ChemInform Abstract: HIGH‐FIELD ALUMINUM‐27 NMR STUDIES ON THE ALUMINUM COORDINATION IN CRYSTALLINE ALUMINUM PHOSPHATES

Mueller, D.; Grunze, I.; Hallas, E.; Ladwig, G.

doi:10.1002/chin.198337004

Cited by 13 publications

(14 citation statements)

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“…Manganese (Mn 2+) replaces aluminium in A1PO4-5 and despite having an unpaired electron, Tle is sufficiently short that only moderate broadening occurs and the contact shift is small [243]. Glasses from the system CaO-A1203-P205 showed three peaks at -21, 4 and 37 ppm which were assigned to AI(OP)6, Al(OAl)6 and AI(OP)4 [244]. Similar spectra were observed from alkali aluminophosphate glasses [245], Sb203-A1203-P205 [246] and the binary A1203-P205 [245] precluding cation effects being their source.…”

Section: Aluminophosphatesmentioning

confidence: 99%

“…Similar spectra were observed from alkali aluminophosphate glasses [245], Sb203-A1203-P205 [246] and the binary A1203-P205 [245] precluding cation effects being their source. Early work was hampered by loss of intensity with some samples showing as little as 20% of the total aluminium content [244].In the antimony system at high antimony contents a fourth resonance at (51-57) ppm became dominant [246]. More recent studies at higher magnetic fields have shown that in xAl203 9 (1-x)NaPO3 for x< 0.125 Al(6) was dominant, but at higher alumina contents Al(4) becomes favoured [245].…”

Section: Aluminophosphatesmentioning

confidence: 99%

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Application of27Al NMR techniques to structure determination in solids

1993

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Abstraer. There have been great improvements in the quality of 27A1 NMR spectra from solids over the last decade. The impact of this technique on structure determination fora wide range of solids is briefly reviewed. Emphasis is placed on the effects arising from the presence of the quadrupolar interaction and strategies that allow unambiguous spectral interpretation. It is demonstrated that in addition to the chemical shift, the quadrupolar interaction itself can be a rich source of local information about solids. The insight obtalned from 27A1 NMR hato atomic level structure often contains surprises, such that previous models of structure and properties have to be reassessed.

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Section: Aluminophosphatesmentioning

confidence: 99%

Section: Aluminophosphatesmentioning

confidence: 99%

Application of27Al NMR techniques to structure determination in solids

1993

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“…30 The overlapping in the bands observed at 350°C and 430°C may be assigned to [AIOs] units having different binding angles. 30 It is interesting to note that the isotropic chemical shift is moved to the strong fields. This may be because of the presence of phosphorus, in particular, within the second sphere of coordination.…”

Section: %mentioning

confidence: 98%

Zeolites: New Synergistic Agents for Intumescent Fire Retardant Thermoplastic Formulations?Criteria for the Choice of the Zeolite

Bourbigot

Bras

Brant³

et al. 1996

Fire Mater.

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The adduct of zeolites in intumescent formulations of thermoplastic polymers (additives ammonium polyphosphate and pentaerythritol) leads to a great improvement in their fire retardant performance. A classification of different groups (A, X, Y, Mordenite and ZSM-5) is presented. The influence of the physicochemical properties of the zeolites is discussed. TG analyses reveal that the zeolite may act as a catalyst for the development of the intumescent carbonaceous material and stabilize the carbonaceous residue resulting in the degradation of the intumescent shield. Characterized by MAS-NMR "AI and %i, it is proposed that alumino-and silicophosphate species formed are catalysts active for the synthesis of a protective carbon-based material.

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“…Among them, Al 2 O 3 is a significant electro ceramic material with low values of dielectric loss and dielectric constant. Introducing Al 2 O 3 into the lithium phosphate glass system alters the cross-links between PO 4 tetrahedra in the sample and reported to occupy both AlO 4 tetrahedral sites and AlO 6 octahedral sites in the glass network that act as network formers and modifiers [8]. Selenium (Se) is disadvantaged because of its short lifetime and low sensitivity.…”

Section: Introductionmentioning

confidence: 99%

Studies on lithium alumino phosphate glasses doped with selenium ions for hard electrolytes

et al. 2012

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Glass samples of the system (100 -x) (0.5 Li 2 O-0.2Al 2 O 3 -0.3P 2 O 5 ) ? xSeO 2 (x is ranging from 0 to 12 mol%, labeled as LAPS x ) were prepared using the melt quenching technique. FTIR spectral studies indicate that selenium ions mostly occupy network modifying sites due to isolated selenite (SeO 3 2-) groups up to 6 mol% of SeO 2 (LAPS 6 ) in the LAPS glass network. This has a tremendous effect on the electrical properties. Glass forming ability parameter (K gl ) and the glass transition temperature (T g ) of LAPS samples were characterized by DTA traces. Electrical measurements were carried out as a function of frequency and temperature over the frequency range of 10 Hz to 10 6 Hz and a temperature range of 303-423 K. The electric modulus formalism was applied to study the relaxation behavior using the impedance data for all the samples at 303 K and also for analyzing the relaxation behavior of the highest conducting sample (6 mol% of SeO 2 ) at different temperatures. An attempt has been made to relate the measured properties to the structural modifications due to the modifying effect of isolated selenite (SeO 3 2-) groups in the glass network.

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ChemInform Abstract: HIGH‐FIELD ALUMINUM‐27 NMR STUDIES ON THE ALUMINUM COORDINATION IN CRYSTALLINE ALUMINUM PHOSPHATES

Abstract: Die im Hochfeld bei schneller Probenrotation um den Magischen Winkel verschmälerten "Al‐NMR‐Spektren gestatten eine direkte Koor ‐ dinationszahlbestimmung des Aluminiums.

Cited by 13 publications

References 1 publication

Application of27Al NMR techniques to structure determination in solids

Application of27Al NMR techniques to structure determination in solids

Zeolites: New Synergistic Agents for Intumescent Fire Retardant Thermoplastic Formulations?Criteria for the Choice of the Zeolite

Studies on lithium alumino phosphate glasses doped with selenium ions for hard electrolytes

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