High-entropy positions

Figure 6 shows the entropy curve obtained during the lithiation process. Starting from a high and positive value of 60J/(mol.K) at x 0, AS(x)... 

Negative A liquid (moderate entropy) combines with a solid to form another solid. Positive One mole of high entropy gas forms where no gas was present before. Positive One mole of high entropy gas forms where no gas was present before. Uncertain Same number of moles of gaseous products as of gaseous reactants. Negative Two moles of gas (and a solid) combine to form just one mole of gas. 

Substances in the solid state tend to have low entropy values. This is not surprising because the particles in a solid occupy approximately fixed positions. They can vibrate, but they cannot move from one place to another. Solids are therefore highly ordered. Gases, however, have very high entropy values. Gases contain particles that have... 

Even if the heat of decomposition of the fluoroborate is positive by as much as 10 kcal./mole, which seems unlikely, stability of the crystal would be limited to low temperatures by the high entropy of dissociation. The sum of the standard entropies of the likely products, NF3 + F2 + BF3, is... 

Gases have such high entropy that if a reaction yields a net increase in moles of gas, the standard entropy change of the reaction is positive (ASot > 0) if there is a net decrease in moles of gas, AS n < 0. 

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