Shape-Controlled Growth and Shape-Dependent Cation Site Occupancy of Monodisperse Fe3O4Nanoparticles

2011 ◽  
Vol 23 (7) ◽  
pp. 1753-1760 ◽  
Author(s):  
Chien-Hsin Ho ◽  
Chih-Pin Tsai ◽  
Chia-Chi Chung ◽  
Chun-Ying Tsai ◽  
Fu-Rong Chen ◽  
...  
2008 ◽  
Vol 62 (10-11) ◽  
pp. 1634-1637 ◽  
Author(s):  
S.G. Chen ◽  
Y.F. Huang ◽  
Y. Cheng ◽  
Q. Xia ◽  
H.W. Liao ◽  
...  

2021 ◽  
Author(s):  
Kartik Sau ◽  
Tamio Ikeshoji ◽  
Sangryun Kim ◽  
Shigeyuki Takagi ◽  
Shin-ichi Orimo

Complex hydrides are potential candidates for the solid electrolyte of all-solid-state batteries owing to their high ionic conductivities, in which icosahedral anion reorientational motion plays an essential role in high cation diffusion. Herein, we report molecular dynamics (MD) simulations based on a refined force field and first-principles calculations of the two complex hydride systems Li<sub>2</sub>B<sub>12</sub>H<sub>12</sub> and LiCB<sub>11</sub>H<sub>12</sub> to investigate their structures, order–disorder phase-transition behavior, anion reorientational motion, and cation conductivities. For both systems, force-field-based MD successfully reproduced the structural and dynamical behavior reported in experiments. Remarkably, it showed an entropy-driven order–disorder phase transition associated with high anion reorientational motion. Furthermore, we obtained comparative insights into the cation around the anion, cation site occupancy in the interstitial space provided by anions, cation diffusion route, role of cation vacancies, anion reorientation, and effect of cation–cation correlation on cation diffusion. We also determined the factors that activate anion reorientational motion leading to a low to high conductivity phase transition. These findings are of fundamental importance in fast ion-conducting solids to diminish the transition temperature for practical applications.<b></b>


2005 ◽  
Vol 69 (2) ◽  
pp. 145-153 ◽  
Author(s):  
R. S. W. Braithwaite ◽  
R. G. Pritchard ◽  
W. H. Paar ◽  
R. A. D. Pattrick

AbstractTiny green crystals from Kabwe, Zambia, associated with hopeite and tarbuttite (and probably first recorded in 1908 but never adequately characterized because of their scarcity) have been studied by X-ray diffraction, microchemical and electron probe microanalysis, infrared spectroscopy, and synthesis experiments. They are shown to be orthorhombic, stoichiometric CuZnPO4OH, of species rank, forming the end-member of a solid-solution series to libethenite, Cu2PO4OH, and are named zincolibethenite. The libethenite structure is unwilling to accommodate any more Zn substituting for Cu at atmospheric pressure, syntheses using Zn-rich solutions precipitating a mixture of zincolibethenite with hopeite, Zn3(PO4)2.4H2O. Single-crystal X-ray data confirm that the Cu(II) occupies the Jahn-Teller distorted 6-coordinate cation site in the libethenite lattice, and the Zn(II) occupies the 5-coordinate site. The space group of zincolibethenite is Pnnm, the same as that of libethenite, with unit-cell parameters a = 8.326, b = 8.260, c = 5.877 Å , V = 404.5 Å 3, Z = 4, calculated density = 3.972 g/cm3 (libethenite has a = 8.076, b = 8.407, c = 5.898 Å , V = 400.44 Å 3, Z = 4, calculated density = 3.965 g/cm3). Zincolibethenite is biaxial negative, with 2Vα(calc.) of 49°, r<v, and α = 1.660, β = 1.705, and γ = 1.715 The mineral is named for its relationship to libethenite.


2007 ◽  
Vol 71 (1) ◽  
pp. 93-104 ◽  
Author(s):  
G. Iezzi ◽  
G. Della Ventura ◽  
F. Bellatreccia ◽  
S. Lo Mastro ◽  
B. R. Bandli ◽  
...  

AbstractThree natural amphibole samples collected from the former vermiculite mine near Libby, Montana. USA, have been analysed by Rietveld X-ray powder diffraction (XRPD) refinement and Fourier transform infrared spectroscopy (FTIR) in the OH-stretching region. The same materials have been analysed previously by electron microprobe analysis (EMPA), Mössbauer spectroscopy and structure refinement (SREF) single crystal X-ray diffraction (SC-XRD), which revealed that these amphiboles have a crystal chemical formula very close to an intermediate composition between winchite and richterite, i.e. AA0.5BNaCaCMg4.5M3+T0.5Si8O22(OH)2 (A = Na and/or K; M3+ = Fe3+ and/or Al). The Rietveld analysis showed the powder samples used for the experiments here to be composed only of amphibole. This in turn allowed us to use FTIR OH-stretching data to derive cation ordering on these powder samples. The three FTIR spectra are quite similar and up to four components can be fitted to the patterns. The two lower-frequency components (labelled A and B) can be attributed to a local O(3)-H dipole surrounded by M(1)M(3)Mg3 and M(1)M(3)Mg2Fe2+; (respectively), an empty A site and rSi8 environments; on the contrary, the higher-frequency C and D bands indicate the presence of an occupied A site. The FTIR OH-stretching data alone allow us to calculate the site occupancy of the A, M(1)–M(3) and T sites with confidence, as compared with previously published data. By contrast M(4)- and M(2)-site occupancies are more difficult to evaluate. This study takes advantage of the large database of well characterized synthetic amphiboles, built over the last two decades. The comparison of vibrational spectroscopy data with micro-chemical and crystallographic data reported in this study demonstrate that the FTIR OH-stretching method alone is a valuable and rapid method to derive or at least sensibly constrain site occupancy for natural amphiboles. A much more detailed cation site occupancy can be obtained by combining micro-chemical and FTIR OH-stretching data.


Small ◽  
2007 ◽  
Vol 3 (9) ◽  
pp. 1508-1512 ◽  
Author(s):  
Jintian Ren ◽  
Richard D. Tilley

CrystEngComm ◽  
2010 ◽  
Vol 12 (11) ◽  
pp. 3797 ◽  
Author(s):  
Dewei Wang ◽  
Qihua Wang ◽  
Tingmei Wang

2011 ◽  
Vol 35 (5) ◽  
pp. 1133 ◽  
Author(s):  
Linda Dyorisse Nyamen ◽  
Viswanadha Srirama Rajasekhar Pullabhotla ◽  
Adeola Ayodeji Nejo ◽  
Peter Ndifon ◽  
Neerish Revaprasadu

2004 ◽  
Vol 15 (7) ◽  
pp. 762-765 ◽  
Author(s):  
Yunxia Zhang ◽  
Guanghai Li ◽  
Jun Zhang ◽  
Lide Zhang

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