Detailed Product Description:

One of the alkali metals, potassium is one of the lowest density metals,

second only to lithium.  It is a soft, low-melting point solid that can

easily be cut with a knife.  Freshly cut potassium is silvery in appearance,

but in air it begins to tarnish toward gray immediately.  Potassium and

its compounds emit a violet color in a flame.  This fact is the basis of

the flame test for the presence of potassium in a sample.  

Chemical Properties

Potassium must be protected from air for storage to prevent disintegration

of the metal from oxide and hydroxide corrosion.  Like the other alkali

metals, potassium reacts violently with water producing hydrogen.  The

reaction is notably more violent than that of lithium or sodium with water,

and is sufficiently exothermic that the evolved hydrogen gas ignites.

Potassium compounds generally have excellent water solubility, due to

the high hydration energy of the K+ ion.  The potassium ion is colorless

in water.

Applications:

Because potassium reacts quickly with even traces of water, and its

reaction products are nonvolatile, it is sometimes used alone, or as NaK

(an alloy with sodium that is liquid at room temperature) to dry solvents

prior to distillation.  In this role, it serves as a potent desiccant.

Precautions

Solid potassium reacts violently with water, and should therefore be kept

under a mineral oil such as kerosene and handled with care.  Unlike lithium

and sodium, however, potassium cannot be stored under oil indefinitely.  If

stored longer than 6 months to a year, dangerous shock-sensitive peroxides

can form on the metal and under the lid of the container, which can detonate

upon opening.  It is recommended that potassium metal not be stored for

longer than three months unless stored in an inert (oxygen free) atmosphere,

or under vacuum.

The extremely alkaline potassium hydroxide (KOH) residue on the surface

of potassium which has been exposed to moisture, is a caustic hazard.  As

with sodium metal, the "soapy" feel of potassium metal on skin is due to

caustic breakdown of the fats in skin into crude soft potassium soap, and

represents the beginning of an alkali burn.  Potassium should obviously be

handled with care, with full skin and eye protection.

Potassium fires are exacerbated by water, and only a few dry chemicals

are effective for them.  Potassium also reacts violently with iodine.

Must be stored in airtight containers or in kerosene, mineral oil, or

similar liquid that does not contain water or free oxygen.

Download MSDS, read and understand fully, the dangers and precautions

associated with the use of this substance.

                Click here to download MSDS (Material Safety Data Sheet)

Packaging:

Contains 25 grams potassium cubes packed in mineral oil in 250ml

wide-mouth jar.

Availability:

This material is available by special order only.  Please allow 2-3 weeks

after receipt of order.