Crystal structure of a natural potassium-barium hexatitanate isostructural with K2Ti6O13

1977 ◽  
Vol 30 (6) ◽  
pp. 1195 ◽  
Author(s):  
AN Bagshaw ◽  
BH Doran ◽  
AH White ◽  
AC Willis
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
High Resolution ◽  
Least Squares ◽  
High Spin State ◽  
High Resolution Electron Microscopy ◽  
X Ray Diffraction ◽  
Full Matrix ◽  
X Ray ◽  
Resolution Electron

The crystal structure of a mineral with the stoichiometry (K0.58Ba0.36)2(Ti0.93FeIII0.06)6O13 has been determined by X-ray diffraction and refined by full-matrix least squares to a residual of 0.076 for 1688 ?observed? reflections. Crystals are monoclinic, C2/m, a = 15.453(2), b = 3.8368(7), c = 9.123(2) Ǻ,β = 99.25(1)�, Z = 2, and are isostructural with the (Na,K,Rb)2Ti6O13 family. High-resolution electron microscopy has confirmed that the Ba and FeIII species (the latter in a high-spin state) are randomly substituted for K and Ti respectively.

High Resolution Electron Microscopy of a Novel Zeolite

1997 ◽  
Vol 3 (S2) ◽  
pp. 441-442
Author(s):  
P.A. Crozier ◽  
I.Y. Chan ◽  
C.Y. Chen ◽  
L.W. Finger ◽  
R.C. Medrud ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Low Dose ◽  
High Resolution Electron Microscopy ◽  
X Ray Diffraction ◽  
High Adsorption ◽  
Structural Units ◽  
X Ray ◽  
Resolution Electron ◽  
Crystal Structural

Low-dose high resolution electron microscopy (HREM) is a useful technique for elucidating the structure of zeolites. In recent years a number of zeolite structures have been solved using combinations of different characterization techniques including adsorption measurements, powder x-ray diffraction and low-dose high resolution electron microscopy (for example see ref. 2). We have used these techniques to study the structure of a novel zeolite material. However, great care must be exercised when interpreting data from these techniques in terms of crystal structural units. In this particular case, the structure was recently determined using single crystal x-ray diffraction and showed some surprises.Details of the synthesis of this zeolite are given elsewhere. The high adsorption capacity suggested that this zeolite possessed two interpenetrating channels (either a 10 and a 12 ring or two 12 ring channels). X-ray powder diffraction showed the material to be monoclinic with a= 18.5Å, b= 13.4 Å, c= 7.6 Å β = 101.5°).

Structure determination of a new polymorph of TiO2 by high-resolution electron microscopy and computer simulations

1989 ◽  
Vol 47 ◽  
pp. 416-417
Author(s):  
Jillian F. Banfield ◽  
David R. Veblen ◽  
David J. Smith
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Electron Diffraction ◽  
Computer Simulations ◽  
High Resolution Electron Microscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Naturally Occurring ◽  
Resolution Electron

A new, naturally occurring polymorph of TiO2 has been identified. This mineral forms lamellae generally only a few nanometers wide in anatase from two localities near Bintal Valais, Switzerland. The abundance of this mineral in anatase is too low to allow investigation by X-ray diffraction. The unit cell determined by electron diffraction is triclinic, with a = 0.754 nm, b = 0.448 nm, c = 0.616 nm, α = 78.90°, β = 124.55°, γ = 96.54°. The coherently intergrown lamellae are oriented with b parallel to a of anatase; the interface is parallel to (103) anatase.

Structural studies of trigonal lamellar particles of gold and silver

1993 ◽  
Vol 440 (1910) ◽  
pp. 589-609 ◽  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Structural Studies ◽  
Growth Mechanisms ◽  
X Ray Diffraction ◽  
Structural Requirements ◽  
Plan View ◽  
X Ray ◽  
Resolution Electron

The results of detailed structural studies of trigonal lamellar particles of both gold and silver are presented. The particles have been characterized both in sol by means of optical spectroscopy and powder X-ray diffraction and ex sol using high resolution electron microscopy in both plan view and profile imaging modes. The results of these studies have indicated that the particles have a trigonal outline and are shortened along a ≺111≻ direction to give a plate-like morphology. The presence of small numbers of parallel {111} twin planes has also been confirmed and used to explain the presence of the formally forbidden ⅓{422} reflections observed in plan view. The precise structural requirements for the observation of such reflections has also been confirmed using multislice calculations. Possible growth mechanisms for these particles are also discussed.

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