Remembering Stoicheff and his rule

It was sad to read about the death of Boris Stoicheff (PHYSICS TODAY, October 2010, page 68 ). In the obituary, Richard Brewer describes Stoicheff as an excellent physicist. I add that his name is also well known in the chemistry community. In 1962 Stoicheff introduced a principle for carbon–carbon bonds that later became known as Stoicheff’s rule; it states that the C–C and C=C bond lengths “increase linearly with an increase in the number of adjacent bonds.” ¹

In 1972 Kozo Kuchitsu suggested a revision ² to Stoicheff’s rule. In 1975 my colleagues and I showed that the rule goes beyond its original purpose—organic chemistry—and is applicable to a higher carbon coordination number, namely 6, which is found in carbon–boron compounds known as carboranes. ³ Stoicheff himself was surprised by that fact when he visited the University of Moscow in the 1970s.