Optimization of the electron spin resonance spectrometric determination of transition-metal ions by variation of temperature

1989 ◽  
Vol 218 ◽  
pp. 93-100 ◽  
Author(s):  
D.Thorburn Burns ◽  
Barry G. Dalgarno ◽  
Brian D. Flockhart
Keyword(s):  
Electron Spin Resonance ◽  
Transition Metal ◽  
Metal Ions ◽  
Electron Spin ◽  
Transition Metal Ions ◽  
Spin Resonance

Applications of electron spin resonance in the analytical chemistry of transition metal ions

1978 ◽  
Vol 96 (1) ◽  
pp. 99-106 ◽  
Author(s):  
Warren G. Bryson ◽  
(the late) David P. Hubbard ◽  
Barrie M. Peake ◽  
Jim Simpson
Keyword(s):  
Analytical Chemistry ◽  
Electron Spin Resonance ◽  
Transition Metal ◽  
Metal Ions ◽  
Electron Spin ◽  
Transition Metal Ions ◽  
Spin Resonance

Electron spin resonance in natural kaolinites containing Fe3+ and other transition metal ions

Clay Minerals ◽  
1975 ◽  
Vol 10 (5) ◽  
pp. 313-345 ◽  
Author(s):  
R. E. Meads ◽  
P. J. Malden
Keyword(s):  
Electron Spin Resonance ◽  
Transition Metal ◽  
Metal Ions ◽  
Electron Spin ◽  
Transition Metal Ions ◽  
Crystal Fields ◽  
Hole Trapping ◽  
Spin Resonance ◽  
Crystal Field Parameters ◽  
A Site

AbstractA number of natural kaolinites from a variety of world sources have been investigated using electron spin resonance at both X-band and Q-band. The results show systematic differences some of which are related to the crystallinity of the material, some to the presence of transition metal ions other than Fe3+ and hole-trapping defects.The results provide evidence for at least three sites for substitution of Fe3+ having large crystal fields : (i) a site with near maximum rhombic character having crystal field parameters D > 1·2, λ = ⅓ the occurrence of which is correlated with lack of crystalline perfection due to stacking defects or to the proximity of surfaces, (ii) a site with less rhombic character with λ = 0·234, D = 0·585 as likely parameters, and (iii) a site with parameters near the values λ = 0·207, D = 0·322.Mössbauer and ESR evidence suggests that the principal sites of Fe3+ substitution are octahedral. The presence of Fe3+ in adjacent cation sites leads to a very broad resonance centred near geff = 2. Other resonances in the spectra are attributed to the effect of trapped holes, some at least of which are situated at oxygen sites adjacent to Al3+ ions substituting in sites normally occupied by Si4+.Hyperfine effects due to the presence of the transition ions Mn2+ and (VO)2+ are also observed.

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