Incorporation of Y and REEs in aluminosilicate garnet: Energetics from atomistic simulation
Yttrium and the rare-earth elements (Y+REEs) are incorporated into aluminosilicate garnet as trivalent ions replacing divalent Mg, Fe, Mn, or Ca (“M2+”) in dodecahedral sites, which requires some form of coupled substitution to maintain electroneutrality. We compare the energetic costs of competing...
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| Format: | Journal Article |
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Mineralogical Society of America
2014
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| Online Access: | http://hdl.handle.net/20.500.11937/32449 |
| _version_ | 1848753666877554688 |
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| author | Carlson, W. Gale, Julian Wright, Kathleen |
| author_facet | Carlson, W. Gale, Julian Wright, Kathleen |
| author_sort | Carlson, W. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Yttrium and the rare-earth elements (Y+REEs) are incorporated into aluminosilicate garnet as trivalent ions replacing divalent Mg, Fe, Mn, or Ca (“M2+”) in dodecahedral sites, which requires some form of coupled substitution to maintain electroneutrality. We compare the energetic costs of competing coupled-substitution schemes, using lattice dynamics calculations to assess defect energies and exchange energies for each scheme. Substitutions with relatively low energetic costs introduce menzerite-like components via the exchange vector [YM–1•(Mg,Fe)Al–1], or alkali components via the exchange vector [Y(Na,Li)M–2]. Substitutions with substantially higher energetic costs introduce a vacancy component via the exchange vector [Y2oM–3], or the yttrogarnet (YAG) component via the exchange vector [YM–1•AlSi–1], or a component with octahedral Li via the exchange vector [Y2M–2•LiAl–1]. Energetic costs decrease significantly as the host-garnet unit-cell dimension expands, decrease very modestly as temperature rises or pressure falls, and decrease substantially with the contraction in ionic radius across the lanthanide series. These results, combined with critical re-examination of arguments cited in favor of each substitution scheme in natural occurrences, suggest that Y+REE incorporation in natural garnet is dominated by coupled substitutions that introduce menzerite and alkali components, that the YAG substitution plays only a subsidiary role, and that the other schemes are likely to be of very minor importance. |
| first_indexed | 2025-11-14T08:28:09Z |
| format | Journal Article |
| id | curtin-20.500.11937-32449 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T08:28:09Z |
| publishDate | 2014 |
| publisher | Mineralogical Society of America |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-324492017-10-02T02:28:10Z Incorporation of Y and REEs in aluminosilicate garnet: Energetics from atomistic simulation Carlson, W. Gale, Julian Wright, Kathleen atomistic simulation lattice dynamics Garnet rare-earth elements yttrium Yttrium and the rare-earth elements (Y+REEs) are incorporated into aluminosilicate garnet as trivalent ions replacing divalent Mg, Fe, Mn, or Ca (“M2+”) in dodecahedral sites, which requires some form of coupled substitution to maintain electroneutrality. We compare the energetic costs of competing coupled-substitution schemes, using lattice dynamics calculations to assess defect energies and exchange energies for each scheme. Substitutions with relatively low energetic costs introduce menzerite-like components via the exchange vector [YM–1•(Mg,Fe)Al–1], or alkali components via the exchange vector [Y(Na,Li)M–2]. Substitutions with substantially higher energetic costs introduce a vacancy component via the exchange vector [Y2oM–3], or the yttrogarnet (YAG) component via the exchange vector [YM–1•AlSi–1], or a component with octahedral Li via the exchange vector [Y2M–2•LiAl–1]. Energetic costs decrease significantly as the host-garnet unit-cell dimension expands, decrease very modestly as temperature rises or pressure falls, and decrease substantially with the contraction in ionic radius across the lanthanide series. These results, combined with critical re-examination of arguments cited in favor of each substitution scheme in natural occurrences, suggest that Y+REE incorporation in natural garnet is dominated by coupled substitutions that introduce menzerite and alkali components, that the YAG substitution plays only a subsidiary role, and that the other schemes are likely to be of very minor importance. 2014 Journal Article http://hdl.handle.net/20.500.11937/32449 10.2138/am.2014.4720 Mineralogical Society of America restricted |
| spellingShingle | atomistic simulation lattice dynamics Garnet rare-earth elements yttrium Carlson, W. Gale, Julian Wright, Kathleen Incorporation of Y and REEs in aluminosilicate garnet: Energetics from atomistic simulation |
| title | Incorporation of Y and REEs in aluminosilicate garnet: Energetics from atomistic simulation |
| title_full | Incorporation of Y and REEs in aluminosilicate garnet: Energetics from atomistic simulation |
| title_fullStr | Incorporation of Y and REEs in aluminosilicate garnet: Energetics from atomistic simulation |
| title_full_unstemmed | Incorporation of Y and REEs in aluminosilicate garnet: Energetics from atomistic simulation |
| title_short | Incorporation of Y and REEs in aluminosilicate garnet: Energetics from atomistic simulation |
| title_sort | incorporation of y and rees in aluminosilicate garnet: energetics from atomistic simulation |
| topic | atomistic simulation lattice dynamics Garnet rare-earth elements yttrium |
| url | http://hdl.handle.net/20.500.11937/32449 |