Detailed Product Description:
Tin (II) chloride (stannous chloride) is a white crystalline solid. It forms
a stable dihydrate, but aqueous solutions tend to undergo hydrolysis,
particularly if hot. SnCl2 is widely used as a reducing agent (in acid solution),
and in electrolytic baths for tin-plating. Tin(II) chloride should not be
with the other chloride of tin; tin (IV) chloride or stannic chloride (SnCl4).
Soluble in water and glycerol, slightly soluble in alcohol. Noncombustible.
Grade & Purity:
This is anhydrous, ACS Reagent Grade material with a minimum purity of 99.5%.
Application Notes:
Tin (II) chloride can dissolve in less than its own mass of water without
apparent decomposition, but as the solution is diluted hydrolysis occurs to
form an insoluble basic salt. Therefore if clear solutions of tin (II) chloride
are to be used, hydrochloric acid must be added in order to maintain the
equilibrium towards the left-hand side (using Le Chatelier's principle).
Solutions of SnCl2 are also unstable towards oxidation by the air.
There are many applications in which tin (II) chloride acts as a reducing
agent, reducing silver and gold salts to the metal, and iron (III) salts to
iron (II).
Chemical Structure:
SnCl2 has a lone pair of electrons, such that the molecule in the gas phase
is bent. In the solid state, crystalline SnCl2 forms chains linked via chloride
bridges. The dihydrate is also three-coordinate, with one water coordinated
on to the tin, and a second water coordinated to the first. The main part of the
molecule stacks into double layers in the crystal lattice, with the "second"
water sandwiched between the layers.
Preparation:
Anhydrous SnCl2 is prepared by the action of dry hydrogen chloride gas on tin
metal. The dihydrate is made by a similar reaction, using hydrochloric acid.
The water is then carefully evaporated from the acidic solution to produce crystals
of SnCl2·2H2O. This dihydrate can be dehydrated to anhydrous using acetic anhydride.
Uses:
A solution of tin (II) chloride containing a little hydrochloric acid is used for the
tin-plating of steel, in order to make tin cans. An electric potential is applied,
and tin metal is formed at the cathode via electrolysis.
Tin(II) chloride is also used as a mordant in textile dyeing because it gives
brighter colors with some dyes e.g. cochineal. This mordant has also been used
alone to increase the weight of silk.
Tin (II) chloride also finds wide use as a reducing agent. This is seen in its use
for silvering mirrors, where silver metal is deposited on the glass.
A related reduction was traditionally used as an analytical test for Hg2+(aq).
For example, if SnCl2 is added dropwise into a solution of mercury (II) chloride,
a white precipitate of mercury (I) chloride is first formed; as more SnCl2 is added
this turns black as metallic mercury is formed. Stannous chloride can be used to
test for the presence of gold compounds. SnCl2 turns bright purple in the presence
of gold.
In organic chemistry, SnCl2 is mainly used in the Stephen reduction, whereby a
nitrile is reduced (via an imidoyl chloride salt) to an imine which is easily
hydrolyzed to an aldehyde.
Precautions:
Harmful if swallowed or inhaled. Causes irritation to skin, eyes, and the
respiratory tract.
Click here to download MSDS (Material Safety Data Sheet)
Packaging:
Contents of 100 grams comes packed in 250ml sized wide-mouth amber
glass bottle.