gold(I,III) chloride
   HOME

TheInfoList



OR:

Gold(I,III) chloride is a black solid with the chemical formula Au4 Cl8. It is an example of a mixed valence compound as it contains gold in two different
oxidation states In chemistry, the oxidation state, or oxidation number, is the hypothetical charge of an atom if all of its bonds to different atoms were fully ionic. It describes the degree of oxidation (loss of electrons) of an atom in a chemical compound. C ...
; square-planar gold(III) and almost linear gold(I). The compound is
photosensitive Photosensitivity is the amount to which an object reacts upon receiving photons, especially visible light. In medicine, the term is principally used for abnormal reactions of the skin, and two types are distinguished, photoallergy and phototoxicit ...
as well as air- and moisture-sensitive.


Synthesis

Gold(I,III) chloride may be prepared by the reaction of
gold(III) chloride Gold(III) chloride, traditionally called auric chloride, is a compound of gold and chlorine with the molecular formula . The "III" in the name indicates that the gold has an oxidation state of +3, typical for many gold compounds. Gold(III) c ...
with gold carbonyl chloride or
carbon monoxide Carbon monoxide (chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simple ...
at room temperature in
thionyl chloride Thionyl chloride is an inorganic compound with the chemical formula . It is a moderately volatile, colourless liquid with an unpleasant acrid odour. Thionyl chloride is primarily used as a chlorinating reagent, with approximately per year bein ...
. :Au2(CO)Cl4 + Au2Cl6 → COCl2 + Au4Cl8 :2 Au2Cl6 + 2 CO → Au4Cl8 + 2 COCl2


Structure and properties

Single crystals of gold(I,III) chloride are triclinic with a P
space group In mathematics, physics and chemistry, a space group is the symmetry group of an object in space, usually in three dimensions. The elements of a space group (its symmetry operations) are the rigid transformations of an object that leave it uncha ...
and consist of discrete Au4Cl8 molecules with idealised C2h symmetry. Within this the Au(I) centers are linearly coordinated with a Cl-Au-Cl bond angle of 175.0° (close to the ideal value of 180°) and an average bond length of 2.30 Å. The Au(III) centers adopt a slightly irregular square-planar conformation with the Au-Cl bond lengths for bridging chlorides (2.33 Å) being slightly longer than those of terminal chlorides (2.24 Å).


References

Gold compounds Chlorides Metal halides Mixed valence compounds Light-sensitive chemicals Gold–halogen compounds {{inorganic-compound-stub