However, cyclopropenylidene is found in significant concentrations in the interstellar medium (ISM) and on Saturn's moon Titan.

[1] A third C2 symmetric isomer, propargylene (HCCCH), has not yet been detected in the ISM, most likely due to its low dipole moment.

This has led to the hypothesis that the photodissociation of polycyclic aromatic hydrocarbons (PAHs) enhances the formation of c-C3H2.

[7] On 15 October 2020, it was announced that small amounts of cyclopropenylidene had been found in the atmosphere of Titan, the largest moon of Saturn[8] using the ALMA telescope.

However, as for most ion-molecule reactions speculated to be important in interstellar environments, this pathway has not been verified by laboratory studies.

[14] Both reactions are rapid at 10 K and have no entrance barrier and provide efficient formation pathways in cold interstellar environments and hydrocarbon-rich atmospheres of planets and their moons.

[15] Matrix isolated cyclopropenylidene has been prepared by flash vacuum thermolysis of a quadricyclane derivative in 1984.

Although the ortho and para forms look identical chemically, the energy levels are different, meaning that the molecules have different spectroscopic transitions.