Copper (II) chloride
|OTP appearance||yellow-brown solid|
|Boiling Point(°C)||993 (decomp)|
|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|
copper (II) chloride
- Catalyst for the production of sulfuric acid
- Metal etchant
- 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.
|Source of chlorine ion|
|hydrochloric acid (aerated)||ammonium chloride||chlorine gas|
|copper (I) chloride||✔||?||?|
copper (I) sulfide
copper (I) oxide
|Copper (II) oxide||✔||✔||?|
|copper (II) sulfide||✔||✔||?|
|Copper (II) acetate||✔||?||no|
|Copper (II) hydroxide||?||?||?|
via hydrochloric acid
- 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. 
- 4 CuCl + 4 HCl + O2 → 4 CuCl2 + 2 H2O // from (I) to (II)
copper (II) minerals
via ammonium chloride
- Combine ammonium chloride and damp copper (II) hydroxide
- Mix thoroughly, allowing the compounds to react
- 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 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
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.
- Combining with sodium hydroxide produces insoluble copper hydroxide, which will then absorb carbon dioxide from the air, resulting in nature-safe carbonate/hydroxide compounds equivalent to malachite and azurite
- Combining with sodium bicarbonate or sodium carbonate shortcuts the carbon dioxide absorption and produces the mineral forms of copper directly.
- Borisov, V.A.; D’yachenko, A.N; Kraidenko, R.I. (2011)
Russian Journal of General Chemistry 81(7); pp1430–1433.
link courtesy researchgate.