I'm trying to find out a term, if it exists. A chemical change is when bonds are broken and new ones made, leading to the creation of a new substance. A physical change is when matter changes state. But what's the term for a change where the molecular structure stays the same, but the manner in which the particles change their arrangement completely changes the properties. Candy floss, for example, has the same molecular structure as sucrose but owing to its amorphous structure, has markedly different properties. Is there a term for this kind of change? I want to call it an "arrangemental change" but I suspect someone else has already coined an accepted term.