نيوديميوم (Nd)

الاكتشاف والتاريخ

تاريخ الاكتشاف: 1885 · Carl Auer von Welsbach

The discovery of neodymium followed investigations of cerite, the mineral in which Jöns Jacob Berzelius and Wilhelm Hisinger, and independently Martin Heinrich Klaproth, identified cerium in 1803. During the late 1830s and early 1840s, Carl Gustaf Mosander's studies of cerium compounds led to the identification of lanthanum and a further component that he named didymium. The name, derived from the Greek for 'twin', referred to didymium's close association with lanthanum. Didymium was initially accepted as an element and appeared in Dmitri Mendeleev's 1869 periodic table. However, its composition was questioned as further samples were studied. In 1882, Bohuslav Brauner reported that didymium obtained from different minerals varied in composition. In 1885, the Austrian chemist Carl Auer von Welsbach separated didymium into praseodymium and neodymium in Vienna. He used repeated fractional c

الاستخدامات والتطبيقات

Neodymium most commonly forms compounds in the +3 oxidation state. Its chloride and nitrate are soluble in water, whereas its oxide and hydroxide are poorly soluble. Dissolved neodymium salts can precipitate as the hydroxide at neutral or alkaline pH. Neodymium salts can appear different colors under different types of illumination.

النظائر

Natural neodymium contains seven isotopes: 142Nd, 143Nd, 144Nd, 145Nd, 146Nd, 148Nd, and 150Nd. The most abundant is 142Nd, which accounts for approximately 27.2% of natural neodymium. Five of these isotopes have no observed radioactive decay. Of those five, 143Nd, 145Nd, 146Nd, and 148Nd are predicted to undergo extremely slow alpha decay and are therefore described as observationally stable. The other two natural isotopes are primordial radionuclides, whose long half-lives have allowed them to survive since before the formation of Earth. Neodymium-144 undergoes alpha decay to 140Ce with a half-life of (2.29±0.16)×1015 years. Neodymium-150 undergoes double beta decay to 150Sm; the NEMO-3 experiment measured a half-life of approximately 9.3×1018 years for decay to the ground state of samarium-150. The other known radioisotopes have much shorter half-lives. The longest-lived of these is 1