Herstellung und Reaktion von Gliedern der Hollandit-Gruppe MxMn8O16 (M = K, Rb, Cs, Ca, Sr, Pb; x = 1 und M = Na; x = 1.9)

Hollandite, cryptomelane, manjiroite, and coronadite were synthesized by hydrothermal methods at 500 °C and 2 kbar in order to determine their unit cell dimensions and analytical composition from fully crystalline samples. Analyses, X-ray diffraction, and electron microscopy have shown that the tun...

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Main Authors: Rudolf Giovanoli, Markus Faller
Format: Article
Language:deu
Published: Swiss Chemical Society 1989-03-01
Series:CHIMIA
Online Access:https://www.chimia.ch/chimia/article/view/9890
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author Rudolf Giovanoli
Markus Faller
author_facet Rudolf Giovanoli
Markus Faller
author_sort Rudolf Giovanoli
collection DOAJ
description Hollandite, cryptomelane, manjiroite, and coronadite were synthesized by hydrothermal methods at 500 °C and 2 kbar in order to determine their unit cell dimensions and analytical composition from fully crystalline samples. Analyses, X-ray diffraction, and electron microscopy have shown that the tunnel structure accommodates 1 K, Rb, Cs, Ca, Sr, or Pb but ca. 2 Na per unit Mn8O16. Crystalline samples show no conceivable ion exchange nor are they attacked by concentrated nitric acid at room temperature. Finely divided cryptomelane, however, is attacked by conc. HNO3. The unit cell dimensions as well as the relations between ionic radius of the tunnel ion, symmetry, and composition are discussed.
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publishDate 1989-03-01
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spelling doaj-art-3c985efdf1924e78828b160ada9131b52025-08-20T02:20:26ZdeuSwiss Chemical SocietyCHIMIA0009-42932673-24241989-03-0143310.2533/chimia.1989.54Herstellung und Reaktion von Gliedern der Hollandit-Gruppe MxMn8O16 (M = K, Rb, Cs, Ca, Sr, Pb; x = 1 und M = Na; x = 1.9)Rudolf Giovanoli0Markus Faller1Laboratorium für Elektronenmikroskopie Institut für Anorganische, Analytische und Physikalische Chemie Universität Bern Freiestrasse 3, Postfach 140, CH-3000 Bern 9Laboratorium für Elektronenmikroskopie Institut für Anorganische, Analytische und Physikalische Chemie Universität Bern Freiestrasse 3, Postfach 140, CH-3000 Bern 9 Hollandite, cryptomelane, manjiroite, and coronadite were synthesized by hydrothermal methods at 500 °C and 2 kbar in order to determine their unit cell dimensions and analytical composition from fully crystalline samples. Analyses, X-ray diffraction, and electron microscopy have shown that the tunnel structure accommodates 1 K, Rb, Cs, Ca, Sr, or Pb but ca. 2 Na per unit Mn8O16. Crystalline samples show no conceivable ion exchange nor are they attacked by concentrated nitric acid at room temperature. Finely divided cryptomelane, however, is attacked by conc. HNO3. The unit cell dimensions as well as the relations between ionic radius of the tunnel ion, symmetry, and composition are discussed. https://www.chimia.ch/chimia/article/view/9890
spellingShingle Rudolf Giovanoli
Markus Faller
Herstellung und Reaktion von Gliedern der Hollandit-Gruppe MxMn8O16 (M = K, Rb, Cs, Ca, Sr, Pb; x = 1 und M = Na; x = 1.9)
CHIMIA
title Herstellung und Reaktion von Gliedern der Hollandit-Gruppe MxMn8O16 (M = K, Rb, Cs, Ca, Sr, Pb; x = 1 und M = Na; x = 1.9)
title_full Herstellung und Reaktion von Gliedern der Hollandit-Gruppe MxMn8O16 (M = K, Rb, Cs, Ca, Sr, Pb; x = 1 und M = Na; x = 1.9)
title_fullStr Herstellung und Reaktion von Gliedern der Hollandit-Gruppe MxMn8O16 (M = K, Rb, Cs, Ca, Sr, Pb; x = 1 und M = Na; x = 1.9)
title_full_unstemmed Herstellung und Reaktion von Gliedern der Hollandit-Gruppe MxMn8O16 (M = K, Rb, Cs, Ca, Sr, Pb; x = 1 und M = Na; x = 1.9)
title_short Herstellung und Reaktion von Gliedern der Hollandit-Gruppe MxMn8O16 (M = K, Rb, Cs, Ca, Sr, Pb; x = 1 und M = Na; x = 1.9)
title_sort herstellung und reaktion von gliedern der hollandit gruppe mxmn8o16 m k rb cs ca sr pb x 1 und m na x 1 9
url https://www.chimia.ch/chimia/article/view/9890
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