What is Praseodymium atom?

     

Praseodymium is a chemical element with the symbol Pr and atomic number 59.  It is the third member of the lanthanide series and is traditionally considered to be one of the rare-earth metals.  Praseodymium is a soft, silvery, malleable and ductile metal, valued for its magnetic electrical, chemical, and optical properties.

     It is too reactive to be found in native form, and pure praseodymium metal slowly develops a green oxide coating when exposed to air. Praseodymium always occcurs naturally together with the other rare-earth metals.  It is the fourth most common rare-earth element making up 9.1 parts per million of the Earth's crust, an abundance similar to that of boron.  In 1841, Swedish chemist Carl Gustav mosander extracted a rare-earth oxide residue he called didyium from a residue he called "lanthana" in turn separted from cerium salts.

     The name praseodymium comes from the Greek prasinos, meaning "green", and didymos,"twin".  Like most rare-earth elements, praseodymium most readily forms the +3 oxidation state, which is the only stable state in aqueous solution, although the +4 oxidation state is known in some solid compound and, uniquely among the lanthanides, the +5 oxidation state is attainable in matrix-isolation conditions.