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General Forums => Generic Discussion => Topic started by: curiouscat on August 20, 2012, 11:05:42 AM

Title: Largest Molecule that is still a gas
Post by: curiouscat on August 20, 2012, 11:05:42 AM

Generally (very crudely) as molecular size increases it is less likely that a molecule is gaseous (say at Room Temp).

Got me thinking: what's the highest MW molecule that is still gaseous? Let's say, BP <20 C at 1 atm.

I can think of Radon (MW 222 ; BP -60 C) or SF6 (MW 146 ;  BP -64 C )

Alternatively, what's the molecule with the largest (number of constituent atoms) that is still a gas?

Wondering how high we can go? Especially interesting among hydrocarbons.

Title: Re: Largest Molecule that is still a gas
Post by: fledarmus on August 20, 2012, 03:34:16 PM

Going down the periodic table, SeF₆ and TeF₆ are both still gases, the later at MW ~ 242 and bp ~-40°C. Wikipedia shows that PoF₆ (MW 323) has been synthesized and was predicted to have a bp around -40°C, but I haven't seen the measurement.

Title: Re: Largest Molecule that is still a gas
Post by: Borek on August 20, 2012, 04:02:51 PM

WF₆?

Title: Re: Largest Molecule that is still a gas
Post by: curiouscat on August 21, 2012, 02:27:20 PM

Quote from: Borek on August 20, 2012, 04:02:51 PM

WF₆?

That does seem the highest so far. Thanks!