Tl:dr: Here is the printable STL: https://www.thingiverse.com/thing:3676897
Part two of our zeolitic exploration and it is on to one of the most important ones. If you drive, fly or do anything relying on petrol or other short-chain hydrocarbons, then you have faujasite to thank.
Faujasite is a naturally occurring zeolite with sodium (Na, the most dominant), calcium (Ca) and magnesium (Mg) forms. It was first discovered in the early 1840s in Germany and forms exquisite tiny crystals (see: https://www.mindat.org/min-35126.html ). It is one of the key components of a hugely important process called ‘Fluid Catalytic Cracking’ (FCC) which is used to convert crude oil into petrol and other short-chain hydrocarbons we currently use for energy storage and fuelling our cars.
It also has a gorgeous structure, formed of sodalite β cages (like zeolite A: https://crystalprint.home.blog/2019/05/11/zeolite-a-lta/ ) connected by double six rings (d6r):
Rare in nature, this structure is commonly used as it’s synthetic versions zeolite X or Y both commonly used as absorbents or as previously mentioned, catalysts.
Right you are now probably thinking – what is the difference between X and Y?
Well these are both synthetic versions of faujasite, discovered by our old friends Robert M. Milton and Donald W. Breck of the Linde Division, Union Carbide Corporation back in the 1950s (along with zeolite A). Zeolite X has a very low silicon to aluminium ratio, the less aluminium, the higher the charge on the framework, the higher the charge on the framework, the more extra-framework cations like sodium or calcium are needed to balance the charge (remember, basic rule of chemistry – everything wants to be stable). So zeolite X is great for cation exchange and can effectively be tailored for different reactions by swapping in and out cations.
Zeolite Y has a much higher silicon to aluminium ratio so it is more stable at higher temperatures and used in FCC.
I won’t go through the structure modification process here – if you are interested about how I make the models check out my zeolite A post: https://crystalprint.home.blog/2019/05/11/zeolite-a-lta/
After getting rid of some rogue double 6 rings we get something like this:
Looks gorgeous doesn’t it? Like a strange fractal flower. Imagine trying to make this without a 3D printer, I’m always in awe of the craftsmanship in jewellery or other intricate designs. When I was younger I wanted to be a jeweller – maybe I should look into it again!
Put through our slicing software, rotated and scaled up 130 % we get the following:
Which I’ve uploaded to thingaverse as: https://www.thingiverse.com/thing:3676897
It prints beautifully, after 10 hours a very little post production work we get this:
I’ve been talking a lot about sodalite in this and the LTA post, so I think with the next post I might take a break from zeolites and try my luck with some unusual filaments and the sodalite structure.. Stay tuned!