Basic Copper Carbonate

Synthesis of basic copper carbonate using household materials

Basic copper carbonate, also known as copper(II) carbonate hydroxide, is a blue-green compound that is used as a pigment, catalyst, and a chemical building block. The main reason behind making this batch of basic copper carbonate is to easily access other copper compounds like copper(II) chloride.

Procedure

The procedure to make basic copper carbonate is simple with few steps and materials that are obtainable from over-the-counter sources.

1. Weigh out 64 grams of copper sulfate pentahydrate (typically found as root killer at the hardware store) and pour into a 400 mL beaker alongside 175 mL of distilled water.
2. Then weigh out 24 grams of anhydrous sodium carbonate (can be made by heating baking soda. Find procedure here) and pour into a 500 mL beaker with 100 mL distilled water.
3. Place both beakers on a hotplate while stirring to help all solids to dissolve.
4. Once everything is in solution, remove the solutions from heat and then slowly pour the sodium carbonate solution into the copper sulfate solution. This this in small portions and with lots of stirring to prevent the beaker from foaming over.
5. After the solutions are mixed, they are stirred for a few minutes before allowing to sit for an hour to ensure everything is reacted.
6. Then filter the solid and wash with some water before allowing to dry. Find the video of the procedure here.

What’s Going on?

The above reaction is occurring when the two solutions are mixed together. Two molecules of copper sulfate react with two molecules of sodium carbonate and one molecule of water to get the product basic copper carbonate, sodium sulfate, and carbon dioxide. The foaming from the reaction is due to the carbon dioxide being formed and released. This is also the reasoning behind why sodium carbonate is used instead of sodium bicarbonate (baking soda). If baking soda is used in place of the sodium carbonate, three molecules of carbon dioxide are produced instead which would lead to an even greater issue with foaming. Additionally, the washing step after filtering removed the water soluble sodium sulfate biproduct and unreacted copper sulfate and sodium carbonate.

Warnings

A short warning about the chemicals used. Anhydrous sodium carbonate is an eye irritant and both copper(II) sulfate and basic copper carbonate are irritants and harmful if ingested.

Conclusion

Basic copper carbonate can be prepared simply from certain household materials. This basic copper carbonate will be used in future experiments to prepare other copper salts. The range of copper salts that are planned will be colorful (blues, purple, some reds, white) and have interesting real world applications from organic synthesis, pigments, to even cloud seeding.

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