Question

Why is octanitrocubane (C\(_8\)(NO\(_2\))\(_8\)) more expensive than pure gold (by mass-for-mass)? Cyclotrimethylenetrinitramine (aka. RDX) by comparison (86.6% of the former's detonation velocity) is cheap. Why the crazy over pricing?

Answer 1

Draw the structure of cubane. Now try to imagine an organic synthesis for it. Tricky. Very expensive.

Incidentally, lots of things are more expensive than gold by mass. Plutonium, microprocessors, Viagra. Gold is actually fairly cheap, compared to high-tech products.

Answer 2

I'm familiar with the, well, cubic structure of octanitrocubane, and the hexagonal structure of RDX. To make RDX you need nitric acid (not that expensive), and hexamethylenetetramine (aka. hexamine) which can be bought from China for ~$1000 per metric ton plus shipping costs. This makes it practical. Octanitrocubane is not economically practical. I'm asking WHY is it impractical to synthesize? (the real-world chemistry of it, not just laboratory synthesis).

These chemicals have a wide variety of uses in industry and military and even in organic energy storage mechanisms (with use of enzymes), but even research with octanitrocubane is rather cost prohibitive.

That is an interesting point though you pointed out, there are a number of things more expensive than gold by mass, even with gold's rather high price point per mass currently. :-)

Answer 3

Ah, I see. The reason the synthesis is difficult is because of the bond-angle strain in the cube. The very reason it is such an energetic material. That is, in short, to prepare a molecule with a great deal of potential energy requires a great deal of energy. You're essentially trying to "set" a mousetrap with a very heavy spring. Calls for delicate and yet forceful operations. That's where the expense comes in.

This is a general answer. I can't help you with a more specific answer, of where the expense comes in, because I'm not familiar with the synthesis. But if I had to guess, I'd say part of the problem is the length of it. Wikipedia shows the original cubane synthesis as requiring 13 steps. That's very long. Imagine you get 80% yield on each step, which would be fabulous for organic synthesis. Your overall yield would be 0.8^13 = 5%, which means you need a lot of starting material, a lot of time, and a lot of purification and workup to get not much product.

Answer 4

Ah yes... the more steps required, the less efficient. Is there no catalyst for this? Some kind of enzyme? The human body does more complex chemical "energizing" and synthesis than this with ease on a regular basis. DNA replication for example, or ADP being synthesized and then activated to for ATP. Is the bond energy of "mousetrap's spring" known for octanitrocubane? How does this compare to ATP for example?