| Reference Type | Journal (article/letter/editorial) |
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| Title | Heat-Induced Mn2+ and Fe2+ Oxidation in Heterophyllosilicates: Kupletskite and Kupletskite-(Cs) |
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| Journal | Minerals |
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| Authors | Zhitova, Elena S. | Author |
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| Zolotarev, Andrey A. | Author |
| Sheveleva, Rezeda M. | Author |
| Shendrik, Roman Yu. | Author |
| Hawthorne, Frank C. | Author |
| Nuzhdaev, Anton A. | Author |
| Vlasenko, Natalia S. | Author |
| Kaneva, Ekaterina V. | Author |
| Yakovenchuk, Victor N. | Author |
| Year | 2025 | Volume | < 15 > |
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| Issue | < 6 > |
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| URL | |
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| DOI | doi:10.3390/min15060587Search in ResearchGate |
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| Generate Citation Formats |
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| Classification | Not set | LoC | Not set |
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| Mindat Ref. ID | 18488754 | Long-form Identifier | mindat:1:5:18488754:5 |
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| GUID | 0 |
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| Full Reference | Zhitova, Elena S.; Zolotarev, Andrey A.; Sheveleva, Rezeda M.; Shendrik, Roman Yu.; Hawthorne, Frank C.; Nuzhdaev, Anton A.; Vlasenko, Natalia S.; Kaneva, Ekaterina V.; Yakovenchuk, Victor N. (2025) Heat-Induced Mn2+ and Fe2+ Oxidation in Heterophyllosilicates: Kupletskite and Kupletskite-(Cs). Minerals, 15 (6). doi:10.3390/min15060587 |
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| Plain Text | Zhitova, Elena S.; Zolotarev, Andrey A.; Sheveleva, Rezeda M.; Shendrik, Roman Yu.; Hawthorne, Frank C.; Nuzhdaev, Anton A.; Vlasenko, Natalia S.; Kaneva, Ekaterina V.; Yakovenchuk, Victor N. (2025) Heat-Induced Mn2+ and Fe2+ Oxidation in Heterophyllosilicates: Kupletskite and Kupletskite-(Cs). Minerals, 15 (6). doi:10.3390/min15060587 |
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| In | Link this record to the correct parent record (if possible) |
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| Abstract/Notes | The crystal–chemical behavior of two layered titanosilicate minerals with porous crystal structures, kupletskite, K2NaMn72+Ti2(Si4O12)2O2(OH)4F, and kupletskite-(Cs), Cs2NaMn72+Ti2(Si4O12)2O2(OH)4F, was investigated under high-temperature conditions using single-crystal and powder X-ray diffraction; infrared and optical absorption spectroscopy and electron-microprobe analysis. Both minerals undergo topotactic transformation to dehydroxylated and oxidized high-temperature (HT) modifications at temperature above 500 °C while maintaining the basic bond topology of the astrophyllite structure-type. The high-temperature structures show contraction of the unit-cell parameters similar to that of Fe2+-dominant astrophyllite, indicating that Mn2+ oxidizes along with Fe2+ in M(2)–M(4) sites. The oxidation of Mn2+ is confirmed by the increase of the Mn3+-related absorption (in optical spectra) that is inversely correlated with the intensity of O–H bands in the infrared spectra. The Fe,Mn-oxidation is also evident by the contraction of the M(2), M(3), and M(4)O6 octahedra. The M(1)–O bond length increases slightly, indicating a preference for mono- and divalent cations to occupy the M(1) site in the heated structure; this may be due to site-selective oxidation and/or migration of unoxidized cations (as previously shown for lobanovite) to this site. The role of extra framework A-site cations (K, Cs) in thermal expansion of these minerals is discussed. |
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