Weird states of matter

Clusters of atoms have been shown to behave a lot like single atoms in chemical reactions.

Whole new classes of compounds can be created from small clusters of atoms acting like single atoms of another element, researchers demonstrate for the first time in work reported in this week's Science. Clusters of 13 aluminum atoms behave like halogens and can combine with them to form halogen compounds with novel properties, the researchers write. And clusters of 14 aluminum atoms act like single alkaline earth atoms capable of forming ionic compounds that are in effect new types of salt.

And the result?

Khanna's team also showed that a 14-atom aluminum cluster could combine with iodine to yield iodide salts. But just as there are differences as well as similarities between elements within columns of the periodic table, so the 14-atom cluster is not exactly like any rare earth alkali, and therefore can be used to create compounds with novel properties not found before, Khanna said. For example, when the 14-atom aluminum cluster combines with three iodine atoms, it creates an ion with overall negative charge which is actually extremely stable. Such novel properties provide the potential for creating radically new nanoscale materials, Khanna said. He noted that the work on clusters containing iodine could have important medical applications, given the element's key role in a number of biochemical pathways.

Wow.