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with contributions by numerous experts

with contributions by numerous experts

Mixed valency is one of various names used to describe compounds which contain ions of the same element in two different formal states of oxidation. The existence of mixed valency systems goes far back into the geological evolutionary history of the earth and other planets, while a plethora of mixed valency minerals has attracted attention since antiquity. Indeed, control of the oxidation states of Fe in its oxides (FeO, Fe304' Fe203) was elegantly used in vase painting by the ancient Greeks to produce the characteristic black and red Attic ceramics (Z. Goffer, "Archaeological Chemistry,"...

The discovery of C60 and C70, icosahedral spherical and ellipsoidal carbon species in September 1985, followed by their successful synthesis in 1990, excited the imagination of many scientists and demanded a radical revision of old, seemingly well-founded, preconceptions in carbon science, leading to the institution of a new, multidisciplinary science of chemistry, physics and materials science in the round.

In September 1985, in an attempt to simulate the chemistry in a carbon star, Harry Kroto, Bob Curl and Richard Smalley set up a mass spectrometry experiment to study the plasma produced by focusing a pulsed laser on solid graphite. Serendipitously, a dominant 720 amu mass peak corresponding to a C60 species was revealed in the time-of-flight mass spectrum of the resulting carbon clusters. It was proposed that this C60 cluster had the closed cage structure of a truncated icosahedron (a soccerball) and was named Buckminsterfullerene because geodesic dome concepts, pioneered by the architect...