scholarly journals Synthesis, Characterization, and Crystal Structure Determination of a New Lithium Zinc Iodate Polymorph LiZn(IO3)3

Author(s):  
Zoulikha Hebboul ◽  
Christine Galez ◽  
Djamal Benbertal ◽  
Sandrine Beauquis ◽  
Yannick Mugnier ◽  
...  

Synthesis and characterization of anhydrous LiZn(IO3)3 powders prepared from an aqueous solution are reported. Morphological and compositional analyses were carried out by scanning electron microscopy and energy dispersive X-ray measurements. The synthesized powders exhibit a needle-like morphology after annealing at 400°C. A crystal structure for the synthesized compound has been proposed from powder X-ray diffraction and density-functional theory calculations. Rietveld refinements led to a monoclinic structure, which can be described with space group P21, number 4, and unit-cell parameters a = 21.874(9) Å, b = 5.171(2) Å, c = 5.433(2) Å, and beta = 120.93(4)º. Density-functional theory calculations supported the same crystal structure. Infrared spectra were also collected and the vibrations associated to the different modes discussed. The non-centrosymmetric space group determined for this new polymorph of LiZn(IO3)3, the characteristics of its infrared absorption spectrum, and the observed second harmonic generation suggest a promising infrared non-linear optical material.

Crystals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 464 ◽  
Author(s):  
Hebboul ◽  
Galez ◽  
Benbertal ◽  
Beauquis ◽  
Mugnier ◽  
...  

Synthesis and characterization of anhydrous LiZn(IO3)3 powders prepared from an aqueous solution are reported. Morphological and compositional analyses were carried out by using scanning electron microscopy and energy-dispersive X-ray measurements. The synthesized powders exhibited a needle-like morphology after annealing at 400 °C. A crystal structure for the synthesized compound was proposed from powder X-ray diffraction and density-functional theory calculations. Rietveld refinements led to a monoclinic structure, which can be described with space group P21, number 4, and unit-cell parameters a = 21.874(9) Å, b = 5.171(2) Å, c = 5.433(2) Å, and  = 120.93(4)°. Density-functional theory calculations supported the same crystal structure. Infrared spectra were also collected, and the vibrations associated with the different modes were discussed. The non-centrosymmetric space group determined for this new polymorph of LiZn(IO3)3, the characteristics of its infrared absorption spectrum, and the observed second-harmonic generation suggest it is a promising infrared non-linear optical material.


2016 ◽  
Vol 18 (23) ◽  
pp. 15798-15806 ◽  
Author(s):  
Thomas M. Tolhurst ◽  
Brett Leedahl ◽  
Justin L. Andrews ◽  
Peter M. Marley ◽  
Sarbajit Banerjee ◽  
...  

An elucidation of structure–property relationships in V2O5 polymorphs using synchrotron X-ray spectroscopy and density functional theory calculations.


2010 ◽  
Vol 114 (50) ◽  
pp. 13175-13181 ◽  
Author(s):  
Rolf W. Berg ◽  
Anders Riisager ◽  
Olivier N. Van Buu ◽  
Steffen Buus Kristensen ◽  
Rasmus Fehrmann ◽  
...  

Author(s):  
Jorge González-López ◽  
Jeremy K. Cockcroft ◽  
Ángeles Fernández-González ◽  
Amalia Jimenez ◽  
Ricardo Grau-Crespo

The cobalt carbonate hydroxide Co2CO3(OH)2is a technologically important solid which is used as a precursor for the synthesis of cobalt oxides in a wide range of applications. It also has relevance as a potential immobilizer of the toxic element cobalt in the natural environment, but its detailed crystal structure is so far unknown. The structure of Co2CO3(OH)2has now been investigated using density functional theory (DFT) simulations and powder X-ray diffraction (PXRD) measurements on samples synthesizedviadeposition from aqueous solution. Two possible monoclinic phases are considered, with closely related but symmetrically different crystal structures, based on those of the minerals malachite [Cu2CO3(OH)2] and rosasite [Cu1.5Zn0.5CO3(OH)2], as well as an orthorhombic phase that can be seen as a common parent structure for the two monoclinic phases, and a triclinic phase with the structure of the mineral kolwezite [Cu1.34Co0.66CO3(OH)2]. The DFT simulations predict that the rosasite-like and malachite-like phases are two different local minima of the potential energy landscape for Co2CO3(OH)2and are practically degenerate in energy, while the orthorhombic and triclinic structures are unstable and experience barrierless transformations to the malachite phase upon relaxation. The best fit to the PXRD data is obtained using a rosasite model [monoclinic with space groupP1121/nand cell parametersa= 3.1408 (4) Å,b= 12.2914 (17) Å,c= 9.3311 (16) Å and γ = 82.299 (16)°]. However, some features of the PXRD pattern are still not well accounted for by this refinement and the residual parameters are relatively poor. The relationship between the rosasite and malachite phases of Co2CO3(OH)2is discussed and it is shown that they can be seen as polytypes. Based on the similar calculated stabilities of these two polytypes, it is speculated that some level of stacking disorder could account for the poor fit of the PXRD data. The possibility that Co2CO3(OH)2could crystallize, under different growth conditions, as either rosasite or malachite, or even as a stacking-disordered phase intermediate between the two, requires further investigation.


2021 ◽  
Vol 60 (8) ◽  
pp. 6016-6026
Author(s):  
Aydar Rakhmatullin ◽  
Maxim S. Molokeev ◽  
Graham King ◽  
Ilya B. Polovov ◽  
Konstantin V. Maksimtsev ◽  
...  

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