| HN Mirror

The excitement is that someone did a lot of work and verified we got the science right on a bizarre compound.

How to explain it? Let's go to the foundations. Let's start with the periodic table: https://en.wikipedia.org/wiki/Periodic_table.

Matter is made up of atoms. Each atom has a nucleus and a cloud of electrons around it. Inside the nucleus we have some number of protons and neutrons. The number of protons determines which element it is. The number of protons + neutrons is basically how heavy it is - that's called an isotope. Isotopes don't matter for chemistry, so we'll ignore that.

For example if you have 6 protons then you're the 6th element. Namely carbon. And 9 electrons gives the 9th element, fluorine. Also protons carry a positive charge, so you'd generally have the same number of electrons as protons. But not always. If an atom or molecule has a different number of electrons and proteins then it is called an ion. More on that soon.

Next up, we have quantum mechanics. In a classical world, the electrons would want to go to the nucleus to hang out with the protons. In a quantum mechanical world, uncertainty in position times uncertainty in momentum has a minimum. Since electrons are light, if we know that an electron is in the nucleus, it probably has a momentum so big that it will soon NOT be in the nucleus. Therefore the best that the electron can do is be somewhere in a kind of probability cloud around the nucleus. Those clouds are called orbitals.

The exact shapes of those clouds have been worked out, and are called orbitals. Orbitals form into shells. Each orbital can contain 0, 1 or 2 electrons. Each shell has a finite (usually fairly short) list of orbitals in it, and all of this has been worked out. This is why the periodic table (see https://en.wikipedia.org/wiki/Periodic_table again) is arranged into columns. Each column usually has the same stuff in its outer shell, and therefore is likely to do somewhat similar things chemically.

Most of chemistry comes from one rule. Atoms like having their outer shell either totally empty, or totally full. They have 2 ways to do. The first is the ionic bond. That's where one atom gives another an electron, making both into ions. The ions then hang out together and are called a salt. The second is a covalent bond, where 2 atoms share an electron each to give each an extra part time electron, making both happy. In the periodic table the farther towards the right and top you are, the more you want a full outer shell. And the farther towards the left and bottom you are, the more you are willing to give up electrons if someone asks.

In fact the elements on the left side care so little for their outer electrons that, when they get together, they let their outer electrons wander around freely. Those electrons make things shiny, and conduct a current when they all move together. Those are metals. By contrast the ones on the right are non-metals - they can steal from metals or share with each other. How many depends on which column they are in.

The very last column is the noble gases. They have a full outer shell and would like it to remain that way, thank you very much. So they don't get involved in this chemistry nonsense.

Now let's talk about the stuff involved in this article.

Fluorine, element 9, is the farthest to the top and right you can get without being a noble gas. It wants one electron and is vicious about getting it. Trying to get it do something unusual usually requires making it temporarily very unhappy. An unhappiness that it is perfectly willing to resolve by reacting with the chemist. This is not an idle threat - histories of fluorine usually start with a list of famous chemists who were killed or maimed in this way. However once it has reacted, it is often very stable. We stick fluoride into toothpaste and cook with teflon - both of which contain fluorine.

Carbon, element 6, comes 3 columns before. Its outer shell has 3 fewer electrons, so it wants 3 more. Making 4 bonds. But where fluorine is vicious, carbon is polite. This makes carbon the tinker toy of complex chemistry. Which is how it became the backbone of pretty much everything required for life as we know it.

Now what does this compound look like?

Let's start with a box. At each corner you put a carbon. Each corner is connected by edges to 3 other corners. That leaves each carbon short one bond. So we stick one fluorine off of each corner. That gives us the diagram at the top right of the article.

Now remember that fluorine is vicious, while carbon is polite. Yes, each fluorine is sharing an electron with a carbon, but it is rather unequal. The electron hangs out with the fluorine a lot more than with the carbon. Therefore the fluorines wind up negatively charged (the extra electron spends more time with them). The carbon atoms therefore wind up with a corresponding positive charge. And all of these positive charges, in theory, make the very center of the box a perfect place for a passing electron to take up residence. An electron that is not part of any atom, just sitting there enjoying a nice home. That extra free electron where an electron normally wouldn't be makes the whole thing an ion.

So it is cool that the theory works out. But in order to do it, some chemist had to do stuff with fluorine that nobody sane wants to happen anywhere near them, let alone be actually doing doing in a lab.