Crystal structure of modular sodium-rich and low-iron eudialyte from Lovozero alkaline massif
- Authors: Rozenberg K.A.1, Rastsvetaeva R.K.1, Aksenov S.M.1,2
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Affiliations:
- Shubnikov Institute of Crystallography
- Vernadsky Institute of Geochemistry and Analytical Chemistry
- Issue: Vol 61, No 5 (2016)
- Pages: 779-785
- Section: Structure of Inorganic Compounds
- URL: https://journals.rcsi.science/1063-7745/article/view/190276
- DOI: https://doi.org/10.1134/S1063774516050187
- ID: 190276
Cite item
Abstract
The structure of the sodium-rich representative of the eudialyte group found by A.P. Khomyakov at the Lovozero massif (Kola Peninsula) is studied by X-ray diffraction. The trigonal cell parameters are: a = 14.2032(1) and c = 60.612(1) Å, V = 10589.13 Å3, space group R3m. The structure is refined to the final R = 5.0% in the anisotropic approximation of atomic displacement parameters using 3742|F| > 3σ(F). The idealized formula (Z = 3) is Na37Ca10Mn2FeZr6Si50(Ti, Nb)2O144(OH)5Cl3 · H2O. Like other 24-layer minerals of the eudialyte group, this mineral has a modular structure. Its structure contains two modules, namely, “alluaivite” (with an admixture of “eudialyte”) and “kentbrooksite,” called according to the main structural fragments of alluaivite, eudialyte, and kentbrooksite. The mineral found at the Lovozero alkaline massif shows some chemical and symmetry-structural distinctions from the close-in-composition labyrinthite modular mineral from the Khibiny massif. The difference between the minerals stems from different geochemical conditions of mineral formation in the two regions.
About the authors
K. A. Rozenberg
Shubnikov Institute of Crystallography
Email: rast@ns.crys.ras.ru
Russian Federation, Leninskii pr. 59, Moscow, 119333
R. K. Rastsvetaeva
Shubnikov Institute of Crystallography
Author for correspondence.
Email: rast@ns.crys.ras.ru
Russian Federation, Leninskii pr. 59, Moscow, 119333
S. M. Aksenov
Shubnikov Institute of Crystallography; Vernadsky Institute of Geochemistry and Analytical Chemistry
Email: rast@ns.crys.ras.ru
Russian Federation, Leninskii pr. 59, Moscow, 119333; ul. Kosygina 19, Moscow, 119991