Showing papers on "Oxidation state published in 1973"

X-Ray photoelectron spectroscopy of chromium–oxygen systems

Abstract: X-Ray photoelectron spectroscopy has been used to study a series of chromium–oxygen compounds. It has been shown that the ionisation energy of the chromium 2p electrons is dependent primarily on the oxidation state of the chromium metal ion, but that small perturbations may be attributed to changes in crystal structure and hence the Madelung potential. Multiplet splitting in chromium(III) compounds contributes to peak widths, and the chemisorption of water and oxygen has a marked effect on the observed peak profiles. In addition such chemisorption apparently contributes to the build up of surface charge, thereby complicating the precise determination of binding energies.

µ3-Oxotrimetal acetato-complexes of chromium, manganese, iron, cobalt, rhodium, and iridium

Abstract: New pyridine- and β-picoline-containing oxo-centred complex ions [M3IIIO(CO2Me)6L3]+, M = Cr, Mn, Fe, Co, Rh, and Ir, L = py and β-pic, were synthesised and their redox behaviour studied electrochemically. There is evidence for reduced species in which the oxo-centred triangular structure is maintained in the case of the Mn, Fe, and Co complexes but these could not be isolated. For iridium, complexes [Ir3III,III,IVO(CO2Me)6L3]+2 in which the metal atom is in the mean oxidation state 3⅓ have also been characterised and shown to undergo reduction to the IrIII species. Attempts to prepare oxo-centred complexes of Cu, Ag, Ni, Pd, Pt, and Mo were unsuccessful. The cobalt complex ion [Co3O(CO2Me)6L3]+ appears to be different from the other oxo-centred ions and a structure with both bridging and chelate acetato-groups is proposed.

The Loose Connection between Electron Configuration and the Chemical Behavior of the Heavy Elements (Transuranics)

Abstract: There is no straightforward relation between the ground electron configuration of the neutral atom and the chemistry of a given element. In particular, the choice of oxidation state depends on the comparison between consecutive ionization energies of the gaseous ions and the hydration energy or Madelung energy which by preference stabilizes increased oxidation numbers. Special ligands, such as oxide, may introduce unexpectedly high oxidation numbers. The baricenters of electron configurations are discussed with vanadium and thorium as specific examples. The chemistry of the elements with Z = 101, 102, 103, 104, 105, and 112 (of which some thousand atoms have been reported) and the (yet unknown) elements with Z=108, 109, 114, 126, 164, and 184 is discussed.

Mössbauer study of quinquevalent gold compounds

Abstract: The recently synthesized Au(V) complex fluorides of the form A+ AuF6− with A = Xe2F11+, XeF5+, and Cs+ have been studied by Mossbauer spectroscopy with the 77.3 keV gamma resonance of 197Au. The values obtained for isomer shift and electric quadrupole interaction are in harmony with the assigned oxidation state Au(V), as well as with the octahedral shape of the AuF6− anion.

Oxidation-reduction process

Abstract: The instant invention relates to a process for changing the oxidation state of a compound or ionic species preferably a dissolved ionic species, and the novel electrochemical cell utilized therein. In the instant process, the compound or ionic species is passed through a porous electrode, which is maintained at a voltage sufficient to change the oxidation state of said compound or ionic species. This process is especially useful for oxidation-reduction processes, wherein said species is an ion having the same charge as the porous electrode. The porous electrode is isolated from the oppositely charged electrode by a semipermeable membrane, said membrane being impermeable to said dissolved species. In a much preferred embodiment, the dissolved species is chromium in the +3 oxidation state, e.g., the chromium available in chromic acid solutions which have been "used" in plastic etching processes or in processes for the oxidation of organic compounds; and the membrane is fluoro sulfonic acid membrane. In this embodiment the "used" chromic acid solutions may be substantially regenerated and cycled for reuse in the above-mentioned processes. The porous anode preferably used in the regeneration of chromic acid solutions comprises a lead alloy or compound.

Mössbauer spectroscopic studies of iron-doped rutile

Abstract: Moessbauer spectra were obtained of single crystal and powdered samples of rutile (TiO2) doped to about one percent by weight in isotopically enriched iron. It is shown that the oxidation state may be reversibly altered in situ. After reduction, the oxygen neighbors of the dopant ion are apparently shifted to accomodate the larger ferrous ion. The agreement of calculated quadrupole splittings with experimental results suggests that impurities and oxygen vacancies are uniformly distributed in powdered samples, giving the dopant ions an 'ideal lattice' local environment. The differences between the single crystal and powder sample hyperfine parameters are attributed to variations in stoichiometry, charge compensation mechanisms, or other diffusion related parameters.

X-Ray photoelectron spectra of compounds containing rhodium–halogen bonds and of rhodium(II) acetate and its derivatives: rhodium 3d and halogen np binding energies

Abstract: Rhodium 3d3/2 and 3d5/2 electron binding energies have been recorded for a series of complexes containing rhodium in the formal oxidation states + 3, + 2, and + 1. The 3d5/2 binding energies were observed to vary over a range of 2·8 eV and for the rhodium(III) complexes these were fairly sensitive to the ligand environment, but little variation was found for adducts of Rh2(OAc)4. In general, there is a decrease in the 3d binding energies with decrease in oxidation state provided comparisons are made within related series of complexes. The chlorine 2p, bromine 3p, and iodine 3d binding energies have also been recorded for several of these complexes.

Mixed Oxidation States and Averaged Electronic Environments in Iron Compounds

Abstract: A survey of the iron-57 Mossbauer spectroscopy of a variety of mixed valence compounds is presented. The systems discussed are grouped into two broad categories: highly covalent iron-sulfur systems and coordination compounds exhibiting a range of covalency. Correlations of intermediate values of the chemical isomer shift as well as average ironligand bond distance with electron exchange and oxidation state averaging are considered.

Preparation and crystal structure of the Hg42+ ion

Abstract: The compound Hg4(AsF6)2 containing mercury in the oxidation state of +½ has been obtained from the reaction of mercury with arsenic pentafluoride in liquid SO2; the Hg42+ ion is shown by X-ray methods to be very nearly linear with Hg–Hg distances of 2·57 and 2·70 A.

Fluorine compounds of nickel(III)

Abstract: Nickel(III) fluoride is formed by the reaction of K2NiIVF6 with AsF5 in HF. In the absence of AsF5, K2NiIVF6, and K3NiIIIF6 yield insoluble products, in which the nickel oxidation state varies between 2·00 and 2·50, and the soluble NiF62– species. Direct fluorination of nickel salts at 200 °C yields NiF2·1. The nature of NiIII in a fluoride environment is discussed.

The blue supersulphide ion, S2–

Abstract: Spectroscopic investigations into solutions of alkali polysulphides in dimethylformamide showed that the formal oxidation state of the species giving rise to the intense blue colour of these solutions is –½. With the actual charge found to be one half of that of a polysulphide ion, the species is identified as the supersulphide ion, S2–.

Mixed-valence complexes of vanadium with 1,10-phenanthroline and 2,2′-bipyridine

Abstract: The electronic structures of some intense purple vanadium complexes, initially formulated as [L2VIII(OH)2VIIIL2]4+[L = 1,10-phenanthroline(phen) or 2,2′-bipyridine(bipy)] have been investigated. The complexes were isolated as the sulphate or mixed hexafluorophosphate–chloride salts. Electronic spectra and magnetic and e.s.r. measurements show that the complexes are novel examples of binuclear mixed-valence species, containing vanadium in the oxidation states II and III bridged, probably, by a hydroxo-group. Characteristic visible bands of high intensity were observed at 16 000 and 19 000 cm–1 and arise because of intervalence electron transfer. Vanadium 2p3/2 and 3p binding energies, obtained from X-ray photoelectron spectra, are characteristic of oxidation states of III and below. Individual bands due to more than one oxidation state of vanadium could not be detected with certainty, though some broadening was observed.

Higher oxidation state iron and cobalt phthalocyanine derivatives. Phthalocyanine radical cation complexes

Abstract: Reaction of cobalt(II) phthalocyanine (CoPc) with thionyl chloride and with bromine leads to the formation of CoPcCl2 and CoPcBr2, respectively; magnetic i.r., oxidative titration, and e.s.r. data indicate these complexes to contain a phchalocyanine radical species, characterised in the solid state for the first time.

Chemical approach to the radiolysis of polyphosphate glass. I. Effects of Sb(III,V), Mo(V,VI) and U(IV,VI) ions

Abstract: The yields of radiation-induced electrons and holes trapped in the glass matrix are easily determined by introducing metal ions, such as Sb, Mo, and U ions, into water-soluble NaPO3 polymer glass. Doping 1 mol % of these ions of a lower oxidation state wholly prevents the trapping of holes and results in oxidation to their higher oxidation states. A reaction in the reverse direction also occurs for the same ions of a higher oxidation state, which are converted into a lower one by reduction. This radiation-induced redox reaction has a minimum yield at a dopant composition corresponding to Sb2O4 for Sb(III)–Sb(V), Mo6O17 for Mo(V)–Mo(VI), and U3O8 for U(IV)–U(VI) redox couples. The largest effective volume among these ions for capturing the holes is for Sb(III). In a high-dose region (1020 to 1021 eV/g), the yields of the redox products of these ions increase logarithmically with the γ-dose absorbed. This makes it difficult to determine the G-value of the redox products precisely. The approximate values are...

An Electron Spin Resonance Study of the Reaction of Nitrogen Dioxide with Metal Acetylacetonates

Abstract: The reaction of nitrogen dioxide with several metal acetylacetonates was studied by electron spin resonance. Those metal complexes that have stable lower oxidation state, (i.e. Cu(II), Fe(III), Co(...

X‐ray photoelectron spectroscopy of chromium‐oxygen systems

Abstract: X-Ray photoelectron spectroscopy has been used to study a series of chromium–oxygen compounds. It has been shown that the ionisation energy of the chromium 2p electrons is dependent primarily on the oxidation state of the chromium metal ion, but that small perturbations may be attributed to changes in crystal structure and hence the Madelung potential. Multiplet splitting in chromium(III) compounds contributes to peak widths, and the chemisorption of water and oxygen has a marked effect on the observed peak profiles. In addition such chemisorption apparently contributes to the build up of surface charge, thereby complicating the precise determination of binding energies.

A Mössbauer Study of the Oxidation State of 119Sn after the Successive EC Decays of 119mTe in Telluric Acid

Abstract: We have been studying the chemical state of Sn after EC decay of 38.0 h Sb in a variety of matrices by Môssbauer emission spectroscopy [1-4]. Use of 4.7 days Te (a parent nuclide of Sb) makes it possible to study the chemical state of Sn arising in matrices with hexa valent cations. This paper describes the experimental result on Sn produced by the successive EC decays of Te via Sb in telluric acid. The procedures for producing Te and for preparing HeTeOe were previously described [5]. The telluric acid samples obtained by the procedure were mainly in the cubic modification with an admixture of several percent of monoclinic form. The samples were let stand at liquid nitrogen temperature for about 2 weeks in order to allow the Sb to attain a state of radioactive equilibrium with Te. The Môssbauer emission spectra of the HeTeOe samples were then measured at liquid nitrogen temperature by means of a Hitachi-Mössbauer spectrometer operated in the constant acceleration mode. The absorber was BaSnOa (0.6 mg Sn/cm) maintained at room temperature. The 23.8 keV Môssbauer y-rays were detected with a 2-mm Nal scintillation counter, Sn KX-rays being eliminated with an 80 μια Pd foil. The spectra obtained were least-squares fitted to a sum of Lorentzians by means of a FACOM 270-30 computer of the Institute. A typical spectrum obtained is shown in Fig. 1. As can be seen in the figure, the Sn emission spectra of HeTeOe consisted of a broad peak centered near the zero relative velocity, which shows that the Sn atoms are in the Sn(IV) state. The isomer shift of the emission line was 0.02 ± 0.05 mm/sec relative to BaSn03, the sign being as in usual absorption spectra. The quadrupole splitting, computed on an assumption that the peak is a symmetric Lorentzian doublet, amounted to about 0.8 mm/sec. No emission line was observed which was attributable to Sn species other than Sn(IV) within the sensitivity of the measurement.

Synthesis and Properties of Polymers with Sulfur-Containing Functional Groups

Abstract: Owing to the fact that sulfur can exist in different oxidation states and that in each oxidation state it can form different functions, the number of different organic sulfur-containing compounds is very large. The compounds can be highly reactive or chemically inert. This article gives a review of the synthesis of polymers which contain the most common sulfur containing functional groups which are moderately or highly reactive. It also discusses the chemical reactions which have been carried out, with these polymers or gives some suggestions of potential uses.

The influence of cations on the formation of high oxidation state compounds of manganese in molten salts

Abstract: The reactions of various oxo compounds of manganese were examined in several melts and peroxide- and/or superoxide-melt solutions. Whilst MnO43- appears to be the most stable species in NaNO2 and Na2O2-NaNO2 solutions, the green MnO42- ion is favoured in KNO2 melts and also in nitrate melts in which K+ predominates over Na+.

The Intensity of Ligand Absorption

Abstract: The ultraviolet absorption spectra of a number of aryl phosphines and amines and transition metal complexes of triphenylphosphine have been determined. These data indicate that the intensity of the O* ¬ O phenyl ring transition is not only sensitive to the central atom attached to the ring but is also affected by the metal ion in the complex. Since the degree of covalency depends on the degree of back donation, the oxidation state of the metal ion was found to be the most important factor in determining the intensity of the absorption. The more covalent the metal-phosphine bond, the lower is the intensity of the O* ¬ O transition of the phenyl ring. The increase in the O* ¬ O absorption intensity can be explained in terms of a reduction of the phenyl ring symmetry from D6h to D2h or C2v.

Some Unusual Oxidation States of Antimony. A Mössbauer Investigation

Abstract: Compounds of antimony normally contain the element In either the III or the V oxidation state. Compounds containing these oxidation states give rise to 121Sb Mossbauer spectra yielding parameters which fall within reasonably well defined limits for each oxidation state. It has been clearly demonstrated by Stevens and Bowen at a previous Symposium1 that antimony in the III oxidation state has a chemical Isomer shift at velocities more negative than IpSb, while Sb (V) has a more positive chemical Isomer shift. The shape of the 121Sb resonance can also yield valuable Information about the antimony environment and both parameters taken together can provide an insight into the nature of the bonding in the compound being studied. Some of the earliest demonstrations of the power of the technique have been in proving that Sb204 contains both Sb (111) and Sb(V) rather than Sb (IV), and in showing that “Sb2S5” does not contain Sb (v), but is rather a Sb (III) polysulphide.2–4

Mixed-valence complexes of vanadium with 1,10-phenanthroline and 2,2′-bipyridine

Abstract: The electronic structures of some intense purple vanadium complexes, initially formulated as [L2VIII(OH)2VIIIL2]4+[L = 1,10-phenanthroline(phen) or 2,2′-bipyridine(bipy)] have been investigated. The complexes were isolated as the sulphate or mixed hexafluorophosphate–chloride salts. Electronic spectra and magnetic and e.s.r. measurements show that the complexes are novel examples of binuclear mixed-valence species, containing vanadium in the oxidation states II and III bridged, probably, by a hydroxo-group. Characteristic visible bands of high intensity were observed at 16 000 and 19 000 cm–1 and arise because of intervalence electron transfer. Vanadium 2p3/2 and 3p binding energies, obtained from X-ray photoelectron spectra, are characteristic of oxidation states of III and below. Individual bands due to more than one oxidation state of vanadium could not be detected with certainty, though some broadening was observed.