Sodium carbonate, commonly known as washing soda, is a white, crystalline powder. This color is due to its chemical composition, which includes sodium, carbon, and oxygen atoms arranged in a specific structure that reflects white light. The purity of the compound also contributes to its color, as impurities can alter the appearance. According to the CRC Handbook of Chemistry and Physics, sodium carbonate has a melting point of 851°C and a density of 2.13 g/cm³, both of which are consistent with its white, crystalline form.