Armstrongite from Khan Bogdo (Mongolia): Crystal structure determination and implications for zeolite-like cation exchange properties

2014 ◽  
Vol 99 (11-12) ◽  
pp. 2424-2432 ◽  
Author(s):  
E. Mesto ◽  
E. Kaneva ◽  
E. Schingaro ◽  
N. Vladykin ◽  
M. Lacalamita ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Cation Exchange ◽  
Structure Determination ◽  
Crystal Structure Determination ◽  
Exchange Properties

Darstellung und Kristallstruktur von Strontiumozonid-Ammoniakat, Sr(O3)2 · 9 NH3 / Synthesis and Crystal Structure of Strontium Ozonide Ammoniate, Sr(O3)2 · 9 NH3

2005 ◽  
Vol 60 (4) ◽  
pp. 426-430 ◽  
Author(s):  
Wilhelm Klein ◽  
Martin Jansen
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Cation Exchange ◽  
Structure Determination ◽  
Liquid Ammonia ◽  
Close Packing ◽  
Single Crystal Structure ◽  
Crystal Structure Determination ◽  
Boiling Temperature ◽  
Synthesis And Crystal Structure

Strontium ozonide has been synthesised, starting from caesium ozonide, via cation exchange in liquid ammonia. From these solutions, if kept at −78 °C for 14 days, an ammoniate, Sr(O3)2 · 9 NH3, crystallises. The coarse, ruby red crystals decompose above the boiling temperature of ammonia and are extremely sensitive to moisture. According to a single crystal structure determination (P4/nmm; a = 7.597(1), c = 13.496(2) Å , Z = 2; R1 = 7.50%; 254 independent reflections) Sr(O3)2 · 9 NH3 consists of ozonide anions and strontium cations. The complex cations form an approximately cubic close packing, where the octahedral and half of the tetrahedral interstices are occupied by ozonide anions. The anions are orientationally disordered

Crystal Structure Determination of Glycerol-Containing Lipids from Electron Diffraction Data. Use of Analog Compounds Based upon Configurational Isomers of Cyclopentane-1, 2, 3-TRIOL

1977 ◽  
Vol 35 ◽  
pp. 24-25
Author(s):  
Douglas L. Dorset ◽  
Anthony J. Hancock
Keyword(s):  
Crystal Structure ◽  
Electron Diffraction ◽  
Diffraction Data ◽  
Structure Determination ◽  
Crystal Surface ◽  
Coherent Scattering ◽  
Crystal Structure Determination ◽  
Electron Diffraction Data ◽  
Polar Group ◽  
Axis Orientation

Lipids containing long polymethylene chains were among the first compounds subjected to electron diffraction structure analysis. It was only recently realized, however, that various distortions of thin lipid microcrystal plates, e.g. bends, polar group and methyl end plane disorders, etc. (1-3), restrict coherent scattering to the methylene subcell alone, particularly if undistorted molecular layers have well-defined end planes. Thus, ab initio crystal structure determination on a given single uncharacterized natural lipid using electron diffraction data can only hope to identify the subcell packing and the chain axis orientation with respect to the crystal surface. In lipids based on glycerol, for example, conformations of long chains and polar groups about the C-C bonds of this moiety still would remain unknown.One possible means of surmounting this difficulty is to investigate structural analogs of the material of interest in conjunction with the natural compound itself. Suitable analogs to the glycerol lipids are compounds based on the three configurational isomers of cyclopentane-1,2,3-triol shown in Fig. 1, in which three rotameric forms of the natural glycerol derivatives are fixed by the ring structure (4-7).

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