Pd12L24 sphere
In The Demon Job he's the Fat Man: a hollow sphere that put itself together from thirty-six pieces, who backs the Demon and pays its bills with ATP that isn't his.
Pd12L24 sphere plays The Fat Man in The Demon Job
A detective made of water, a client who was the first molecule there ever was, and a demon who says he can sort for nothing.
Watch from 7:12, where The Fat Man first appears → or from the start
Booking photographs
The suspect, from its real atomic coordinates. Drag to turn it. Height chart in nanometers, ruled every 0.2 nm. A ping-pong ball is about ten million times wider. Mugshot: its X-ray crystal structure.
Rap sheet
- Building itself: 12 palladium ions and 24 bent ligands close a hollow ball with no assembly crew.
- Making order look free: 36 particles become one, and the flask doesn't object.
- Keeping a protein: once assembled around a whole ubiquitin and held on to it (2012).
- Switching sizes on a technicality: straighten its arms slightly and 72 pieces build a bigger sphere.
- Harboring a 144-piece cousin, in a shape graph theory predicted first.
- Answers to
- M12L24, or “the nanosphere.”
- Height
- 4.2 nm, any way up.
- Weight
- 13 zeptograms, before its 24 counterions.
- Build
- A hollow cuboctahedron: 12 palladiums, 24 bent arms.
- Weakness
- Straighten its arms slightly and 72 pieces build a bigger sphere.
- Associates
- Once built itself around a whole protein, and kept it.
- Family
- A 144-piece cousin, in a shape first predicted by graph theory.
- Last seen
- As a crystal in an X-ray beam, at room temperature.
- M.O.
- Mix palladium(II) ions with bent bis-pyridyl ligands, one to two, and wait. Each palladium takes four pyridine nitrogens; 48 palladium-nitrogen bonds close a cuboctahedron with a palladium at each of its 12 corners and a ligand along each of its 24 edges. The yield is quantitative.
- Associates
- ubiquitin, once held inside one; its 72-piece sibling, Pd24L48; a 144-piece cousin, a Goldberg polyhedron (2016)
- Priors
- First reported in 2004, in a paper titled for its '36 small components'. The crystal in the mugshot is from 2013, measured at room temperature.
of them in a milligram, and every one built itself.
You’ve never seen one.
“Order isn't a crime. The Law only minds free lunches.” — Keltar, on the case
Case notes: why a self-built sphere is legal
The client's job is what Planck called a perpetual motion machine of the second kind (he credits Ostwald with the name): a machine that, in a cycle and with no other effect, turns heat from one reservoir entirely into work. Kelvin's 1851 statement of the Second Law forbids it to 'inanimate material agency'. The client reads that as an exemption.
Order on its own is not forbidden. Small palladium cages like this one form under thermodynamic control: the sphere is the free-energy minimum. The field states the rule as 'maximum site occupancy' (every metal-ligand interaction satisfied) together with 'maximizing the number of system particles'. Each palladium starts out holding solvent molecules; each pyridine that binds sets one loose. Twelve palladiums times four sites is 48 palladium-nitrogen bonds and 48 freed solvent molecules, while 36 pieces become one: thirteen more free particles than before (a count, not a measured entropy; nobody has published the enthalpy and entropy of this particular assembly). The sphere doesn't even form directly: smaller closed cages appear first and are annealed away.
Sources
- Tominaga M. et al. 2004, Angew. Chem. Int. Ed. 43:5621-5625, doi:10.1002/anie.200461422
- Piskorz T. K. et al. 2022, ACS Catal. 12:5806-5826, doi:10.1021/acscatal.2c00837
- Kai S. et al. 2017, Chem. Asian J. 12:3203, doi:10.1002/asia.201701351
- Thomson W. (Kelvin) 1851, 'On the dynamical theory of heat', Trans. R. Soc. Edinb. (the 'inanimate material agency' statement)
- Planck M., Treatise on Thermodynamics, §116
- Eddington A. S. 1928, The Nature of the Physical World, p. 74
- Full notes for the series: content/cases/series/demonjob.md
The interrogation room
Keltar is an AI character. He sticks to the file; the conversation is saved and Kent, the CEO, can read it.
The poster on the street
This is the photocopied wanted poster for Pd12L24 sphere, No. 131 of the exotic forty. They were made for noticeboards around Boston, Cambridge and the rest of the east coast.
Found one? Scan its QR code with your phone. If you're a signed-in player, the sighting goes on your record with +1 XP.
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