"A spectacular anomaly came up with the hydrides of the nonmetals—an ugly bunch, about as inimical to life as one could get. Arsenic and antimony hydrides were very poisonous and smelly; silicon and phosphorous hydrides were spontaneously inflammable. I had made in my lab the hydrides of sulfur (H2S), selenium (H2Se), and tellurium (H2Te), all Group VI elements, all dangerous and vile-smelling gases. The hydride of oxygen, the first Group VI element, one might predict by analogy, would be a foul-smelling, poisonous, inflammable gas, too, condensing to a nasty liquid around −100°C. And instead it was water, H2O—stable, potable, odorless, benign, and with a host of special, indeed unique properties (its expansion when frozen, its great heat capacity, its capacity as an ionizing solvent, etc.) which made it indispensable to our watery planet, indispensable to life itself. What made it such an anomaly? […] (This question, I found, had only been resolved recently, in the 1930s, with Linus Pauling's delineation of the hydrogen bond.)"