Number 197 (Story #4), October 5, 1994 by Phillip F. Schewe and Ben Stein CRYSTALS THAT SHRINK ISOTROPICALLY WHEN HEATED have been devised by Arthur Sleight at Oregon State University. Ordinarily crystals expand when heated because the added energy serves to prize neighboring atoms further apart. In Sleight's compound, however, a network of oxygen, vanadium, and phosphorus atoms rearranges its internal chemical bonds so as actually to shrink when heated from 200 C up to 800 C. The shrinkage in volume is small, only 0.3%, but, when this network is compounded with materials that normally expand when heated, an overall thermal stability can be achieved. This would be advantageous, for instance, in the construction of telescope mirrors or electronic circuits. A few previous materials have been known to contract in one direction while expanding in another dimension. Sleight's materials seem to be the first to contract in all directions. (New Scientist, 10 September 1994.)