The tentative identification of silylidyne, SiH, toward Orion KL was reported by
P. Schilke, D. J. Benford, T. R. Hunter, D. C. Lis, and T. G. Philips,
A Line Survey of Orion-KL from 607 to 725 GHz
Astrophys. J. Suppl. Ser. 132, 281–364 (2001).
The two λ components of the J = 1.5 – 0.5 transition pertaining to the energetically lower lying Π_1/2 spin-state near 624.9 and 627.7 GHz were detected. However, they were at least partially overlapped. As the source is rather line rich, the detection was viewed as tentative.

Contributor(s): H. S. P. Müller; 06, 2006