Platinum Metals Review - Volume 10, Issue 3, 1966

Glass technologists are well aware of the advantages of cladding furnace refractories with platinum in order to avoid contamination. This article emphasises the even greater advantages to be obtained by giving careful thought to the design of the refractories to ensure that they are in the most suitable form for platinum cladding.

The nature of the bonds between catalyst surfaces and the adsorbed intermediates formed during catalytic reactions is still a matter for discussion. A recent symposium organised by the American Chemical Society was devoted to this subject, as well as a General Discussion of the Faraday Society held in Liverpool in April. Although many new techniques have become available and have been exploited during the past decade, they have only served to reveal a multiplicity of adsorbed states whose relevance to catalysis is uncertain, and there has been no corresponding advance in basic theory. The purpose of this article is to present a sketch of a possible new approach to the bonding of adsorbed species on metal surfaces.

The loss of weight of platinum heated in air is fortunately low, owing to the very low vapour pressure of the PtO2 that volatilises. This article reviews recent studies of heated platinum filaments which suggest that a viscous boundary layer of gas hinders escape of the PtO2 molecules that are formed. At atmospheric pressure 99.85 per cent of the molecules of PtO2 formed may be trapped in this layer.

In this paper the electronic structures of the elements of Group VIII of the Periodic Table are outlined, and the difference between the platinum metals and other metals in the group is emphasised. The constitution of the alloys of the platinum metals with silver and gold is then discussed, and an interpretation is offered. The alloying behaviour of the platinum metals with a number of transition metals is interpreted in terms of some recently established electron concentration principles.