Untersuchungen an Alkali—Aluminium‐Silicaten

Gruner, Erhard

doi:10.1002/zaac.19291820130

Cited by 5 publications

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“…The synthesis was accomplished at 225-300 • C and 26-90 bar with a duration of 5 d. Gruner (1939Gruner ( , 1944 synthesised muscovite from a reaction mixture of Al(OH) 3 , silica and KCl in HCl solutions (400 • C, 350 bar, duration 5 d). Another successful synthesis of muscovite is the recrystallisation from its decomposition products reported by Gruner (1929) and Rov (1949). Gruner (1929) obtained "kaliophilite" with muscovite grown on it by decomposing natural muscovite with 0.5 M KOH in a bomb at 400 • C. Rov (1949) heated muscovite up to 1050 • C until only α-Al 2 O 3 or spinel was observed.…”

Section: Introductionmentioning

confidence: 99%

“…Another successful synthesis of muscovite is the recrystallisation from its decomposition products reported by Gruner (1929) and Rov (1949). Gruner (1929) obtained "kaliophilite" with muscovite grown on it by decomposing natural muscovite with 0.5 M KOH in a bomb at 400 • C. Rov (1949) heated muscovite up to 1050 • C until only α-Al 2 O 3 or spinel was observed. By treating the sample at 400-650 • C and 69-690 bar for 12-100 h, muscovite could be observed.…”

Section: Introductionmentioning

confidence: 99%

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Cation and anion ordering in synthetic lepidolites and lithian muscovites: influence of the OH ∕ F and Li ∕ Al ratios on the mica formation studied by NMR (nuclear magnetic resonance) spectroscopy and X-ray diffraction

2023

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Abstract. A large number of lepidolites K(LixAl3−x)[Si2xAl4−2xO10](OH)yF2−y and Li-muscovites K(LixAl2-x/3□1-2x/3)[Si3AlO10](OH)yF2−y were synthesised by a gelling method in combination with hydrothermal syntheses at a pressure of 2 kbar and a temperature of 873 K. The nominal composition ranged between 0.0≤x≤2.0 and 0.0≤y≤2.0, i.e. from polylithionite K[Li2.0Al][Si4.0O10](OH)yF2−y over trilithionite K[Li1.5Al1.5][AlSi3.0O10](OH)yF2−y to muscovite K[Al2.0□][AlSi3.0O10](OH)yF2−y. 1H, 19F, 29Si and 27Al magic-angle spinning nuclear magnetic resonance (MAS NMR) and 27Al multiple-quantum magic-angle spinning (MQMAS) NMR spectroscopy has been performed to investigate the order and/or disorder state of Si and Al in the tetrahedral layers and of Li, Al, OH and F in the octahedral layer. The synthetic mica crystals are very small, ranging from 0.1 to 5 µm. With increasing Al content, the crystal sizes decrease. Rietveld structure analyses on 12 samples showed that nearly all samples consist of two mica polytypes (1M and 2M1) of varying proportions. In the case of lepidolites, the 1M / 2M1 ratio depends on the Li/Al ratio of the reaction mixture. The refinement of the occupancy factors of octahedral sites shows that lepidolites (1.5≤x≤2.0) represent a solid solution series with polylithionite and trilithionite as the endmembers. In the case of the Li-muscovites (0.0≤x≤1.5), the 1M / 2M1 ratio depends on the number of impurity phases like eucryptite or sanidine depleting the reaction mixture of Li or Al. There is no solid solution between trilithionite and muscovite; instead, the Li-muscovite crystals consist of domains differing in the relative proportions of muscovite and trilithionite. The overall composition of the synthesised micas which consist of two polytypes can be characterised by 29Si, 1H and 19F MAS NMR spectroscopy. The Si/Al ratio in the tetrahedral layers and thus the content of [4]Al were calculated by analysing the signal intensities of the 29Si MAS NMR experiments. The Li content xest was calculated from the measured tetrahedral Si/Al ratio of the 29Si MAS NMR signals. The calculated Li contents xest of samples between polylithionite and trilithionite agree with the expected values. The F-rich samples show slightly increased values and the OH samples lower values. Lepidolites with only F (x = 1.5 to 2.0, y = 0.0), but not lepidolites with only OH (x = 1.5 to 2.0 and y = 2.0), were observed after synthesis. With decreasing Li content, x≤1.2, Li-muscovites containing mostly hydroxyl (y>1.0) are formed. It was possible to synthesise fluorine containing micas with a Li content as low as 0.3 and y = 0.2 to 1.8. The 19F and 1H MAS NMR experiments reveal that F and OH are not distributed statistically but local structural preferences exist. F is attracted by Li-rich and OH by Al-rich environments. The quadrupolar coupling constant which represents the anisotropy of the Al coordination is low for polylithionite with CQ=1.5 MHz and increases to CQ=3.8 MHz for trilithionite. For tetrahedral Al a smaller increase of CQ from 1.7 to 2.8 MHz is observed. Advancing from trilithionite to muscovite both quadrupolar coupling constants decrease to 2.5 MHz for octahedral and 1.5 MHz for tetrahedral Al. In polylithionite there is the most isotropic environment for octahedral Al; there are only Li2Al sites coordinated by F in the octahedral sheets and O from the tetrahedral sheets which are regular, containing only Si. The distortion and anisotropy for Al in tetrahedral as well as octahedral sheets increases with rising Al content. The most anisotropic environment can be found in trilithionite, especially for octahedral Al.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Cation and anion ordering in synthetic lepidolites and lithian muscovites: influence of the OH ∕ F and Li ∕ Al ratios on the mica formation studied by NMR (nuclear magnetic resonance) spectroscopy and X-ray diffraction

2023

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Ultramarinisierung verschiedener Natriumaluminiumsilicate

Hoffmann¹

1930

Angewandte Chemie

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Zeitschr. iiir angew. I 'Chemie, 43. J. 1930 396Hofftnann: Ultramarinisierung verschiedener Natriumaluminiumsilicate Wellenlangen ersichtlich. Ferner findet man bei allen Kohlenwasserstoffen ein,e charaktmeristische Wellenlange, die man der C-H-Bindung zuschreiben muD, aber sie ist T a b e 11 e 5. Charakteristische Wellenlangen fur die C-Hund die CH,-Gruppe in aromatischen und aliphatischen Verbindungen, aus Raman-Frequenzen errechnet.

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Untersuchungen an Alkali–Aluminium‐Silikaten. IX. Über den silikatischen Anteil der Ultramarine

Grunter

1935

Z. Anorg. Allg. Chem.

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Untersuchungen an Alkali—Aluminium‐Silicaten

Abstract: 1. Bei der Synthese des Nephelins aus Glimmer und Alkali in wäßrigem Medium wird die Abhängigkeit der Nephelinbildung von der Temperatur festgestellt.

Cited by 5 publications

References 7 publications

Cation and anion ordering in synthetic lepidolites and lithian muscovites: influence of the OH ∕ F and Li ∕ Al ratios on the mica formation studied by NMR (nuclear magnetic resonance) spectroscopy and X-ray diffraction

Cation and anion ordering in synthetic lepidolites and lithian muscovites: influence of the OH ∕ F and Li ∕ Al ratios on the mica formation studied by NMR (nuclear magnetic resonance) spectroscopy and X-ray diffraction

Ultramarinisierung verschiedener Natriumaluminiumsilicate

Untersuchungen an Alkali–Aluminium‐Silikaten. IX. Über den silikatischen Anteil der Ultramarine

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