Didn't think to look up the temperature issue, but of course it makes sense, otherwise you couldn't use a mercury thermometer on a freezer.
When I was a kid, we had a jar of mercury, maybe about 1/4 cup, left over from my grandfather having worked at mining gold in the 30s. We played with it a lot, including in our bare hands. I remembered it being frozen once but as I think of it again, I realize that freezer was from a bio-science lab that my father had bought out where they stored all kinds of super cold stuff that, if you touched it with bare skin, would essentially burn you (as we referred to it at the time). So I guess it must have been capable of -40F. My brother froze the mercury and hit it with a hammer, shattering it all across the garage floor. Then when all the little pieces liquified again and we collected them with an eye dropper. As I recall, my Dad was not ammused.