sodium carbonate       
noun [ U ]  chemistry specialized uk/ˌsəʊ.di.əm ˈkɑː.bən.eɪt/ us/ˌsoʊ.di.əm ˈkɑːr.bən.eɪt/
 碳酸钠
a chemical compound used as a water softener and in foods and industry, in the form of white powder or crystals
 Compare: soda