Praseodymium


 * LSec WSol

Name: ** Praseodymium **Period:** 6 **Group Number:** None **Crystal Structure:** Hexagonal **Second Energy Level:** 8 **Fifth Energy Level:** 8 ** Abundance earth's crust: ** 0.9 log  ** cost, pure: ** 170 $/100g  ** Uses: ** alloys, Welder's mask ** Number of isotopes :**  1 **Important Compounds formed by Praseodymium:** Praseodymium chloride =|| || ||       = =       History        = <span style="font-family: Tahoma, Geneva, sans-serif;"> <span style="font-family: Tahoma, Geneva, sans-serif;"> The element was isolated and named by<span style="font-family: Tahoma, Geneva, sans-serif;"> Baron  <span style="font-family: Tahoma, Geneva, sans-serif;"><span style="font-family: Tahoma, Geneva, sans-serif;">Carol Auer von Welsbach in 1885. Praseodymium was discovered in Austria. He named praseodymium with the Greek roots //prasios//, for “green,” reflecting the tarnish that forms on this element, and //didymos//, for “twin. ”
 * Symbol:** Pr
 * Atomic Number:** 59
 * Group Name:** Lanthanide
 * Atomic Mass:** 140.90765 amu
 * Melting Point:** 935.0 °C (1208.15 K, 1715.0 °F)
 * Boiling Point:** 3127.0 °C (3400.15 K, 5660.6 °F)
 * Number of Protons/Electrons:** 59
 * Number of Neutrons:** 82
 * Classification:** Rare Earth
 * Density @ 293 K:** 6.77 g/cm3
 * Color:** Unknown
 * Number of Energy Levels:6**
 * First Energy Level:** 2
 * Third Energy Level:** 18
 * Fourth Energy Level: **       <span style="font-family: Tahoma, Geneva, sans-serif;"><span style="font-family: Tahoma, Geneva, sans-serif;">21
 * <span style="font-family: Tahoma, Geneva, sans-serif;"><span style="font-family: Tahoma, Geneva, sans-serif;">Sixth Energy Level: ** <span style="font-family: Tahoma, Geneva, sans-serif;"><span style="font-family: Tahoma, Geneva, sans-serif;"> 2
 * <span style="font-family: Tahoma, Geneva, sans-serif;">State at room temparute: **  <span style="font-family: Tahoma, Geneva, sans-serif;"><span style="font-family: Tahoma, Geneva, sans-serif;"><span style="font-family: Tahoma, Geneva, sans-serif;">     <span style="font-family: Tahoma, Geneva, sans-serif;"><span style="font-family: Tahoma, Geneva, sans-serif;"> <span style="font-family: Tahoma, Geneva, sans-serif;">   Solid
 * cost, bulk: ** $/100g

__**Biological Role:**__ Praseodymium has no biological role but is said to stimulate the metabolism praseodymium compounds are encountered rarely by most people. All praseodymium compounds should be regarded as highly toxic although initial evidence would appear to suggest the danger is limited. Praseodymium compounds are skin and eye irritants. The metal dust presents a fire and explosion hazard.
 * __Hazards:__**

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