Industrial gas

• Scientists believe undiscovered chemical compounds could help remove greenhouse gases, or trigger a medical breakthrough much like penicillin did.
• We needed nuclear fusion (firing atoms at each other at the speed of light) to make the last handful of elements.
• But to understand the full scale of the chemical universe, you need to understand chemical compounds too.
• So, how many chemical compounds can we make with the 118 different sorts of element Lego blocks we currently know?

Big numbers

• There are lots of these: N2 (nitrogen) and O2 (oxygen) together make up 99% of our air.
• It would probably take a chemist about a year to make one compound and there are 6,903 two-atom compounds in theory.
• So that’s a village of chemists working a year just to make every possible two-atom compound.
• And to make all these chemical compounds, we’d also need to recycle all the materials in the universe several times over.

Surely not all those compounds are possible?

• It’s true there are rules – but they are kind of bendy, which creates more possibilities for chemical compounds.
• Even the solitary “noble gases” (including neon, argon and xenon and helium), which tend to not bind with anything, sometimes form compounds.
• So, if you include extreme environments in your calculations, the number of possible compounds increases.

How scientists search for new compounds

• Often the answer is to search for compounds that are related to ones that are already known.
• The X-ray technique that Crowfoot Hodgkin invented on her way to identifying penicillin’s structure is still used worldwide to study compounds.
• And the same MRI technique that hospitals use to diagnose disease can also be used on chemical compounds to work out their structure.
• For many useful compounds, like penicillin, it’s easier and cheaper to “grow” and extract them from moulds, plants or insects.
• Thus the scientists searching for new chemistry still often look for inspiration in the tiniest corners of the world around us.