What is difference between iodine and Iodide?
Warr, I hope you don't mind, but I think it will be better to discuss this interesting topic in it's own thread, so I moved it here.
Sorry i did Google it but got these answers, which i am not sure are 100%.
" Best Answer - Chosen by Asker
Hi,
I think that iodide is an ion, i.e. it has reacted with a metal so it has gained electrons and is now a negative ion.
Where as, iodine is just a neutral atom.
The quote is correct, but that does not make it easier to understand
Iodine (I) is an element, the same as nitrogen (N) and phosphorus (P). Iodide (I-) and Iodate (IO3-) are ions of iodine, just the same as nitrite (NO2-) and nitrate (NO3-) are ions of nitrogen, and phosphate (PO4-) is an ion of phosphorus.
It is my understanding (chemical boffins, please correct if I'm wrong...) that the "...ite" and "...ate" at the end of these names indicate the level of oxidation of the elements, with the "...ate" referring to the highest, most easily accessible oxidation state of the ions. Thus iodate and nitrate are the most oxidized common forms of iodine and nitrogen.
We probably all know the term “denitrification.” This process happens in regions of the aquarium where the oxygen concentration is low (anaerobic), such as for example, within live rock and in deep sand beds. Iodide is converted to iodate in the same type of (anoxic) processes.
Can both these be used in Marine Tanks ?
The total concentration if iodine (and all it's ions) is approximately 0.06ppm, with approximately two-thirds being iodide and one-third being iodine. This concentration changes with depth, with the iodide ion concentration decreasing and the iodate ion increasing as the water becomes more anaerobic.
As far as I know (marine biologists and bio-chemists, please confirm...) marine organisms which uses iodine (and not many do...) mostly take up iodide and iodate, and only a few species are capable of using iodine (for more info, read
this excellent article by Dr. Randy Holmes-Farley). Fortunately, elemental iodine changes quite rapidly into iodide once added to our tanks.
Inorganic (elemental) iodine is rather insoluble in water, and commercially available iodine additives (and DIY additives such as Lugols) contain a large proportion of iodide in addition to iodine.
Hennie