Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
The synthetic nosean- and haüyne-like aluminosilicates with (MoO4)2− and (WO4)2− extra-framework anions were synthesized in H2O-bearing systems (3 kbar, 750 °C) and studied by means of electron microprobe analysis, Raman spectroscopy, powder and single-crystal X-ray diffraction. The nosean-like phase contains up to 10.6 wt% MoO3 and up to 5.1 wt% WO3; the maximum content of MoO3 in the haüyne-like phase is 22.5 wt%. The nosean-like phase with (MoO4)2− and (WO4)2− is cubic, P-43m, a = 9.1278(10) Å, V = 760.498(14) Å3, Z = 1. This compound with the crystal chemical formula Na7.68[(Al,Si)12O24] {[(Mo0.65W0.35)O4]0.78□0.22}·H2O has a disordered Al/Si framework, that is caused by the high temperature of crystallization (t = 750 °C) with further quenching at room temperature. Despite the same conditions of synthesis, the haüyne-like phase with (MoO4)2−, Na5.12Ca1.92[Al6Si6O24](MoO4)1.52 has an Al/Si-ordered framework. Its space group is P-43n, a = 9.1516(4) Å, V = 766.46(6) Å3, Z = 1. In both synthesized sodalite-type aluminosilicates the anion groups (MoO4)2− and (WO4)2− are dynamically disordered. The polarized Raman spectra of both aluminosilicates show that Raman-active modes of (MoO4)2− and (WO4)2− correspond to vibrations of tetrahedral anions with symmetry Td. The presence of H2O was fixed only in the nosean-like compound and no preferred orientation of water molecule was detected.
Язык оригинала | английский |
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Номер статьи | 19 |
Число страниц | 11 |
Журнал | Physics and Chemistry of Minerals |
Том | 48 |
Номер выпуска | 5 |
DOI | |
Состояние | Опубликовано - мая 2021 |
ID: 76725287