13769-43-2Relevant academic research and scientific papers
Influence of neodymium doping on dielectric properties of ferroelectric KVO3 and LiVO3
Patil,Patil,Kashid,Chavan
, p. 57 - 62 (1990)
The dielectric properties of pure and doped with different concentrations of Nd2O3 ferroelectric KVO3 and LiVO3, have been studied by using a digital LCR meter VLCR-7 at fixed frequency (1KHz) in the region of their phase transition. The dielectric constant shows a sharp peak at the phase transition in all the compositions. The dielectric constant is found to increase significantly, when dopant concentration is increased up to 0.5 mol % Nd2O3, however decreases for higher concentrations. The Curie temperature of all the samples decreases with increase in Nd concentration.
Monoperoxo-vanadium(V) complexes of R,S-N-(carboxymethyl)-aspartate
?asny, Marian,Sivák, Michal,Rehder, Dieter
, p. 223 - 228 (2003)
Monoperoxo complexes of vanadium(V), M2[VO(O2) cmaa(H2O)] (M=K+, NH4+) and M[VO(O2)Hcmaa(H2O)] (M=K+, Cs+, NBu4+), where cm
New aspects for modeling supramolecular interactions in vanadium haloperoxidases: β-cyclodextrin inclusion compounds of cis-dioxovanadium(V) complexes
Lippold, Ines,Goerls, Helmar,Plass, Winfried
, p. 1487 - 1491 (2007)
The reaction of potassium vanadate and the hydrazone ligand derived from Schiff base condensation of salicylaldehyde and biphenyi-4-carboxylic acid hydrazide (H2salhybiph) in the presence of β-cyclodextrin (β-CD) in water yields the 1:1 inclusi
Observation of metal-insulator transition in hollandite vanadate, K 2V8O16
Isobe, Masahiko,Koishi, Shigenori,Kouno, Naomi,Yamaura, Jun-Ichi,Yamauchi, Touru,Ueda, Hiroaki,Gotou, Hirotada,Yagi, Takehiko,Ueda, Yutaka
, (2006)
We have synthesized hollandite vanadate, K2V8O 16, by a solid-state reaction under 4 GPa at 1473 K for one hour, and investigated its structural and electromagnetic properties. We found a metal-insulator transition with a two-step jump of resistivity of about three orders at around 170 K. The magnetic susceptibility is reduced to a small value at the transition, suggesting the formation of V4+-V4+ singlet pairs and V3+-V3+ pairs in the low-temperature insulator phase. The transition is of first order accompanied by a structural change from a tetragonal to a monoclinic structure. The low-temperature phase has a superlattice of √2a × √2a × 2c, where a and c denote the parameters of the primitive cell for the simple tetragonal hollandite structure, suggesting a charge ordering of V4+ and V3+. We construct a possible charge order model from the obtained results, in which two kinds of double-chain formed by V3+ and V4+ chains and by single V4+ chains order in a manner that gives a superlattice of √2 × √2 in the a-b plane. The V4+-V4+ and V3+-V3+ pairs are formed in each chain along the c-axis, resulting in a duplication of the c-axis. 2006 The Physical Society of Japan.
Synthesis, structure, and physicochemical properties of K[VO 2(SeO4)(H2O)] and K[VO2(SeO 4)(H2O)2] ? H2O
Tyutyunnik,Krasil'Nikov,Berger,Zubkov,Perelyaeva,Baklanova
, p. 1168 - 1177 (2011)
The vanadium(V) complexes K[VO2(SeO4)(H 2O)] and K[VO2(SeO4)(H2O) 2] ? H2O were synthesized using original procedures; their physicochemical properties were studied, and the crystal structure was determined on the basis of X-ray diffraction and neutron diffraction data. The structure of K[VO2(SeO4)(H2O)2] ? H2O is composed of VO6 octahedra connected to form infinite chains by bridging SeO4 tetrahedra. Each VO6 tetrahedron has short terminal V-O bonds forming the bent dioxovanadium group VO 2 + The unit cell parameters of K[VO2(SeO 4)(H2O)2] ? H2O are a = 6.4045(1) ?, b = 9.9721(2) ?, c = 6.6104(1) ?, β = 107.183(1)°, V = 403.34 ?3, Z = 2, monoclinic system, space group P21. The complex K[VO2(SeO4)(H 2O)] forms a two-dimensional layered structure composed of highly distorted VO6 octahedra having two short terminal V-O bonds and SeO4 groups coordinated simultaneously by three vanadium atoms. This compound crystallizes in the monoclinic system (space group P21/c): a = 7.3783(1) ?, b = 10.5550(2) ?, c = 10.3460(2) ?, β = 131.625(1)°, V = 602.894(5) ?3, Z= 4. The vibrational spectra of the studied compounds are fully consistent with their structural features.
KV6O11: A magnetic metal synthesized at high pressure
Kanke, Yasushi
, p. 3764 - 3776 (1999)
An AV6O11-type magnetic metal KV6O11 was discovered by a high-pressure synthesis. It crystallizes in hexagonal P63/mmc at 295 K, whereas in hexagonal P63mc at 154 K. KV6O11 shows three magnetic transitions at 190, 66.8, and 35.1 K. KV6O11 is paramagnetic above 66.8 K. Its inverse magnetic susceptibility is slightly concave upward with respect to temperature above 190 K, but the relationship is significantly concave upward below 190 K. KV6O11 shows uniaxial magnetic anisotropy with an easy axis of magnetization parallel to the [001] direction below 66.8 K. The magnetization shows an anomaly at 35.1 K. The resistivity normal to [001] is of the order of 10-4 Ω cm-1. The resistivity versus temperature shows a positive slope above 190 K, a broad maximum at around 90 K, a linear relationship with a positive slope between 35.1 and 66.8 K, and Fermi-liquid-type behavior below 35.1 K. The paramagnetic state below 190 K is discussed on the basis of two types of spin-gap models. Problems of the models are also pointed out. The saturated magnetization versus temperature shows a hyperbolic relationship. The magnetization cannot be explained by the well-known mean field theory or the spin fluctuation mechanism. 1999 The American Physical Society.
Explorations of new second-order nonlinear optical materials in the potassium vanadyl iodate system
Sun, Chuan-Fu,Hu, Chun-Li,Xu, Xiang,Yang, Bing-Ping,Mao, Jiang-Gao
, p. 5561 - 5572 (2011)
Four new potassium vanadyl iodates based on lone-pair-containing IO 3 and second-order Jahn-Teller distorted VO5 or VO 6 asymmetric units, namely, α-KVO2(IO 3)2(H2O) (Pbca), β-KVO2(IO 3)2(H2O) (P21212 1), K4[(VO)(IO3)5] 2(HIO3)(H2O)2 H2O (P1), and K(VO)2O2(IO3)3 (Ima2) have been successfully synthesized by hydrothermal reactions. α-KVO 2(IO3)2(H2O) and β-KVO 2(IO3)2(H2O) exhibit two different types of 1D [VO2(IO3)2]- anionic chains. Neighboring VO6 octahedra in the α-phase are corner-sharing into a 1D chain with the IO3 groups attached on both sides of the chain in a uni- or bidentate bridging fashion, whereas those of VO5 polyhedra in the β-phase are bridged by IO3 groups into a right-handed helical chain with remaining IO3 groups being grafted unidentately on both sides of the helical chain. The structure of K4[(VO)(IO3)5]2(HIO 3)(H2O)2 H2O contains novel isolated [(VO)(IO3)5]2- units composed of one VO 6 octahedron linked to five IO3 groups and one terminal O2- anion. The structure of K(VO)2O2(IO 3)3 exhibits a 1D [(VO)2O2(IO 3)3]- chain in which neighboring VO6 octahedra are interconnected by both oxo and bridging iodate anions. Most interestingly, three of four compounds are noncentrosymmetric (NCS), and K(VO)2O2(IO3)3 displays a very strong second-harmonic generation response of about 3.6 × KTP, which is phase matchable. It also has high thermal stability, a wide transparent region and moderate hardness as well as an excellent growth habit. Thermal analyses and optical and ferroelectric properties as well as theoretical calculations have also been performed.(Figure Presented)
Interaction between chiral ions: Synthesis and characterization of tartratovanadates(V) with tris(2,2'-bipyridine) complexes of iron(II) and nickel(II) as cations
Antal, Peter,Schwendt, Peter,Tatiersky, Jozef,Gyepes, Rbert,Drbik, Milan
, p. 893 - 900 (2014)
Four new compounds composed of chiral complex cations and anions: Δ-[Fe(bpy)3] Λ-[Fe(bpy)3][V4O8((2R,3R)-tart)2]·12H2O (1), Δ-[Fe(bpy)3]2Λ-[Fe(bpy)3]2
Investigation of the high temperature reaction of the alkali metal metavanadates MVO3 (M=Na,K) with the lanthanide oxides Ln2O3 (Ln=Nd,Er)
de Waal,Heyns,Range
, p. 1193 - 1199 (1991)
The changes occurring in the dielectric constant of an alkali metal metavanadate after it has been treated at high temperatures with a small percentage of a lanthanide oxide have been ascribed to solid solution formation. Analysis of the products obtained by means of Raman spectroscopy, X-ray powder diffraction, SEM and EDX analysis, however, revealed that a small amount of the lanthanide orthovanadate is formed in the metavanadate mass. The reaction that takes place could be described by the following equation: 2MVO3 + Ln2O3 Δ/→ LnVO4 + M2O. With stoichiometric amounts of the reagents under vacuum conditions full conversion to the lanthanide orthovanadate occurs.
Mesoporous VN prepared by solid-solid phase separation
Yang, Minghui,Ralston, Walter T.,Allen, Amy J.,Disalvo, Francis J.,Tessier, Franck
, p. 398 - 401,4 (2013)
We recently reported a simple route to prepare mesoporous, conducting nitrides from Zn containing ternary transition metal oxides. Those materials result from the condensation of atomic scale voids created by the loss of Zn by evaporation, the replacement of 3 oxygen anions by 2 nitrogen anions, and in most cases the loss of oxygen to form water on the reduction of the transition metal. In this report, we present a different route to prepare mesoporous VN from K containing vanadium oxides. In this case, ammonolysis results in a multiphase solid product that contains VN, and other water soluble compounds such as KOH or KNH2. On removing the K containing products by washing with degassed water, only mesoporous VN remains. VN materials with different pore sizes (10 nm-20 nm) were synthesized at 600 °C by varying the reaction time, while larger pores are obtained at higher temperatures (50 nm at 800 °C).
