Over three years have passed since the last of our additions to the cube series when we really thought that that was it. The remaining elements were all too this or too that to, if not at a theoretical level, then certainly at a practical one for a small business to accomplish.

Thankfully, we were wrong!

Over the years, scores of customers have sent in emails wondering why we hadn’t added lithium yet. On the surface it seems like it should be a task easy enough to accomplish. Everyone knows about lithium and it’s cheap and plentiful. The fact that it’s reactive with air seems to present only a minor challenge. We had already brought to market cubes made of far livelier (chemically speaking), difficult to work with and more exotic metals like thallium and europium. So what’s the big deal?

The big deal is that lithium first and foremost is just too soft. All the other metal cubes are tooled to some degree. During the various stages of manufacture they’re cut and shoved and squeezed and manhandled a hundred times over with a variety of grabby tools that exert forces upon it. And the marks they leave can all in the end be polished away to leave behind a machined cube of perfect proportions. There is though a threshold after which all that machining becomes impossible. Indium comes close. If you look at that metal it can only just barely be formed. Its surfaces are rather rough; evidence of an earlier stage of preparation where the process must be halted to protect the all-important geometry of the whole. That final polishing stage - to speak nothing of the optional mirroring one - is impossible with conventional tooling. Lithium on the other hand makes indium seem like steel in comparison. Take it between your forefingers and it will squish like so much peanut butter. The pressure of that first clamp is enough to turn it all into a pile of ooze.

Fine. There is a second method of attack. Just cast the damn thing into a square mold et voila, there’s your cube. It’s the method used for sulfur and selenium, themselves two examples of delicate non-metals. Well, no, not so fast. Here the obstacle is chemical. Lithium, docile enough in solid form, is when molten viciously reactive with other materials and, almost perversely unique, attacks even glass; a substance that is inert to almost anything the periodic table can throw at it. You can find a precious metal mold which will hold lithium in its molten state, however it will oxidize with trace amounts of nitrogen. This normally inert gas is not as aggressively removed from inert atmosphere glove boxes (the glass enclosures found at labs with gloves sticking out) where these air-sensitive metals are worked on. Nitrogen reacts to varying degrees with other reactive metals and it conspires to dull the shine of several of our other cubes, notably barium and europium. But in the case of lithium it would spoil the surface to the point that it would turn any cubes made this way pitch black.

How exactly all the various technical challenges were overcome is obviously a bit of a trade secret we’re not privy to (not that we’d have the technical expertise to understand any of it anyway) but the gist of it is that it was made via extrusion. That’s a fancy word to describe the exact same process used in a meat grinder to form strands of spaghetti. Taking advantage of the softness of the metal you plop a big chunk of it in one opening and on the other side a square outlet and you apply pressure and out the end comes a big stick of lithium butter. With a razor blade you then section them off into rough cubes and, I assume, you shave more and more until the nitrogen in that glove box is exhausted leaving behind a relatively clean surface and a decent approximation of a cube. The genius really is on how you slice through (or shave) without applying sufficient pressure to deform the object!

Having never expected to add lithium to our lineup we unfortunately failed to design a holder for this slot in our display case. Anyone considering the purchase of one of these will have to for the time being leave it orphaned from the rest of their collection. In a sense, given the extreme challenges this metal presented it rather deserves a place of honor anyway. To the uninitiated, whoever you show it to, will likely just shrug with an implied “so?”. Well, now you can now tell them what makes this so special :-)