Precipitation and complexation of copper(II) with an ammonia solution

Chemicals needed

ammonia solution 3,5 %

distilled water

copper(II) sulfate (or pentahydrate) GSGESUND.gif (476 Byte) Xn  GSUMWELT.gif (758 Byte)  N    R 22-36/38-50/53    S (2)-26-36/37/39-60-61

Equipment needed

test tube

Test procedure


The diluted solution can be discharged into the drainage.


Copper(II) precipitates like many metallic cations in an alkaline milieu as a hydroxide. With a surplus of ammonia the soluble copper(II) tetraammine complex is formed - [Cu(NH3)4]2+.


cuko1.jpg (3134 Byte)

diluted copper(II) sulfate solution

cuko2.jpg (2887 Byte)

Precipitation of copper(II) hydroxide

cuko3.jpg (4242 Byte)

copper(II) tetraammine solutions


derived from a school experiment