Rare Earth Elements
The Rare Earth Elements
58 Cerium(Ce): melting point- 765c boiling point-3360c
EX:Glass polishing powders
59 Praseodymium(Pr): melting point- 935c boiling point- 3290c
EX:Strong magnets
60 Neodymium(Nd): melting point- 1024c boiling point- 3100c
EX:Additive in glasses
61 Promethium(Pm): melting point-1100c boiling point- 3000c
EX:One stable oxidation
Cerium
Cerium was discovered in 1803 by Jöns Jacob Berzelius and Wilhelm Hisinger and independently by Martin Klaproth. It was isolated from a mineral from an iron mine at Bastn°s
Praseodymium
In 1885, Carl Auer von Welsbach separated an "earth" called didymia obtained from the mineral samarskite into two earths, praseodymium and neodymium, which gave salts of different colours. The separation required the repeated fractionation of ammonium didymium nitrate
Neodymium
Promethium
Earlt discovered promethium in 1924 but these appear have been substantiated. A group at Ohio State University (USA) claimed element 61 in experiments involving its synthesis in a cyclotron, but again the evidence did not satisfy everyone. In 1947, Marinsky, Glendenin, and Coryell at Oak Ridge, Tennessee, USA, made the first chemical identification of promethium
Were these Earth metals can be found
Safety concerns about rare earth elements
2) Some of the rare earth elements are very toxic such as lanthanum