This element is classified as a lanthanide and it is the most abundant of the rare-earth elements of the earth’s crust. It is the most reactive of the rare-earth metals and is used as a catalyst to refine petroleum.
This element is the lightest alkali metal and it is very reactive. This metal is used for the production of dry cells and storage batteries (for cell phones, car batteries, etc.). The carbonate of this metal is used for the treatment of some mental decease.
This is a transition metal. This is a metal of the platinum family and it is the most corrosion-resistant metal known. It is used in the production of the alloys with osmium and platinum and in the production of crucibles and devices requiring high temperatures.