The crystal structures of MnSiO3 polymorphs (rhodonite- and pyroxmangite-type)

Abstract

The structures of two polymorphs of MnSiO3 have been determined from the single crystal X-ray data collected by a counter method. The rhodonite-type is triclinic, P-1, with a=7.616(3), b=11.851(5), c=6.707(2)Å, α=92°33′(6′), β=94°21′(6′) and γ=105°40′(6′), Z=10. The pyroxmangite-type is triclinic, P-1, with a=6.721(2), b=7.603(3), c=17.455(6)Å, α=113°10′(6′), β=82°16′(6′) and γ=94°08′(6′), Z=14. The structures of the rhodonite- and pyroxmangite-type were refined by full matrix least-squares method to the R-values of 0.050 and 0.071 for all 1664 and 1984 reflections, respectively. The configuration of the single silicate chains and coordination polyhedra in the MnSiO3 polymorphs, indicates that the pyroxmangite structure consists of parts of the rhodonite and pyroxene structures.