Sodium Bicarbonate also known as Sodium Hydrogen Carbonate Na2CHO3
sodium carbonate (known as washing soda – or soda ash) and sodium bicarbonate know as sodium hydrogen carbonate (known as baking soda) are very similar. The formula for sodium carbonate is Na2CO3, while the formula for sodium bicarbonate is NaHCO3. Both are ionic compounds, which, when dissolved in water, release a positively charged sodium (Na) ion and negatively charged carbonate (CO3) ion.
Used in toners, developers and fixers, a pH modifier to create an alkaline environment eg hypo baths for fixing self-toning papers
In gold toning baths and in developers to inhibit fog