Die Isopolymolybdationen in wäßrigen Medien im Bereich Z ≦ 1,14 / Concerning Isopolymolybdate Ions in Aqueous Media in the Range Z ≦ 1.14

1980 ◽  
Vol 35 (1) ◽  
pp. 45-56 ◽  
Author(s):  
Karl-Heinz Tytko ◽  
Georgios Petridis ◽  
Bernd Schönfeld
Keyword(s):  
Main Product ◽  
Structural Parameters ◽  
Aqueous Media ◽  
Ratio Method ◽  
Intensity Difference ◽  
Ionic Medium ◽  
Theoretical Investigations ◽  
Detailed Evaluation ◽  
Mole Ratio Method ◽  
Statistical Certainty

The system H+/MoO42- was investigated by Raman spectroscopy in the range Z = 0 to 1.14 at initial concentrations CMoO₄ 2- = 0.02 to 2M and concentrations of the ionic medium CMe+ = 2CMoO₄ 2- to 3M Me(Cl,NO3) (Me=Li, Na, K,NH4 , Mg/2). The mole-ratio method and intensity difference diagrams do not indicate any species between MoO42- and Mo7O246- contrary to propositions in recent papers. A detailed evaluation of the extensive data shows the possible portion of such species to be < 3 % , this value having a statistical certainty of 95%. Comparing the solutions having Z = 1.1 by fingerprint procedures, in all cases Mo7O246- is the first main product (detectable by static methods) irrespective of the nature and concentration of the ionic medium. Thus, Mg2+ ions do not influence the course of aggregation of molybdate ions as has been proposed in the literature. This is in accordance with theoretical investigations since the Mo7O246- ion has the distinction of a number of favourable structural parameters in the system that become operative in case of scarcity of H+ ions.

Theoretical Investigations on Mechanical Stability and Electronic Structure of NbN under Pressures

2011 ◽  
Vol 90-93 ◽  
pp. 1264-1271
Author(s):  
Xiao Feng Li ◽  
Jun Yi Du
Keyword(s):  
Debye Temperature ◽  
Density Functional ◽  
Mechanical Stability ◽  
Structural Parameters ◽  
Theoretical Data ◽  
Hexagonal Structure ◽  
Functional Theory ◽  
Theoretical Investigations ◽  
Crystallographic Structures ◽  
Good Agreement

The ground structure, elastic and electronic properties of several phases of NbN are determined based on ab initio total-energy calculations within the framework of density functional theory. Among the five crystallographic structures that have been investigated, the hexagonal phases have been found to be more stable than the cubic ones. The calculated equilibrium structural parameters are in good agreement with the available experimental results. The elastic constants of five structures in NbN are calculated, which are in consistent with the obtained theoretical and experimental data. The corresponding Debye temperature and elastic ansitropies are also obtained. The Debye temperature of NbN in various structures consistent with available experimental and theoretical data, in which the Debye temperature of δ-NbN is highest. The anisotropies of ZB-NbN, NaCl-NbN, CsCl-NbN gradually increases. For hexagonal structure, the anisotropies of ε-NbN are stronger than that of δ-NbN. The electronic structures of NbN under pressure are investigated. It is found that NbN have metallization and the hybridizations of atoms in NbN under pressure become stronger.

Magnetophoretic mole-ratio method in solvent extraction systems

2020 ◽  
Vol 1111 ◽  
pp. 60-66
Author(s):  
Hitoshi Watarai ◽  
Mariko Kurahashi
Keyword(s):  
Solvent Extraction ◽  
Ratio Method ◽  
Mole Ratio Method

scholarly journals Determination of Stability Constants and Thermodynamic parameters of Cefotaxime –Fe(III) Complex at Different Temperatures

2020 ◽  
Vol 45 (4) ◽  
Author(s):  
O. V. Ikpeazu ◽  
I. E. Otuokere ◽  
K. K. Igwe
Keyword(s):  
Stability Constants ◽  
Chelating Agent ◽  
Continuous Variation ◽  
Molar Ratio ◽  
Variation Method ◽  
Ratio Method ◽  
Lactam Antibiotic ◽  
Different Temperatures ◽  
Mole Ratio Method ◽  
Continuous Variation Method

Cefotaxime, a β-lactam antibiotic, has a structure which enables it to act as a chelating agent. The formation of Fe(III) complex with cefotaxime has been studied colorimetrically at an absorption maximum of 480 nm at different temperatures. The data showed that Fe(III) and cefotaxime combine in the molar ratio of 1:1  at pH 7.4 with ionic strength maintained using 0.1M KNO3. The stability constants of the complex were calculated to be 1.56 - 1.90 x 104 by continuous variation method and 1.34 - 1.71 x 104 by mole ratio method at 25 and 40 oC respectively. ∆HƟ values for the complex were calculated to be -1.02 x 104 and -1.05 x 104 J by continuous variation method and mole ratio method respectively. ∆GƟ of the complex were calculated to be -2.44 – (-2.51) x 104 J by continuous variation method and -2.41- (- 2.48)  x 104 J by mole ratio method at 25 and 40 oC.  ∆SƟ of the complex were calculated to be 2.44 - 2.51 x 104 J/K by continuous variation method and -2.41 -2.48) x 104 J/K by mole ratio method at 25 and 40 oC respectively. Cefotaxime is a good chelating agent and can be an efficient antidote in the therapy of copper overload or poisoning.  

Theoretical investigations on correlations between elastic behavior of Al-based alloys and their electronic structures

2021 ◽  
Vol 112 (8) ◽  
pp. 636-641
Author(s):  
Wen Liu ◽  
Chi Zhang ◽  
Chunge Wang ◽  
Xiang Yan ◽  
Xiaoxiong Hu ◽  
...  
Keyword(s):  
Intermetallic Compounds ◽  
Elastic Properties ◽  
First Principles ◽  
Electronic Structures ◽  
Structural Parameters ◽  
Elastic Behavior ◽  
Theoretical Investigations ◽  
Valence Electrons ◽  
Cohesive Energies ◽  
Formation Energies

Abstract In this work, using the first-principles method, the alloying stability, electronic structure, and elastic properties of Al-based intermetallics were investigated. It was found that these alloys have a strong alloying ability and structural stability due to the negative formation energies and the cohesive energies. The valence bonds of these intermetallic compounds are attributed to the valence electrons of Cu 3δ states for AlCu3, Cu 3δ and Zr 4δ states for AlCu2Zr, and Al 3s, Zr 5s and 4δ states for AlZr3, respectively. Furthermore, the correlation between elastic properties of these intermetallic compounds and their electronic structures was revealed. The results show that structural parameters and elastic properties such as bulk modulus, shear modulus, Young’s modulus, Poisson’s ratio and anisotropy agreed well with experimental results.

Study of iron(II) complexes with halides and thiocyanate in acetonitrile

1970 ◽  
Vol 48 (9) ◽  
pp. 1414-1419 ◽  
Author(s):  
Byron Kratochvil ◽  
Robert Long
Keyword(s):  
Formation Constants ◽  
Ratio Method ◽  
Mole Ratio Method ◽  
Stepwise Formation

In acetonitrile, iron(II) forms stable 1:1 complexes with chloride, bromide, and iodide and both 1:1 and 1:2 complexes with thiocyanate. Stepwise formation constants for the complexes were determined spectrophotometrically by a mole-ratio method. The log K values are: FeCl+, 5.8; FeBr+, 5.5; FeI+,4.3; Fe(SCN)+, 5.5; and Fe(SCN)2, 3.7.

scholarly journals DEVELOPMENT OF EXTRACTIVE SPECTROPHOTOMETRIC METHOD FOR THE DETERMINATION OF IRON (III) WITH SCHIFF BASE 2-[(2-HYDROXYPHENYLIMINO) METHYL]-4-NITROPHENOL

2016 ◽  
Vol 8 (4) ◽  
pp. 89 ◽  
Author(s):  
Datta B. Mandhare ◽  
Vasant D. Barhate
Keyword(s):  
Aqueous Solution ◽  
Schiff Base ◽  
Spectrophotometric Method ◽  
Molar Absorptivity ◽  
Maximum Absorption ◽  
Ratio Method ◽  
Pharmaceutical Samples ◽  
Mole Ratio Method ◽  
Ph Range

Objective: A simple spectrophotometric method has been developed for the determination of Iron (III) by using Schiff base 2-[(2-hydroxyphenylimino) methyl]-4-nitrophenol [HPIMNP].Methods: HPIMNP extracts Fe (III) quantitatively (99.95%) into chloroform from an aqueous solution of pH range 4.0-6.0.Results: The chloroform extracts show maximum absorption at 510 nm (λ max). Beer’s Law is obeyed over the Fe (III) concentration range of 0.5 to 20.0 µg/ml. The Molar absorptivity and Sandell’s sensitivity for Fe–HPIMNP system is 5000 L mol ˉ1 cmˉ1 and 0.011 µg cmˉ2respectively. The composition of extracted species is found to be 1: 3 [Fe-HPIMNP] by Job’s continuous variation and Mole-ratio method. Interference by various ions has been studied.Conclusion: The proposed method is rapid, sensitive, reproducible and accurate and it has been satisfactory applied for the determination of Iron in Pharmaceutical Samples.

Magnetophoretic Mole-Ratio Method

2017 ◽  
Vol 89 (19) ◽  
pp. 10141-10146 ◽  
Author(s):  
Hitoshi Watarai ◽  
Jiayue Chen
Keyword(s):  
Ratio Method ◽  
Mole Ratio Method

Theoretical investigations of the g factors of orthorhombic Cu2+ site in oxycarbonate phase YBa2Cu2.95(CO3)0.35O6.6

2015 ◽  
Vol 29 (25n26) ◽  
pp. 1542016 ◽  
Author(s):  
Yong-Qiang Xu ◽  
Shao-Yi Wu ◽  
Zhi-Hong Zhang ◽  
Hui-Ning Dong
Keyword(s):  
Experimental Data ◽  
Structural Parameters ◽  
Theoretical Formula ◽  
Length Variation ◽  
Apical Oxygen ◽  
Oxygen Ions ◽  
Theoretical Investigations ◽  
Jahn Teller ◽  
Jahn Teller Effect ◽  
Good Agreement

The [Formula: see text] factors of orthorhombic [Formula: see text] site in oxycarbonate phase [Formula: see text] are theoretically investigated using the perturbation formulas of the [Formula: see text] factors for an orthorhombically elongated [Formula: see text] cluster. This pseudo-octahedral [Formula: see text] center is formed by two apical oxygen ligands and four coplanar oxygen ions belonging to the respective four neighboring carbonate groups. The [Formula: see text] cluster is found to suffer the relative axial elongation of about 0.04 Å and the perpendicular bond length variation of about 0.12 Å due to the Jahn–Teller effect. The theoretical [Formula: see text] factors based on the local structural parameters show good agreement with the experimental data.

scholarly journals SYNTHESIS OF SPINEL Mn3O4 AND SPINEL Mn3O4/ZrO2 NANOCOMPOSITES AND USING THEM IN PHOTO-CATALYTIC DECOLORIZATION OF Fe(II)-( 4,5- DIAZAFLUOREN-9-ONE 11) COMPLEX

2020 ◽  
Vol 17 (34) ◽  
pp. 689-699
Author(s):  
Mohammed Kareem HAYAWI ◽  
Mohanad Mousa KAREEM ◽  
Luma Majeed AHMED
Keyword(s):  
Model Material ◽  
Spherical Particles ◽  
Ratio Method ◽  
Nano Composites ◽  
Precipitation Process ◽  
X Ray Diffraction ◽  
Force Microscopy ◽  
Atomic Force ◽  
Mole Ratio Method ◽  
Co Precipitation

The spinel structure Mn3O4 and the spinel Mn3O4/ZrO2 nano-composites particles were synthesized successfully as photocatalysts by employing the co-precipitation process and ultrasonic technique, respectively. The morphology of the top mention prepared photocatalysts was distinguished using X-ray diffraction (XRD) technology and atomic force microscopy (AFM) and indicated that the mean crystal sizes and particle sizes for all studied samples were nanometric. In addition, the optical properties of the obtained photocatalysts were investigated using a UV-Visible spectrophotometer with Labsphere diffuse reflectance accessory to measure the bandgaps of them. Based on the Tauc equation, the bandgaps (Bg) for the studied photocatalysts were determined. The bandgaps are indirect for all samples, and it is increased in values for the nanocomposites with the increasing the ratio of ZrO2. So, the sequence of bandgaps values is: Bg spinel Mn3O4 Bg Comp.1 Bg Comp.2 Bg Comp.3 Bg ZrO2, and equal to 2.21 eV 3.15 eV 4.51 eV 4.26 eV 5.29 eV. The research revealed that the spinel Mn3O4 and the spinel Mn3O4 ZrO2 nano-composites particles were quasispherical and spherical particles respectively. Moreover, the incorporation of spinel Mn3O4 particle with ZrO2 particle was successfully carried out that was proved by XRD and AFM analyses. This work discovered that the photocatalytic reaction response via employing Fe(II)-(4,5-Diazafluoren-9-one 11) complex as model material under UV-A lamp with the use of the studied photocatalysts. The primary photo experiments for these photocatalysts found that the decolorization of Fe(II)-(4,5-Diazafluoren-9-one 11) complex is not active without addition of H2O2, that attitude is due to the very high stability of these complex with having an octahedral structure, which was proved with using mole ratio method. Whereas, after the addition of H2O2 to the aqueous solution of these complex, the activity with using the spinel Mn3O4 ZrO2 nanocomposite 3 was found to be the double active than that using the spinel Mn3O4 alone, and the sequence of phootdecolorization efficiency (E%) is being: E% composite 3 E% composite 2 E% composite 1 E% spinel Mn3O4.

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