Baking soda and bicarbonate of soda are exactly the same thing. They are different names for the same chemical compound, sodium bicarbonate (NaHCO3). The term "baking soda" is commonly used in the United States, while "bicarbonate of soda" is the term used in the United Kingdom, Australia, and New Zealand. Both refer to a natural alkaline compound that is used in baking as a leavening agent and also for cleaning and deodorizing purposes.