system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why is baking soda called "bicarbonate of soda" when the formula is NaHCO3 (only one carbon)?
gpt
It's really old nomenclature. Bi means twice. So sodium bicarb has twice the carbonate ratio to sodium, compared to sodium carbonate (Na2CO3).

It's a horrible naming system, it's changed now, but nomenclature is very difficult to change, most especially amongst chemists, so most people still use sodium bicarb. Official modern name is hydrogen carbonate.