bicarbonate

noun

1. the univalent anion HCO₃⁻; any salt of carbonic acid in which only one of the hydrogen atoms has been replaced.

   “The next question that occurs relates to the composition of this crystallized carbonate of potash, which I am induced to call bi-carbonate of potash, for the purpose of marking more decidedly the distinction between this salt and that which is commonly called a subcarbonate, and in order to refer at once to the double dose of carbonic acid contained in it.”

2. Sodium bicarbonate used as a mild antacid; bicarbonate of soda.

   “Fans will pump air through the alkaline stream, which causes carbon dioxide to form solid calcium carbonate, the material from which seashells are formed, which will look like a fine sand, as well as dissolved bicarbonate.”