potassium iodide

Chemical Formula: KI
Molecular Weight: 166.0
Melting Point: 681 C
Boiling Point: 1330 C
MSDS Number: P5906
Specific Gravity: 3.13
Vapor Pressure: 1 MMHG
Hardness: Knoop 5
Dielectric Constant: 4.94 at 2MHz
Solubility: 140g/100g water
Density: 3.1 g/cc
pH: 7-9
Stability: Stable

Conditions to Avoid:
May decompose on exposure to light, air and moisture.

Incompatabilities:
Tin
Strong reducing agents
Nickel
Strong acids and their alloys
Steel
Aluminum
Alkali metals
Brass
Magnesium
Zinc
Cadmium
Copper

Uses:
Used for various laboratory purposes.
Added to table salt to produce Iodized salt.
Used to prevent bodily harm caused by radioactive isotopes of iodine.

Hazards:
This chemical is toxic when taken in large amounts and may cause harm to unborn babies as well as cause iodism by inhalation and skin contact. It targets the blood and thyroid. Upon combustion/decomposition KI produces hydrogen iodide and/or potassium oxides.

Precautions:
Wear protective clothing when working with KI, including gloves, eye and face protection. Use only in a chemical fume hood.

Side Effects (Toxicological Information):
Effects include iodism, neonatal death, fever, irritation to eyes and mucous membranes, goiter, gastrointestinal effects, fetal deformation, convulsions, and decreased fertility.

Disposal:
KI can be disposed of by mixing with a combustable solvent and burning in a chemical incinerator equipped with and afterburner and scrubber.

How KI prevents radiation damage:
KI is taken in pill form, working best when taken 1/2 to 1 hour before exposure to radioactive iodine. The thyroid gland readily absorbs any iodine available, radioactive or not, and retains much of what it absorbs. When the iodine in KI is made available to the thyroid, it absorbs as much as it can, becomming saturated. When the radioactive iodine is ingested the thyroid can absorb only small amounts, allowing the rest to be filtered by the kidneys and eliminated.

KI can also be used soon after exposure to radioactive iodine to prevent further absorbtion of radioactive iodine by the thyroid.

Children are at highest risk for developing cancer or other injury from radioactive iodine, so they are usually the first to recieve KI in an emergency, such as Chernobyl.

Stockpiling:
All communities near and downwind from nuclear facilities are urged to stockpile KI. Without stockpiles, if any accident were to occur many unnecessary injuries and deaths would result.

Stockpiling has caused many debates in nuclear communities, leading to ordinary people keeping a stock of KI in their own homes. In some of these communities it is available at drugstores, although their supplies would last minutes in an emergency situation. It can also be purchased over the Internet.

Reference:
MSDS sheets
http://www.ki4u.com/