Open AccessCrystal structure and indicatopy significance of odikhinchaite from the Khibiny alkaline complex
Author(s) -
Р. К. Расцветаева,
Н. В. Чуканов,
D. V. Lisitsin,
M. V. Voronin,
Д. А. Варламов
Publication year - 2021
Publication title -
vestnik geonauk
Language(s) - English
Resource type - Journals
ISSN - 2712-7761
DOI - 10.19110/geov.2021.4.1
Subject(s) - crystallography , pegmatite , mineral , infrared spectroscopy , chemistry , crystal structure , mössbauer spectroscopy , crystal (programming language) , structural formula , materials science , mineralogy , organic chemistry , computer science , programming language , alkyl
Odikhinchaite, a Sr-Mn-Nb-CO3-dominant eudialyte-group mineral from the Khibiny alkaline complex has been investigated using the methods of electron probe microanalysis, X-ray diffraction, infrared and Mössbauer spectroscopy. The crystal structure was refined to R = 3.4 % in the anisotropic approximation of atomic displacements using 3815 independent reflections with F > 3(F). The unit-cell parameters are: a = 14.2709(1), c = 30.023(1) Å, V = 5295.33(7) Å3; the space group is R3m. The simplified formula of the mineral is (Z = 3): Na11Sr3(Mn2+,Fe2+,Fe3+)Ca6Zr3Nb[Si25O72(OH)](CO3)Cl(OH,O)4. The studied sample is the second find of this rare mineral worldwide, represented by a variety with high Fe content in the M2 micro-region, belonging to the taseqite — odikhinchaite solid-solution series. The significance of odikhinchaite as an indicator of a stage corresponding to maximum Sr activity in specific ultraagpaitic pegmatites is discussed.