Description of experiment
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Needed compounds:
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cupric chloride dihydrate : CuCl2 . 2H2O
dimethyl sulfoxide : (CH3)2SO
methanol : CH3OH
Class:
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elem=C,Cu
organic
coordination
Summary:
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Copper (II) ions form a complex with DMSO and chloride at the same time. This
is a green complex (somewhat limegreen, however, a little bit more towards pure
green). This complex is soluble in water and probably also is decomposed by
replacement of ligands by water molecules.
Description:
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Carefully heat some copper (II) chloride dihydrate until it has lost all of its
water. This is the case, when the solid is dark brown without any green specks
in it.
Dissolve the anhydrous copper (II) chloride in methanol, which is free of
water: A yellow/green solution is obtained.
Add a small amount of DMSO to the yellow/green solution and shake: The DMSO
mixes with the yellow/green solution. The solution becomes a little bit more
green but remains clear.
Put aside the clear solution and wait a few hours: Lime green (somewhat more
green) crystals have formed on the glass and a layer of fine crystals has
settled at the bottom.
Add a lot of water: The liquid mixes with the water, the crystals quickly
dissolve and the liquid becomes clear and light blue. After a short while,
however, the liquid has turned a little bit turbid.