Neodymium, determination of atomic

Neodymium, determination of atomic weight of, in neodymium oxalate, 2 61 separation of, from samarium from monazite, as magnesium nitrate double salt, 2 56, 57... 

Neodymium oxalate, determination of atomic weight of neodymium in, 2 60... 

The method evolved by Moseley (1887 to 1915) of determining the atomic number enabled chemists to ascertain, as has already been seen, the maximum number of elements that can exist in serial order between any two selected ones. As the atomic numbers of lanthanum and lutecium are 57 and 71, it is clear that it is possible for 13 elements to exist of atomic numbers between these. Now europium was the twelfth to be discovered, but no element corresponding to 61 had been recorded. This should lie between neodymium (60) and samarium (62), and as early as 1902 Bohuslav Brauner had predicted its existence. In 1926 Hopkins, of Illinois, with his collaborators Harris and Yntema, announced the discovery of a new element in the neodymium extracted from monazite sand, the lines of the X-ray spectrum agreeing with those expected for element 61. He called it Illinium. 

Similarly, this raises questions regarding the determination of isotope amount ratios of neodymium or osmium - is it adequate to use the ratio for nonradiogenic isotopes for the mass bias correction of other isotope ratios Are they indeed invariant in Nature The 2009 lUPAC report on Atomic Weights addressed this question rather explicitly by abrogating the conventional notation of Standard Atomic Weights in favor of the interval of the Standard Atomic Weights [57]. Furthermore, concerning the mass bias correction, it is now established that mass bias correction factors are not identical for all isotopes of the same element. Hence the limitations of traditional mass bias correction methods must be accepted. 

Compound 65f was isolated as a sky-blue crystalline solid which is highly soluble in nonpolar organic solvents. The molecular structure of 65f was determined by a single crystal X-ray analysis. It showed the neodymium atom in a distorted octahedral coordination environment (Fig. 20) [78]. Dark red crystalline [Me2Si(OtBu)(NrBu)]3Eu was prepared analogously. 

Monomeric Ce(tritox)3 was claimed in 1989 [29]. However, the structure determination was hampered by disordering problems both in solvent-free Ce(tritox)3 and Nd(tritox)3(THF) [36]. Appropriate crystallization conditions were borrowed from cyclopentadienyl chemistry. The corresponding LnCp3 systems show remarkable crystallization behavior in the presence of neutral bases like acetonitrile and DMSO which impose polarities into the molecule [37], Indeed, this phenomenon could be transferred to Nd(tritox)3 in a 2-phase system n-pentane/acetonitrile at — 35°C [38], X-ray analysis revealed a monomeric alkoxide of formula Nd(tritox)3(NCCH3)2 with a trigonal bipyramidal geometry at the neodymium center (Fig. 2, Table 1). The alkoxide O-atoms and... 

For example, the isotopic composition and the atomic weight of neodyminm," dysprosium and erbium have been determined using synthetic mixtnres prepared gravimetrically from highly enriched isotopes of neodymium in the form of oxides of weU defined pnrity by TIMS. No natnral isotopic variation was found in terrestrial neodymium, dysprosium or erbium samples. These isotopic compositions of Dy and Er measnred by TIMS are accepted as the best measurements from a single terrestrial source as noted in the table of isotopic composition of elements, 2001. °... 

Seven naturally occurring isotopes of neodymium are known. They are neodymium-142, neodymium-143, neodymium-144, neodymium-145, neodymium-146, neodymium-148, and neodymium-150. Five of the isotopes are stable and two, neodymium-144 and neodymium-150, are radioactive. Isotopes are rwo or more forms of an element. Isotopes differ from each other according to their mass number. The number written to the right of the element s name is the mass number. The mass number represents the number of protons plus neutrons in the nucleus of an atom of the element. The number of protons determines the element, but the number of neutrons in the atom of any one element can vary. Each variation is an isotope. 

Shift magnitudes (Ai ) determined for the compounds of known composition, were compared. The increments, contributing to the shift in the presence of neodymium bond with nitrogen and oxygen atoms of the carboxy-, oxy- and hydroxy-groups were established. These increments may be used to investigate composition and structure of the neodymium compounds. Table I... 

Meggers 1942) and that of element 61 is obtained by interpolation consequently, these are subject to some doubt. The ground states given for neodymium (Schuurmans 1946), samarium, europium and gadolinium are those spectroscopically determined (Meggers 1942) for the neutral atoms and should be considered as well established. 

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