What is Iodide?
Iodide is described as an anion having a valency of -1. The iodine compounds having an oxidation state of -1 are referred to as iodides. The chemical formula for iodide is given as I–.
Iodine is an element that is a halogen. This compound tends to accept an electron and exists as an ion, which is negatively charged. Thus, the anion name iodide can be used interchangeably with iodine. The IUPAC name is given as Iodide.
Structure and Characteristics of Inorganic Iodides
Iodide is given as the largest monatomic anion, and it is assigned with a radius of around 206 picometers. Additionally, in comparison, the lighter halides are considerably much smaller: chloride (181 pm), fluoride (133 pm), bromide (196 pm). In contrast, because of its size, iodide produces relatively weak bonds with most of the elements.
Most of the iodide salts are soluble in water, but they are often less related to the related bromides and chlorides. Being large, iodide is very less hydrophilic compared to the smaller anions. A consequence of this is given as sodium iodide is highly soluble in acetone, but sodium chloride is not. The low solubility of lead iodide and silver iodide represents the covalent nature of these iodide metals. The iodide ion presence test is given as the formation of yellow precipitates of these compounds after the treatment of either lead(II) nitrate or silver nitrate solution.
Also, the iodide salt's aqueous solutions dissolve iodine better than pure water. This effect is because of the formation of the triiodide ion, which is brown in colour, which is chemically represented as follows:
I− + I2 ⇌ I3−
Redox, Including Antioxidant Properties
Iodide salts are defined as mild reducing agents, and several react with oxygen to form iodine. A reducing agent is described as a chemical term for an antioxidant. Its antioxidant properties are expressed as a redox potential quantitatively:
I− ⇌ 1⁄2 I2 + e− E° = 0.54 volts.
Since the iodide is easily oxidized, a few enzymes readily transform it into electrophilic iodine agents as needed for the biosynthesis of myriad iodide-containing natural products. Also, iodide function as an antioxidant reducing species that can destroy the species of reactive oxygen like hydrogen peroxide, where the chemical equation is represented as follows:
2 I− + peroxidase + H2O2 + histidine, tyrosine, lipid,..... → iodide-compounds + H2O + 2 e− (which are antioxidants). Iodide structure I- can be given as follows.
Properties of Iodide
Let us look at the important properties of Iodide as tabulated below.
Physical Properties of Iodide I–
Chemical Properties of Iodide I–
Pb(NO3)2(aq) + 2 NaI(aq) → 2 NaNO3(aq) + PbI2(s) (which is a yellow precipitate)
2KI + Cl2 → 2KCl + I2
Uses of Iodide I–
Let us look at the important uses of the iodide compound as listed below:
Iodide holds a disinfectant property. It is not readily affected because of the chlorine by organic content or water pH, but the cold water temperature markedly reduces iodide disinfectant activity.
Iodine preparations like povidone-iodine can be used to disinfect the skin before surgery. The allergic reactions to the iodine are more common and should be evaluated carefully since the resultant stain may mask the swelling and redness.
Potassium iodide can also be added as a nutrient to prevent goitre, a thyroid problem, which is caused by a lack of iodine and prevent a mental retardation form associated with the deficiency of iodine.
Valency of Iodide
Iodine valence is -1 because, in its last shell, it has 7 electrons and receives one electron from making it stable.
Health Hazard of Iodide
A few of the Health Hazard of iodide can be given as follows.
The major and primary effects of long-term oral exposure to the elevated amounts of inorganic iodide are given as paradoxically, hypothyroidism and hyperthyroidism. The excess intake of this iodide compound can inhibit the synthesis and release of thyroid hormone, resulting in goitre and hypothyroidism.