Copper (II) chloride

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Copper (II) chloride
aka cupric chloride
Chemical formula CuCl2
OTP appearance yellow-brown solid 
Molar Mass(g/mol) 134.45(anh)
Melting Point(°C) 498 
Boiling Point(°C) 993 (decomp) 
Density(g/cc) 3.386 
Solubility in water(g/L) 757 
Solubility in ethanol(g/L) 530 
Solubility in methanol(g/L) 680 
Solubility in ether(g/L) 1.1 
Solubility in acetone(g/L) 30
NFPA 704


Thermal Decomposition
copper (II) chloride



Natural occurrence

  • Does occur naturally as the very rare minerals tolbachite and eriochalcite


Soluble copper compounds are toxic to mammals and can be deadly to fish.



The main routes are divided by the source and valence of the copper, and the source of the chloride ion.

Production of copper chloride
  Source of chlorine ion
hydrochloric acid (aerated) ammonium chloride chlorine gas
Copper (0)
copper metal ?
Copper (I)
copper (I) chloride ? ?
copper (I) sulfide
? ? ?
copper (I) oxide
? ? ?
Copper (II)
Copper (II) oxide ?
copper (II) sulfide ?
Malachite ?
Azurite ?
Copper (II) acetate ? no
Copper (II) hydroxide ? ? ?

via hydrochloric acid

metallic copper
  • Bubble air through copper metal immersed in hydrochloric acid. This will not work without the air, and even then it takes days. This may go in two separate steps, first to copper (I) chloride, and thence to copper(II) chloride, shown separately below.
    4 Cu + 4 HCl + O2 4 CuCl + 2 H2O // from copper(0) to copper (I)
    4 CuCl + 4 HCl + O2 4 CuCl2 + 2 H2O // from copper(I) to copper (II)
copper (I) chloride
  • Bubble air through copper (I) chloride in hydrochloric acid. This will not work without the air, and even then it takes days. [1]
    4 CuCl + 4 HCl + O2 4 CuCl2 + 2 H2O // from (I) to (II)
copper (II) minerals

via ammonium chloride

copper hydroxide
  1. Combine ammonium chloride and damp copper (II) hydroxide
  2. Mix thoroughly, allowing the compounds to react
  3. Heat above 40°C, driving off the ammonium hydroxide
    NB keep temperature below 200°C to prevent decomposing the copper hydroxide
    keep temperature below 350°C to prevent decomposing the ammonium chloride
    Both ammonium hydroxide and copper chloride are thermally stable.
copper carbonate / malachite / azurite

These reactions work in the presence of excess ammonium chloride

4 NH4Cl + Cu2CO3(OH)2 2 CuCl2 + 3 H2O + 4 NH3 + CO2 // 2x excess of -chloride
6 NH4Cl + Cu3(CO3)2(OH)2 3 CuCl2 + 4 H2O + 6 NH3 + 2 CO2 // UNTESTED
copper (II) oxide / sulfide
...hydrochlorination of the copper(II) compounds begins at 190°C to form ammonium chlorocuprates, (NH4)2CuCl4 in with copper (II) oxide and NH4CuCl3 with copper (II) sulfide, which at the temperature higher than 300°C decompose affording CuCl2[2]

Compound  I.  A  mixture  of  copper  oxide,  6.67  g,  and  ammonium  chloride,  17.61  g,  was  calcined  at  a  temperature of 320°C for 12 h.
Compound  II.  Prepared  similarly  from  5.46  g  of  copper sulfide and 18.04 g of ammonium chloride at a temperature of 320°C for 12 h
  1. Combine 1ubm copper (II) oxide and 2.6ubm dry ammonium chloride
  2. Heat to 320°C for 12h
    2 NH4Cl + CuO
    CuCl2 + H2O + 2 NH3
  3. Cool to RT with dryer in place.

via chlorine

metallic copper

At or above red heat (~500°C), copper reacts directly with gaseous chlorine, giving molten CuCl2. The reaction is sufficiently exothermic that the reaction will continue once started.

via calcium chloride

Metathesis reaction between copper (II) sulfate with calcium chloride or barium chloride, producing copper chloride in solution and calcium sulfate as a precipitate. Obviously this is only useful after the production of both materials, so there's a bootstrapping problem.

CuSO4 + CaCl2 CuCl2 + CaSO4
CuSO4 + BaCl2 CuCl2 + BaSO4


Recrystallize from hot dilute aqueous HCl by cooling in a calcium chloride-ice bath


  • Visual: Yellow-brown (anhydrous) dark green (excess chloride) or bright blue (partially hydrated) crystals
  • Reacts vigorously with aluminum
    3 CuCl2 + 2 Al 3 Cu + 2 AlCl3


  • Do not store with excess copper. This can result in decomposition to copper (I) chloride:
    Cu + CuCl2 2 CuCl
  • Do not store in acidic conditions.


See Also


  1. US patent 2586579 "Method of production of cuprous oxide and copper chlorides"
    Link courtesy Google
  2. Borisov, V.A.; D’yachenko, A.N; Kraidenko, R.I. (2011) "Reaction of Ammonium Chloride with the Copper(II) Sulfide and Oxide, and Identification of the Reaction Products"
    Russian Journal of General Chemistry 81(7); pp1430–1433. 
    link courtesy researchgate.