Barbour and co-workers have defined a crystal of (S,S)-octa-3,5-diyn-2,7- diol, the packing arrangement of an organic dumbbell-shaped molecule, which is expected to bring about a large thermal contraction of its crystal lattice. The dumbbells stack such that the hydrogen bonds at their ends form helices running parallel to one of the crystal axes. This arrangement connects the molecules in a
... [Show full abstract] similar way to the flexible networks suggesting the large thermal expansion between molecules might also bring about NT. Barbour's crystal is held together between the molecules and hydrogen bonds between the OH groups at either end of the dumbells. The results of Barbour and co-workers highlight the importance of looking to weakly bound materials for extreme, and extremely useful, mechanical behavior.
