Sodium sesquicarbonate 钠倍半
Sodium sesquicarbonate (Systematic name trisodium hydrogendicarbonate) Na3H(CO3)2 is a double salt of sodium bicarbonate and sodium carbonate, and has a needle-like crystal structure. 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.