Carbonate is the salt derived from carbonic acid, which is a chemical compound that forms when water interacts with carbon dioxide gas. It’s a kind of carbonyl group that has a couple of oxygen atoms bonding directly to carbonyl carbon, which looks like three oxygen atoms surrounding a single carbon atom. Lime juice leaves behind a white mark when spilled on the floor, thanks to carbonate’s presence in the juice. Similarly, the club soda fizz, baking and washing soda, toothpaste, minerals (calcium carbonate, zinc carbonate, iron carbonate, magnesium carbonate, etc.), blackboard chalks, medicines, etc. have carbonate.    

Making Carbonates

As aforementioned, carbonate is formed when carbon dioxide is dissolved in water. However, the more common way to make carbonates is subjecting carbon dioxide to alkaline solutions. Small traces of carbon dioxide passing through alkaline solutions could lead to carbonate formation. If the carbon dioxide amount is excessive, the end result would likely be bicarbonates. Setting lime mortar (used for constructing buildings) could result in the creation of calcium carbonate. 

Carbonate Physical Traits

Carbonate is a solid at room temperature. Upon heating, most carbonates decompose to carbon dioxide and metal oxide, which could be calcium oxide, lithium oxide, or any other metal oxide. However, not all carbonates decompose at the same temperature. The decomposition temperature varies across different carbonates, which depends on the group they belong to in the periodic table. These groups are determined or the elements categorized based on their physical properties.

Carbonates belonging to group 1 and group 2 of the periodic table are colorless. Carbonates belonging to transition metals groups (groups 3 to 12) have some color. Also, group 1 carbonates are relatively water-soluble; group 2 carbonates aren’t as soluble. All types of carbonates have some level of water solubility. They could dissolve in and recrystallize from water.

Carbonate Uses

There are different carbonate variants – such as potassium carbonate, calcium carbonate, lithium carbonate, sodium carbonate, etc. These could be of use in their own unique ways. The following are some examples:

  • Soda ash (sodium carbonate) is used for manufacturing paper, glass, rayon, detergents and soaps. It’s also used for softening water.
  • Limestone (comprising calcium carbonate) is used to refine iron ore and manufacture steel, make agricultural lime, cement, etc.
  • Potash (potassium carbonate) is used to manufacture glass.
  • Lithium carbonate is used to make ceramics, glasses, aluminum, and pharmaceuticals.
  • Nickel carbonate is used to make ceramics and it’s also used in electroplating.

Cobalt carbonate plays the catalyst role in the refining sector, as a livestock mineral supplement, and ceramic pigment.