When Elements Go Extinct

But now comes word that it isn’t just wildlife that can go extinct. The element gallium is in very short supply and the world may well run out of it in just a few years. Indium is threatened too, says Armin Reller, a materials chemist at Germany’s University of Augsburg. He estimates that our planet’s stock of indium will last no more than another decade. All the hafnium will be gone by 2017 also, and another twenty years will see the extinction of zinc. Even copper is an endangered item, since worldwide demand for it is likely to exceed available supplies by the end of the present century.

Running out of oil, yes. We’ve all been concerned about that for many years and everyone anticipates a time when the world’s underground petroleum reserves will have been pumped dry. But oil is just an organic substance that was created by natural biological processes; we know that we have a lot of it, but we’re using it up very rapidly, no more is being created, and someday it’ll be gone. The disappearance of elements, though—that’s a different matter. I was taught long ago that the ninety-two elements found in nature are the essential building blocks of the universe. Take one away—or three, or six—and won’t the essential structure of things suffer a potent blow? Somehow I feel that there’s a powerful difference between running out of oil, or killing off all the dodos, and having elements go extinct.

Gallium’s atomic number is 31. It’s a blue-white metal first discovered in 1831, and has certain unusual properties, like a very low melting point and an unwillingness to oxidize, that make it useful as a coating for optical mirrors, a liquid seal in strongly heated apparatus, and a substitute for mercury in ultraviolet lamps. It’s also quite important in making the liquid-crystal displays used in flat-screen television sets and computer monitors.

As it happens, we are building a lot of flat-screen TV sets and computer monitors these days. Gallium is thought to make up 0.0015 percent of the Earth’s crust and there are no concentrated supplies of it. We get it by extracting it from zinc or aluminum ore or by smelting the dust of furnace flues. Dr. Reller says that by 2017 or so there’ll be none left to use. Indium, another endangered element—number 49 in the periodic table—is similar to gallium in many ways, has many of the same uses (plus some others—it’s a gasoline additive, for example, and a component of the control rods used in nuclear reactors) and is being consumed much faster than we are finding it. Dr. Reller gives it about another decade. Hafnium, element 72, is in only slightly better shape. There aren’t any hafnium mines around; it lurks hidden in minute quantities in minerals that contain zirconium, from which it is extracted by a complicated process that would take me three or four pages to explain. We use a lot of it in computer chips and, like indium, in the control rods of nuclear reactors, but the problem is that we don’t have a lot of it. Dr. Reller thinks it’ll be gone somewhere around 2017. Even zinc, commonplace old zinc that is alloyed with copper to make brass, and which the United States used for ordinary one-cent coins when copper was in short supply in World War II, has a Reller extinction date of 2037.