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Phonons and Colossal Thermal Expansion Behavior of Ag3Co(CN)6 and Ag3Fe(CN)6  [PDF]
R Mittal,M. Zbiri,H. Schober,S. N. Achary,A. K. Tyagi,S. L. Chaplot
Physics , 2012, DOI: 10.1088/0953-8984/24/50/505404
Abstract: Recently colossal positive volume thermal expansion has been found in the framework compounds Ag3Co(CN)6 and Ag3Fe(CN)6. Phonon spectra have been measured using the inelastic neutron scattering technique as a function of temperature and pressure. The data has been analyzed using ab-initio calculations. We find that the bonding is very similar in both compounds. At ambient pressure modes in the intermediate frequency part of the vibrational spectra in the Co compound are shifted to slightly higher energies as compared to the Fe compound. The temperature dependence of the phonon spectra gives evidence for large explicit anharmonic contribution to the total anharmonicity for low-energy modes below 5 meV. We found that modes are mainly affected by the change in the size of unit cell, which in turn changes the bond lengths and vibrational frequencies. Thermal expansion has been calculated via the volume dependence of phonon spectra. Our analysis indicates that Ag phonon modes in the energy range from 2 to 5 meV are strongly anharmonic and major contributors to thermal expansion in both compounds. The application of pressure hardens the low-energy part of the phonon spectra involving Ag vibrations and confirms the highly anharmonic nature of these modes.
The influence of K4Fe(CN)6 on the photosensitivity of cubic AgCl microcrystal
The influence of K4Fe(CN)6 on the photosensitivity of cubic AgCl microcrystal

Li Xiao-Wei,Liu Rong-Juan,Geng Ai-Cong,Yang Shao-Peng,Fu Guang-Sheng,
李晓苇
,刘荣鹃,耿爱丛,杨少鹏,傅广生

中国物理 B , 2005,
Abstract: The influence of K4Fe(CN)6 at various doping concentrations on the photosensitivity of cubic AgCl microcrystals has been investigated by using the microwave absorption and phase-sensitive measurement technique. The time behaviour of free photoelectrons in AgCl microcrystals is analysed by using computer simulation as a function of three parameters of shallow electron trap (SET) including doping concentration, trap depth and capture cross-section (CCS). It is found that the three parameters of SET play different roles on the free photoelectron decay time (FDT). After considering the threshold effects of the three parameters and their collective effects, the trap depth value, the CCS value, and the optimal doping concentration of the SET introduced by the dopant K4Fe(CN)6 in cubic AgCl microcrystals can also be determined, and the best photosensitivity of cubic AgCl can be obtained.
Magnetic field effects on electric behavior of [Fe(CN)6]3 at bare and membrane-coated electrodes
Govindachetty Saravanan, Katsuhiko Fujio and Sumio Ozeki
Science and Technology of Advanced Materials , 2008,
Abstract: The cyclic voltammetric behavior of [Fe(CN)6]3 was investigated under homogeneous magnetic fields perpendicular to the electrode surface in order to determine the effects of magnetic fields on the distribution of an Fe2+/Fe3+ redox couple. The cathodic current was enhanced much more than the anodic current by a homogeneous magnetic field, suggesting that the concentration gradient of paramagnetic [Fe(CN)6]3 and diamagnetic [Fe(CN)6]4 formed at an electrode surface may also contribute to the asymmetric current. The apparent diffusion coefficient of the redox couple increased by over 30% in both cathodic and anodic processes upon applying a magnetic field. For a gold electrode coated with dioctadecyldimethylammonium, the application of a magnetic field perpendicular to the surface increased the peak-to-peak separation, and enhanced the asymmetric current. It is inferred that the application of a magnetic field promotes the electron-tunneling process by tilting chain molecules in the barrier membrane.
Origin of the ESR spectrum in the Prussian Blue analogue RbMn[Fe(CN)6]*H2O  [PDF]
á. Antal,A. Jánossy,L. Forró,E. J. M. Vertelman,P. J. van Koningsburgen,P. H. M. van Loosdrecht
Physics , 2010, DOI: 10.1103/PhysRevB.82.014422
Abstract: We present an ESR study at excitation frequencies of 9.4 GHz and 222.4 GHz of powders and single crystals of a Prussian Blue analogue (PBA), RbMn[Fe(CN)6]*H2O in which Fe and Mn undergoes a charge transfer transition between 175 and 300 K. The ESR of PBA powders, also reported by Pregelj et al. (JMMM, 316, E680 (2007)) is assigned to cubic magnetic clusters of Mn2+ ions surrounding Fe(CN)6 vacancies. The clusters are well isolated from the bulk and are superparamagnetic below 50 K. In single crystals various defects with lower symmetry are also observed. Spin-lattice relaxation broadens the bulk ESR beyond observability. This strong spin relaxation is unexpected above the charge transfer transition and is attributed to a mixing of the Mn3+ - Fe2+ state into the prevalent Mn2+ - Fe3+ state.
An efficient solvent-free synthesis of imidazolines and benzimidazoles using K 4[Fe(CN) 6] catalysis  [PDF]
Kabeer A. Shaikh,Vishal A. Patil
Organic Communications , 2012,
Abstract: Imidazolines and Benzimidazoles have been efficiently synthesized in high yields by treatment of 1,2-diamine with aldehydes using the metal co-ordinate complex K 4[Fe(CN) 6] as a catalysis. The method was carried out under solvent free condition via oxidation of carbon-nitrogen bond. The process is green, mild and inexpensive.
Negative thermal expansion in the Prussian Blue analog Zn3[Fe(CN)6]2: X-ray diffraction and neutron vibrational studies  [PDF]
S Adak,L L Daemen,H Nakotte
Physics , 2011, DOI: 10.1088/1742-6596/251/1/012007
Abstract: The cubic Prussian Blue (PB) analog, Zn3 [Fe(CN)6]2, has been studied by X-ray powder diffraction and inelastic neutron scattering (INS). X-ray data collected at 300 and 84 K revealed negative thermal expansion (NTE) behaviour for this material. The NTE coefficient was found to be -31.1 x 10-6 K-1. The neutron vibrational spectrum for Zn3[Fe(CN)6]2.xH2O, was studied in detail. The INS spectrum showed well-defined, well-separated bands corresponding to the stretching of and deformation modes of the Fe and Zn octahedra, all below 800 cm-1.
磁场下K_4[Fe(CN)_6]·3H_2O的穆斯堡尔谱  [PDF]
汪信
科学通报 , 1984,
Abstract: 用~57Co/Pd单线放射源,在室温下测得了K_4[Fe-(CN)_6]·3H_2O在外磁场中的M(?)ssbauer谱。实验中吸收体K_4[Fe(CN)_6]·3H_2O(A.R.级)被置于磁场方向与r射线垂直的外磁场中。K_4[Fe(CN)_6]·3H_2O中的Fe~(2+)处于O_h对称性的配体场中,其电子构型为t_(2g)~6e_g~0因而晶体场和价电子对电场梯度的贡献均为零,在没有外加磁场的情况下,其M(?)ssbauer谱呈单线吸收。
Synthesis of the SrFeO2.5 and BaFeO3-x perovskites by thermal decomposition of SrNH4[Fe(CN)6] 3H2O and BaNH4[Fe(CN)6]
Córdoba,Lucrecia M.; Gómez,María Inés; de Morán,Juana A.; Aymonino,Pedro J.;
The Journal of Argentine Chemical Society , 2008,
Abstract: in the present work the synthesis, physicochemical characterization and thermoanalytical results of srnh4[fe(cn)6]3h2o y banh4[fe(cn)6] are described. the thermal decompositions in oxygen atmosphere for both salts are carried out in the stages that lead to the formation of mixed oxides, i. e., srfeo2.5 and bafeo3-x at 1173 k. barium carbonate is also obtained in the residue in the case of the decomposition of the barium complex. the total weight loss are 49,95% and 35,45 % for the strontium and barium salts, respectively. a decomposition mechanism is suggested for the pyrolisis processes from the data provided by ir spectroscopy, x-ray powder diffraction and chemical analysis. the specific surface area of the obtained oxides is also determined in order to evaluate its eventual catalytic activity.
K4[Fe(CN)6]作为氰源在氰基化反应中的应用**  [PDF]
王丽丽,赵伟宁,段征
化学进展 , 2010,
Abstract: 过渡金属催化氰基化反应成为合成芳基腈化物的重要手段之一。2004年,无毒、廉价的K4[Fe(CN)6]首次被用来代替传统的KCN、NaCN及CuCN等作为氰源用于芳基卤代物的氰基化反应。K4[Fe(CN)6]作为氰源时无需复杂的预处理,其6个氰根均可参与反应。该反应为氰基化反应开创了一个新的研究方向,迅速得到了众多研究者的青睐。K4[Fe(CN)6]用于氰基化反应的研究也得到了较快的发展。本文主要综述了近年来K4[Fe(CN)6]作为氰源用于卤代芳烃和芳基氟代磺酸酯的氰基化反应。主要介绍了在钯催化剂和铜催化剂作用下,以K4[Fe(CN)6]为氰源的氰基化反应在配体、反应介质和底物适用范围等方面的研究成果。
NaxMyFe(CN)6(M=Fe,Co,Ni):一类新颖的钠离子电池正极材料  [PDF]
钱江锋,周敏,曹余良,杨汉西
电化学 , 2012,
Abstract: 应用化学沉淀法合成了3种普鲁士蓝类化合物NaxMyFe(CN)6(M=Fe,Co,Ni),并研究以此类化合物作钠离子电池正极材料的可行性.XRD和SEM分析表明,合成的3种目标产物均具有典型的立方晶型结构,粒子尺寸约为20~50nm.循环伏安扫描和恒电流充放电测试表明,这类化合物均能实现可逆的钠离子嵌入-脱嵌反应,但不同的金属表现出不同的电化学性质.如材料中的Fe(CN)64+和Fe2+/Co2+离子这两个电化学活性中心都能参与氧化还原反应,因此,NaFeFe(CN)6和Na2CoFe(CN)6的首周可逆容量分别为113mAh?g-1和120mAh?g-1,且循环性比较稳定.由于这类结构中Ni离子不能参入氧化还原反应,导致Na2NiFe(CN)6的可逆容量仅为64mAh?g-1,但循环性能非常优异.本工作的初步结果证明了普鲁士蓝类化合物具有良好的钠离子脱嵌能力,有望成为一类价格低廉、环境友好的钠离子电池正极材料.
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