This element is no longer available.
Uranium is a hard, dense, malleable, ductile, silver-white, radioactive metal. Uranium metal has very high density. When finely divided, it can react with cold water. In air it is coated by uranium oxide, tarnishing rapidly. It is attacked by steam and acids. Uranium can form solids solutions and intermetallic compounds with many of the metals.
Uranium gained importance with the development of practical uses of nuclear energy. Depleted uranium is used as shielding to protect tanks, and also in bullets and missiles. The first atomic bomb used in warfare was a uranium bomb. This bomb contained enough of the uramium-235 isotope to start a runaway chain reaction which in a fraction of a second caused a large number of the uranium atoms to undergo fission, there by releasing a fireball of energy.
The main use of uranium in the civilian sector is to fuel commercial nuclear power plants. This require uranium to be enriched with the uranium-235 isotope and the chain reaction to be controlled so that the energy is released in a more manageable way.
The isotope uranium 238 is used to estimate the age of the earliest igneous rocks and for other types of radiometric dating.
Phosphate fertilizers are made from material typically high in uranium, so they usually contain high amounts of it.