Cadmium is a blue-gray soft metal. It can be considered a transition metal or a post-transition metal. It is malleable and ductile. It is similar to zinc. It melts at 321°C.
Cadmium has 8 natural isotopes. 5 are radioactive, but 3 have very long half-lives so their radioactivity is almost nothing.
Cadmium is a moderately reactive metal. It corrodes in moist air and dissolves in acids. It burns in air when powdered to make the brown cadmium oxide.
Cadmium forms chemical compounds in two oxidation states: +1 and +2. The +1 state is rare and unstable. The +2 state is much more common. Most +2 compounds dissolve easily in water and are white to yellow. Cadmium oxide can be brown, red, or white. Cadmium sulfide is bright yellow. Cadmium chloride and cadmium sulfate are colorless solids that dissolve easily in water. Cadmium fluoride is slightly soluble. Cadmium compounds are toxic when inhaled.
- Cadmium bromide, pale yellow solid, dissolves in water
- Cadmium chloride, colorless solid, dissolves in water
- Cadmium fluoride, gray solid, does not dissolve good in water
- Cadmium iodide, pale yellow solid, dissolves in water
- Cadmium oxide, white, brown, or red solid, dissolves in acids
- Cadmium sulfate, colorless solid, dissolves in water
- Cadmium sulfide, bright yellow solid, does not dissolve in water
- Cadmium telluride, black solid, semiconductor