A Mossbauer spectral study of the Jilin meteorite

The iron-57 Mossbauer spectra of three different samples of the Jilin meteo rite have been measured at 78 and 295 K. Five iron containing major compone nts are identified, two magnetic components, kamacite and troilite, and thr ee non-magnetic components, olivine, pyroxene, and an iron(III) component. The relative absorption areas of these five components show that sample A c ontains a larger fraction of magnetic components, ca. 50 percent, than samp les B and C, which contain ca. 30 percent. This difference indicates a sign ificant compositional inhomogeneity in the Jilin meteorite. The fit of the troilite component sextet is extensively discussed in the paper and require s the adjustment of not only the isomer shift and hyperfine held, but also of the quadrupole interaction, the asymmetry parameter of the electric fiel d gradient tensor, and the orientation of the hyperfine field in the princi pal axes of the electric field gradient tensor. The smaller isomer shift an d hyperfine field of the kamacite mineral in sample B indicate that this sa mple contains less nickel than the kamacite in samples A and C, in which th e amount of nickel is estimated to be ca. 9 percent. On the basis of its hy perfine parameters, the iron(III) component is assigned to iron(III) substi tuted on the M1 site of pyroxene.