Allotropy/Talk

Clearly, steam, water, and ice are not allotropes. However, what about the various solid phases of water (ice(I), ice(II), etc...)? I believe they would be considered polymorphs, but probably not allotropes because water isn't a pure element. Is this correct? --Matt Stoker

Right. Allotropy refers specifically to elements. I double-checked my understanding of this with the Penguin Dictionary of Chemistry (DWA Sharp, Penguin:1990 ISBN 0-145-051232-2), but I'd encourage anyone to consult whatever credible reference they feel necessary. --JoeAnderson