Polyiodides are a class of polyhalogen anions (a group of polyatomic negative charged ions) composed of entirely iodine atoms.
The number of elements that are capable of forming a polymer (macromolecule, composed of many repeated subunits) just by themselves and without the assistance of other elements is very small. A large part of this is due to most of the periodic table being made of metals, elements that not capable of forming polymers (at least as far as we currently understand). Throw out the noble gases and you only have a very tiny wedge of the table for consideration, consisting of the metalloids, the nonmetals and the halogens - a total of 16 out of the 92 naturally occurring elements.
Boron, carbon, silicon and germanium are all known to form covalent network solids. Covalent network solids are chemical compounds made up of entirely covalent bonds in a large continues network. This is something I would consider to be polymers because of the fact that they are made up of the same materials in a sense. Polymers are created of many subunits repeatedly, while covalent network bonds are made of the same covalent bond repeatedly. Below is an image of diamond and graphite, they form covalent network solids as you can see the carbon atom creating covalent bonds with one another in a large structure. Also, Sulfur can polymerize under high pressure, but that is it. Only 5 elements can do this.…show more content… Not as polyiodine, but as polyiodide (the anion). Oligomeric forms of iodide are already known. I mentioned I3- (triiodide) many times in my general chemistry class last year (it's a good one for drawing a Lewis structure) and higher iodides such as I5- and I7- are known to exist, but now comes proof of In-. Where n stands for any number or Iodide
