Iodine is a study of contrasts - a most unusual element which may find a dominant place in alternative energy and especially advanced batteries, just as it has an exceptional role in cellular metabolism.
Iodine is an essential nutrient, the heaviest of all elements which are essential for life - and this is so despite also being a strong antimicrobial agent that has been used in the treatment of wounds for hundreds of years. It has a broad spectrum of antibiotic activity against bacteria, viruses, fungi, protozoa and single cell organism and yet iodine is essential for human health in the thyroid. More humans suffer iodine deficiency than malaria and with worse consequences. Go figure. Aside from biochemistry, the most unusual trait for alternative energy is iodine’s ionization potential of 6.8 eV and its photo reactivity. As a halide, it has an electron vacancy in its outer shell and is chemically reactive. It has a strong optical bandwidth, high spin and high magnetic moment and is composed of a single isotope (127) so coherence is easier for optical uses. It is a rare element but relatively cheap due to being naturally enriched in brine. Why is 6.8 eV important in the ionization potential? Well, that value happens to be the binding energy of positronium for one thing, as well as some forms of structured carbon - and in terms of the Rydberg value (Ry) of 13.6 eV as well as the ionization potential of hydrogen it is precisely half. Thus when one provides an overlap or carbon, hydrogen or water, and iodine, Rydberg (and Mills) are in play. Four atoms of iodine can present a catalytic “hole” at low temperature. This post is actually leading somewhere important: advanced batteries – which may exploit the Hotson BEC (or a newer version :-) but that will have to wait for the next installment. Elon Musk may have gone all-in for lithium too soon (but Li does work with Iodine in a traditional electrolyte system, so maybe he is already there).