Praseodymium

Praseodymium is a <a href="/facts/Chemical_element/0jducgWD">chemical element</a>; it has <a href="/facts/Symbol_(chemistry)/2Fe1VAL0">symbol</a> Pr and <a href="/facts/Atomic_number/bgAr581S">atomic number</a> 59. It is the third member of the <a href="/facts/Lanthanide/rt3XIRCl">lanthanide</a> series and is considered one of the <a href="/facts/Rare-earth_metal/PQSUQumk">rare-earth metals</a>. It is a soft, silvery, malleable and ductile <a href="/facts/Metal/PT8hNX6R">metal</a>, valued for its magnetic, electrical, chemical, and optical properties. It is too reactive to be found in <a href="/facts/Native_element_mineral/kWjWAus5">native form</a>, and pure praseodymium metal slowly develops a green oxide coating when exposed to air.
Praseodymium always occurs naturally together with the other rare-earth metals. It is the sixth-most abundant rare-earth element and fourth-most abundant lanthanide, making up 9.1 <a href="/facts/Parts_per_million/PozRuoLM">parts per million</a> of the Earth's crust, an abundance similar to that of <a href="/facts/Boron/Pmwgd7Mf">boron</a>. In 1841, Swedish chemist <a href="/facts/Carl_Gustav_Mosander/nlB4bhRp">Carl Gustav Mosander</a> extracted a rare-earth oxide residue he called <a href="/facts/Didymium/qrefFWn8">didymium</a> from a residue he called "lanthana", in turn separated from <a href="/facts/Cerium/a7UjMBQ6">cerium</a> salts. In 1885, the Austrian chemist <a href="/facts/Carl_Auer_von_Welsbach/b1654JpC">Carl Auer von Welsbach</a> separated didymium into two elements that gave salts of different colours, which he named praseodymium and <a href="/facts/Neodymium/GzDkTIoI">neodymium</a>. The name praseodymium comes from the Ancient Greek πράσινος (prasinos), meaning '<a href="/facts/Leek/5f7HXCfS">leek</a>-green', and δίδυμος (didymos) 'twin'.
Like most <a href="/facts/Rare-earth_element/PQSUQumk">rare-earth elements</a>, praseodymium most readily forms the +3 <a href="/facts/Oxidation_state/W53W6s6V">oxidation state</a>, which is the only stable state in <a href="/facts/Aqueous_solution/eRNr3MH2">aqueous solution</a>, although the +4 oxidation state is known in some solid compounds and, uniquely among the lanthanides, the +5 oxidation state is attainable at low temperatures. The 0, +1, and +2 oxidation states are rarely found. Aqueous praseodymium ions are yellowish-green, and similarly, praseodymium results in various shades of yellow-green when incorporated into glasses. Many of praseodymium's industrial uses involve its ability to filter yellow light from light sources.

Praseodymium open-in-new

Praseodymium