Magnetic properties paramagnetism

Magnetic Properties Paramagnetism Nuclear magnetic resonance Electron paramagnetic resonance... 

Magnetic properties Paramagnetic Eerro and diamagnets Diamagnets... 

Ligand-field theory is concerned only with the low-lying electronic states of a d- or y block metal complex which can be described by the rearrangements of electrons within the d- or y shell. These states describe the magnetic properties (paramagnetism, g-values) and the ""d-d (or ""f-f ) electronic spectra (color, linear, and circular dichroism). 

Correlate the structure and cFelectron counts of complexes to their magnetic properties (paramagnetic versus diamagnetic). 

A major weakness of valence bond theory has been its inability to predict the magnetic properties of molecules. We mentioned this problem in Chapter 7 with regard to the 02 molecule, which is paramagnetic, even though it has an even number (12) of valence electrons. The octet rule, or valence bond theory, would predict that all the electrons in 02 should be paired, which would make it diamagnetic. 

Answer (a) The complex becomes paramagnetic (b) there is no change in magnetic properties.]... 

The valences of the rare-earth metals are calculated from their magnetic properties, as reported by Klemm and Bommer.14 It is from the fine work of these investigators that the lattice constants of the rare-earth metals have in the main been taken. The metals lutecium and ytterbium have only a very small paramagnetism, indicating a completed 4/ subshell and hence the valences 3 and 2, respectively (with not over 3% of trivalent ytterbium present in the metal). The observed paramagnetism of cerium at room temperature corresponds to about 20% Ce4+ and 80% Ce3+, that of praseodymium and that of neodymium to about 10% of the quadripositive ion in each case, and that of samarium to about 20% of the bipositive ion in equilibrium with the tripositive ion. 

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