Constraints on the molecular properties of interstellar X-ogen derived from radio observations Twenty-eight X-ogen emission sources at 89.189 GHz have been detectedand observed. Twenty of these are new X-ogen sources which also containother interstellar molecules. No infrared stars are found to be X-ogensources. A new rest frequency (89,188.65 MHz) is derived for X-ogen. Itis shown that X-ogen is not SiC, C2H, or any molecule withspin-doubling, hyperfine structure, or both.
