How the inertness of a complex differ from its thermodynamic stability?
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The word “stability” can be used in two different senses: 1) “thermodynamic” stability, or 2) “kinetic” stability. The first tells us whether something is possible (“inevitability”), the second whether it will happen quickly (“speed”). Suppose we have two substances, A and B, that have different energy contents, with B being lower in energy than A. The transformation (=reaction) A → B, will lead to lower energy and so will inevitably take place, but it doesn’t give us any information as to how fast it will occur. A is thermodynamically unstable in comparison to A. In thermodynamic terms, if the free energy change in going from A to B [∆G˚] is negative, the reaction will be spontaneous, though it may be spontaneous and rapid, or spontaneous and s-l-o-w. What accounts for the speed or slowness?
Imagine the energies of A and B as two points on a hill. A, with higher energy content, is at the top, and B is at the bottom. If the hill were a straight downgrade, then if you placed a ball (A) at the top, it would immediately roll down under it reached the bottom (B); it would need no help from you. on the other, suppose that the hill had a bump in it that was higher than the top. The ball you placed at the top would not spontaneously roll down unless it had some assistance from you in getting over the hump (in technical terms this is the activation energy for the reaction). The higher the hump, the more energy is needed to get there and the slower the reaction will be. This is kinetic stability.
A simple example is carbon, which exists in two forms: graphite a.
Imagine the energies of A and B as two points on a hill. A, with higher energy content, is at the top, and B is at the bottom. If the hill were a straight downgrade, then if you placed a ball (A) at the top, it would immediately roll down under it reached the bottom (B); it would need no help from you. on the other, suppose that the hill had a bump in it that was higher than the top. The ball you placed at the top would not spontaneously roll down unless it had some assistance from you in getting over the hump (in technical terms this is the activation energy for the reaction). The higher the hump, the more energy is needed to get there and the slower the reaction will be. This is kinetic stability.
A simple example is carbon, which exists in two forms: graphite a.
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