What is a material, other than water, whose solid form can float on its liquid form?

Hello,

The reason why ice floats on water is because it expands as it cools
due to some interesting crystaline structure stuff which is a little
over my head. Suffice to say, it's a very unique property which is
often assumed as the only compound to exhibit such a quality. Gallium
metal actually does the same thing because of similar properties:

From the Mineral Information Institute:
"Gallium has some physical properties that are worth noting. Like
water, gallium expands as it freezes which means it becomes less
dense."


Search Strategy:

"not +the only" "expands when it freezes" on google groups:
http://groups.google.com/groups?q=%22not+%2Bthe+only%22+%22expands+when+it+freezes%22


Additional Links:

Mineral Information Institute information on Gallium:
://www.google.com/search?q=gallium+%22less+dense%22


This was a VERY tough question because most people assume that water
is the only compound to have this property, and although I knew it
wasn't, it was hard to find a source, or train of evidence to prove
otherwise. I actually had to sift through countless religious debates
with ice as a proof of God. Enjoy your answer, and thank you for
asking the question.

skermit-ga

---

Clarification of Answer by skermit-ga on 28 May 2003 14:02 PDT

I'll also refer you to another researcher's answer which I found
later, and has other sources with more materials which behave this
way, including another source for gallium.

https://answers.google.com/answers/main?cmd=threadview&id=207449

skermit-ga

You rock.