Direct determination of the zero-field splitting for Fe ion in a synthetic polymorph of the oxalate mineral stepanovite NaMgFe(C2O4)3·9H2O: a natural MOF

of the oxalate mineral stepanovite NaMgFe(C2O4)3·9H2O: a natural MOF Tao Xie, S. E. Nikitin, 3, ∗ A. I. Kolesnikov, E. Mamontov, L. M. Anovitz, G. Ehlers, I. Huskić, T. Frǐsčić, and A. Podlesnyak † Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA Max Planck Institute for Chemical Physics of Solids, D-01187 Dresden, Germany Institut für Festkörperund Materialphysik, Technische Universität Dresden, D-01069 Dresden, Germany Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA Neutron Technologies Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, H3A 0B8 Quebec, Canada.