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 
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



Natural occurrence


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



The main routes are divided by the source of the chloride ion. The simplest is hydrochloric acid:

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 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 (II) minerals
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)

via sodium chloride

Relative Solubilities
  water ethanol
g/L M g/L M
copper chloride 757 5.63 530.00 3.94
sodium chloride 359 6.10 0.65 0.01
copper acetate 65 0.36 71.40 0.39
sodium acetate 1233 15.00 23.00 0.28
copper sulfate 200 1.26 ins 0
sodium sulfate 139 1.02 ins 0
copper (II) acetate
0.035M (100ml) scale
  1. Gather 7g (0.035M) of copper (II) acetate monohydrate
  2. Heat to 160°C (325F) for 10 minutes to drive off the water
  3. Measure mass again: should be 6.35(7)g (0.035M)
  4. Dissolve in 100ml dried ethanol (saturated limit, 0.35M)
  5. Transfer ethanol to separation funnel
  6. Prepare saturated saline solution (6M)
  7. Repeat
    1. Add 5.7ml of saturated saline solution to ethanol in sep funnel, shaking regularly
    2. Draw off aqueous layer and evaporate
      NB: Should contain mostly sodium acetate, less sodium chloride.
  8. Until mostly sodium acetate remains
  9. Evap the ethanol layer, leaving mostly copper chloride

When using salt as a source of chlorine, choose an anion whose copper salt that is more soluble in water than ethanol, such as copper (II) acetate or copper sulfate, and preferably an anion for which the sodium salt also prefers water. Mix them in a water/ethanol solution, and allow the copper chloride to dominate the ethanol phase.

via ammonium chloride

...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]
  1. Combine (dry) ammonium chloride and copper (II) oxide in a flask
  2. Direct gasses from flask through CaO dryer, then a suckback trap, and thence to a water bubbler.
  3. Heat to 190°C
    4 NH4Cl(s) + CuO(s)
    (NH4)2CuCl4(s) + NH4OH(g) + NH3(g) // gasses condense or are absorbed by water
  4. remove dryer
  5. Heat to 300°C
    CuCl2(s) + 2 NH4Cl(g) // may condense in trap or be absorbed in bubbler
    CuCl2(s) + 2 NH3(g) + 2 HCl(g) // may recombine to 2 NH4Cl in trap, or be absorbed in bubbler.
  6. Remove bubbler
  7. Cool to RT with dryer in place.


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


  • 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.