Crystal chemistry features of the Sr-rich aqualite-like mineral from the Konder alkaline complex

A hydrated Sr-rich member of the eudialyte-group mineral from Konder (Southern Yakutia) alkaline complex has been investigated by the methods of electron probe microanalysis and X-ray diffraction. The crystal structure was refined to R = 3.9 % in the anisotropic approximation of atomic displacements using 2188 independent reflections with F > 3 (F). The unit-cell parameters are: a = 14.1039(2), c = 31.0743(4) Å, V = 5353.1 Å3; the space group R3. The chemical composition of the studied mineral (Z = 3): Na3.87K0.06Sr1.01Ba0.16Ca4.65REE0.47Y0.3Fe0.38Mn1.27Zr2.92Hf0.3Ti0.09Nb0.12Mg0.07Si25.83O72Cl0.17. The crystal chemistry features of the mineral and its place among hydrated eudialytes are discussed.