Tantalium (Ta) is found uncombined in nature. It is found in coloumbite-tantalite. Tantalium also comes as a result of Mining. It is separated from others by Electrolysis.
Osmium comes when there is a reaction of Nickel refining as by-product. It is rare element which is found naturally as a free element. It is also found naturally in Alloys with copper and nickel.
Rhodium is obtained as the by-product of Copper as well as Nickel refining.
temperature 3000 km below the surface of earth is varied, it's harder to know the actual temperature, it can be found around 3,000 - 3,500 degrees Celsius
