Thorium, African Elephants, and the Periodic Table of DEATH and Mystery

Imagine it’s (Th)ORsday (1)…

You are a Swedish chemist in the early 1800s credited with the discovery of the periodic table elements cerium and selenium, are the first to isolate silicon and zirconium, and students from your laboratory are the first to isolate lithium, lanthanum, and vanadium. You are also the originator of the scientific terms catalyst, polymer, protein, and isomer.

You are a (Th)ORoughly bad-a** scientist, a true (Th)ORnament in the scientific heavens. Your name is Jöns Jacob Berzelius (1779-1848), you have been proclaimed the “Father of Swedish Chemistry,” and Sweden even celebrates you with a holiday (2).

But there was this one (Th)ORny problem you had to deal with. It turns out you “discovered” an element that wasn’t actually an element, and even named it and everything, then had to retract. That made you (Th)ORnery. After all, you have the track record of being a (Th)ORoughbred of chemistry.

Therefore, the NEXT element you discovered, you named after the mighty hammer-wielding god of thunder, lightning, storms, and strength, a god intertwined with the Vikings and Scandinavia: the god of war, THOR (3). And you called the element Thorium (Th), an actinide in period 7 with an atomic number of 90. Th is soft and malleable, a silvery color, and has a VERY high melting point—1750°C (3182°F) (4). This becomes important because when Th is heated by burning gaseous fuels, it becomes brilliantly incandescent with a pretty light that glows golden white instead of sickly greenish, like light from Actinophor in the earliest Welsbach mantles.

Let’s back up the truck for a moment and define. It turns out that 19^th century streetlights burned gaseous fuels under a Welsbach mantle (Carl Auer von Welsbach was the guy who invented this kind of mantle). Mantles were gauzy fabric bags made of cotton or silk or some other fabric impregnated with various chemicals (like Actinophor, a mixture of magnesium, lanthanum, and yttrium oxide). When the mantles were placed in a gas fire, the fabric burned away, and the chemicals converted into a solid mesh that gave off different spectra of light dependent on the elements present. The solid mesh could then be used for a long time before it needed to be replaced.

It turns out thorium dioxide mesh was amazingly great at giving off the right kind of brilliant light necessary for streetlamps (5). Thorium oxide mantles were produced for lanterns used by the military, in households, and for camping. In fact, it wasn’t until the 1990s that a MAJOR lantern maker (company name starts with a C …) stopped using Th mantles. Why?

Because Th is radioactive (6).

Th is not nearly as bad as radium or plutonium or those radioactive elements the Russians use to poison their enemies (7). There was even a study of Th mine workers done in the 1980s and 90s that couldn’t even tease out smoking from Th exposure as the major cause of the lung and pancreatic cancer they found (8–9: I only read the abstracts. I couldn’t get past the paywall).

So, Th doesn’t really cause deaths. But these articles about atomic elements are filed under the Periodic Table of DEATH. What’s the link?

Bear with me a little longer.

It turns out that for a while in the early 20^th century, doctors and scientists promoted radioactivity as good you for. Radioactive elements, including Th, were added into everyday products, like make-up and water and bread and suppositories and pillows. (10—You REALLY need to visit this site and click on some of the products. Horrifying and fascinating.) The Nazis put Th in toothpaste, brand name, Doramad (11). The toothpaste probably didn’t kill anyone either, but the Nazis did. And there’s your link (12). To quote Indiana Jones, “I hate these guys.” (13)

Just FYI, Thor’s hammer Mjölnir isn’t made of Th but of the Asgardian metal uru, although Ironman is skeptical (14).

As always, these are my own opinions based on my biases, knowledge, and understanding, and the websites I’ve linked are in no way a product endorsement.

The obvious movie to link to this is Thor (2011). Meh. It was okay.