| Atomic Mass | 112.414 |
|---|---|
| Electron Configuration | [Kr]5s24d10 |
| Oxidation States | +2 |
| Year Discovered | 1817 |
| Atomic Mass | 112.414 |
|---|---|
| Electron Configuration | [Kr]5s24d10 |
| Oxidation States | +2 |
| Year Discovered | 1817 |
| Element Name | Cadmium |
|---|---|
| Element Symbol | Cd |
| InChI | InChI=1S/Cd |
| InChIKey | BDOSMKKIYDKNTQ-UHFFFAOYSA-N |
| Atomic Weight |
112.414(4) 112.414 112.4 112.414(4) |
|---|---|
| Electron Configuration |
[Kr]5s24d10 |
| Atomic Radius |
Van der Waals Atomic Radius : 158 pm (Van der Waals) Empirical Atomic Radius : 155pm (Empirical) Covalent Atomic Radius : 144(9) pm (Covalent) |
| Oxidation States |
+2 2, 1, -2 (a mildly basic oxide) |
| Ground Level |
1S0 |
| Ionization Energy |
8.994 eV 8.993820 ± 0.000016 eV |
| Electronegativity |
Pauling Scale Electronegativity : 1.69(Pauling Scale) Allen Scale Electronegativity : 1.52(Allen Scale) |
| Electron Affinity |
0eV 0.27eV |
| Atomic Spectra |
Lines Holdings Levels Holdings |
| Physical Description |
Solid |
| Element Classification |
Metal |
| Element Period Number |
5 |
| Element Group Number |
12 |
| Density |
8.69 grams per cubic centimeter |
| Melting Point |
594.22 K (321.07°C or 609.93°F) 321.07°C |
| Boiling Point |
1040 K (767°C or 1413°F) 767°C |
| Estimated Crustal Abundance |
1.5×10-1 milligrams per kilogram |
| Estimated Oceanic Abundance |
1.1×10-4 milligrams per liter |
The name derives from Greek kadmeia for "calamine" (zinc carbonate), with which it was found as an impurity in nature. It may have been found in furnace flue dust in Thebes, a city in the Boeottia region of central Greece. The mythological king of Phoenicia, Cadmus, founded Thebes and would be a source for the name of the ore. The element was discovered and first isolated by German physician Friedrich Stromeyer in 1817.
Cadmium was discovered by Friedrich Strohmeyer, a German chemist, in 1817 while studying samples of calamine (ZnCO3). When heated, Strohmeyer noticed that some samples of calamine glowed with a yellow color while other samples did not. After further examination, he determined that the calamine that changed color when heated contained trace amounts of a new element. There is only one mineral that contains significant amounts of cadmium, greenockite (CdS), but it is not common enough to mine profitably. Fortunately, small amounts of cadmium are found in zinc ores and most of the cadmium produced today is obtained as a byproduct of mining and refining zinc.
From the Latin word cadmia, Greek kadmeia - the ancient name for calamine, zinc carbonate. Discovered by Stromeyer in 1817 from an impurity in zinc carbonate. Cadmium most often occurs in small quantities associated with zinc ores, such as sphalerite (ZnS). Greenockite (CdS) is the only mineral of any consequence bearing cadmium. Almost all cadmium is obtained as a by-product in the treatment of zinc, copper, and lead ores. It is a soft, bluish-white metal which is easily cut with a knife. It is similar in many respects to zinc. In 1927 the International Conference on Weights and Measures redefined the meter in terms of the wavelength of the red cadmium spectral line (i.e. 1m = 1.553,164.13 wavelengths). This definition has been changed (see Krypton).
| Year | Atomic Weight (uncertainty) [u] | Reference |
|---|---|---|
| 2013 | 112.414(4) | https://doi.org/10.1515/pac-2015-0305 |
| 1985 | 112.411(8) | https://doi.org/10.1351/pac198658121677 |
| 1975 | 112.41(1) | https://doi.org/10.1351/pac197647010075 |
| 1969 | 112.40(1) | https://doi.org/10.1351/pac197021010091 |
| 1961 | 112.40 | https://doi.org/10.1021/ja00881a001 |
| 1925 | 112.41 | https://doi.org/10.1039/CT9252700913 |
| 1909 | 112.40 | https://doi.org/10.1021/ja01931a001 |
| 1902 | 112.4 | https://doi.org/10.1007/BF01370337 |
Cadmium is a poisonous metal and its use is somewhat limited for this reason. Like zinc, cadmium can be electroplated to other materials to protect them from corrosion. Cadmium easily absorbs neutrons and is used to make control rods for nuclear reactors. Cadmium is also used in rechargeable nickel-cadmium batteries.
Cadmium is alloyed with silver to form solder, a metal with a relatively low melting point used to join electrical components, pipes and other metallic items. Cadmium based solders must be handled with care to prevent cadmium poisoning. Cadmium alloys are also used to make low friction bearings that are highly resistant to fatigue.
Hydrated cadmium sulfate (3CdSO4·5H2O), one of cadmium's compounds, is used in a device called a Weston cell, a type of battery that produces a precise voltage used to calibrate medical and laboratory equipment. Cadmium sulfide (CdS), another cadmium compound, is a yellow powder that is used as a pigment. Other cadmium compounds are used in the phosphors of black and white television sets and in the blue and green phosphors in color television sets.
Cadmium is a component of some of the lowest melting alloys; it is used in bearing alloys with low coefficients of friction and great resistance to fatigue; it is used extensively in electroplating, which accounts for about 60% of its use. It is also used in many types of solder, for standard E.M.F. cells, for Ni-Cd batteries, and as a barrier to control nuclear fission. Cadmium compounds are used in black and white television phosphors and in blue and green phosphors for color TV tubes. It forms a number of salts, of which the sulfate is most common; the sulfide is used as a yellow pigment. Cadmium and solutions of its compounds are toxic.
See more information at the Cadmium compound page.
| CID | Name | Formula | SMILES | Molecular Weight |
|---|---|---|---|---|
| 23973 | cadmium | Cd | [Cd] | 112.41 |
| 31193 | cadmium(2+) | Cd+2 | [Cd+2] | 112.41 |
| 104782 | cadmium-109 | Cd | [109Cd] | 108.90499 |
| 107638 | cadmium-115 | Cd | [115Cd] | 114.905437 |
| 161055 | cadmium-113 | Cd | [113Cd] | 112.904408 |
| 177457 | cadmium-107 | Cd | [107Cd] | 106.90661 |
| 25087147 | cadmium-114 | Cd | [114Cd] | 113.903365 |
| 25087163 | cadmium-111 | Cd | [111Cd] | 110.904184 |
| 182018 | cadmium-104 | Cd | [104Cd] | 103.90986 |
| 177571 | cadmium-117 | Cd | [117Cd] | 116.90723 |
| 156022709 | cadmium-111(2+) | Cd+2 | [111Cd+2] | 110.904184 |
| 11996922 | cadmium-103 | Cd | [103Cd] | 102.91342 |
| 25184604 | cadmium-112 | Cd | [112Cd] | 111.902764 |
| 46182348 | cadmium-110 | Cd | [110Cd] | 109.903007 |
| 46898736 | cadmium-109(2+) | Cd+2 | [109Cd+2] | 108.90499 |
| 121233901 | cadmium-106 | Cd | [106Cd] | 105.90646 |
| 131708372 | cadmium-108 | Cd | [108Cd] | 107.90418 |
| 131708373 | cadmium-116 | Cd | [116Cd] | 115.904763 |
Failure to appreciate the toxic properties of cadmium may cause workers to be unwittingly exposed to dangerous fumes. Silver solder, for example, which contains cadmium, should be handled with care. Serious toxicity problems have been found from long-term exposure and work with cadmium plating baths. Exposure to cadmium dust should not exceed 0.01 mg/m3 (8-hour time-weighted average, 40-hour week). The ceiling concentration (maximum), for a period of 15 min, should not exceed 0.14 mg/m3. Cadmium oxide fume exposure (8-hour, 40-hour week) should not exceed 0.05 mg/m3, and the maximum concentration should not exceed 0.05 mg/m3. These values are presently being restudied and recommendations have been made to reduce the exposure.
| Stable Isotope Count | 3 |
|---|
Metal accumulation is a threat to our world’s water systems and wildlife. As a way to measure the influence of heavy metals on wildlife utilizing mass spectrometric techniques, some researchers use animal food enriched in specific cadmium isotopes. These experiments work by exposing the animals to a diet enriched in 106Cd and/or other stable isotopes of metals (for example, 65Cu and/or 62Ni) for a period of time. Depending on the purpose of the experiment, the residence time of the food in the gut is determined and isotopic compositions of the gut and/or feces are measured viainductively coupled plasma mass spectrometry (ICP-MS). This information is used to measure bio-uptake (absorption and incorporation of a substance by living tissue) and accumulation rates of metals in an exposed animal [355], [356].
Molecules, atoms, and ions of the stable isotopes of cadmium possess slightly different physical and chemical properties, and they commonly will be fractionated during physical, chemical, and biological processes, giving rise to variations in isotopic abundances and in atomic weights. There are small but measureable variations in the isotopic abundances of dissolved cadmium in ocean water, which are a consequence of isotopic fractionation associated with biological uptake (Fig. IUPAC.48.1) [357], [358], [359].
![Fig. IUPAC.48.1: Variations in the isotope-amount ratio n(¹¹⁴Cd)/n(¹¹⁰Cd) of dissolved ocean cadmium as a function of latitude south for Zero Meridian surface water samples (modified from Xue et al. [359], with data from Abouchami et al. [358] assuming a n(¹¹⁴Cd)/n(¹¹⁰Cd) value of isotopic reference material SRM 3108 of 2.304 07 [360]).](https://pubchem.ncbi.nlm.nih.gov/images/iupac/j_pac-2015-0703_fig_071.jpg)
112Cd is used to produce the diagnostic radioisotope 111In (with a half-life of 2.8 days) via the reaction 112Cd (p, 2n) 111In [94].
| Isotope | Atomic Mass (uncertainty) [u] | Abundance (uncertainty) | |
|---|---|---|---|
| 106Cd | 105.906 460(8) | 0.012 45(22) | 0.0125(6) |
| 108Cd | 107.904 184(8) | 0.008 88(11) | 0.0089(3) |
| 110Cd | 109.903 008(3) | 0.124 70(61) | 0.1249(18) |
| 111Cd | 110.904 184(3) | 0.127 95(12) | 0.1280(12) |
| 112Cd | 111.902 764(2) | 0.241 09(7) | 0.2413(21) |
| 113Cd | 112.904 408(2) | 0.122 27(7) | 0.1222(12) |
| 114Cd | 113.903 365(2) | 0.287 54(81) | 0.2873(42) |
| 116Cd | 115.904 763(1) | 0.075 12(54) | 0.0749(18) |
| Nuclide | Atomic Mass and Uncertainty [u] | Half Life and Uncertainty | Discovery Year | Decay Modes, Intensities and Uncertainties [%] |
|---|---|---|---|---|
| 94Cd | 93.956586 ± 0.000537 [Estimated] | 80 ms >760ns [Estimated] | 2016 | β+ ?; β+p ? |
| 95Cd | 94.949483 ± 0.000607 [Estimated] | 32 ms ± 3 | 2011 | β+=100%; β+p=4.6±1.1% |
| 96Cd | 95.940341 ± 0.00044 [Estimated] | 1003 ms ± 47 | 2008 | β+=100%; β+p=1.6±0.3% |
| 96Cdm | 95.940341 ± 0.00044 [Estimated] | 511 ms ± 26 | 2011 | β+=100%; β+p=15.4±2.1% |
| 96Cdn | 95.940341 ± 0.00044 [Estimated] | 198 ns ± 18 | 2019 | IT=100% |
| 97Cd | 96.934799343 ± 0.000451073 | 1.16 s ± 0.05 | 1978 | β+=100%; β+p=7.4±0.2% |
| 97Cdm | 96.934799343 ± 0.000451073 | 730 us ± 70 | 2019 | IT=100% |
| 97Cdn | 96.934799343 ± 0.000451073 | 3.86 s ± 0.06 | 1982 | β+=100%; β+p=25.1±0.5% |
| 98Cd | 97.927389315 ± 0.000055605 | 9.29 s ± 0.10 | 1978 | β+=100%; β+p<0.029% |
| 98Cdm | 97.927389315 ± 0.000055605 | 154 ns ± 16 | 1996 | IT=100% |
| 98Cdn | 97.927389315 ± 0.000055605 | 224 ns ± 5 | 2004 | IT=100% |
| 99Cd | 98.924925845 ± 0.0000017 | 17 s ± 1 | 1978 | β+=100%; β+p=0.21±0.2%; β+α<1e-4% |
| 100Cd | 99.920348829 ± 0.0000018 | 49.1 s ± 0.5 | 1970 | β+=100% |
| 101Cd | 100.918586209 ± 0.0000016 | 1.36 m ± 0.05 | 1969 | β+=100% |
| 102Cd | 101.914481797 ± 0.000001784 | 5.5 m ± 0.5 | 1969 | β+=100% |
| 103Cd | 102.913416922 ± 0.000001943 | 7.3 m ± 0.1 | 1960 | β+=100% |
| 104Cd | 103.909856228 ± 0.000001795 | 57.7 m ± 1.0 | 1955 | β+=100% |
| 105Cd | 104.909463893 ± 0.000001494 | 55.5 m ± 0.4 | 1950 | β+=100% |
| 105Cdm | 104.909463893 ± 0.000001494 | 4.5 us ± 0.5 | 1976 | IT=100% |
| 106Cd | 105.906459791 ± 0.000001184 | Stable >1.1Zy | 1935 | IS=1.245±2.2%; 2β+ ? |
| 107Cd | 106.906612049 ± 0.000001782 | 6.50 h ± 0.02 | 1946 | β+=100% |
| 108Cd | 107.904183588 ± 0.000001205 | Stable >410Py | 1935 | IS=0.888±1.1%; 2β+ ? |
| 109Cd | 108.904986697 ± 0.000001649 | 461.3 d ± 0.5 | 1950 | ε=100% |
| 109Cdm | 108.904986697 ± 0.000001649 | 11.8 us ± 1.6 | 1956 | IT=100% |
| 109Cdn | 108.904986697 ± 0.000001649 | 10.6 us ± 0.4 | 1964 | IT=100% |
| 110Cd | 109.903007470 ± 0.000000407 | Stable | 1925 | IS=12.470±6.1% |
| 111Cd | 110.904183776 ± 0.000000383 | Stable | 1925 | IS=12.795±1.2% |
| 111Cdm | 110.904183776 ± 0.000000383 | 48.50 m ± 0.09 | 1945 | IT=100% |
| 112Cd | 111.902763896 ± 0.000000268 | Stable | 1925 | IS=24.109±0.7% |
| 113Cd | 112.904408105 ± 0.000000262 | 8.04 Py ± 0.05 | 1925 | IS=12.227±0.7%; β-=100% |
| 113Cdm | 112.904408105 ± 0.000000262 | 13.89 y ± 0.11 | 1965 | β-=99.9036±1.9%; IT=0.0964±1.9% |
| 114Cd | 113.903364998 ± 0.000000296 | Stable >92Py | 1925 | IS=28.754±8.1%; 2β- ? |
| 115Cd | 114.905437426 ± 0.000000699 | 53.46 h ± 0.05 | 1939 | β-=100% |
| 115Cdm | 114.905437426 ± 0.000000699 | 44.56 d ± 0.24 | 1959 | β-≈100%; IT ? |
| 116Cd | 115.904763230 ± 0.000000172 | 26.9 Ey ± 0.9 | 1925 | IS=7.512±5.4%; 2β-=100% |
| 117Cd | 116.907226039 ± 0.000001087 | 2.503 h ± 0.005 | 1939 | β-=100% |
| 117Cdm | 116.907226039 ± 0.000001087 | 3.441 h ± 0.009 | 1966 | β-=100% |
| 118Cd | 117.906921956 ± 0.000021471 | 50.3 m ± 0.2 | 1961 | β-=100% |
| 119Cd | 118.909847052 ± 0.000040467 | 2.69 m ± 0.02 | 1961 | β-=100% |
| 119Cdm | 118.909847052 ± 0.000040467 | 2.20 m ± 0.02 | 1974 | β-=100% |
| 120Cd | 119.909868065 ± 0.000004 | 50.80 s ± 0.21 | 1973 | β-=100% |
| 121Cd | 120.912963660 ± 0.000002085 | 13.5 s ± 0.3 | 1965 | β-=100% |
| 121Cdm | 120.912963660 ± 0.000002085 | 8.3 s ± 0.8 | 1982 | β-=100% |
| 122Cd | 121.913459050 ± 0.000002468 | 5.24 s ± 0.03 | 1973 | β-=100% |
| 123Cd | 122.916892460 ± 0.000002894 | 2.10 s ± 0.02 | 1983 | β-=100% |
| 123Cdm | 122.916892460 ± 0.000002894 | 1.82 s ± 0.03 | 1986 | β-=?; IT ? |
| 124Cd | 123.917659772 ± 0.0000028 | 1.25 s ± 0.02 | 1974 | β-=100% |
| 125Cd | 124.921257590 ± 0.0000031 | 680 ms ± 40 | 1986 | β-=100% |
| 125Cdm | 124.921257590 ± 0.0000031 | 480 ms ± 30 | 1986 | β-=100% |
| 125Cdn | 124.921257590 ± 0.0000031 | 19 us ± 3 | 2011 | IT=100% |
| 126Cd | 125.922430290 ± 0.000002473 | 512 ms ± 5 | 1978 | β-=100% |
| 127Cd | 126.926203291 ± 0.000006656 | 480 ms ± 100 | 1986 | β-=100%; β-n ? |
| 127Cdm | 126.926203291 ± 0.000006656 | 360 ms ± 40 | 2019 | β-=100% |
| 127Cdn | 126.926203291 ± 0.000006656 | 17.5 us ± 0.3 | 2010 | IT=100% |
| 128Cd | 127.927816778 ± 0.000006905 | 246 ms ± 2 | 1986 | β-=100%; β-n ? |
| 128Cdm | 127.927816778 ± 0.000006905 | 270 ns ± 7 | 2009 | IT=100% |
| 128Cdn | 127.927816778 ± 0.000006905 | 3.56 us ± 0.06 | 2009 | IT=100% |
| 128Cdp | 127.927816778 ± 0.000006905 | 6.3 ms ± 0.8 | 2016 | IT=100% |
| 129Cd | 128.932235597 ± 0.0000057 | 147 ms ± 3 | 2003 | β-=100%; β-n=? |
| 129Cdm | 128.932235597 ± 0.0000057 | 157 ms ± 8 | 1986 | β-=100%; β-n=? |
| 129Cdn | 128.932235597 ± 0.0000057 | 3.6 ms ± 0.2 | 2014 | IT=100% |
| 130Cd | 129.934387563 ± 0.000024 | 126.8 ms ± 1.8 | 1986 | β-=100%; β-n=3.5±1% |
| 130Cdm | 129.934387563 ± 0.000024 | 240 ns ± 16 | 2007 | IT=100% |
| 131Cd | 130.940727740 ± 0.000020653 | 98 ms ± 2 | 2000 | β-=100%; β-n=3.5±1%; β-2n ? |
| 132Cd | 131.945823136 ± 0.000064485 | 84 ms ± 5 | 2000 | β-=100%; β-n=60±1.5%; β-2n ? |
| 133Cd | 132.952614 ± 0.000215 [Estimated] | 61 ms ± 6 | 2010 | β-=100%; β-n=?; β-2n ? |
| 134Cd | 133.957638 ± 0.000322 [Estimated] | 65 ms ± 15 | 2015 | β-=100%; β-n ?; β-2n ? |
| 135Cd | 134.964766 ± 0.000429 [Estimated] | Not-specified | β- ?; β-n ? |
