"4K-metal chelated" A chemical term used in Sagan's Cosmos Maybe this question doesn't belong here. It's about a hypothetical xenobiology imagined by a prominent scientist in a seminal work of popular science. So I dunno. Tell me to go away and I'll see if some other SE can help me.

I'll never forget the races Sagan made up in his book Cosmos. He gave descriptions of them in the form of excerpts from his imagined Encyclopedia Galactica, a compendium of all the races in the galaxy.

There was one term that never made sense to me: "4K-metal chelated". What does the "4K" part mean? Here is the context:

Civilization Type: 2.3 R
Society Code: 1H1, "We Who Became One".
Interstellar civilization, no planetary communities, 
  utilizes 1504 supergiants, OV, BV, AV stars and 
  pulsars.
Civilization Age: 6.09 * 10^15 s.
First local initiated contact: 6.09 * 10^15 s ago.
Receipt first galactic nested code: 6.09 * 10^15 s ago.
Source civilization, neutrino channel.
Local Group polylogue.
Biology: C, H, O, Be, Fe, Ge, He. 4K metal-chelated 
  organic semiconductors, types various. Cryogenic 
  superconducting electrovores with neutron crystal 
  dense packing and modular starminers; polytaxic.


(By the way, if anyone knows what "Local Group polylogue" is supposed to mean, I care about that too.)
These guys are "cryogenic superconducting electrovores" who apparently have "no planetary communities" so my guess is that "4K" should probably be taken to mean "4 Kelvin" and "metal-chelated organic semiconductors" as that they are composed of various types of semiconductors whose molecules are organics chelated with a metallic ion. About the "Local Group polylogue" thing, it's probably fictional stuff like a sort of interstellar Commonwealth or something.