Synthetic versiliaite and apuanite: investigation by ⁵⁷Fe Mössbauer spectroscopy

Abstract

The minerals versiliaite and apuanite have been synthesised for the first time. The ⁵⁷Fe Mössbauer spectra recorded at 298 and 4 K are reported. The results are indicative of a formulation for versiliaite as $\left (\text {Fe}_{4}^{2+}\text {Fe}_{4}^{3+}\right )^{\text {oct}}\left [\text {Fe}_{4}^{3+}\text {Sb}_{12}^{3+}\right ]^{\text {tet}}\textit {O}_{32}\textit {S}_{2}$ and of apuanite as $\left (\text {Fe}_{4}^{2+}\text {Fe}_{8}^{3+}\right )^{\text {oct}}\left [\text {Fe}_{8}^{3+}\text {Sb}_{16}^{3+}\right ]^{\text {tet}}\textit {O}_{48}\textit {S}_{\mathrm {4.}}$ The spectra recorded at low temperature are indicative of complex magnetic interactions. The results indicate the potential for the synthesis of further new structurally-related materials with different compositions and new low dimensional physical properties.