Mössbauer spectra of synthetic Ca-Fe pyroxenoids and lunar pyroxferroite

Resolution of the iron sites in the Mössbauer spectra of Ca-Fe pyroxenoids is only partial, two doublets being apparent in each case, whereas there are up to nine cation sites in each structure. Thus the inner and outer doublets represent, respectively: two sites and two sites in Ca_0.5Fe_0.5SiO₃(ferrobustamite); five sites and two sites in Ca_0.15Fe_0.85SiO₃ (pyroxferroite); and five sites and four sites in FeSiO₃ (ferrosolite III). Disorder of iron and calcium which exists in the two calcium-bearing pyroxenoids is not readily apparent in the spectra.