The Platinum Metals

Powell, A. R.

doi:10.1038/172700a0

Cited by 3 publications

(2 citation statements)

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“…Such a mechanism is known for platinum. 21 The insensitivity of evaporation rate to oxygen pressure would imply a virtually complete coverage by oxygen, while the fact that evaporation rate is independent of time and of filament purity would follow if the amount of impurity was insufficient appreciably to reduce the effective reaction area. Investigation by electron-diffraction and by cathodic reduction failed 22 to produce any evidence of an oxide of gold on the surface of the filaments.…”

Section: Discussionmentioning

confidence: 99%

The interaction of oxygen and hot gold. Part 1

Carpenter¹,

Mair²,

Gilbey³

1959

Trans. Faraday Soc.

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The behaviour of hot gold filaments, in vacuum and in oxygen at pressures of a few microns of mercury, has been studied. Two main effects were observed-the disappearance of gaseous oxygen and a rate of evaporation of gold considerably greater in oxygen than in vacuum.The rate of disappearance of oxygen ( E ) depended on the purity of the gold, but the amount which disappeared was too large to be explained as oxidation of impurities in the metal. The disappearance is attributed to an impurity-catalyzed conversion of oxygen molecules from the ground to the metastable lAg state, the 0; attacking the walls of the reaction vessel. E decreased as the walls became protected by a film of evaporated gold. The enhanced rate of evaporation of gold in 0 2 is attributed to the removal of an inhibiting surface film of impurity. In N2, E was zero and there was no enhanced evaporation of gold.The activation of molecular oxygen is discussed in appendix 1 by D. M. Gilbey. Appendix 2 by D. Clark reports on the structure of the evaporated gold deposits.

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Section: Discussionmentioning

confidence: 99%

The interaction of oxygen and hot gold. Part 1

Carpenter¹,

Mair²,

Gilbey³

1959

Trans. Faraday Soc.

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“…It was the first of Wollaston's several successful technological inventions, and is said to have yielded him £30,000. Although the process was probably perfected about 1805, it is not until some years later that large platinum vessels are known to have been used industrially (lb) (6) Thus in a letter to Samuel Parkes of Haggerston Chemical Works, London, Dr. Wollaston wrote in January 1812 (7) As it is now more than twelve months that you have been in irosessioii of your large vessel it may reasonably be supposed that you have full trial of its merits and I hope you will not think it unreasonable in me to request a few lines upon that subject, as it would gratify me to hear that it has fully answered your expectations ... if you would take the trouble of adding any further information on points of economy which I presume you have carefully estimated (saving of time, saving of fuel, saving of breakage, saving of labour) you would confer an additional favour on, Sir, your most obedient humble servant, Wm. H. Wollaston.…”

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William Hyde Wollaston: The man and his "equivalents"

Hinde¹

1966

J. Chem. Educ.

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Geología económica del Chocó. Bibliografía geológica–minera del Chocó

Wokittel

1959

Bol.geol.

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De los 16 departamentos de Colombia, el Chocó es uno de los más extensos, pero figura en el último puesto en lo que se refiere a la población. En su territorio, de 47 468 km2, vivían en 1955 aproximadamente 138 000 habitantes, lo cual corresponde a una densidad de 2,9 habitantes por km2, siendo la densidad para el conjunto de los 16 departamentos de 24, y de 11 para el territorio total de Colombia, incluyendo las Intendencias y Comisarías. El territorio del Chocó, limitado en el Oriente en parte por la cresta de la cordillera Occidental y en parte por el río Atrato, se extiende al Occidente hasta el Océano Pacífico comprendiendo las hoyas ele los ríos Atrato y San Juan, y las Serranías ele Baudó y de la Costa Pacífica, y al Norte hasta el Océano Atlántico. En la parte norocciclental limita con la República ele Panamá.

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The Platinum Metals

Cited by 3 publications

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The interaction of oxygen and hot gold. Part 1

The interaction of oxygen and hot gold. Part 1

William Hyde Wollaston: The man and his "equivalents"

Geología económica del Chocó. Bibliografía geológica–minera del Chocó

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