|Molar mass||509.9685 g/mol|
|Appearance||fine white to pale yellow-white powder|
|Solubility in water||insoluble|
|Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)|
|(what is: / ?)|
Bismuth subcarbonate Bi2O2(CO3), sometimes written (BiO)2CO3 is a chemical compound of bismuth containing both oxide and carbonate anions. Bismuth is in the +3 oxidation state. Bismuth subcarbonate occurs naturally as the mineral bismutite. Its structure consists of Bi-O layers and CO3 layers and is related to kettnerite, CaBi(CO3)OF. It is light sensitive.
It is highly radiopaque and for example is used as a filler in radiopaque catheters which can be seen by x-ray. In modern medicine, bismuth subcarbonate has been made into nanotube arrays that exhibit antibacterial properties. It is also used in fireworks  to make Dragon's eggs. It is a constituent of milk of bismuth which was a popular digestive tract panacea in the 1930s
Bismuth subcarbonate may be harmful if swallowed. It may irritate the respiratory and gastrointestinal tract.
- Joel D. Grice (2002). "A Solution to the crystal structures of bismutite and beyerite". The Canadian Mineralogist 40 (2): 693–698. doi:10.2113/gscanmin.40.2.693.
- Flexible, highly radiopaque plastic material catheter - Patent 5300048
- Rong Chen, Man Ho So, Jun Yang, Feng Deng, Chi-Ming Che and Hongzhe Sun (2006). "Fabrication of bismuth subcarbonate nanotube arrays from bismuth citrate". Chem. Commun. (21): 2265–2267. doi:10.1039/b601764a. PMID 16718324.
- How To Make Cheaper Crackling Firework Stars (Dragon Eggs) With Bismuth Subcarbonate
- Park & Davis Co catalog entry for milk of bismuth