1 MV super-high-resolution electron microscopy of Nb2O5-WO3complex compounds with TTB type subcells

1978 ◽  
Vol 36 (1) ◽  
pp. 298-299
Author(s):  
Shigeo Horiuchi
Keyword(s):  
Crystal Structure ◽  
High Resolution ◽  
Composition Range ◽  
Tungsten Bronze ◽  
High Resolution Electron Microscopy ◽  
X Ray Diffraction ◽  
Tetragonal Tungsten Bronze ◽  
X Ray ◽  
Voltage Electron ◽  
Resolution Electron

It is known that, over a composition range in a Nb2-O5-WO3 system, the crystal structure of compounds is composed of subcells with tetragonal tungsten bronze ( TIB ) type.) Different models have however been reported for some of them. The crystals are usually prepared in sealed tubes and sometimes show different colours due to a reduction in spite of a definite starting composition. Moreover, they frequently include small domains, which make the structure analysis by x-ray diffraction very difficult. In the present study we examine a series of these compounds, prepared under various conditions, by a super-high-resolution, high-voltage electron microscope ( Hitachi 1250 ),in which the lattice fringes of 2.0 Å in width can be resolved at an accelerating voltage of 1 MV under an axial illumination with equipping a specimen goniometer.2)Fig.l is a crystal structure image of 4Nb2O5.9WO3. According to electron diffractions the lattice parameters are a=12.3, b=36.6 and c=3.94 Å (orthorhombic).

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.

scholarly journals Characterization of K6Ta10.8O30 Microrods with Tetragonal Tungsten Bronze-Like Structure Obtained from Tailings from the Penouta Sn-Ta-Nb Deposit

Nanomaterials ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 2289
Author(s):  
Belén Sotillo ◽  
Lorena Alcaraz ◽  
Félix A. López ◽  
Paloma Fernández
Keyword(s):  
Crystal Structure ◽  
Tungsten Bronze ◽  
X Ray Diffraction ◽  
Tetragonal Tungsten Bronze ◽  
X Ray ◽  
The North ◽  
Recovered Material ◽  
North Of Spain ◽  
Scanning Electron

In this work, a deep characterization of the properties of K6Ta10.8O30 microrods has been performed. The starting material used to grow the microrods has been recovered from mining tailings coming from the Penouta Sn-Ta-Nb deposit, located in the north of Spain. The recovered material has been submitted to a thermal treatment to grow the microrods. Then, they have been characterized by scanning electron microscopy, X-ray diffraction, micro-Raman and micro-photoluminescence. The results of our study confirm that the K6Ta10.8O30 microrods have a tetragonal tungsten bronze-like crystal structure, which can be useful for ion-batteries and photocatalysis.

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°).

Structural Nature of Nanocrystalline Silicon

1993 ◽  
Vol 297 ◽  
Author(s):  
Weiqiang Han ◽  
Gaorong Han ◽  
Jianmin Qiao ◽  
Piyi Du ◽  
Zhishang Ding ◽  
...  
Keyword(s):  
High Resolution ◽  
Crystalline Silicon ◽  
Chemical Vapor ◽  
High Resolution Electron Microscopy ◽  
Nanocrystalline Silicon ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resolution Electron ◽  
Average Grain Size ◽  
Structural Nature

Nanocrystalline silicon (nc-Si:H) films with an average grain size ranging between 2 and 10 nm are prepared in a modified plasma chemical vapor deposition system. X-ray diffraction, transmission electron diffraction, and high resolution electron microscope are used to elucidate the structural nature in the deposited nc-Si:H films. The lattice network of the deposited silicon films changes from disordered structure to ordered structure with the increasing of plasma energy. The results also show that the crystal lattice of the nc-Si:H film is distorted from those of microcrystalline silicon and crystalline silicon. In the observed x-ray diffraction, there are two anomalous peaks at 2θ = 29.5° and 32.5° of Si besides the normal peaks at 2θ = 28.5° of Si(111) and 2θ = 47.3°of Si(220). By the high resolution electron microscopy study, a new crystallography structure with distorted Si(111) crystallites in nc- Si:H films is found. Based on our results, a structure model of nc-Si:H films is proposed.

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