BINDING d-ELEMENT OF THE 4TH PERIOD OF V-GROUP OF THE PERIODIC SYSTEM OF D.I. MENDELEYEV AND ITS PARAMAGNETIC PROPERTIES

2020 ◽  
Vol 5 (443) ◽  
pp. 92-98
Author(s):  
Nasirov R., ◽  
◽  
Kuspanova B., ◽  
Kalauova A.S., ◽  
Satenov K.G., ◽  
...  
Keyword(s):  
Oxidation State ◽  
Total Concentration ◽  
Practical Importance ◽  
Chemical Compounds ◽  
Electronic Configuration ◽  
Valence States ◽  
Experimental Works ◽  
Tetravalent State ◽  
Paramagnetic Properties ◽  
Main Subgroup

Vanadium is a connecting element between the main subgroup VA and the subgroup VB. In the opinion of B.V. Nekrasov, if we compare the VВ group of vanadium elements with the valence states of P and Аs VА main subgroup, then in the oxidation states of -3, 0, +3 arsenic is an analogue of phosphorus, and in the oxidation state +5, it will not be an analogue of phosphorus. In contrast, in the low oxidation degrees of vanadium, it differs from phosphorus, and in the oxidation state of +5 vanadium is not a complete analogue of phosphorus. The similarity of the electronic configuration of atoms for vanadium and phosphorus in the +5 oxidation state specifies the similarity of the properties of their chemical compounds. When comparing vanadium and its compounds with elements of the VA subgroup, we conclude that vanadium is a binding element between the VA subgroup and the VB subgroup and the compounds have similar properties. As a result of many years of work, it was found that vanadium in the penta- and tetravalent states has paramagnetic properties. In crude oil, it is in a tetravalent state. In order to improve the standard photocalorimetric method for determining vanadium in oil and petroleum ashes, a more rapid method was proposed for estimating the total concentration of vanadium based on the interaction of V2O5 with concentrated hydrochloric acid. Studies of the EPR spectra of porphyrin complexes with transition metals such as copper were of great importance in the identification of natural porphyrin complexes. In the course of comparison of experimental works of paramagnetic properties of vanadium and phosphorus with each other, it can be said that their application is of great practical importance in different fields of science. Summing up the results of studying the reduction of triphenylphosphine with an alkali metal, we proposed a scheme for the splitting of triphenylphosphine, including the formation of radical anions.

scholarly journals The thermochemistry of carbon: valence states, heats of sublimation and energies of linkage

1946 ◽  
Vol 187 (1010) ◽  
pp. 337-357 ◽  
Keyword(s):  
Ground State ◽  
Electronic Configuration ◽  
Dissociation Energies ◽  
True Value ◽  
Valence States ◽  
Chemical Combination ◽  
The Right ◽  
Right Order ◽  
Unambiguous Assignment ◽  
Apparent Conflict

The controversy which exists at the present time between the figures 125 and 170 kcal./g.- atom for the latent heat of sublimation of carbon into monatomic vapour in the ground state originates largely from the neglect to take into consideration the energy required to raise the carbon atoms from the ground ( 3 P ) state to the lowest tetravalent ( 5 S ) electronic configuration corresponding to that in which it is normally found in chemical combination. Consideration of the energies of removal of a hydrogen atom from the methane and ethane molecules and of the energies of reorganization of the resulting radicals leads to the figure 190 ± about 10 kcal. for L 2 , the heat of sublimation into free atoms in the 5 S state. This in turn leads to a satisfactory and unambiguous assignment of values to bond energies (as distinct from dissociation energies) which can now be expressed with an uncertainty of not more than a few kcal. In the light of the valency distinction there remains no sound evidence to maintain the higher value put forward for L 1 and 125 kcal. is unquestionably of the right order. There are strong indications that an earlier estimate of 100 kcal. for the energy level of the 5 S state above the 3 P (ground) state is about 50 % in excess of the true value. The necessity for establishing this branch of thermochemistry on a sound theoretical and experimental footing has long been a very obvious need. The scheme here suggested reconciles points hitherto in apparent conflict, and brings virtually all established experimental knowledge into alignment.

The Influence of Ni on the Transport Properties of CoSb3

2000 ◽  
Vol 626 ◽  
Author(s):  
Ctirad Uher ◽  
Jeffrey S. Dyck ◽  
Wei Chen ◽  
Gregory P. Meisner ◽  
Jihui Yanga
Keyword(s):  
Thermal Conductivity ◽  
Low Temperature ◽  
Temperature Dependence ◽  
Hall Effect ◽  
Hall Coefficient ◽  
Lower Energy ◽  
Electronic Configuration ◽  
Ni Doping ◽  
Measured Resistivity ◽  
Tetravalent State

ABSTRACTThe effect of Ni doping on the Co site of the binary skutterudite CoSb3 is investigated. We measured resistivity, Hall effect, magnetoresistance, thermopower, thermal conductivity, and magnetization of a series of samples of the form Co1-xNixSb3 with x in the range x=0 to x=0.01. We find that Ni takes the tetravalent state Ni4+, assumes the d6 electronic configuration for the lower energy non-bonding orbitals, and gives an electron to the conduction band. Ni doping dramatically suppresses the thermal conductivity, changes the temperature dependence of the thermopower, and increases the carrier concentration. Low temperature anomalies in thermopower, Hall coefficient and magnetoresistance are found.

scholarly journals Ruthenium redox equilibria: 2. Thermodynamic analysis of disproportionation and comproportionation conditions

2016 ◽  
Vol 6 (1) ◽  
pp. 135 ◽  
Author(s):  
Igor Povar ◽  
Oxana Spinu
Keyword(s):  
Linear Algebra ◽  
Thermodynamic Analysis ◽  
Metal Ion ◽  
Ph Value ◽  
Total Concentration ◽  
Chemical Species ◽  
Heterogeneous Chemical ◽  
Valence States ◽  
Degree Of Oxidation ◽  
Redox Equilibria

<p class="PaperKeywordTitle"><em>The key property of Frost diagram has been confirmed using thermodynamic and linear algebra methods. On the basis of the thermodynamic data, the areas of thermodynamic stability of ruthenium chemical species in different valence states as a function of pH for each degree of oxidation have been determined. Subsequently, based on the </em><em> diagrams, calculated for several values of pH, a narrow </em>Δ<em>pH value is determined, in which the dismutation of appropriate form takes place. Based on thermodynamic analysis, the exact </em><em> value of the beginning of disproportionation (or comproportionation) is found. Finally, the developed revised Frost diagrams of ruthenium heterogeneous chemical and redox equilibria, as a function of pH and the total concentration of metal ion in solution, have been built. </em></p>

scholarly journals An X-ray Absorption Near-Edge Structure (XANES) Study on the Oxidation State of Chromophores in Natural Kunzite Samples from Nuristan, Afghanistan

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 463
Author(s):  
Habib Ur Rehman ◽  
Gerhard Martens ◽  
Ying Lai Tsai ◽  
Chawalit Chankhantha ◽  
Pinit Kidkhunthod ◽  
...  
Keyword(s):  
Oxidation State ◽  
Inductively Coupled Plasma ◽  
Oxidation States ◽  
Transition Elements ◽  
Edge Structure ◽  
X Ray ◽  
Inductively Coupled ◽  
Valence States ◽  
Icp Ms ◽  
X Ray Absorption

Kunzite, the pink variety of spodumene is famous and desirable among gemstone lovers. Due to its tenebrescent properties, kunzite always remains a hot research candidate among physicists and mineralogists. The present work is continuing the effort towards value addition to kunzite by enhancing its color using different treatments. Before color enhancement, it is essential to identify the chromophores and their oxidation states. In this paper, the authors investigated the main impurities in natural kunzite from the Nuristan area in Afghanistan and their valence states. Some impurities in the LiAlSi2O6 spodumene structure were identified and quantified by using sensitive techniques, including Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS), UV−VIS and X-ray absorption near-edge structure (XANES). LA-ICP-MS indicated many trace elements as impurities in kunzite, among which Fe and Mn are the main elements responsible for coloration. The oxidation states of these two transition elements were determined by the XANES technique. The study reveals that Mn is present in both Mn2+ and Mn3+ oxidation states, while Fe is present only in Fe3+ oxidation state.

New molecular compounds of the layer lattice type. III. The intercalation of metal sulphides and oxides in graphite

1956 ◽  
Vol 9 (2) ◽  
pp. 201 ◽  
Author(s):  
RC Croft
Keyword(s):  
Electronic Configuration ◽  
Type Iii ◽  
Lattice Type ◽  
Valence States ◽  
Molecular Compounds

It has been shown that a number of sulphides and oxides of multivalent metals can be intercalated in graphite. The results of this investigation support the conclusion, reached in Part II of this series (Croft 1956a), that the electronic configuration of the cation of a compound determines the possibility of its intercalation, and that the nature of the anion has little significance. As in the case of chlorides reported in Part I of this series (Croft 1956b), the cations of intercalated sulphides and oxides are in higher valence states.

scholarly journals Distribution of mixed-valence ions in Mn1+xFe2-xO4ferrites

2014 ◽  
Vol 70 (a1) ◽  
pp. C1354-C1354
Author(s):  
Yoshio Aoyagi ◽  
Maki Okube ◽  
Satoshi Sasaki
Keyword(s):  
Magnetic Moments ◽  
Mixed Valence ◽  
Site Occupancy ◽  
Resonant Scattering ◽  
Electronic Configuration ◽  
Site Preference ◽  
Careful Study ◽  
Intensity Measurements ◽  
Valence States ◽  
A Site

Mn ferrite has a spinel structure to show the ferrimagnetism, where the magnetic moments show a collinear ferrimagnetic ordering between tetrahedral A and octahedral B sites. Since Mn2+ and Fe3+ have the same electronic configuration, it is not easy to determine the cation distribution of Mn ferrite from usual magnetization measurements. Especially in Mn ferrite, both Mn2+ and Fe3+ have a large spin polarization to give strong magnetic moments through the super exchange interaction between the two sites. Replacing Fe3+ by Mn2+ and Mn4+, the ferrimagnetic property weakens through magnetic balance between the sites. Since Mn and Fe ions may have multiple valences in the oxide structure, the scheme of site preference, based on careful study of various valence states, has been investigated for Mn1+xFe2-xO4. Single crystals for Mn1+xFe2-xO4 (x = 0.05, 0.20, 1.36 and 1.50) were synthesized from stoichiometric proportions of Mn3O4 and Fe3O4 in an evacuated silica capsule at 1353 K for 96 h. Each of spherical or parallel-piped crystals, ranging 0.05 to 0.08 mm, was mounted on the glass fiber. Conventional intensity measurements were made using a Rigaku AFC-5S four-circle diffractometer with a graphite (002) monochromator for Mo Kα radiation. Least-squares refinements were made to obtain atomic parameters, converged with R factors ranging 0.023 to 0.029. The site occupancy of Mn and Fe atoms was then determined on the basis of the resonant scattering effect at the Fe K absorption edge (λ = 1.7535 Å), by using a vertical-type four-circle diffractometer at PF-BL-10A. The results show that 89, 82, 100 and 100 percent of Mn atoms occupy the A site for the four samples, respectively. In the third step of analyses, absorption experiments were performed at PF-BL-6C. XANES and XMCD spectra were used at Mn and Fe K edges for determining the valence states of Mn and Mn ions. Finally, the distribution of mixed-valence ions for Mn1.20Fe1.80O4 was determined by the valence-difference contrast method, where the intensity data were collected for a spherical single crystal of 0.08 mm in a diameter at both threshold and pre-edge regions of Mn K edge, by using an AFC-5u four-circle diffractometer installed in PF-BL-6C. The site occupancy with the valence state will be discussed in the presentation, compared with the other type of transition-metal ferrites.

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