductile, bluish-white metal, which is easily cut with a knife. It is an excellent electrical conductor and shows good resistance to corrosion and attack by chemicals. It is similar in many respects to zinc in its chemical properties. Cadmium tarnishes in air and is soluble in acids but not in alkalis. The metal burns in air to form brown cadmium oxide (CdO).

Uses of Cadmium
Cadmium's major use is in batteries (especially rechargeable nickel-cadmium, NiCad, batteries). As a result of its low coefficient of friction and its high fatigue resistance, cadmium is used in alloys for bearings. Cadmium is used in low melting alloys and is a component of many kinds of solder. It is also is used in electroplating. Compounds containing cadmium are used in black and white television phosphors, and in the blue and green phosphors for color television picture tubes. Cadmium sulfide is used as a yellow pigment, and cadmium selenide is used as a red pigment, often called cadmium red. Cadmium and tellurium can be compounded into CdTe thin-film photovoltaic modules whose physical characteristics are ideal for solar cell production. They are relatively low cost and have an almost perfect bandgap for solar energy harvesting. Cadmium is used extensively in electroplating.


 * Number of Energy Levels:** 5
 * First Energy Level:**2
 * Second Energy Level:**8
 * Third Energy Level:**18
 * Fourth Energy Level:**18
 * Fifth Energy Level:**2

Isotopes

 * ** Isotope ** || ** Half Life ** ||
 * Cd-106 || Stable ||
 * Cd-108 || Stable ||
 * Cd-109 || 462.0 days ||
 * Cd-110 || Stable ||
 * Cd-111 || Stable ||
 * Cd-111m || 48.5 minutes ||
 * Cd-112 || Stable ||
 * Cd-113 || 9.0E15 years ||
 * Cd-113m || 14.1 years ||
 * Cd-114 || Stable ||
 * Cd-115 || 2.2 days ||
 * Cd-115m || 44.6 days ||
 * Cd-116 || Stable ||
 * Cd-117 || 2.5 hours ||
 * Cd-118 || 3.4 hours ||

Facts

 * Date of Discovery:** 1817 **Discoverer:** Fredrich Stromeyer **Name Origin:** From the Greek word //kadmeia// (ancient name for calamine) and from the Latin word //cadmia// **Uses:** poisonous, nickel-cadmium batteries **Obtained From:** by-product of zinc refining

Cadmium is somewhat limited element due to the fact that it is poisonous. It is used to make control rods for nuclear reactors as well as being used in rechargeable nickle-cadmium batteries. Alloys of Cadmium are used to make low friction batteries that highly resistant to fatigue.

This soft, bluish-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it prefers oxidation state +2 in most of its compounds and like mercury it shows a low melting point compared to transition metals.

Cadmium has no known useful role in higher organisms The diatoms live in environments with very low zinc concentrations and cadmium performs the function normally carried out by zinc in other anhydrases. The discovery was made using X-ray absorption fluorescence spectroscopy.

The most dangerous form of occupational exposure to cadmium is inhalation of fine dust and fumes, or ingestion of highly soluble cadmium compound. Cigarettes contain cadmium in the use of tobacco products.

High levels of Cadmium is found in the liver and kidneys of adult animals, which makes food another source of Cadmium.

Physic al properties
Cadmium is a soft, malleable, ductile, bluish-white divalent metal. It is similar in many respects to zinc but forms complex compounds. Unlike other metals, cadmium is resistant to corrosion and as a result it is used as a protective layer when deposited on other metals. As a bulk metal, cadmium is insoluble in water and is not flammable; however, in its powdered form it may burn and release toxic fumes.

Chemical properties
Although cadmium usually has an oxidation state of +2, it also exists in the +1 state. Cadmium and its congeners are not always considered transition metals, in that they do not have partly filled d or f electron shells in the elemental or common oxidation states. Cadmium burns in air to form brown amorphous cadmium oxide (CdO); the crystalline form of this compound is a dark red which changes color when heated, similar to zinc oxide. Hydrochloric acid, sulfuric acid and nitric acid dissolve cadmium by forming cadmium chloride (CdCl2), cadmium sulfate(CdSO4), or cadmium nitrate (Cd(NO3)2). The oxidation state +1 can be reached by dissolving cadmium in a mixture of cadmium chloride and aluminium chloride, forming the Cd22+ cation, which is similar to the Hg22+ cation in mercury chloride. Cd + CdCl2 + 2 AlCl3 → Cd2(AlCl4)2

Cadmium-responsive Element of the Human Heme Oxygenase-1 Gene Mediates Heat Shock Factor 1-dependent Transcriptional Activation


 * 1)  Mechanism of Health Effect Research Group, National Institute of Occupational Safety and Health, Kawasaki 214-8585, Japan
 * 2) 1 To whom correspondence should be addressed: Mechanism of Health Effect Research Group, National Institute of Occupational Safety and Health, 6-21-1, Nagao, Tama-ku, Kawasaki 214-8585, Japan. Tel.: 81-44-865-6111; Fax: 81-44-865-6124; E-mail: koizumi@h.jniosh.go.jp

Abstract
Transcription of a number of mammalian genes is activated by heavy metals, but mechanisms of signaling and transcriptional regulation are not well understood. From a comparison of heavy metal responses of several human genes, it was noted that the heme oxygenase-1 (HO-1) gene is quite similar in the spectrum of metal response and induction kinetics to the heat shock protein 70 (HSP70) gene, suggesting a common regulatory mechanism shared by these genes. The cadmium-responsive element (CdRE) known to be responsible for the metal regulation of // ho-1 // formed complexes with proteins from heavy metal-treated HeLa cells in an electrophoretic mobility shift assay (EMSA). These complexes were indistinguishable in mobility from those formed by the heat shock factor 1 (HSF1) and the heat shock element involved in // hsp70 // regulation, suggesting the involvement of HSF1 also in the CdRE complexes. Competitive EMSA and supershift analysis with an anti-HSF1 antibody revealed that HSF1 was in fact a component of the CdRE complexes. A fine analysis on the affinity of HSF1 to a series of mutant CdRE sequences showed that HSF1 recognizes a sequence motif TnCTAGA. Transient transfection analysis with overexpressed recombinant HSF1 demonstrated that CdRE has HSF1-dependent enhancer-like activity that requires direct binding of HSF1. In the absence of overexpressed HSF1, however, CdRE by itself was insufficient to mediate heavy metal-induced transcription, suggesting requirement of additional regulatory sequences. The finding that HSF1 is directly involved in the regulation of // ho-1 // with an anti-oxidative role revealed a new aspect of the biological defense mechanism.

Nuclear fission
Cadmium is used as a barrier to control neutrons in nuclear fission The pressurized water reactor designed by Westinghouse Electrical Company uses an alloy consisting of 80% silver, 15% indium, and 5% cadmium.