LUDWIG MOND LECTURE. High-carat Gold Compounds

摘要

The title of this lecture was chosen in an attempt to catch the eye of the large majority of potential readers, who probably have a genuine interest in gold, but perhaps less so in the chemistry of gold. 'Carat' is the traditional measure of the gold content of alloys which are used for coins, jewellery and objects of art and cult, in dentistry and in engineering. 'High-carat gold' thus has been an emblem of wealth and culture throughout the history of mankind. The most common secondary components of gold alloys are the congeners copper and silver, but also, e.g. palladium or - more recently - titanium. The composition of the alloy determines the colour and malleability of the metal, its corrosion- and wear-resistance, and other physical properties. The cubic close-packed structure of pure gold changes gradually at first as gold atoms are substituted by other metal atoms in the lattice, but eventually the structure changes more fundamentally.