Is Carbon Dioxide a MIXTURE or a PURE SUBSTANCE? I think that it is a mixture since it has two types of atoms; Carbon and OxygenIs Carbon Dioxide a MIXTURE or a PURE SUBSTANCE? I think that it is a mixture since it has two types of atoms; Carbon and Oxygen But I am not sure. Is that if two differant element or compounds are together than it is a mixture? Follow Report Abuse Are you sure you want to delete this answer? Yes No