A multinuclear,high-resolution solid-state NMR study of sorensenite (Na4SnBe2(Si3O9)·2H2O) and comparison with wollastonite and pectolite

This paper presents a solid state ¹H, ²³Na, ²⁹Si, and ¹¹⁹Sn nuclear magnetic resonance (NMR) study of sorensenite. New ²⁹Si NMR data for two related pyroxenoids, wollastonite and pectolite, are included for comparison. By more sensitively probing chemical bonding, the element-specific NMR observations both complement and reinforce the x-ray diffraction results. The role of hydrogen and its interactions with neighboring atoms in sorensenite is further clarified. The wollastonite and pectolite ²⁹Si spectra resolve for the first time all three crystallographic sites and their comparison with sorensenite reveals subtle, systematic differences in sites along the pyroxenoid chains. Effects of corner-shared BeO₄ tetrahedra on ²⁹Si shifts show that sorensenite may also be viewed as a more polymerized silicoberyllate. Contribution to the mineralogy of Ilimaussaq No. 86