MOLECULES DETECTED IN ICE

NOTES: After being included along with gas phase ISM/CSM detections for 20+ years, I have decided to collect together detections of molecules found in astrophysical ices on its own page (as of April 2024). The primary reason for the change is the explosion of new ice detections and confirmations made possible by the James Webb Space Telescope. Some entries here will go into a bit more bibliographic detail than gas phase detections due to the often extended debates associated with claimed detections. Note that ALL current ice detections are based on vibrational spectra.

Recently added entries are highlighted; tentative detections are indicated with italic font.
Extragalactic detections (as collected in the Cologne Database) are linked
to galaxy images added below the dates of the initial reports.

YEAR SPECIES CITATION SOURCE(S)/LINES
1973 H2O
water
ASTROMOLECULE OF THE MONTH FOR DEC 2011
Spectra of the Becklin-Neugebauer point source and the Kleinmann-Low nebula from 2.8 to 13.5 microns
F. C. Gillett and W. C. Forrest, ApJ 179:483-491 (1973).
Absorption features in the 5-8 micron spectra of protostars.
A. G. G. M. Tielens, L. J. Allamandola, J. Bregman, J. Goebbel, L. B. d'Hendecourt, and F. C Whittborn. ApJ 287:697-706 (1984).
The c2d Spitzer spectroscopic survey of ices around low-mass young stellar objects. I. H2O and the 5-8 μm bands.
A. C. A. Boogert, K. M. Pontoppidan, C. Knez, F. Lahuis, J. Kessler-Silacci, E. F. van Dishoeck, G. A. Blake et al. ApJ 678:985-1004 (2008)
An Ice Age JWST inventory of dense molecular cloud ices
M. K. McClure, W. R. M. Rocha, K. M. Pontoppidan, N. Crouzet, L. E. U. Chu, E. Dartois, T. Lamberts, J. A. Noble, Y. J. Pendleton, G. Perotti, D. Qasim, M. G. Rachid, Z. L. Smith, F. Sun et al. Nat Astron 7:431-443 (2023).
Orion KL
OH stretch
3.1 μm / 3220 cm–1

W33A & others
HOH bend
6 μm / 1667 cm–1

41 Young Stellar Objects
librations
13 μm / 770 cm–1

NIR38
dangling OH stretch
2.73 μm / 3664 cm–1
Additional references for H2O:
1978 
Is Water-Ice the Carrier of the 3 μm Absorption in Infrared Objects?

T. Mukai, S. Mukai, and K. Noguchi. Astrophys Space Sci 53:77-84 (1978).
1979 
The 3.1 μm absorption in molecular clouds is probably due to amorphous H2O ice.

A. Léger, J. Klein, S. de Chevigne, C. Guinet, D. Defourneau, and M. Belin, A&A 79:256-259 (1979).
2000 
An Inventory of Interstellar Ices toward the Embedded Protostar W33A

E. L. Gibb, D. C. B. Whittet, W. A. Schutte, A. C. A. Boogert, J. E. Chiar, P. Ehrenfreund, P. A. Gerakines, J. V. Keane, A. G. G. M. Tielens, E. F. van Dishoeck, and O. Kerkhof. ApJ 536:347-356 (2000).
1979 NGC4945
NGC4945
OCN
cyanate anion
ASTROMOLECULE OF THE MONTH FOR OCT 2004
The 4-8 micron spectrum of the infrared source W33A
B. T. Soifer, R. C. Puetter, R. W. Russell, S. P. Willner, P. M. Harvey, and F. C. Gillett, ApJ 232:L53-L57 (1979).
4.6 micron absorption features due to solid phase CO and cyano group molecules toward compact infrared sources.
J. H. Lacy, F. Baas, L. J. Allamandola, S. E. Persson, P. J. MacGregor, C. J. Lonsdale, T. R. Geballe, and C. E. P. van der Bult. ApJ 276:533-543 (1984).
Spectroscopy of the 4.6-4.7 micon interstellar absroption features.
T. R. Geballe. Occ Rep Royal Obs Edinburgh 12:56-60 (1984).
JWST Observations of Young protoStars (JOYS+): Detecting icy complex organic molecules and ions - I. CH4, SO2, HCOO, OCN, H2CO, HCOOH, CH3CH2OH, CH3CHO, CH3OCHO, and CH3COOH
W. R. M. Rocha, E. F. van Dishoeck, M. E. Ressler, M. L. van Gelder, K. Slavicinska, N. G. C. Brunken, H. Linnartz, T. P. Ray et al. A&A 683:A124 (2024).
W33A
OCN asymmetric stretch
4.62 μm / 2165 cm–1

NGC 1333 IRAS 2A,
IRAS 23385+6053

combination (2ν2)
7.62 μm / 1312 cm–1
Additional references for OCN:
2000 
An Inventory of Interstellar Ices toward the Embedded Protostar W33A

E. L. Gibb, D. C. B. Whittet, W. A. Schutte, A. C. A. Boogert, J. E. Chiar, P. Ehrenfreund, P. A. Gerakines, J. V. Keane, A. G. G. M. Tielens, E. F. van Dishoeck, and O. Kerkhof. ApJ 536:347-356 (2000).
1989 CO
carbon monoxide
Infrared spectroscopy of dust in the Taurus dark clouds: solid carbon monoxide
D. C. B. Whittet, A. J. Adamson, W. W. Duley, T. R. Geballe, and A. D. McFadzean. MNRAS 241:707-720 (1989).
TMC
stretch
4.67 μm / 2140 cm–1
Additional references for CO:
1995 
High-Resolution Studies of Solid CO in the Taurus Dark Cloud: Characterizing the Ices in Quiescent Clouds

J. E. Chiar, A. J. Adamson, T. H. Kerr, and D. C. B. Whittet. ApJ 455:234-243 (1995).
2000 
An Inventory of Interstellar Ices toward the Embedded Protostar W33A

E. L. Gibb, D. C. B. Whittet, W. A. Schutte, A. C. A. Boogert, J. E. Chiar, P. Ehrenfreund, P. A. Gerakines, J. V. Keane, A. G. G. M. Tielens, E. F. van Dishoeck, and O. Kerkhof. ApJ 536:347-356 (2000).
1991 CH3OH
methanol
Detection of solid methanol toward W33A
R. J. A. Grim, B. Bass, T. R. Geballe, J. M. Greenberg, and W. Schutte. A&A 243:473-477 (1991).
W33A
CH3 symmetric stretch
3.53 μm / 2830 cm–1
Additional references for CH3OH:
2000 
An Inventory of Interstellar Ices toward the Embedded Protostar W33A

E. L. Gibb, D. C. B. Whittet, W. A. Schutte, A. C. A. Boogert, J. E. Chiar, P. Ehrenfreund, P. A. Gerakines, J. V. Keane, A. G. G. M. Tielens, E. F. van Dishoeck, and O. Kerkhof. ApJ 536:347-356 (2000).
2010 
The c2d Spitzer Spectroscopic Survey of Ices Around Low-mass Young Stellar Objects. IV. NH3 and CH3OH

S. Bottinelli, A. C. A. Boogert, J. Bouwman, M. Beckwith, E. F. van Dishoeck, K. I. Öberg, K. M. Pontoppidan, H. Linnartz, G. A. Blake, N. J. Evans II, and F. Lahuis. ApJ 718:1100-1117 (2010).
1991 CH4
methane
Discovery of Interstellar Methane - Observations of Gaseous and Solid CH4 Absorption Toward Young Stars in Molecular Clouds
J. H. Lacy, J. S. Carr, N. J. Evans II, F. Baas, J. M. Achtermann, and J. F. Arens, ApJ 376:556-560 (1991).
Methane abundance variations toward the massive protostar NGC 7538 IRS 9
A. C. A. Boogert, G. A. Blake, and K. Ouml;berg. ApJ 615:344-353 (2004).
NGC 7538 IRS 9...
bend
7.67 μm / 1300 cm–1

NGC 7538 IRS 9
symmetric stretch
3.3 μm / 3030 cm–1
Additional references for CH4:
2000 
An Inventory of Interstellar Ices toward the Embedded Protostar W33A

E. L. Gibb, D. C. B. Whittet, W. A. Schutte, A. C. A. Boogert, J. E. Chiar, P. Ehrenfreund, P. A. Gerakines, J. V. Keane, A. G. G. M. Tielens, E. F. van Dishoeck, and O. Kerkhof. ApJ 536:347-356 (2000).
2008 
The c2d Spitzer Spectroscopic Survey of Ices around Low-Mass Young Stellar Objects. III. CH4

K. I. Öberg, A. C. A. Boogert, K. M. Pontoppidan, G. A. Blake, N. J. Evans, F. Lahuis, and E. F. van Dishoeck. ApJ 678:1032-1041 (2008).
2024 
JWST Observations of Young protoStars (JOYS+): Detecting icy complex organic molecules and ions - I. CH4, SO2, HCOO, OCN, H2CO, HCOOH, CH3CH2OH, CH3CHO, CH3OCHO, and CH3COOH

W. R. M. Rocha, E. F. van Dishoeck, M. E. Ressler, M. L. van Gelder, K. Slavicinska, N. G. C. Brunken, H. Linnartz, T. P. Ray et al. A&A 683:A124 (2024).
1995 OCS
carbonyl sulfide
Solid Carbonyl Sulphide (OCS) in W33A
M. E. Palumbo, A. G. G. M. Tielens, and A. T. Tokunaga. ApJ 449:674-680 (1995).
W33A
CO stretch
4.9 μm / 2041 cm–1
Additional references for OCS:
2000 
An Inventory of Interstellar Ices toward the Embedded Protostar W33A

E. L. Gibb, D. C. B. Whittet, W. A. Schutte, A. C. A. Boogert, J. E. Chiar, P. Ehrenfreund, P. A. Gerakines, J. V. Keane, A. G. G. M. Tielens, E. F. van Dishoeck, and O. Kerkhof. ApJ 536:347-356 (2000).
2023 
An Ice Age JWST inventory of dense molecular cloud ices

M. K. McClure, W. R. M. Rocha, K. M. Pontoppidan, N. Crouzet, L. E. U. Chu, E. Dartois, T. Lamberts, J. A. Noble, Y. J. Pendleton, G. Perotti, D. Qasim, M. G. Rachid, Z. L. Smith, F. Sun et al. Nat Astron 7:431-443 (2023).
1998 NH3
ammonia
Unraveling the 10 Micron "Silicate" Feature of Protostars: The Detection of Frozen Interstellar Ammonia
J. H. Lacy, H. Faraji, S. A. Sandford, and L. J. Allamandola. ApJ 501:L105-L109 (1998).
The Composition and Distribution of Dust along the Line of Sight toward the Galactic Center
J. E. Chiar, A. G. G. M. Tielens, D. C. B. Whittet, W. A. Schutte, A. C. A. Boogert, D. Lutz, E. F. van Dishoeck, and M. P. Bernstein. ApJ 537:749-762 (2000).
NGC 7538 IRS 9
inversion
9.0 μm / 1110 cm–1

Galactic center
NH stretch
2.95 μm / 3390 cm–1
Additional references for NH3:
2000 
An Inventory of Interstellar Ices toward the Embedded Protostar W33A

E. L. Gibb, D. C. B. Whittet, W. A. Schutte, A. C. A. Boogert, J. E. Chiar, P. Ehrenfreund, P. A. Gerakines, J. V. Keane, A. G. G. M. Tielens, E. F. van Dishoeck, and O. Kerkhof. ApJ 536:347-356 (2000).
2001 
Searching for Ammonia in Grain Mantles toward Massive Young Stellar Objects

E. L. Gibb, D. C. B. Whittet, and J. E. Chiar. ApJ 558:702-716 (2001).
2010 
The c2d Spitzer Spectroscopic Survey of Ices Around Low-mass Young Stellar Objects. IV. NH3 and CH3OH

S. Bottinelli, A. C. A. Boogert, J. Bouwman, M. Beckwith, E. F. van Dishoeck, K. I. Öberg, K. M. Pontoppidan, H. Linnartz, G. A. Blake, N. J. Evans II, and F. Lahuis. ApJ 718:1100-1117 (2010).
1999 CO2
carbon dioxide
Observations of Solid Carbon Dioxide in Molecular Clouds with the Infrared Space Observatory
P. A. Gerakines, D. C. B. Whittet, P. Ehrenfreund, A. C. A. Boogert, A. G. G. M. Tielens, W. A. Schutte, J. E. Chiar, E. F. van Dishoeck, T. Prusti, F. P. Helmich, and T. de Graauw. ApJ 522:357-377 (1999).
14 sources
asymmetric stretch
4.27 μm / 2340 cm–1
bend
15.2 μm / 660 cm–1
Additional references for CO2:
2000 
An Inventory of Interstellar Ices toward the Embedded Protostar W33A

E. L. Gibb, D. C. B. Whittet, W. A. Schutte, A. C. A. Boogert, J. E. Chiar, P. Ehrenfreund, P. A. Gerakines, J. V. Keane, A. G. G. M. Tielens, E. F. van Dishoeck, and O. Kerkhof. ApJ 536:347-356 (2000).
2005 
Spitzer Observations of CO2 Ice Towards Field Stars in the Taurus Molecular Cloud

E. A. Bergin, G. J. Melnick, P. A. Gerakines, D. A. Neufeld, and D. C. B. Whittet. ApJ 627:L33-L36 (2005).
2008 
The c2d Spitzer Spectroscopic Survey of Ices around Low-Mass Young Stellar Objects. II. CO2

K. M. Pontoppidan, A. C. A. Boogert, H. J. Fraser, E. F. van Dishoeck, G. A. Blake, F. Lahuis, K. I. Öberg, N. J. Evans II, and C. Salyk. ApJ 678:1032-1041 (2008).
2023 NH+
4

ammonium cation
An Ice Age JWST inventory of dense molecular cloud ices
M. K. McClure, W. R. M. Rocha, K. M. Pontoppidan, N. Crouzet, L. E. U. Chu, E. Dartois, T. Lamberts, J. A. Noble, Y. J. Pendleton, G. Perotti, D. Qasim, M. G. Rachid, Z. L. Smith, F. Sun et al. Nat Astron 7:431-443 (2023).
NIR38, J110621
NH stretch
6.85 μm / 1459 cm–1
Additional references for NH+
4
:

1989 
Ions in Grain Mantles: A New Explanation for the 6.86 Micron Absorption in W33A

R. Grim, J. M. Greenberg, W. Schutte, and B. Schmitt. ApJ 341:L87-L90 (1989).
2003 
TOrigin of the 6.85 μm band near young stellar objects: The ammonium ion (NH+
4
) revisited

W. A. Schutte and R. K. Khanna. A&A 398:1049-1062 (2003).
2006 
Theoretical Modeling of Formic Acid (HCOOH), Formate (HCOO), and Ammonium (NH+
4
) Vibrational Spectra in Astrophysical Ices

J.-Y. Park and D. E. Woon. ApJ 638:1285-1290 (2006).
2010 
Ammonium and Formate Ions in Interstellar Ice Analogs

O. Gálvez, B. Maté V. J. Herrero, and R. Escibanao. ApJ 724:539-545 (2010).
2024 SO2
sulfur dioxide
JWST Observations of Young protoStars (JOYS+): Detecting icy complex organic molecules and ions - I. CH4, SO2, HCOO, OCN, H2CO, HCOOH, CH3CH2OH, CH3CHO, CH3OCHO, and CH3COOH
W. R. M. Rocha, E. F. van Dishoeck, M. E. Ressler, M. L. van Gelder, K. Slavicinska, N. G. C. Brunken, H. Linnartz, T. P. Ray et al. A&A 683:A124 (2024).
NGC 1333 IRAS 2A,
IRAS 23385+6053

asymmetric stretch
7.60 μm / 1320 cm–1
Additional references for SO2:
2023 
An Ice Age JWST inventory of dense molecular cloud ices

M. K. McClure, W. R. M. Rocha, K. M. Pontoppidan, N. Crouzet, L. E. U. Chu, E. Dartois, T. Lamberts, J. A. Noble, Y. J. Pendleton, G. Perotti, D. Qasim, M. G. Rachid, Z. L. Smith, F. Sun et al. Nat Astron 7:431-443 (2023).
2024 HCOO
formate anion
JWST Observations of Young protoStars (JOYS+): Detecting icy complex organic molecules and ions - I. CH4, SO2, HCOO, OCN, H2CO, HCOOH, CH3CH2OH, CH3CHO, CH3OCHO, and CH3COOH
W. R. M. Rocha, E. F. van Dishoeck, M. E. Ressler, M. L. van Gelder, K. Slavicinska, N. G. C. Brunken, H. Linnartz, T. P. Ray et al. A&A 683:A124 (2024).
NGC 1333 IRAS 2A,
IRAS 23385+6053

CO stretch
7.23 μm / 1383 cm–1
CO stretch
7.38 μm / 55 cm–1
Additional references for HCOO:
TBD
2024 H2CO
formaldehyde
JWST Observations of Young protoStars (JOYS+): Detecting icy complex organic molecules and ions - I. CH4, SO2, HCOO, OCN, H2CO, HCOOH, CH3CH2OH, CH3CHO, CH3OCHO, and CH3COOH
W. R. M. Rocha, E. F. van Dishoeck, M. E. Ressler, M. L. van Gelder, K. Slavicinska, N. G. C. Brunken, H. Linnartz, T. P. Ray et al. A&A 683:A124 (2024).
NGC 1333 IRAS 2A,
IRAS 23385+6053

CH2 rock
8.04 μm / 1244 cm–1
Additional references for H2CO:
TBD
2024 HCOOH
formic acid
JWST Observations of Young protoStars (JOYS+): Detecting icy complex organic molecules and ions - I. CH4, SO2, HCOO, OCN, H2CO, HCOOH, CH3CH2OH, CH3CHO, CH3OCHO, and CH3COOH
W. R. M. Rocha, E. F. van Dishoeck, M. E. Ressler, M. L. van Gelder, K. Slavicinska, N. G. C. Brunken, H. Linnartz, T. P. Ray et al. A&A 683:A124 (2024).
NGC 1333 IRAS 2A,
IRAS 23385+6053

CO stretch
8.22 μm / 1216 cm–1
Additional references for HCOOH:
TBD
2024 CH3CHO
acetaldehyde
JWST Observations of Young protoStars (JOYS+): Detecting icy complex organic molecules and ions - I. CH4, SO2, HCOO, OCN, H2CO, HCOOH, CH3CH2OH, CH3CHO, CH3OCHO, and CH3COOH
W. R. M. Rocha, E. F. van Dishoeck, M. E. Ressler, M. L. van Gelder, K. Slavicinska, N. G. C. Brunken, H. Linnartz, T. P. Ray et al. A&A 683:A124 (2024).
NGC 1333 IRAS 2A,
IRAS 23385+6053

CH3 sym def/CH wag
7.41 μm / 1349 cm–1
Additional references for CH3CHO:
2023 
An Ice Age JWST inventory of dense molecular cloud ices

M. K. McClure, W. R. M. Rocha, K. M. Pontoppidan, N. Crouzet, L. E. U. Chu, E. Dartois, T. Lamberts, J. A. Noble, Y. J. Pendleton, G. Perotti, D. Qasim, M. G. Rachid, Z. L. Smith, F. Sun et al. Nat Astron 7:431-443 (2023).
2024 C2H5OH
ethanol
JWST Observations of Young protoStars (JOYS+): Detecting icy complex organic molecules and ions - I. CH4, SO2, HCOO, OCN, H2CO, HCOOH, CH3CH2OH, CH3CHO, CH3OCHO, and CH3COOH
W. R. M. Rocha, E. F. van Dishoeck, M. E. Ressler, M. L. van Gelder, K. Slavicinska, N. G. C. Brunken, H. Linnartz, T. P. Ray et al. A&A 683:A124 (2024).
NGC 1333 IRAS 2A,
IRAS 23385+6053

CH3 sym def
7.23 μm / 1383 cm–1
Additional references for C2H5OH:
2023 
An Ice Age JWST inventory of dense molecular cloud ices

M. K. McClure, W. R. M. Rocha, K. M. Pontoppidan, N. Crouzet, L. E. U. Chu, E. Dartois, T. Lamberts, J. A. Noble, Y. J. Pendleton, G. Perotti, D. Qasim, M. G. Rachid, Z. L. Smith, F. Sun et al. Nat Astron 7:431-443 (2023).
2024 CH3OCHO
methyl formate
JWST Observations of Young protoStars (JOYS+): Detecting icy complex organic molecules and ions - I. CH4, SO2, HCOO, OCN, H2CO, HCOOH, CH3CH2OH, CH3CHO, CH3OCHO, and CH3COOH
W. R. M. Rocha, E. F. van Dishoeck, M. E. Ressler, M. L. van Gelder, K. Slavicinska, N. G. C. Brunken, H. Linnartz, T. P. Ray et al. A&A 683:A124 (2024).
NGC 1333 IRAS 2A,
IRAS 23385+6053

CO stretch
8.25 μm / 1211 cm–1
Additional references for CH3OCHO:
TBD
2024 CH3COOH
acetic acid
JWST Observations of Young protoStars (JOYS+): Detecting icy complex organic molecules and ions - I. CH4, SO2, HCOO, OCN, H2CO, HCOOH, CH3CH2OH, CH3CHO, CH3OCHO, and CH3COOH
W. R. M. Rocha, E. F. van Dishoeck, M. E. Ressler, M. L. van Gelder, K. Slavicinska, N. G. C. Brunken, H. Linnartz, T. P. Ray et al. A&A 683:A124 (2024).
NGC 1333 IRAS 2A,
IRAS 23385+6053

OH bend
7.82 μm / 1278 cm–1
Additional references for CH3COOH:
TBD

infrared (vibrational)

Maintained by DE Woon
Updated 14 April 2024