Reduction of manganate(VI) by mandelic acid and its significance for development of a general mechanism of oxidation of organic compounds by high-valent transition metal oxides

1993 ◽  
Vol 115 (24) ◽  
pp. 11231-11236 ◽  
Author(s):  
Donald G. Lee ◽  
Tao Chen
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Organic Compounds ◽  
Transition Metal Oxides ◽  
Mandelic Acid ◽  
General Mechanism ◽  
Oxidation Of Organic Compounds ◽  
Mechanism Of Oxidation ◽  
High Valent

Catalytic Effects of High-Valent Transition Metal Oxides on Different Carbonization Behaviours of Polyvinyl Alcohol

2017 ◽  
Vol 2 (29) ◽  
pp. 9450-9453 ◽  
Author(s):  
Qiao Hu ◽  
Jia-Ying Liao ◽  
Ran Yu ◽  
Zhong-Feng Tang ◽  
Chun-Hua Chen
Keyword(s):  
Transition Metal ◽  
Polyvinyl Alcohol ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
High Valent ◽  
Catalytic Effects

Oxidation of hydrocarbons. 12. Kinetics and mechanism of the oxidation of trans-cinnamic acid by ruthenate and perruthenate ions

1984 ◽  
Vol 62 (6) ◽  
pp. 1085-1092 ◽  
Author(s):  
Donald G. Lee ◽  
Stuart Helliwell
Keyword(s):  
Activation Energy ◽  
Transition Metal ◽  
Metal Oxides ◽  
Cinnamic Acid ◽  
Transition Metal Oxides ◽  
Theoretical Calculations ◽  
Kinetics And Mechanism ◽  
Oxidation Of Hydrocarbons ◽  
High Valent

Recent theoretical calculations by Rappé and Goddard have pointed to the importance of spectator oxo groups in stabilizing intermediates produced during the reduction of high-valent transition metal oxides; intermediates which contain triply-bonded metal oxo groups are predicted to be unusually stable. In an attempt to test these conclusions experimentally, the rates of oxidation of cinnamate ion by ruthenate and perruthenate ions have been studied. Since the most likely intermediate formed from perruthenate ion (but not ruthenate ion) would contain a stabilizing, triply-bonded spectator oxo group, it would be expected to react faster if the calculations are correct. In agreement with these predictions, it was found that the activation energy (ΔG‡) for the ruthenate reaction was about 7 kcal/mol higher than for the corresponding perruthenate reaction.

HREM Study of electron-induced surface radiation damage in ReO3

1991 ◽  
Vol 49 ◽  
pp. 636-637
Author(s):  
R. Ai ◽  
H.-J. Fan ◽  
L. D. Marks
Keyword(s):  
Transition Metal ◽  
Metal Ions ◽  
Metal Oxides ◽  
Electron Irradiation ◽  
Transition Metal Oxides ◽  
Carbon Film ◽  
Transition Metal Ions ◽  
Surface Radiation ◽  
Valence Transition ◽  
Electron Microscopes

It has been known for a long time that electron irradiation induces damage in maximal valence transition metal oxides such as TiO2, V2O5, and WO3, of which transition metal ions have an empty d-shell. This type of damage is excited by electronic transition and can be explained by the Knoteck-Feibelman mechanism (K-F mechanism). Although the K-F mechanism predicts that no damage should occur in transition metal oxides of which the transition metal ions have a partially filled d-shell, namely submaximal valence transition metal oxides, our recent study on ReO3 shows that submaximal valence transition metal oxides undergo damage during electron irradiation.ReO3 has a nearly cubic structure and contains a single unit in its cell: a = 3.73 Å, and α = 89°34'. TEM specimens were prepared by depositing dry powders onto a holey carbon film supported on a copper grid. Specimens were examined in Hitachi H-9000 and UHV H-9000 electron microscopes both operated at 300 keV accelerating voltage. The electron beam flux was maintained at about 10 A/cm2 during the observation.

Problems with oxygen analysis in the system MgO-Al2O3-SiO2 with the electron microprobe

1992 ◽  
Vol 50 (2) ◽  
pp. 1624-1625
Author(s):  
Michel Fialin ◽  
Guy Rémond
Keyword(s):  
Transition Metal ◽  
Metal Oxides ◽  
Transition Metal Oxides ◽  
Electrostatic Charge ◽  
Carbon Layer ◽  
Sample Holder ◽  
Rock Matrix ◽  
Electrical Discharges ◽  
Thin Carbon ◽  
Beam Instabilities

Oxygen-bearing minerals are generally strong insulators (e.g. silicates), or if not (e.g. transition metal oxides), they are included within a rock matrix which electrically isolates them from the sample holder contacts. In this respect, a thin carbon layer (150 Å in our laboratory) is evaporated on the sections in order to restore the conductivity. For silicates, overestimated oxygen concentrations are usually noted when transition metal oxides are used as standards. These trends corroborate the results of Bastin and Heijligers on MgO, Al2O3 and SiO2. According to our experiments, these errors are independent of the accelerating voltage used (fig.l).Owing to the low density of preexisting defects within the Al2O3 single-crystal, no significant charge buildup occurs under irradiation at low accelerating voltage (< 10keV). As a consequence, neither beam instabilities, due to electrical discharges within the excited volume, nor losses of energy for beam electrons before striking the sample, due to the presence of the electrostatic charge-induced potential, are noted : measurements from both coated and uncoated samples give comparable results which demonstrates that the carbon coating is not the cause of the observed errors.

scholarly journals Electronic Phenomena of Transition Metal Oxides

Crystals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 256
Author(s):  
Christian Rodenbücher ◽  
Kristof Szot
Keyword(s):  
Solid State ◽  
Transition Metal ◽  
Metal Oxides ◽  
Real World ◽  
Transition Metal Oxides ◽  
Major Research ◽  
Research Fields ◽  
Real World Applications

Transition metal oxides with ABO3 or BO2 structures have become one of the major research fields in solid state science, as they exhibit an impressive variety of unusual and exotic phenomena with potential for their exploitation in real-world applications [...]

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