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.

New molecular compounds of the layer lattice type. I. New molecular compounds of graphite

1956 ◽  
Vol 9 (2) ◽  
pp. 184 ◽  
Author(s):  
RC Croft
Keyword(s):  
Molecular Shape ◽  
Test Substance ◽  
Type I ◽  
Compound Formation ◽  
Metal Chlorides ◽  
Lattice Type ◽  
Valence States ◽  
Graphite Intercalation ◽  
Molecular Compounds

An extension of previous work (Croft 1952) on molecular compounds of graphite has led to the discovery of over 30 new molecular compounds of the layer lattice type. In addition, the experimental data revealed some necessary conditions for compound formation. Thus, intercalation was found to be most probable with multivalent chlorides of the transition metals, but only when the latter are in their higher valence states. Chlorides of all Group IIIA elements can also form molecular compounds with graphite. Intercalation is related to the position of the cation of the test substance in the periodic table. Molecular shape, polarity, and the covalent nature of the test substance have little, if any, relation to its reactivity with graphite. Graphite compounds formed from Group IIIA chlorides are distinguished from those containing transition metal chlorides by the possibility of hydrolysing intercalated cations of the former but not those of the latter. The metal cations of graphite-ZrCl4 and graphite-YCl3 are also capable of hydrolysis in situ. The results of this investigation suggest the possibility of employing graphite compound formation to effect many chemical separations and purifications.

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.

New molecular compounds of the layer lattice type. II. Theory of formation of graphite compounds

1956 ◽  
Vol 9 (2) ◽  
pp. 194 ◽  
Author(s):  
RC Croft
Keyword(s):  
Electronic Interaction ◽  
Metal Chlorides ◽  
Electron Pairs ◽  
Valence States ◽  
Other Substances ◽  
Electronic Configurations ◽  
Theoretical Considerations ◽  
Hydrolysis Of ◽  
Molecular Compounds

Experimental results given in Part I of this series (Croft 1956a) have been examined theoretically with particular attention given to finding reasons for the specificity shown by graphite towards various chlorides. This specificity cannot be accounted for in terms of "molecular sieving" or polar interaction. It is suggested that intercalation involves transfer of electrons from the conducting band of graphite to cations of reactive chlorides. Intercalation of transition metal chlorides can be correlated with possession of unsaturated penultimate electron shells by the cations concerned. However, correlation is only complete when the cations exhibit maximum electron affinities, as in their higher valence states. Reaction of Group IIIA chlorides appears due to accommodation of electron pairs from the π band of graphite in n(p) orbitals (or their hybrids) of the cations. The distinctive hydrolysis of these chlorides in situ indicates that graphite is a weaker donor than water. Similar consideration of unreactive chlorides indicates that they are not intercalated because their cations are incapable of electronic interaction with graphite. Several important conclusions, supported experimentally in Parts III and IV of this series (Croft 1956b, 1956c), have been drawn from these theoretical considerations. Firstly, since intercalation depends on electronic configurations of cations, any compound containing a suitable cation should be capable of intercalation in graphite irrespective of the anion associated with it. Secondly, provided they satisfy two conditions, other substances should be capable of intercalating foreign compounds in a similar manner to graphite. The necessary conditions are that a host substance is able to interact electronically with an intercalated substance, and that it must afford physical accommodation for the latter. The potential value of graphite reactions, in elucidating fundamental problems, is also discussed.

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.

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.

Some Observations on Changes in Denervated Taste Buds of Circumvallate Papillae of Rabbits

1969 ◽  
Vol 27 ◽  
pp. 308-309
Author(s):  
Sunao Fujimoto ◽  
Raymond G. Murray ◽  
Assia Murray
Keyword(s):  
Taste Buds ◽  
Taste Bud ◽  
Cell Type ◽  
Dark Cells ◽  
Type Iii ◽  
Circumvallate Papillae ◽  
Taste Bud Cells ◽  
Light Cells

Taste bud cells in circumvallate papillae of rabbit have been classified into three groups: dark cells; light cells; and type III cells. Unilateral section of the 9th nerve distal to the petrosal ganglion was performed in 18 animals, and changes of each cell type in the denervated buds were observed from 6 hours to 10 days after the operation.Degeneration of nerves is evident at 12 hours (Fig. 1) and by 2 days, nerves are completely lacking in the buds. Invasion by leucocytes into the buds is remarkable from 6 to 12 hours but then decreases. Their extrusion through the pore is seen. Shrinkage and disturbance in arrangement of cells in the buds can be seen at 2 days. Degenerated buds consisting of a few irregular cells and remnants of degenerated cells are present at 4 days, but buds apparently normal except for the loss of nerve elements are still present at 6 days.

Methionine-Specific Staining of Collagen

1982 ◽  
Vol 40 ◽  
pp. 294-295
Author(s):  
E.M. Kuhn ◽  
K.D. Marenus ◽  
M. Beer
Keyword(s):  
Amino Acids ◽  
Collagen Fibers ◽  
Type Iii Collagen ◽  
Type I ◽  
Electron Microscopic ◽  
Good Correspondence ◽  
Specific Staining ◽  
Type Iii ◽  
Different Types ◽  
Sulfur Containing

Fibers composed of different types of collagen cannot be differentiated by conventional electron microscopic stains. We are developing staining procedures aimed at identifying collagen fibers of different types.Pt(Gly-L-Met)Cl binds specifically to sulfur-containing amino acids. Different collagens have methionine (met) residues at somewhat different positions. A good correspondence has been reported between known met positions and Pt(GLM) bands in rat Type I SLS (collagen aggregates in which molecules lie adjacent to each other in exact register). We have confirmed this relationship in Type III collagen SLS (Fig. 1).

Labelling of non-A, non-B hepatitis infected chimpanzee hepatocytes with nuclease-gold conjugates

1984 ◽  
Vol 42 ◽  
pp. 250-251
Author(s):  
G. D. Gagne ◽  
M. F. Miller ◽  
D. A. Peterson
Keyword(s):  
Endoplasmic Reticulum ◽  
Experimental Infection ◽  
Uranyl Acetate ◽  
Type I ◽  
Cellular Injury ◽  
Type Ii ◽  
Tubular Structures ◽  
Type Iii ◽  
Type Iv ◽  
Infected Chimpanzee

Experimental infection of chimpanzees with non-A, non-B hepatitis (NANB) or with delta agent hepatitis results in the appearance of characteristic cytoplasmic alterations in the hepatocytes. These alterations include spongelike inclusions (Type I), attached convoluted membranes (Type II), tubular structures (Type III), and microtubular aggregates (Type IV) (Fig. 1). Type I, II and III structures are, by association, believed to be derived from endoplasmic reticulum and may be morphogenetically related. Type IV structures are generally observed free in the cytoplasm but sometimes in the vicinity of type III structures. It is not known whether these structures are somehow involved in the replication and/or assembly of the putative NANB virus or whether they are simply nonspecific responses to cellular injury. When treated with uranyl acetate, type I, II and III structures stain intensely as if they might contain nucleic acids. If these structures do correspond to intermediates in the replication of a virus, one might expect them to contain DNA or RNA and the present study was undertaken to explore this possibility.

Valence state analysis of elements by EPMA and its application

1990 ◽  
Vol 48 (2) ◽  
pp. 230-231
Author(s):  
Chen Liqing ◽  
Liu Zuqin ◽  
Zhang Wei
Keyword(s):  
Valence State ◽  
Line Intensities ◽  
Valence States ◽  
Valence Electrons ◽  
Fe And Mn ◽  
Intensity Ratios ◽  
State Analysis

Valence state analyses of Fe and Mn in oxides by EPMA have been reported in literature. In this paper, the effects of valence state on intensity ratios ILα/IKα and ILα/ILβ of Cu, Ni, Co, Fe, Mn, Cr and their oxides, and on intensity ratios ILβ2/ILα1 and ILγ1/ILα1 of Mo, Nb, Zr and their oxides were studied. It was observed that intensity ratios change with valence states in accordance with some regularities, and these effects could be utilized for analyzing the valence states of catalysts.Valence state analysis of elements by EPMA is based on the fact that changes in the states of valence electrons in the outer shells of an atom cause corresponding changes in line intensities. The M electrons of Cu, Ni, Co, Fe, Mn, Cr and the N electrons of Mo, Nb, Zr are valence electrons. Line Kα1,2 and six lines of L are produced from the transitions of K-L2,3 and L-M or L-N respectively.

Sign in / Sign up

Export Citation Format

Share Document