Microcalorimetric studies. Thermal decomposition and iodination of metal carbonyls

1972 ◽  
Vol 68 (0) ◽  
pp. 1754 ◽  
Author(s):  
J. A. Connor ◽  
H. A. Skinner ◽  
Y. Virmani
Keyword(s):  
Thermal Decomposition ◽  
Metal Carbonyls

Theoretical views on Szilard Chalmers reactions in solid systems. II. Parent reformation by billiard-ball collisions

1968 ◽  
Vol 46 (20) ◽  
pp. 3201-3209 ◽  
Author(s):  
W. H. Wong ◽  
D. R. Wiles
Keyword(s):  
Experimental Data ◽  
Thermal Decomposition ◽  
Initial Energy ◽  
Projectile Energy ◽  
Metal Carbonyls ◽  
Present Stage ◽  
Complex Ions ◽  
Billiard Ball ◽  
Lower Limits ◽  
Mathematical Operations

The problem of billiard-ball replacement reactions of atoms centrally located in the molecule has been approached, using the approximation of simple two-body collisions. The reentry process has been separated into steps which can be handled by straightforward mathematical operations. Collision diameters for given energy transfer were calculated using an exponentially screened potential.Species treated include dicyclopentadienyl metals, arene metal carbonyls, and hexacoordinated complex ions, although the method is applicable to many other types of compound. An important result is that the probability of successful billiard-ball replacement is not sensitive to the initial energy, as long as this is not too low. It is concluded that this method is, at its present stage, most useful in calculating lower limits for billiard-ball reformation by following the projectile energy down to ca. 100 eV. Below this energy it is considered that thermal decomposition of the reformed molecule is likely. Results of the calculation are compared with experimental data, and further experiments are suggested by which the contribution of billiard-ball collisions may be directly assessed.

Thermal decomposition of metal carbonyls on oxide supports containing surface hydrides: A route to highly dispersed metal catalysts with unusual properties

1989 ◽  
Vol 55 (1) ◽  
pp. 235-258 ◽  
Author(s):  
A.S. Lisitsyn ◽  
A.V. Golovin ◽  
A.L. Chuvilin ◽  
V.L. Kuznetsov ◽  
A.V. Romanenko ◽  
...  
Keyword(s):  
Thermal Decomposition ◽  
Metal Catalysts ◽  
Metal Carbonyls ◽  
Oxide Supports ◽  
Highly Dispersed

Applications of Photoelectron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 506-507
Author(s):  
William J. Baxter
Keyword(s):  
Electron Microscopy ◽  
Thermal Decomposition ◽  
Chemical Composition ◽  
Ultraviolet Radiation ◽  
Thin Layer ◽  
Edge Effects ◽  
Electron Optics ◽  
Surface Layers ◽  
Crystalline Orientation ◽  
Fluorescent Screen

In this form of electron microscopy, photoelectrons emitted from a metal by ultraviolet radiation are accelerated and imaged onto a fluorescent screen by conventional electron optics. image contrast is determined by spatial variations in the intensity of the photoemission. The dominant source of contrast is due to changes in the photoelectric work function, between surfaces of different crystalline orientation, or different chemical composition. Topographical variations produce a relatively weak contrast due to shadowing and edge effects.Since the photoelectrons originate from the surface layers (e.g. ∼5-10 nm for metals), photoelectron microscopy is surface sensitive. Thus to see the microstructure of a metal the thin layer (∼3 nm) of surface oxide must be removed, either by ion bombardment or by thermal decomposition in the vacuum of the microscope.

Preparation and characterisation of vanadium pentoxide supported rhodium catalyst

1988 ◽  
Vol 46 ◽  
pp. 946-947
Author(s):  
A. Legrouri
Keyword(s):  
Aqueous Solution ◽  
Thermal Decomposition ◽  
Physicochemical Properties ◽  
Surface Area ◽  
Vanadium Pentoxide ◽  
High Purity ◽  
Gas Adsorption ◽  
Rhodium Catalyst ◽  
Optical Methods ◽  
Reducible Oxides

The industrial importance of metal catalysts supported on reducible oxides has stimulated considerable interest during the last few years. This presentation reports on the study of the physicochemical properties of metallic rhodium supported on vanadium pentoxide (Rh/V2O5). Electron optical methods, in conjunction with other techniques, were used to characterise the catalyst before its use in the hydrogenolysis of butane; a reaction for which Rh metal is known to be among the most active catalysts.V2O5 powder was prepared by thermal decomposition of high purity ammonium metavanadate in air at 400 °C for 2 hours. Previous studies of the microstructure of this compound, by HREM, SEM and gas adsorption, showed it to be non— porous with a very low surface area of 6m2/g3. The metal loading of the catalyst used was lwt%Rh on V2Q5. It was prepared by wet impregnating the support with an aqueous solution of RhCI3.3H2O.

Observations of the Thermal Decomposition of Brucite

1968 ◽  
Vol 26 ◽  
pp. 446-447
Author(s):  
P. L. Burnett ◽  
W. R. Mitchell ◽  
C. L. Houck
Keyword(s):  
Thermal Decomposition ◽  
Magnesium Oxide ◽  
Basal Plane ◽  
Magnesium Ions ◽  
A Value ◽  
Reaction Proceeds

Natural Brucite (Mg(OH)2) decomposes on heating to form magnesium oxide (MgO) having its cubic ﹛110﹜ and ﹛111﹜ planes respectively parallel to the prism and basal planes of the hexagonal brucite lattice. Although the crystal-lographic relation between the parent brucite crystal and the resulting mag-nesium oxide crystallites is well known, the exact mechanism by which the reaction proceeds is still a matter of controversy. Goodman described the decomposition as an initial shrinkage in the brucite basal plane allowing magnesium ions to shift their original sites to the required magnesium oxide positions followed by a collapse of the planes along the original <0001> direction of the brucite crystal. He noted that the (110) diffraction spots of brucite immediately shifted to the positions required for the (220) reflections of magnesium oxide. Gordon observed separate diffraction spots for the (110) brucite and (220) magnesium oxide planes. The positions of the (110) and (100) brucite never changed but only diminished in intensity while the (220) planes of magnesium shifted from a value larger than the listed ASTM d spacing to the predicted value as the decomposition progressed.

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