Editing Copper(II) chloride (section)

===Coordination complexes===
{{chem2|CuCl2}} reacts with HCl or other [[chloride]] sources to form complex ions: the red {{chem2|[CuCl3]−}} (found in [[potassium trichloridocuprate(II)]] {{chem2|K[CuCl3]}}) (it is a [[dimerization (chemistry)|dimer]] in reality, {{chem2|[Cu2Cl6](2−)}}, a couple of tetrahedrons that share an edge), and the green or yellow {{chem2|[CuCl4](2−)}} (found in [[potassium tetrachloridocuprate(II)]] {{chem2|K2[CuCl4]}}).<ref name="greenwood" /><ref name="tetra">{{cite book|author=Naida S. Gill |author2=F. B. Taylor |series=Inorganic Syntheses |year=1967 |volume=9 |pages=136–142 |doi=10.1002/9780470132401.ch37 |title=Tetrahalo Complexes of Dipositive Metals in the First Transition Series |isbn=978-0-470-13240-1}}</ref><ref name="handbook" />

:{{chem2|CuCl2 + Cl- ⇌ [CuCl3]-}} 
:{{chem2|CuCl2 + 2 Cl- ⇌ [CuCl4](2-)}}

Some of these complexes can be crystallized from aqueous solution, and they adopt a wide variety of structures.<ref name="tetra" />

Copper(II) chloride also forms a variety of [[complex (chemistry)|coordination complexes]] with [[ligand]]s such as [[ammonia]], [[pyridine]] and [[triphenylphosphine oxide]]:<ref name="Ullmann" /><ref name="greenwood" /><ref>{{cite journal |author1=W. Libus |author2=S. K. Hoffmann |author3=M. Kluczkowski |author4=H. Twardowska |title=Solution equilibriums of copper(II) chloride in pyridine and pyridine-diluent mixtures |journal=Inorganic Chemistry |date=1980 |volume=19 |issue=6 |pages=1625–1632 |doi=10.1021/ic50208a039 |language=en}}</ref>
:{{chem2|CuCl2 + 2 C5H5N → [CuCl2(C5H5N)2]}} (tetragonal)
:{{chem2|CuCl2 + 2 (C6H5)3P\dO → [CuCl2((C6H5)3P\dO)2]}} (tetrahedral)
However "soft" ligands such as [[phosphine]]s (e.g., [[triphenylphosphine]]), iodide, and [[cyanide]] as well as some tertiary [[amine]]s induce [[Redox|reduction]] to give copper(I) complexes.<ref name="greenwood" />