Guess what? - I need one!! 27A. White crystalline sugar widely occurring in fruit, honey and the blood of animals: formula C6H1206? (Not glucose or fructose) *E*T**S*
Sorry all. 21A is - any of the two or more different physical forms in which an element can exist, e.g. graphite and diamond as forms of carbon? ALLOTROP* (It either ends in Y or E - I hope)
Thanks for the extra information, paross. According to my dictionary, there is a subtle difference betwee "allotrope" and "allotropy".
Allotrope: one of the many forms in which a chemical element occurs, each differing in physical properties.
Allotropy: the existence of a chemical element in more than one form, each having different physical but the same chemical properties.
So, it looks as though Allotropy is more a state of being, rather than the thing itself.