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Potassium Iodide - KI

Last updated date: 23rd May 2024
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What is Potassium Iodide (KI)?

Potassium iodide is described as an inorganic chemical compound which is denoted by the chemical formula - KI. This compound is defined as a metal-halide salt featuring an ionic bond between potassium cation (K+) and iodide anion (I–). This compound is colorless to white, and it appears as cubical crystals or white or powder granules. It has a saline taste and is highly bitter.

This compound is prepared using iodine and mixing potassium hydroxide. It is also one of the safe and most effective medicines required in a health system, and it is on the list of the World Health Organization of Essential Medicines.

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Potassium Iodide Structure (KI Structure)

A potassium iodide molecule contains one iodide anion and one potassium cation, which are held together with an ionic bond. The structure of a Potassium Iodide molecule can be illustrated below.

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Properties of Potassium Iodide

Let us look at the properties of Potassium Iodide below:

Physical Properties of Potassium Iodide


Potassium Iodide

Chemical Formula



3.12 g/cm3

Molecular Weight or Molar Mass

166.0028 g/mol

Boiling Point

1,330 °C

Melting Point

681 °C

Chemical Properties of Potassium Iodide

Potassium iodide compound can be oxidized into an I2 molecule by introducing an oxidizing agent to it. One of the examples of such a reaction is given below:

2KI + Cl2 → 2 KCl + I2

This compound can be used as an iodide source in many organic synthesis reactions. One such example is given as the synthesis of aryl iodides from the arene's diazonium salts.

Benefit of Taking Potassium Iodide Compound During a Radiological Accident

  • It is assumed that the 'accident' produces notable amounts of iodine's radioactive isotopes (such as I-131 and I-125), and those get into the supply of food. They would then enter into the body and be taken up by the thyroid gland, which would become non-functional or cancerous.

  • By taking the KI compound, the thyroid gland would become saturated with Iodine, and for a while, quit taking up new (which is radioactive) Iodine. And then the thyroid gland would be saved.

  • Also, it is not completely clear how this would normally take place and whether it would be much useful to that of a fart in a whirlwind.

  • First, the radio-Iodine injury would take place slowly, and if the medical facilities still existed, treatment is available for the injury correction. Also, many do not know how many people would experience this specific injury mode.

  • And also, it does not do anything for the people exposed to radio-cesium, Strontium-90, and more related.

Saturated Potassium Iodide Solution

A saturated solution is defined as a solution that contains a similar amount of potassium iodide salt as would be in equilibrium with undissolved salt. It means this is a solution that we represent by the equilibrium.

KI(s) ⇌ K++I

Uses of Potassium Iodide

Let us discuss the use of potassium iodide as follows:

Medical Uses

Dietary Supplement

Potassium iodide can be used in the human diet and also as a nutritional supplement in animal feeds. It is the most common additive for the latter used to "iodize" table salt (which is a public health measure to prevent iodine deficiency in populations that get little seafood). Also, iodide oxidation causes a slow loss of iodine content from the iodized salts exposed to excess air.

Thyroid Protection

Thyroid iodide compound uptake blockade with potassium iodide can be used in nuclear he medicine scintigraphy and some radioiodinated compound therapy that are not targeted to the thyroid, like iobenguane (MIBG), which can be used either to image or treat the iodinated fibrinogen or neural tissue tumors, which is used in the fibrinogen scans in clotting investigation. These compounds consist of iodine, but not in the form of iodide.

Nuclear Accidents

The U.S. Food and Drug Administration, in 1982, has approved potassium iodide to protect thyroid glands from radioactive iodine by involving fission emergencies or accidents. In an accidental attack or event in nuclear bomb fallout or on a nuclear power plant, volatile fission product radionuclides can be released. Out of these products, 131 (Iodine-131) is the most common and is specifically much dangerous to the thyroid gland since it can lead to thyroid cancer.

Side Effects of Potassium Iodide

There is a reason for caution by prescribing the ingestion of a high dose of iodate and potassium iodide, as their unnecessary usage can cause conditions like the trigger, Jod-Basedow phenomenon, and/or hypothyroidism and worsen hyperthyroidism, and then causes either temporary or even permanent thyroid conditions. Also, it can cause sialadenitis (which is an inflammation of the salivary gland), rashes, and gastrointestinal disturbances. Also, potassium iodide compound is not recommended for people having hypocomplementemic vasculitis and dermatitis herpetiformis - conditions that are linked to iodine sensitivity risk.

FAQs on Potassium Iodide - KI

1. How to Make Potassium Iodide?

Answer: Potassium iodide (KI) compound can be prepared by reacting potassium hydroxide with iodine using a hot solution. It is mainly used in a saturated solution form, with 100 grams of potassium iodide to 100 ml water, which equates to 50 mg/drop nearly. Until drinking, this respective solution is generally applied to the fruit juice, tea, or milk.

2. What is Potassium Iodide Used for?

Answer: Anti-thyroid and potassium iodide medications can also be used to prepare the thyroid gland for surgical removal, treat the other overactive thyroid disorders (which is hyperthyroidism), and protect the thyroid issue in radiation exposure emergencies.

3. What are the Side Effects of Potassium Iodide?

Answer: Severe side effects of Potassium Iodide compound include swelling of different body parts, such as the lips, face, neck, tongue, feet, or hands; allergic reactions (which are skin rashes such as hives; difficulty in breathing, swallowing, or speaking, shortness or wheezing of breath); fever with joint pain.

4. What Does Potassium Iodide Compound Do for the Body?

Answer: KI (potassium iodide) is defined as a stable (which is not radioactive) iodine salt that helps to prevent the radioactive iodine absorption by the thyroid gland, hence, shielding this gland from radiation injury. The thyroid gland is considered to be the most sensitive component of the body to radioactive iodine.