Smelling salts is ammonium carbonate.
Barium carbonate occurs as the mineral witherite.
Iron carbonate is a ferrous compound that occurs in nature as siderite . White lead used as a pigment in paints is basic lead carbonate. Only ammonium, potassium, and sodium carbonates are readily soluble in water. Alkali metal carbonates are stable when heated, but other carbonates decompose, releasing carbon dioxide . Carbonates also give off carbon dioxide when treated with dilute acids, e.g., hydrochloric acid.