History of Cadmium• Discovered in 1817 by German chemist and professor Friedrich Stromeyer at Göttingen University while studying samples of calamine (zinc carbonate).• Noticed that calamine gave off a yellow color when heated.• Later found traces of a new element in heated samples of calamine: Cadmium.• Name comes from Latin word cadmia and Greek word kadmeia: ancient names for calamine. Friedrich Stromeyer
Properties of• Poisonous transitional metal• State at Room Temperature: Solid• Color: Silver• Melting Point: 594.22 K (321.07°C)• Boiling Point: 1040 K (767°C)• Density: 8.69 g/cm3• Oxidation State: +2• Electron Shell Configuration: 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p6 4d10 5s2
Availability of • The only mineral that contains significant amounts of cadmium is greenockite (CdS), which is not very common. • Most cadmium produced today is obtained from the small amounts that are found in zinc ores and as a byproduct of mining zinc. • Cadmium is relatively inexpensive and easy to obtain. A 99.9% pure cadmium rod weighing half a pound is only $15greenockite online. • 99.999% pure cadmium is $70 per 1.5” bar. 99.999% pure
Uses of• 70% of mined cadmium is used in rechargeable nickel-cadmium batteries.• Formerly electroplated to protect materials from corrosion.• Cadmium alloy used in fire sprinklers as a plug.• Because of low cost, (controversially) used in inexpensive jewelry, especially children’s jewelry.• Alloyed with silver to make solders.• Used to make control rods for nuclear reactors, because it easily absorbs neutrons. children’s jewelry
Uses of CADMIUM• Cadmium telluride is used for less expensive solar panels.• Hydrated cadmium sulfate is used in Weston cells, which are used to calibrate medical and laboratory equipment.• Cadmium sulfide is a yellow pigment used in paint.• Cadmium compounds are found in phosphors of black and white TVs and the blue and green phosphors of colored TVs.
• Cadmium is highly toxic.• Toxic when ingested or inhaled, but cannot be absorbed by the skin.
Exposure to• Most exposure occurs from cigarette smoke and coal burning.• Car engine exhaust contains cadmium.• May be found in groundwater contaminated by landfills, phosphate fertilizers, or crops grown with contaminated water or fertilizer.• Cadmium is used as a heat stabilizer in PVC pipes and PVC coating material.• Tobacco leaves naturally accumulate large amounts of cadmium: one cigarette is estimated to have 1-3μg of cadmium. About 10% is inhaled into a smoker’s lungs during active smoking. smoking