Thermal decomposition of monocalcium aluminate decahydrate (CaAl2O4·10H2O) investigated by in-situsynchrotron X-ray powder diffraction, thermal analysis and27Al,2H MAS NMR spectroscopy

The crystal structures of the leucite analogues Cs2MgSi5O12, Cs2ZnSi5O12 and Rb2MgSi5O12 have been determined by synchrotron X-ray powder diffraction using Rietveld refinement in conjunction with 29Si MAS NMR spectroscopy. These leucites are framework structures with distinct tetrahedral sites (T sites) occupied by Si and a divalent cation (either Mg or Zn in these samples); there is also a monovalent extra-framework cation (either Cs or Rb in these samples). The refined crystal structures were based on the Pbca leucite structure of Cs2CdSi5O12, thus a framework with five ordered Si T sites and one ordered Cd T site was used as the starting model for refinement. 29Si MAS NMR shows five distinct Si T sites for Cs2MgSi5O12 and Rb2MgSi5O12, but six Si T sites for Cs2ZnSi5O12. The refined structures for Cs2MgSi5O12 and Rb2MgSi5O12 were determined with complete T-site ordering, but the refined structure for Cs2ZnSi5O12 was determined with partial disorder of Mg and Si over two of the T sites.

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ChemInform Abstract: Crystal Structure of Silica-ZSM-12 by the Combined Use of High-Resolution Solid-State MAS NMR Spectroscopy and Synchrotron X-Ray Powder Diffraction.

ChemInform ◽

10.1002/chin.199031005 ◽

1990 ◽

Vol 21 (31) ◽

Author(s):

C. A. FYFE ◽

H. GIES ◽

G. T. KOKOTAILO ◽

B. MARLER ◽

D. E. COX

Keyword(s):

Crystal Structure ◽

Solid State ◽

Nmr Spectroscopy ◽

High Resolution ◽

Powder Diffraction ◽

Mas Nmr ◽

X Ray ◽

Combined Use

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ChemInform Abstract: Cation Location and Migration in Lanthanum-Exchanged Zeolite NaY Studied by X-Ray Powder Diffraction and MAS NMR Spectroscopy.

ChemInform ◽

10.1002/chin.199543003 ◽

2010 ◽

Vol 26 (43) ◽

pp. no-no

Author(s):

H. KLEIN ◽

H. FUESS ◽

M. HUNGER

Keyword(s):

Nmr Spectroscopy ◽

Powder Diffraction ◽

Mas Nmr ◽

X Ray ◽

Zeolite Nay ◽

And Migration

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Investigations on the Thermal Decomposition of Coordination Polymers Based on Copper(I) Halides and 2-Methylpyrazine

Zeitschrift für Naturforschung B ◽

10.1515/znb-2001-1006 ◽

2001 ◽

Vol 56 (10) ◽

pp. 997-1002 ◽

Cited By ~ 11

Author(s):

Chnstian Näther ◽

Inke Jeß ◽

Harald Studzinski

Keyword(s):

Thermal Analysis ◽

Thermal Decomposition ◽

Differential Thermal Analysis ◽

Thermal Behaviour ◽

Powder Diffraction ◽

Coordination Polymers ◽

Intermediate Phase ◽

Compound I ◽

X Ray

The thermal behaviour of the three coordination polymers 2∞poly[CuX(μ-2-methylpyrazine- N,N′)] (X = Cl (I), Br (II)), and 2∞poly[{Cu2l2 (μ-pyrazine-N,N′)2 } · 2-methylpyrazine] (III) was investigated using differential thermal analysis and thermogravimetry (DTA-TG) measurements as well as temperature resolved X-ray powder diffraction in argon and in air. On heating all compounds decompose in two steps. In the first step compound I and II loose one and compound III looses two of the 2-methylpyrazine ligands to form the corresponding 2:1 compounds Cu2Cl2(2 -methylpyrazine) (IV) and 2∞poly[Cu2X2 (μ-2 -methylpyrazine-N,N′)] (X = Br (V), I (VI)). From the experiments there is no evidence for the formation of a 1:1 compound of Cul and 2-methylpyrazine as an intermediate phase during the thermal decomposition. On further heating the 2:1 compounds IV, V and VI transform directly to the corresponding copper(I) halides.

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