"It's such a basic question, the structure of water," says chemical physicist Anders Nilsson of Stanford. "It's amazing we don't really understand it."
Dr. Nilsson made a splash, so to speak, when he and colleagues took a page from director Michelangelo Antonioni. They planned to use X-rays generated by the synchrotron, a kind of particle accelerator, to study chemical bonds in molecules in water. But just as the photographer in Antonioni's 1966 existential classic, "Blow-Up," found that the lovers' tryst he had shot was less interesting than the background (which contained a man with a gun), so the scientists found the background water to be where the action was.
Liquid water, they concluded from the X-ray data, has a structure totally at odds with what textbooks say and what scientists have believed for more than a century. Rather than being a sea of tetrahedrons - little pyramids with triangular bases, formed when each water molecule connects to four others - it seems to be an ocean of rings and chains, with most molecules hooking up with only two others via strong bonds.
As often happens when the conventional wisdom starts to collapse, on closer inspection there wasn't much holding it up in the first place. The notion that water molecules form pyramids actually had little empirical support, Dr. Nilsson says: "Experimental findings have been so sparse that theoretical work has dominated the field," and the theory is so inexact "that you can get almost any result you want just by tweaking" a few numbers.
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This may seem like an esoteric question, "but different structures (of water) should behave differently," says Prof. Galli. Because life runs on water, fathoming its true structure could overturn key ideas in biology.[..]
