Gas with greatest molecular weight

[Loren Booda]

What room-temperature gas has the greatest molecular weight?

[Gokul43201]

Atomic weight of Rn is 222. That's right up there with the giants.

I think the record is held by one of the heavy-metal hexa halides. The halide ions provide a nice repulsive shield.

[Gokul43201]

Could be WF6 (tungsten hexafluoride) at 298 g/mol.

[shrumeo]

Since we're talking metal fluorides, PtF6 = 309 g/mol

[Gokul43201]

Since we're talking metal fluorides, PtF6 = 309 g/mol

But it's a solid at room temp. In fact it is liquid only from 63C to 69C, a pretty small range, wot ?

[shrumeo]

yeah, i guess 70C would be a pretty hot room
well, if we want to stretch it a little UF6 and PuF6 are dern heavy and gases right above room temp, if i'm not mistaken (again) their boiling points are in the 30s or 40s.