[Ernest_at_the_Beach]

What is “Hot Ice”?

[LantzALot]

Ice, which is hot.

Actually (and I know it's not the same thing) "hot ice" is the term we used to apply to what is generally called "dry ice." I think it was because it is so much colder than H₂O ice that the initial sensation if you touch it feels like a burn.

[PBRSTREETGANG]

Apparently an exotic form of solid water under extreme pressure. Not really “ice” as we know it, however.

http://cordis.europa.eu/fetch?CALLER=EN_NEWS&ACTION=D&SESSION=&RCN=27689

[Brett66]

From the newscientist article:

Exotic ice

But now, a team led by Michael Gillon of Geneva University in Switzerland have observed the planet transiting its host star using a telescope at the Observatoire Francois-Xavier Bagnoud (OFXB) in Saint-Luc, Switzerland.

They have been able to measure the planet's width, which provides clues to its composition and structure. It turns out to be about 50,000 kilometres wide, roughly four times the width of Earth and about the size of Neptune.

The planet is therefore too compact to be made mostly of hydrogen gas, like Jupiter, the researchers say, but not compact enough to be a rocky 'super Earth', as some had speculated. Instead, they believe it must be made mostly of an exotic form of water.

Although the parent star is much cooler than the Sun, the planet orbits 13 times closer to the star than Mercury's orbit around the Sun. That means the surface must be a blazing hot 300° C or more, keeping water in its atmosphere in vapor form.

But the high pressures in the planet's interior would compress the water so much that it would stay solid even at hundreds of degrees Celsius – the expected temperatures inside the planet. There are a variety of exotic 'hot ice' states possible in such conditions, with names like 'Ice VII' and 'Ice X'

Seems like wild speculation to me, why couldn't it be a light rock substance or rock that's not as densely packed as it is in earth?

[SunkenCiv]

in addition to the helpful comments above...

Unsolved mysteries of water in its liquid and glassy phases
http://adsabs.harvard.edu/abs/2000JPCM...12..403S

8 Phases of Water
http://www.newton.dep.anl.gov/askasci/chem00/chem00505.htm