However, the term is also applied to an equimolar mixture of those two salts, with whatever water of hydration the sodium carbonate includes, supplied as a powder.

Sodium sesquicarbonate is used in bath salts, swimming pools, as an alkalinity source for water treatment, and as a phosphate-free product replacing the trisodium phosphate for heavy duty cleaning.

Treatment with sodium sesquicarbonate removes copper(II) chlorides from the corroded layer.

[5] It is the carbonate moiety which forms the precipitate, the bicarbonate being included to moderate the material's alkalinity.

In Chinese cuisine, it is known as mǎyájiǎn (simplified:马牙碱 traditional: 馬牙鹼) which roughly translates to “horse tooth alkaline” and traditionally used as an ingredient in the marinade for century eggs, a dish generally made from duck eggs preserved whole in an highly alkaline mixture[citation needed].