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Chemistry Forums for Students => Physical Chemistry Forum => Topic started by: Altered State on May 19, 2013, 06:21:31 AM

Title: "Waterlike" density of some compounds
Post by: Altered State on May 19, 2013, 06:21:31 AM
I've been told in class that the behavior that follows water as his density is lower in solid state (I known, not in every solid state), than in liquid state, is followed by very few compounds/elements, but I do not anyone else that applies. I Googled a bit, but I was not able to find out, so, please, I would really apreciate if you enlight me in this. And if you tell me why, would be "the bomb".

Thanks in advance
Title: Re: "Waterlike" density of some compounds
Post by: Corribus on May 19, 2013, 10:14:13 AM
Could you please clarify your question?  I am finding it hard to understand what exactly you are asking.
Title: Re: "Waterlike" density of some compounds
Post by: Altered State on May 19, 2013, 11:18:26 AM
Could you please clarify your question?  I am finding it hard to understand what exactly you are asking.

I want to know if there is any other element or compound that, like water, its density is higher in liquid state than in solid state. I also want to know which ones are they and why is that.
Just curiosity.
Title: Re: "Waterlike" density of some compounds
Post by: Corribus on May 19, 2013, 01:04:57 PM
The property is fairly unusual.  In fact off the top of my head I was unable to think of other substances that have it.  A little digging at reveals that there are a few other examples.  As to the why - because of the strong hydrogen bonding interaction, water becomes highly ordered in its solid state, and the order is orientation dependent.

But rather than reinvent the wheel with a long-winded explanation of my own, just have a look here:

http://en.wikipedia.org/wiki/Properties_of_water

Scroll down, there's a nice long section on water/ice density.
Title: Re: "Waterlike" density of some compounds
Post by: Enthalpy on May 19, 2013, 01:08:44 PM
Silicon, germanium, gallium, antimony, bismuth. Many compounds probably as well.

If you find one such compound that freezes at +10°C or +15°C, it will wimplify the design of a submarine that uses temperature differences in Ocean water to dive and rise perpetually.
http://www.scienceforums.net/topic/72310-pour-your-brains-here-on-how-to-build-this-contraption/#entry725478