Symbol | Cd |
Atomnummer | 48 |
Gruppe | 12 (Zinkgruppe) |
Periode | 5 |
Blok | d |
Klassifikation | Overgangsmetal |
Udseende | Silvery bluish-gray metallic |
Farve | Sølv |
Antal protoner | 48 p+ |
Antal neutroner | 64 n0 |
Antal elektroner | 48 e- |
Fase ved STP | Fast |
Massefylde | 8.65 g/cm3 |
Atommasse | 112.414 u |
Smeltepunkt | 594.22 K 321.07 °C 609.926 °F |
Kogepunkt | 1040 K 766.85 °C 1412.33 °F |
Fordampningsvarme | 99.87 kJ/mol |
Elektronegativitet (Pauling Scale) | 1.69 |
Elektronaffinitet | -68 kJ/mol |
Oxidationstrin | −2, +1, +2 (a mildly basic oxide) |
Ioniseringsenergier |
|
Opdagelse og første isolation | Karl Samuel Leberecht Hermann, Friedrich Stromeyer, Karl Samuel Leberecht Hermann (1817) |
Navngivet af | Friedrich Stromeyer (1817) |
Opdagelse af cadmium Cadmium (Latin cadmia, Greek καδμεία meaning "calamine", a cadmium-bearing mixture of minerals that was named after the Greek mythological character Κάδμος, Cadmus, the founder of Thebes) was discovered in contaminated zinc compounds sold in pharmacies in Germany in 1817 by Friedrich Stromeyer. Karl Samuel Leberecht Hermann simultaneously investigated the discoloration in zinc oxide and found an impurity, first suspected to be arsenic, because of the yellow precipitate with hydrogen sulfide. Additionally Stromeyer discovered that one supplier sold zinc carbonate instead of zinc oxide. Stromeyer found the new element as an impurity in zinc carbonate (calamine), and, for 100 years, Germany remained the only important producer of the metal. The metal was named after the Latin word for calamine, because it was found in this zinc ore. Stromeyer noted that some impure samples of calamine changed color when heated but pure calamine did not. He was persistent in studying these results and eventually isolated cadmium metal by roasting and reducing the sulfide. |