I am a fish
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Gases composed of solid elements
Can anybody think of a gas composed entirely of solid elements (at standard temperature and pressure)? It's a question that's really been
bugging me!
I can think of examples at elevated temperature. For example, between 50C and 110C, carbon disulphide is a gas, whilst carbon and sulphur are both
solids.
I can also think of solids that are composed of gaseous elements. For example, ammonium nitrate and ammonium chloride.
1f `/0u (4|\\| |234d 7|-|15, `/0u |234||`/ |\\|33d 70 937 0u7 /\\/\\0|23.
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Pyrovus
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Tricky! A couple of possibilities spring to mind. I'm pretty sure carbon monosulphide is a gas at room temperature. The phosphorous analogue of
cyanogen (CP)2, if it exists, may also be a contender, but I've got a feeling it probably polymerises.
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BromicAcid
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Now you got me thinking. At first I was just looking over the periodic table thinking of all the differnt compounds then I approaced it more
stratigically. Of course ionic compounds have a higher melting point so a covalent compound would be the culpruit, so I stuck to the left side of the
periodic table thinking about the differences in electronegativity. Really there are not many options because as you go down the family the atomic
weight goes up and the london forces increase and thus the melting and boiling points rise as well.
Regardless, I hardly came up with anything, sulfur does not form an iodide and it would probably be a liquid anyway, lower members of the family
experience an increase in melting points. Phosphous compounds of iodide and the chalcogens are are solid and in the other direction they are solid as
well.
There are other combinations of everything to be sure but I really can't pick anything out right now, it's really annoying.
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Pyrovus
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The trouble with the solid nonmetals is that with metals, they form ionic compounds, and with each other they aren't that good at forming
multiple bonds, meaning that any compounds they form will have a high molecular weight. As for the metals, most of the time they will form metallic
bonds to form alloys. The alkali metals in the gas phase form stable diatomic molecules. If it weren't for the tendency to form metallic bonds,
compounds such as NaK would be expected to be gases. Unless there's some exceptionally stable molecules containing two or more light metals, to
give an energy incentive for them to form rather than the alloy, there's probably not much hope there.
Some metal carbonyls (eg Ni(CO)4) are gases; perhaps if CS has an analogous tendency to form complexes this could give a few gaseous compounds.
An intriguing problem - I think I'm going to be thinking on this one for a while!
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