Iodine is a purple or black non-metallic element with an orthogonal crystal structure. This toxic element is prone to sublimation and can be easily purified in this way. Insoluble in water, but soluble in commonly used solvents such as ethanol, ether, and carbon tetrachloride. Iodine is used as a fungicide and preservative in dyes, tinctures, and medicines.
The pure state of iodine is a black solid that sublimates at room temperature (from a solid to a gas, rather than passing through a liquid state). Iodine is prone to form non-metallic diatomic molecules (I2) and is the heaviest naturally occurring halogen. Iodine has the lowest activity among the five halogens. Iodine compounds have weaker activity than other halogens, which can easily displace them from iodides. Iodine has some properties similar to metals in Chemicalbook. It is easily soluble in chloroform, carbon tetrachloride, or carbon disulfide, forming a beautiful purple solution. It is only slightly soluble in water. Iodine compounds are important in organic chemistry and very useful in medicine. It has 42 isotopes and isomers. There is only one stable isotope, iodine-127, which is found in nature. The half-life of artificial radioactive isotope 131 is 8 days.