What is "cyclopropenylidene"

Cyclopropenylidene, or c-CH, is an aromatic molecule belonging to a highly reactive class of organic molecules known as carbenes. Due to its reactivity, cyclopropenylidene is only seen terrestrially in the laboratory. However, it is found in significant concentrations in the interstellar medium (ISM) due to the extreme environment. The linear isomer of c-CH is also found in the ISM, but its column density is generally about an order of magnitude lower.