57 Fe NCR of Fe phases in “magnetic cassiterites”

A pyralspite garnet from an anomalously magnetic concentrate of a pegmatitic cassiterite ore has been investigated using 57 Fe nuclear gamma-ray resonance spectroscopy. The quadrupole splitting and isomer shift values of 3.6 mm/s and 1.4 mm/s, respectively, are among the largest observed for Fe 2+ ions and indicate a very low covalency of the dodecahedral Fe 2+ — O 2 -bonds. These data support the more recent and lower value (10.2–10.1 kcal/ mole) of White and Moore (1972) for the CFSE of the dodecahedral Fe 2+ ion and suggest that the CFSE should be a useful approximation to the site preference energy of Fe 2+ for this site.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47320/1/410_2004_Article_BF00372603.pd