Bohr magneton value

We close this discussion by observing that Cu and Cu nuclei are usually not resolved in the ESR spectra of calcined Cu -zeoHtes. Both nuclei have spin 7= 2, have relative abundancies of respectively 69.2% and 30.8% and differ slightly in their nuclear Bohr magneton values and quadrupolar moment values. These values are respectively for Cu and Cu ] n( Cu)=3.743x10 J T" ]3n( =Cu)=4.005x 10-27 j. j-i. q(63cu)=-0.222 exlO cm and Q ( =Cu)=-0.195 ex 10 24 cm2.s iaU differences are often not resolved in the broad powder spectra. 

Here NO plays a role similar to that of Cl or CN in complexes, and may appropriately be called electronegative.) This 32 complex should have a magnetic moment of 2.83 Bohr magnetons, a value in excellent agreement with the observed 2.81. 

S is the spin quantum number. The expected magnetic moments for a sextet and a doublet state are 5.91 and 1.73 respectively, measured in Bohr magnetons. The values calculated from the observed paramagnetic susceptibilities of the crystals are 5.88 for (NH aFeFg and 2.0 for... 

The multiplicity can be determined from the experimental values of the magnetic susceptibility, the magnetic moment in Bohr magnetons being equal to 2 VS(S + l), in which S is the spin quantum number. (The multiplicity is 2S + 1.) The moments for 22 and 62 are 1.73 and 5.91, respectively. The experimental values for K3Fe(CN)6 and (NH jFeF are 2.0 and 5.88, respectively, so that the bonds in the [FefCN ] ion are electron-pair bonds, and those in [FeFe]a are ionic. 

Values 3.8 to 4.0 Bohr magnetons are observed for iron-group ions with this configuration. 

The values for the atomic saturation magnetization at the absolute zero, ferromagnetic metals iron, cobalt, and nickel are 2.22, 1.71, and 0.61 Bohr magnetons per atom, respectively.9 These numbers are the average numbers of unpaired electron spins in the metals (the approximation of the g factor to 2 found in gyromagnetic experiments shows that the orbital moment is nearly completely quenched, as in complex ions containing the transition elements). 

Fig. 1. Comparison of experimental values (solid curves) and predicted values (dashed lines) of the saturation ferromagnetic moment per atom, in Bohr magnetons, for Fe-Co, Co-Ni, and Ni-Cu alloys. The short vertical lines indicate change in crystal structure (from Ref. (2)).

For high spin Fe " with five unpaired d electrons and zero orbital angular momentum, both the calculated and measured magnetic moments are 5.9 Bohr magnetons (BM). The measured magnetic moment of Fe of 5.1 to 5.5 BM is, however, higher than the calculated value of 4.9 BM owing to a contribution from the orbital moment of the ion. 

The g-value of the methyl radical whose centre of ESR spectrum appears at 329.4 mT in a spectrometer operating at 9-233 G. Hz (h = 6-627 x 1034 Js, electron Bohr Magneton = 9-27 X 1024 JTl) is. The number of lines in the ESR spectrum of this methyl radical predicated ... 

Bohr magneton, N is the number of moles in the sample, and g is the (dimensionless) electron free-spin factor (g-factor), which has the value 2.0023. 

The angular momentum is quantized in units of h/2n and the lowest nonzero value of p is the Bohr magneton, P... 

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