Iodine — not too widespread in the nature, but at the same time very scattered substance. Its earth crust contains no more than 0.00005%. At the same time it is practically present at microscopic doses everywhere. For the first time iodine was emitted in 1811 by the French chemist Bernard Courtois from ashes of seaweed.
In chemistry iodine belongs to group of halogens, and its formula looks as I. Chemical activity this substance is characterized by not too high. Iodine differs from other halogens in what does not react with the majority of nonmetals, and with metals reacts only when heating.
Whether iodine has a smell
Iodine can be dissolved in carbon tetrachloride, gasoline, benzene. But more often as solvent alcohol and water are applied to this halogen nevertheless. Aqueous-alcoholic tinctures of iodine, for example, are used in medicine as disinfectant.
In pure form this substance represents black-gray crystals with a violet reflection. One of distinctive features of iodine is its pungent and specific smell. And can smell both crystals of this substance, and its solutions, including water and spirit.
As iodine belongs to toxic agents, it is impossible to accept inside, for example, its crystals or medical tincture. For the person a lethal dose are only 2 g of this halogen.
Even at small temperature increase iodine begins to let out couples of violet color intensively. Their interesting property is that when cooling they turn directly into solid substance.
Iodine vapors also have a pungent specific smell, are poisonous and it is impossible to inhale them too long. It can lead to burns, irritation of bodies of a respiratory system and also to organism intoxication.
What else has properties
Distinctive feature of iodine is that it consists only of one isotope — ioda-127. Under big pressure and at high temperature this halogen can turn into liquid state. Also such form of iodine differs in a pungent, characteristic smell.
In terms of chemistry, iodine is strong oxidizer. Also on its basis a number of acids, for example, of HIO4 is formed:
- 2HCLO4 + I2 = 2HIO4 + CL2.
In interaction with metals this halogen forms iodides. Such minerals in the nature usually meet in the form of kristallik, scaly and lamellar units or even continuous masses in fields of non-ferrous metals.