2. 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
3. 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
4. Properties of
• Known Isotopes: 44
• Known Natural Stable Isotopes: 5
– 108: 0.89% natural abundance
– 110: 12.49% natural abundance
– 111: 12.80% natural abundance
– 112: 24.13% natural abundance
– 114: 28.73% natural abundance
• Known Natural Radioactive Isotopes: 3
– 106: half-life ≥ 2.6×10+17 years, 1.25% natural abundance
– 113: half-life 7.7×10+15 years, 12.22% natural abundance
– 116: half-life > 1.2×10+21 years, 7.49% natural abundance
5. 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 $15
greenockite
online.
• 99.999% pure cadmium is
$70 per 1.5” bar.
99.999% pure
6. 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
7. 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.
8. • Cadmium is highly toxic.
• Toxic when ingested or inhaled, but cannot be
absorbed by the skin.
9. 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
