Contracting substance under decreased pressure?

[AcidRainLiTE]

I know this seems impossible, and it probably is, but is there a substance (a solid) that will contract under a decrease in pressure?
If I place the substance in a sealed container at say atmospheric pressure and then suck out the air to make it almost a vacuum, I need the substance to have a smaller volume when the container is a vacuum than when it is at 1atm.
The reason that I leave a very small possibility for there to be a such a substance is because I am wondering if the temperature of the substance will change when it is in a vacuum causing the volume to change as well.

Thanks.

 

[Navin A S]

No, there is no known substance that will contract under a decrease in pressure. The reason for this is because of the gas law equation: PV = nRT, where P is pressure, V is volume, n is the number of moles, R is the gas constant, and T is temperature. This equation states that if pressure decreases, then volume also decreases, meaning that the overall volume of a substance or material cannot change as a result of a decrease in pressure.

 

[ravenprp]

It is highly unlikely that a solid substance would contract under decreased pressure. According to the ideal gas law, pressure and volume are inversely proportional, meaning that as pressure decreases, volume increases. This is consistent with our everyday experience, as we see objects expand when taken to higher altitudes where the air pressure is lower.

There are some exceptions to this rule, such as water freezing at high pressures, but these are due to changes in the molecular structure of the substance, not simply a decrease in pressure. In order for a solid substance to contract under decreased pressure, it would have to undergo a significant change in its molecular structure, which is highly unlikely.

Additionally, the temperature of a substance in a vacuum would not change significantly unless it is exposed to extreme temperatures or radiation. So, it is unlikely that a change in temperature would cause a significant change in volume.

In conclusion, while it is not impossible for a substance to contract under decreased pressure, it is highly unlikely and not supported by scientific principles. It is more likely that the substance would expand or remain the same volume under decreased pressure.