Is there any material that can molecularly restructure so as to expand its intra- or inter-molecular distance by no less than three-fold without substantially losing its structural integrity and remain solid without substantial thermal change to the touch, say, other than during the expansion process by the use of electricity, electromagnetism, ultraviolet light, radio frequency, easily reversible chemical exposure, or any other effect other than substantial heat loss or increase?

A lower scale example would be water where if talking about actual H<sub>2</sub>O, it will freeze with substantial discharge on audible wavelengths at some −40 °C (not at 0 °C, only contaminated water freezes at 0 °C), however, in that case, water is in a much less dense structure than when contaminated. Theoretically one could contaminate and decontaminate water (plus heat refreeze) and change its density.

I am aware of no other molecular procedures that could achieve the same with the material being at room temperature before and after whatever affect it is subjected, and seeking to learn if we are aware of any.