scholarly journals Crystal chemistry of leucite from the Roman Comagmatic Province (central Italy): a multi-methodological study

2007 ◽  
Vol 71 (06) ◽  
pp. 671-682 ◽  
Author(s):  
G. D. Gatta ◽  
N. Rotiroti ◽  
F. Bellatreccia ◽  
G. Della Ventura

Abstract A multi-methodological study, based on electron microprobe analysis (in wavelength dispersive mode), single-crystal X-ray diffraction (XRD), transmission electron microscopy and single-crystal Fourier transform infrared spectroscopy was performed in order to describe the crystal chemistry of four leucite samples from different localities of the Roman Comagmatic Province (central Italy). All the crystals examined were found to be tetragonal (space group I41/a with a = 13.076–13.103 Å and c = 13.744–13.784 Å) and characterized by a complex twinning (merohedric twins: on the tetragonal planes (110) and (1̄10) with the two individuals having parallel crystallographic axes with a and b interchanged; pseudo-merohedric twins: on the tetragonal planes (101), (011), (1̄01), (01̄ 1), with the two individuals having parallel a (or b) axes and the remaining two axes not parallel). The chemical analyses show that all the samples contain minor Na and Fe. Infrared spectroscopy shows that all samples contain structurally bound water molecules, up to unexpectedly large amounts (~0.4 wt.%) for a nominally anhydrous mineral, suggesting that ‘analcime-like’ substitution (K to Na + H2O) occurs in the leucite samples investigated here. The detection limits of the ‘analcime-like’ substitution by singlecrystal XRD are also discussed.

2013 ◽  
Vol 803 ◽  
pp. 80-84
Author(s):  
Yu Qi Liu ◽  
Yong Yang ◽  
Rui Yang ◽  
Xiao Jun Xu

A novel metalorganic coordination polymer, namely [Co3(bpd)5.5(NCS)6(NH3)]n2H2O (1) (bpd=1,4-bis (4-pyridyl)-2,3-diaza-1,3-butadiene), has been synthesized and characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray diffraction. Compound 1 presents 2D[3,4,-connected 3-nodal net with the point symbol (4268210)(4462)(8210). In addition, four identical 2D single nets is interlocked with each other in parallel, thus directly leading to the formation of a polycatenated layer (2D2D).


2017 ◽  
Vol 72 (4) ◽  
pp. 257-261 ◽  
Author(s):  
Gao-Feng Wang ◽  
Xiao Zhang ◽  
Shu-Wen Sun ◽  
Hong Sun ◽  
Hui Li ◽  
...  

AbstractTwo new copper(II) complexes, {[Cu(bipmo)(npa)]}n (1) and {[Cu(bipmo)(pa)]}n (2) (bipmo=bis(4-(1H-imidazol-1-yl)phenyl)methanone), were synthesized by solvothermal methods and structurally characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray diffraction. The results from single-crystal X-ray diffraction data indicate that the solid state structures of 1 and 2 consist of neutral metal aromatic carboxylate layers, which are pillared by the weak interactions to generate 3D architectures. The topological structures of 1 and 2 are uninodal nets based on 4-connected nodes with the Schläfli symbol of (65·8).


2018 ◽  
Vol 8 (10) ◽  
pp. 1794 ◽  
Author(s):  
Fang Zhou ◽  
Yujing Zhao ◽  
Weichang Zhou ◽  
Dongsheng Tang

Bi 2 Se 3 has extensive application as thermoelectric materials. Here, large-scale Bi 2 Se 3 single-crystal hexagonal nanoplates with size 7.50–10.0 μ m were synthesized successfully by hydrothermal method. X-ray diffraction (XRD), scanning electron microscope (SEM), and transmission electron microscope (TEM) were used to characterize the Bi 2 Se 3 nanoplates, which confirm the single-crystal quality and smooth surface morphology with large size. Micro-Raman spectra over a temperature range of 83–603 K were furthermore used to investigate the lattice dynamics of Bi 2 Se 3 nanoplates. Both 2A g 1 and 1E g 2 modes shift evidently with reduced temperature. The line shape demonstrates a significant broadening of full width at half maximum (FWHM) and red-shift of frequency with increased temperature. The temperature coefficient of A 1 g 1 , E g 2 , A 1 g 2 modes were determined to be −1.258 × 10 − 2 cm − 1 /K, −1.385 × 10 − 2 cm − 1 /K, −2.363 × 10 − 2 cm − 1 /K, respectively. Such low temperature coefficient may favor the obtaining of a high figure of merit (ZT) and indicate that Bi 2 Se 3 nanoplates were used as excellent candidates of thermoelectric materials.


2020 ◽  
Vol 42 (2) ◽  
pp. 249-249
Author(s):  
Guo Jun Wu Guo Jun Wu

[Cu(L)(AIP)·1.5H2O]n (1) [L= 3,5-di(benzimidazol-1-yl)pyridine, H2AIP= 5-aminoisophthalic acid] was prepared by the solvothermal reaction, which was characterized by single-crystal X–ray diffraction, infrared spectroscopy, and elemental analysis. 1 exhibits an infinite two dimensional [Cu(AIP)]n sheet parallel to (0 1 1) crystal plane. Furthermore, complex 1 displays good photocatalytic degradation of methyl blue (MB).


Author(s):  
Sergey M. Aksenov ◽  
Anastasia D. Ryanskaya ◽  
Yuliya V. Shchapova ◽  
Nikita V. Chukanov ◽  
Nikolay V. Vladykin ◽  
...  

Specific features of the crystal chemistry of lamprophyllite-group minerals (LGMs) are discussed using the available literature data and the results of the single-crystal X-ray diffraction and a Raman spectroscopic studies of several samples taken from the Murun alkaline complex (Russia), and Rocky Boy and Gordon Butte pegmatites (USA) presented here. The studied samples are unique in their chemical features and the distribution of cations over structural sites. In particular, the sample from the Gordon Butte pegmatite is a member of the barytolamprophyllite–emmerichite solid solution series, whereas the samples from the Murun alkaline complex and from the Rocky Boy pegmatite are intermediate members of the solid solution series formed by lamprophyllite and a hypothetical Sr analogue of emmerichite. The predominance of O2− over OH− and F− at the X site is a specific feature of sample Cha-192 from the Murun alkaline complex. New data on the Raman spectra of LGMs obtained in this work show that the wavenumbers of the O—H stretching vibrations depend on the occupancies of the M2 and M3 sites coordinating with (OH)− groups. Cations other than Na+ and Ti4+ (mainly, Mg and Fe3+) can play a significant role in the coordination of the X site occupied by (OH)−. Data on polarized Raman spectra of an oriented sample indicate that the OH groups having different local coordinations have similar orientations with respect to the crystal. The calculated measures of similarity (Δ) for lamprophyllite and ericssonite are identical (0.157 and 0.077 for the 2M- and 2O-polytypes, respectively), which indicates that these minerals are crystal-chemically isotypic and probably should be considered within the same mineral group by analogy to the other mineralogical groups which combine isotypic minerals.


CrystEngComm ◽  
2014 ◽  
Vol 16 (44) ◽  
pp. 10262-10272 ◽  
Author(s):  
A. Ostasz ◽  
R. Łyszczek ◽  
L. Mazur ◽  
B. Tarasiuk

Novelp-xylylene-bis(thioacetic) acid (p-XBTA) and its co-crystals with 2-amino-4,6-dimethylpyrimidine (DMP) have been synthesized and characterized by single-crystal X-ray diffraction, infrared spectroscopy and thermal analysis methods (TG/DSC).


1997 ◽  
Vol 485 ◽  
Author(s):  
G. M. Riker ◽  
M. M. Al-Jassim ◽  
F. S. Hasoon

AbstractWe have investigated CdS thin films as possible passivating window layers for InP. The films were deposited on single crystal InP by chemical bath deposition (CBD). The film thickness, as optically determined by ellipsometry, was varied from 500 to 840Å. The film morphology was investigated by high resolution scanning electron microscopy (SEM), whereas the film microstructure was studied by X-ray diffraction (XRD) and cross-sectional transmission electron microscopy (TEM). Most of the films were fine-grained polycrystalline CdS, with some deposition conditions resulting in epitaxial growth. Cross-sectional TEM examination revealed the presence of interface contaminants. The effect of such contaminants on the film morphology and microstructure was studied, and various approaches for InP surface cleaning/treatment were investigated. The epitaxial films were determined to be hexagonal on both the (111) and (100) InP substrates; however, they were heavily faulted.


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