Crystal Chemistry and Properties of Elpidite and Its Ag-Exchanged Forms
| Autor: | T. S. Larikova, Nadezhda A. Chervonnaya, Vladislav Kostov-Kytin, Natalia V. Zubkova, Olga N. Kazheva, Igor V. Pekov, Dmitry Yu. Pushcharovsky, Rositsa P. Nikolova, Dmitry A. Varlamov, Nikita V. Chukanov, Gennadiy V. Shilov |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
crystal structure
lcsh:QE351-399.2 Crystal chemistry Infrared spectroscopy 02 engineering and technology Crystal structure Electron microprobe ion exchange thermogravimetry 010502 geochemistry & geophysics 01 natural sciences Crystal Group (periodic table) silver zeolitic properties 0105 earth and related environmental sciences elpidite lcsh:Mineralogy Chemistry Geology 021001 nanoscience & nanotechnology Geotechnical Engineering and Engineering Geology Thermogravimetry Crystallography Octahedron microporous zirconosilicate IR spectroscopy Lovozero alkaline complex 0210 nano-technology Khan Bogdo alkaline complex |
| Zdroj: | Minerals, Vol 9, Iss 7, p 420 (2019) Minerals Volume 9 Issue 7 |
| Popis: | Elpidite from the Lovozero alkaline complex, Kola Peninsula, Russia, and Ag-exchanged forms of elpidite from two different localities (Lovozero and Khan Bogdo, Mongolia) were studied by means of single-crystal X-ray diffraction, electron microprobe analysis, thermogravimetry and IR spectroscopy. All studied samples retain the heteropolyhedral framework consisting of double Si6O15 chains (ribbons) and isolated ZrO6 octahedra. Zeolitic cavities in the initial elpidite from Lovozero (space group Pbm2, a = 14.6127(7), b = 7.3383(4), c = 7.1148(3) Å V = 762.94(6) Å 3) are occupied by Na+ cations and H2O molecules. Both Ag-exchanged forms are characterized by evident distortions of the heteropolyhedral framework and a strongly disordered arrangement of extra-framework cations which results in the appearance of the 14-14-14 Å unit cell (a = 14.1755(7), b = 14.6306(9), c = 14.2896(7) Å V = 2963.6(3) Å 3 for the Ag-exchanged form of elpidite from Lovozero and a = 14.1411(5), b = 14.5948(4), c = 14.3035(5) Å V = 2952.04(17) Å 3 for the Ag-exchanged form of elpidite from Khan Bogdo) and space group Cmce. Elpidite from both localities demonstrates a high exchange capacity to Ag. Exchanged Ag+ cations preferably occupy the sites that are close to the Na sites in the initial elpidite. The paper also contains a review of crystal chemical data on elpidite and its laboratory-modified forms. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|