There is, actually, a carbonite ion: [CO2]2-. It sounds like it is not as reactive as carbonate, though it does turn into carbonate around oxygen. http://en.wikipedia.org/wiki/Dihydroxymethylidene
The sound stuttering is a well known problem that has been around for a few months. If I remember correctly, it is a result of some underlying mechanic of the Unity engine that is very difficult to change.