"' Praseodymium "'is a chemical element with symbol "'Pr "'and atomic number 59 . Praseodymium is a soft, silvery, malleable and ductile metal in the lanthanide group.
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Praseodymium makes up an average of 8 parts per million of soil's dry weight, though the element's concentration there can be as low as 1 part per million or as high as 15 parts per million.
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Wang, Swimmer, and Laughton ( 2007 ) reported aversive responses to neodymium-praseodymium mischmetals placed near baits offered to adult Galapagos ( " C . galapagensis " ) and Sandbar sharks on bamboo poles in Hawaii.
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However, a similar color could be achieved with colorants costing only a minute fraction of what praseodymium cost in the late 1920s, such that the color was not popular, few pieces were made, and examples are now extremely rare.
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Early neodymium glasses made in the 1930s have a more reddish or orange tinge than modern versions which are more cleanly purple, due to the difficulties in removing the last traces of praseodymium in the era when manufacturing relied upon fractional crystallization technology.
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A modern ferrocerium firesteel product is composed of an alloy of rare earth metals called mischmetal ( containing approximately 50 % cerium, 25 % lanthanum, and small amounts of praseodymium and neodymium ), plus iron and a small amount of magnesium.
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Brill et al . ( 2008 ) reported that captive juvenile sandbar sharks ( " Carcharhinus plumbeus " ) maintained a 50 60 cm clearance in their swimming patterns when a piece of neodymium-praseodymium mischmetal was placed in the tank.
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SolV, although the great chemical similarity of the lanthanides means that it may be substituted with cerium, praseodymium, or neodymium without ill effects, and with the smaller samarium, europium, or gadolinium giving no side effects other than slower growth.
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Because it has 84 neutrons ( two more than 82, which is a magic number which corresponds to a stable neutron configuration ), it may emit an alpha particle ( which has 2 neutrons ) to form praseodymium-141 with 82 neutrons.
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The first enduring commercial use of purified praseodymium, which continues today, is in the form of a yellow-orange stain for ceramics, " Praseodymium Yellow ", which is a solid-solution of praseodymium in the zirconium silicate ( zircon ) lattice.
