Experimental data are given for the sodium carbonate -poly(ethylene glycol)-water system at 313.15 K. Two interesting results are that at 313.15 K sodium carbonate crystallizes as an anhydrous molecule and the system forms two aqueous phases: one free of sodium carbonate and the other free of poly(ethylene glycol). These two characteristics allow the exclusion of steps for the extractive crystallization of anhydrous sodium carbonate from Trona or other raw materials.