Hidden story of tapiolite
| Autor: | T. S. Ercit |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
010504 meteorology & atmospheric sciences
Crystal chemistry Chemistry Thermodynamics engineering.material 010502 geochemistry & geophysics Intensity ratio 01 natural sciences law.invention Crystallography Geochemistry and Petrology Rutile law engineering Crystallization Tapiolite 0105 earth and related environmental sciences Solid solution |
| Zdroj: | Mineralogical Magazine. 74:715-730 |
| ISSN: | 1471-8022 0026-461X |
| Popis: | The crystal chemistry of tapiolite is more complicated than previously recognized. Perusal and synthesis of relatively recent publications reveals a ‘hidden’ story about tapiolite, one that: (1) permits quantification of the effects of Mn, Fe3+, Ti (and Sn) upon the unit-cell parameters of maximally ordered tapiolite; (2) shows that the effect of Nb = Ta substitution upon unit-cell parameters is insignificant; (3) casts doubt on the usefulness of heating experiments for accurately evaluating cation order in tapiolite; (4) suggests that rutile exsolves from tapiolite upon heating in air at lower temperatures than previously established; (5) shows that the maximum solubility of TiO2 in FeTa2O6 tapiolite during the later stages of crystallization of granitic pegmatites is ∼1 mol.%; (6) shows that the heating paths for at least some natural tapiolite samples are not necessarily linear, consisting of two sequential steps; (7) sheds doubt on the usefulness of unit-cell parameters as quantitative measures of long-range cation order, Q, in tapiolite; but (8) does show that the intensity ratio I011/I110 can provide an accurate and reasonably precise measure of cation order in tapiolite. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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