Formamide, HC(O)NH₂, is a fairly typical hot core molecule that is quite abundant. The first transition of this molecule was detected toward Sgr B2 and likely toward Sgr A by
R. H. Rubin, G. W. Swenson, Jr., R. C. Solomon, and H. L. Flygare,
Microwave Detection of Interstellar Formamide
Astrophys. J. 169, L39–L43 (1971).
They detected all three ΔF = 0 hyperfine components of the K_a = 1, J =  2 – 2 transition near 4619 MHz. Only the strongest component, overlapped in part with the H112α transition, was tentatively detected toward Sgr A.
The detection of a second, related, 1 – 1 transition toward Sgr B2 and Sgr A was reported by
C. A. Gottlieb, P. Palmer, L. J. Richard, and B. Zuckerman
Studies of Interstellar Formamide
Astrophys. J. 182, 699–710 (1973).

Detection of the ¹³C Isotope of Formamide in the Galactic Center
was described by
B. Lazareff, R. Lucas, and P. Encrenaz,
Astron. Astrophys. 70, L77–L78 (1978).
The F = 2 – 2 HFS component of the J = 1 – 1 transitions was observed near 1571 GHz toward Sgr B2.

A. Coutens, J. K. Jørgensen, M. H. D. van der Wiel, H. S. P. Müller, J. M. Lykke, P. Bjerkeli, T. L. Bourke, H. Calcutt, M. N. Drozdovskaya, C. Favre, E. C. Fayolle, R. T. Garrod, S. K. Jacobsen, N. F. W. Ligterink, K. I. Öberg, M. V. Persson, E. F. van Dishoeck, and S. F. Wampfler
reported on
The ALMA-PILS Survey: First Detections of Deuterated Formamide and Deuterated Isocyanic Acid in the Interstellar Medium
Astron. Astrophys. 590, Art. No. L6 (2016).
Carrying out a line survey toward IRAS 16293-2422 between 329 and 363 GHz, a deuteration degree of about two percent was derived for source B and for all three isotopomers assuming a ¹²C/¹³C ratio of 68 because lines of the main isotopolog are frequently affected by optical depth effects.

A. Belloche, R. T. Garrod, H. S. P. Müller, K. M. Menten, I. Medvedev, J. Thomas, and Z. Kisiel
reported on
Re-exploring Molecular Complexity with ALMA (ReMoCA): Interstellar Detection of Urea
Astron. Astrophys. 628, Art. No. A10 (2019).
In the course of a new unbiased line survey toward the high-mass star-forming region Sagittarius (Sgr) B2(N) close to the Galactic center, HC(¹⁸O)NH₂ and HC(O)¹⁵NH₂ were detected. The ¹⁶O/¹⁸O ratio of 140 is in the range of values found in the Galactic center, the ¹⁴N/¹⁵N ratio is about 300.

The molecule was also detected in several other hot core sources, such as Orion KL, G327.3–0.6, G34_3+0.15, and NGC 6334(I).

In addition,
C. Kahane, C. Ceccarelli, A. Faure, and E. Caux
gave an account on the
Detection of Formamide, the Simplest but Crucial Amide, in a Solar-type Protostar
Astrophys. J. 763, Art. No. L38 (2013).
The protostar is the usual suspect, IRAS 16293–2422.

V. Thiel, A. Belloche, K. M. Menten, R. T. Garrod, and H. S. P. Müller,
reported on
Complex Organic Molecules in Diffuse Clouds along the Line of Sight to Sgr B2
Astron. Astrophys. 605 (2017), Art. No. L6.
Four low-J a-type transitions of formamide were detected with ALMA between 84.5 and 105.5 GHz in absorption in two velocity components corresponding to Galactic center diffuse clouds. The absorption was detected toward the ultracompact H II region K4 in the Sagittarius B2(N) complex.
V. Thiel, A. Belloche, K. M. Menten, A. Giannetti, H. Wiesemeyer, B. Winkel, P. Gratier, H. S. P. Müller, D. Colombo, and R. T. Garrod,
continued their investigation of
Small-scale Physical and Chemical Structure of Diffuse and Translucent Molecular Clouds along the Line of Sight to Sgr B2
Astron. Astrophys. 623 Art. No. A68 (2019).
Their statement above was modified such that these complex organic molecules reside in translucent clouds rather than in diffuse and translucent molecular clouds.

R. A. Motiyenko, B. Tercero, J. Cernicharo, and L. Margulès
described the
Rotational Spectrum of Formamide up to 1 THz and First ISM Detection of its //v//₁₂ Vibrational State
Astron. Astrophys. 548, Art. No. A71 (2012).

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Contributor(s): H. S. P. Müller; 05, 2009; 08, 2012; 02, 2013; 06, 2016; 10, 2017; 01, 2019

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