The energy contents of different polymorphous but chemically identical compounds in a system can be determined by comparing their heats of chemical reaction. The most instable form will have the highest heat of chemical reaction where as the most stable form will have the lowest heat of chemical reactions. Since generally the glass obtained by rapid cooling of the melt represents the most instable form where as a glass corresponding to the formula Al2O3.SiO2 should be the least stable form of this compound.
Unfortunately, this glass can not be made because it’s strong diversification tendency. The heat evolution properties of the three minerals were studied by dissolving in hydrofluoric acid calorimeters.
To be contd………….
