Mutual transformation between crystalline phases and dielectric properties of coordination polymers with the formula [Cd(N-methylimidazole)2(H2O)x(glutarate)]·nH2O (x = 0 or 1; n = 0 or 4)

CrystEngComm ◽  
2014 ◽  
Vol 16 (42) ◽  
pp. 9857-9865 ◽  
Author(s):  
Chen Xue ◽  
Heng Xu ◽  
Rong-Yi Huang ◽  
Xiao-Ming Ren
Keyword(s):  
Dielectric Properties ◽  
Coordination Polymers ◽  
Crystallization Temperature ◽  
Mutual Transformation ◽  
Crystalline Phases

Two pseudo-polymorphs obtained through controlling the crystallization temperature are mutual transformable via absorbing or losing water.

Crystallization in Metal-Metalloid Multilayers

1995 ◽  
Vol 382 ◽  
Author(s):  
R. Sinclair ◽  
T. J. Konno ◽  
T. Itoh ◽  
N. C. Zhu
Keyword(s):  
Phase Diagrams ◽  
Crystallization Temperature ◽  
Metal Layer ◽  
Eutectic Phase ◽  
Crystal Nucleation ◽  
General Phenomenon ◽  
Crystalline Phases ◽  
Reaction Systems ◽  
Binary Eutectic ◽  
Rapid Diffusion

ABSTRACTWe have studied the reactions which occur in metal-metalloid multilayers made from elements which have binary eutectic phase diagrams. The metal mediates crystallization of the amorphous as-deposited metalloid by crystal nucleation inside the metal layer followed by rapid diffusion through the metal from amorphous to crystalline phases. The metalloid crystallization temperature is significantly reduced by this reaction. Systems showing this behavior are Al-Si, Ag-Si, Ag-Ge, Co-C, Ni-C and Fe-C. We believe, therefore, that it is a general phenomenon which we have now extended to the case of Ag-SiC.

Calcium and Strontium Coordination Polymers Based on Rigid and Flexible Aromatic Dicarboxylates: Synthesis, Structure, Photoluminescence and Dielectric Properties

2017 ◽  
Vol 2 (27) ◽  
pp. 8567-8576 ◽  
Author(s):  
Balendra ◽  
Azeem Banday ◽  
Sevi Murugavel ◽  
Pawan K. Kanaujia ◽  
G. Vijaya Prakash ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Coordination Polymers

Structure and Dielectric Properties of Homogeneous Srm-3Bi4TimO3m+3 (m = 3, 4, 5, and 6) Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 133-135 ◽  
Author(s):  
Wang Sheng Fang ◽  
Pi Yi Du ◽  
Wen Jian Weng ◽  
Gao Rong Han
Keyword(s):  
Dielectric Properties ◽  
Solid State ◽  
Curie Temperature ◽  
Solid State Reaction ◽  
Hysteresis Loops ◽  
Reaction Process ◽  
Conventional Solid State Reaction ◽  
Crystalline Phases ◽  
Impedance Analyzer ◽  
Phase Structures

Srm-3Bi4TimO3m+3 (m =3, 4, 5, and 6) bulk ceramics were prepared by conventional solid-state reaction process. Their phase structures and morphologies were observed by XRD and SEM respectively. The dielectric properties and hysteresis loops of the ceramics were measured by impedance analyzer and hysteresis meter respectively. Results showed that the lattice parameters along the c axis are 32.79, 41.11, 48.83, and 58.17Ǻ for m=3, 4, 5, and 6 respectively. The microstructures of plate-like crystalline phases are shown in all the ceramics with different m. Curie temperature of Srm-3Bi4TimO3m+3 decreases from 668°C to 295°C with increasing m from 3 to 6. The remnant polarizations Pr are 32.46 and 19.44 μC/cm2 for odd m of 3 and 5, and 11.84 and 10.58 μC/cm2 for even m of 4 and 6 respectively.

Ga2O3-Doped ZnO-Nb2O5-TiO2 Dielectric Resonators for Terrestrial and Space Telecommunications Applications

2016 ◽  
Vol 869 ◽  
pp. 79-84 ◽  
Author(s):  
Maria do Carmo de Andrade Nono ◽  
Pedro José Castro ◽  
E.G.L. Rangel ◽  
Sergio Luiz Mineiro
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Dielectric Resonators ◽  
Crystalline Phases ◽  
Low Dielectric ◽  
Gallium Doping ◽  
Doped Zno ◽  
Dielectric Ceramics ◽  
Quality Factor Q

Dielectric ceramics find application as dielectric resonators (DRs) in communications systems operating at microwave frequencies. RDs for this application require a unique set of properties: high value of the dielectric constant, low dielectric loss and high frequency stability. This paper presents an investigation of the correlation between the dielectric properties, the characteristics of microstructure and the crystalline phases of Ga2O3-doped ZnO-Nb2O5-TiO2 ceramic system. The ceramics sintered at 1200 °C were characterized as for density, crystalline phases, microstructure and microwave dielectric properties. The results showed that these dielectric ceramics, obtained from the TiO2 anatase crystalline structure, present dielectric constant and quality factor (Q) values appropriate for their use as dielectric resonators in microwave circuits. According to the experiments, as the gallium doping has raised, the dielectric constant increased, the Q factor decreased and the temperature coefficient had a tendency to decrease to a certain extent.

Development of Mica-Based Glass-Ceramic with 4 Mol% of Fluorapatite

2014 ◽  
Vol 1077 ◽  
pp. 8-13
Author(s):  
Bai Jia ◽  
Chaysuwan Duangrudee
Keyword(s):  
Vickers Hardness ◽  
Glass Ceramic ◽  
Crystallization Temperature ◽  
Bending Strength ◽  
Crystalline Phases ◽  
Three Point Bending ◽  
Heat Treated ◽  
Dental Applications ◽  
Glass Heat ◽  
Natural Tooth

SiO2, Al2O3, MgO, MgF2, SrCO3, CaCO3, CaF2 and P2O5 were used to prepare machinable glass-ceramic with 4 mol% of fluorapatite for restorative dental applications. XRD showed that the glass heat treated at 792°C (the first crystallization temperature+20°C) for 6 hours consisted of calcium-mica, fluorapatite, strontium apatite, anorthite, forsterite, fluorite and stishovite crystalline phases. The microstructures of the resultant glass-ceramic, observed by SEM, were found to exhibit plate-like mica crystals and many tabular particles embedded in the mica phases. The particles, determined by EDS, were rich in calcium. The three-point bending strength (158 MPa) closely matched that of nature tooth. Average Vickers hardness of the received glass-ceramic (2.6 GPa) was lower than that of natural tooth.

Alkaline-earth metal based coordination polymers assembled from two different V-shaped ligands: Synthesis, structure, and dielectric properties

2019 ◽  
Vol 495 ◽  
pp. 118940 ◽  
Author(s):  
Balendra ◽  
Azeem Banday ◽  
Shailabh Tewari ◽  
Bharti Singh ◽  
Sevi Murugavel ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Coordination Polymers ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Alkaline Earth Metal

The Microwave Characteristics of Glass-Ba2Ti9O20 Ceramics

2007 ◽  
Vol 336-338 ◽  
pp. 262-264
Author(s):  
Hui Xing Lin ◽  
Xiang Yu Zhao ◽  
Ai Min Yang ◽  
Hua Xin Li ◽  
Wei Chen ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Crystalline Phases ◽  
Sintering Aid ◽  
Microwave Dielectric ◽  
Different Temperatures ◽  
Microwave Characteristics

In this study, 2BaO-3B2O3 (BB) glass was used as a sintering aid to lower the sintering temperature of Ba2Ti9O20 ceramics. Microwave Characteristics of the BB-added Ba2Ti9O20 ceramics sintered at different temperatures were investigated. The crystalline phases of BB-Ba2Ti9O20 ceramics are Ba2Ti9O20, BaTi(BO3)2 and TiO2. Good microwave dielectric properties (εr = 26, Q*f = 28770GHz and τf = 14.6ppm/oC) were obtained by sintering the BB-added Ba2Ti9O20 ceramics at 1040oC for 2 h.

On the Formation of AlPO4-Based Molecular-Sieves in the Presence of Cyclohexylamine

1993 ◽  
Vol 46 (2) ◽  
pp. 171 ◽  
Author(s):  
J Batista ◽  
V Kaucic ◽  
S Hocevar
Keyword(s):  
Crystal Structure ◽  
Hydrothermal Synthesis ◽  
Crystallization Temperature ◽  
Molecular Sieves ◽  
Chemical Compositions ◽  
Crystalline Phases ◽  
Complete Breakdown ◽  
Solid Phases ◽  
Synthesized Materials

The hydrothermal synthesis of the AlPO4-17, SAPO-44, MnAPSO-44 and intermediate solid phases [samples (APO)N, (APSO)N and Mn (APSO)N] in the presence of cyclohexylamine (cha) is described. (APO)N, (APSO)N and Mn (APSO)N represent unknown, layer-type, crystalline phases with different chemical compositions. These phases are predominantly formed at a high cha concentration and low crystallization temperature. All synthesized materials contain protonated cha in their structure, but only in AlPO4-17, (APO)N,(APSO)N and Mn (APSO)N is the -OH group also found. The calcination of the unknown phases leads to the loss of crystallinity and causes a complete breakdown of the crystal structure above 270°C.

Synthesis, Crystal Structures, and Thermal and Spectroscopic Properties of Thiocyanato Coordination Compounds with 3-Acetylpyridine as a Ligand

2014 ◽  
Vol 69 (11-12) ◽  
pp. 1419-1428
Author(s):  
Julia Werner ◽  
Inke Jeß ◽  
Christian Näther
Keyword(s):  
Transition Metal ◽  
Crystal Structures ◽  
Coordination Polymers ◽  
Coordination Compounds ◽  
Spectroscopic Properties ◽  
Second Step ◽  
Crystalline Phases ◽  
Thermogravimetric Investigations ◽  
New Compounds ◽  
Ir Spectroscopic

Abstract The reaction of transition metal thiocyanates with 3-acetylpyridine (3-Acpy) leads to the formation of compounds of compositions M(NCS)2(3-Acpy)4 (M1; M = Mn, Fe, Ni) and M(NCS)2(3- Acpy)2(H2O)2 (M2; M = Mn, Fe, Ni). Thermogravimetric investigations show that in the first step some of these compounds transform into the new coordination polymers M(NCS)2(3-Acpy)2 (M3 with M = Mn, Fe and Ni), that decompose into the new compounds M(NCS)2(3-Acpy) (M4 with M = Mn and Ni) in the second step. Unfortunately, the powder patterns of compounds M3 and M4 cannot be indexed, and there are strong indications that these compounds are contaminated with a small amount of the precursor or unknown crystalline phases. IR spectroscopic investigations indicate that in compounds M3 the metal cations are linked by μ-1,3-bridging thiocyanato anions into 1D or 2D coordination polymers that are further linked by the 3-Acpy ligands in compounds M4.

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