Known Interstellar Molecules (Total: 136 as of May 2002)
Number of Atoms
2
3
4
5
6
7
8
9
H
2
H
2
O
NH
3
SiH
4
CH
3
OH
CH
3
COH
CH
3
CO
2
H
CH
3
CH
2
OH
OH
H
2
S
H
3
O
+
CH
4
NH
2
CHO
CH
3
NH
2
HCO
2
CH
3
(CH
3
)
2
O
SO
SO
2
H
2
CO
CHOOH
CH
3
CN
CH
3
CCH
CH
3
C
2
CN
CH
3
CH
2
CN
SO
+
HN
2
+
H
2
CS
HCCCN
CH
3
NC
CH
2
CHCN
C
7
H
H(CC)
3
CN
SiO
HNO
HNCO
CH
2
NH
CH
3
SH
HC
4
CN
H
2
C
6
H(CC)
2
CH
3
SiS
SiH
2
?
HNCS
NH
2
CN
C
5
H
C
6
H
C
8
-
?
C
8
H
NO
NH
2
CCCN
H
2
CCO
HC
2
CHO
c-CH
2
OCH
2
C
9
-
?
NS
H
3
+
HCO
2
+
C
4
H
CH
2
=CH
2
C
7
-
HCl
NNO
CCCH
c-C
3
H
2
H
2
CCCC
10
NaCl
HCO
c-CCCH
CH
2
CN
HC
3
NH
+
Carbon chains in red
KCl
HCO
+
CCCO
C
5
C
5
N
Rings in green
CH
3
COCH
3
AlCl
OCS
CCCS
SiC
4
C
6
-
?
(view by organic vs. inorganic)
CH
3
(CC)
2
CN?
AlF
CCH
HCCH
H
2
CCC
C
5
S?
PN
HCS
+
HCNH
+
HCCNC
11
SiN
c-SiCC
HCCN
HNCCC
NH
CCO
H
2
CN
H
3
CO
+
H(CC)
4
CN
CH
CCS
c-SiC
3
CH
+
C
3
CH
2
D
+
?
13
CN
MgNC
CO
NaCN
H(CC)
5
CN
CS
CH
2
C
2
MgCN
Total: 124
SiC
HOC
+
CP
HCN
CO
+
HNC
HF
KCN?
SH
HD
FeO?