===== On the Detection of the Butadiynylide Ion, C4H–, in Space =====

The butadiynylide ion has been detected toward the carbon rich star IRC +10216 in 5 rotational transitions from //J// = 9 – 8 to 15 – 14 which occur in the 3 and 2 mm regions:\\
J. Cernicharo, M. Guélin, M. Agúndez, K. Kawaguchi, M. C. McCarthy, and P. Thaddeus,\\
**[[https://doi.org/10.1051/0004-6361:20077415|Astronomical Detection of C<sub>4</sub>H<sup>–</sup>, the Second Interstellar Anion]]**\\
//Astron. Astrophys.// **467**, L37–L40 (2007).\\
Several additional transitions of C<sub>6</sub>H<sup>–</sup>, detected and reported earlier, were also observed.

The molecule was detected tentatively toward a low-mass protostar:\\
N. Sakai, T. Sakai, and S. Yamamoto,\\
**[[https://doi.org/10.1086/527376|Tentative Detection of C<sub>4</sub>H<sup>–</sup> toward the Low-Mass Protostar IRAS 04368+2557 in L1527]]**\\
//Astrophys. J.// **673**, L71–L74 (2008);\\
this detection was confirmed in a rather extensive study of anions and related neutral species:\\
M. Agúndez, J. Cernicharo, M. Guélin, M. Gerin, M. C. McCarthy, and P. Thaddeus,\\
**[[https://doi.org/10.1051/0004-6361:20078985|Search for Anions in Molecular Sources: C<sub>4</sub>H<sup>–</sup> Detection in L1527]]**\\
//Astron. Astrophys.// **478**, L19–L22 (2008).


----

Contributor(s): H. S. P. Müller; 5, 2007; 1, 2008

----