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III.A.1.b. (III.G.1.d.)

Comparison of bond angles in isoelectronic and isovalent triatomics

Results from MP2/6-31G* calculations
HAH triatomics (2 hydrogens)
electrons molecule
angle
5 BeH2+
180.0
BeH2+
180.0
6 BeH2
180.0
BeH2
180.0
BH2+
180.0
7 BH2
127.6
CH2+
139.6
8 BH2-
123.3
CH2
131.6
CH2
131.6
CH2
180.0
NH2+
150.9
9 CH2-
97.9
NH2
103.3
H2O+
109.8
10 NH2-
98.4
H2O
104.0
H2O
102.6
H2F+
111.1
11 H2O-
100.8
14 MgH2
180.0
AlH2+
180.0
15 AlH2
118.3
SiH2+
120.1
16 AlH2-
93.8
SiH2
92.5
SiH2
92.6
PH2+
93.4
17 SiH2-
92.3
PH2
92.6
H2S+
94.7
18 PH2-
91.8
H2S
93.4
H2S
93.3
H2Cl+
96.6
19 H2S-
80.8
22 CaH2
180.0
32 ZnH2
180.0
34 GeH2
91.6
AsH2+
91.6
35 GeH2-
91.5
AsH2
91.2
H2Se+
91.9
36 H2Se
91.2
H2Se
91.2
HAB triatomics (1 hydrogen)
electrons molecule
angle
12 C2H+
180.0
LiOH
180.0
LiOH
180.0
13 C2H
180.0
HCN+
180.0
HNB
180.0
BeOH
138.6
14 C2H-
180.0
HCN
180.0
HCN
180.0
HCN
180.0
HNC
180.0
HNC
180.0
NNH+
180.0
HBO
180.0
HCO+
180.0
15 HCN-
129.8
NNH
121.2
HNO+
134.4
HCO
123.3
HO2+
112.6
16 HCO-
108.2
HNO
107.4
HNO
109.9
HCF
101.9
17 HO2
104.5
HNO-
105.2
18 HO2-
96.6
HOF
97.2
HOF
99.2
20 FHF-
180.0
NaOH
180.0
21 MgOH
139.6
22 HCP
180.0
HCP
180.0
HBS
180.0
HBS
180.0
HCS+
180.0
23 HCS
134.0
24 HPO
105.6
HNS
108.1
HCS-
105.3
HCCl
102.9
25 HNS-
104.7
26 HOCl
102.6
HOCl
103.9
29 CaOH
180.0
33 HS2
102.1
42 CHBr
101.0
43 HOBr+
110.0
44 HOBr
101.6
HOBr
101.6
HOBr
103.2
ABC triatomics (no hydrogens)
electrons molecule
angle
13 Li2O+
180.0
Li2O+
180.0
14 Li2O
180.0
17 C3+
180.0
18 C3
180.0
C3
180.0
C3
180.0
20 NCN
180.0
CN2
62.2
CN2
62.2
CN2
55.6
21 N3
180.0
N2O+
180.0
CO2+
180.0
CO2+
180.0
BO2
180.0
NCO
180.0
NCO
180.0
22 N3-
180.0
BO2-
180.0
N2O
180.0
N2O
180.0
NO2+
180.0
CO2
180.0
CNO-
180.0
NCO-
180.0
FCN
180.0
FCN
180.0
BeF2
180.0
23 NO2
133.7
NO2
134.9
O3+
134.0
CO2-
134.2
CF2+
124.8
24 O3
116.3
O3
118.8
NO2-
115.4
FNO
110.4
FNO
113.2
CF2
104.2
CF2
106.0
NF2+
107.6
25 O3-
114.8
NF2
103.3
CF2-
99.4
FO2
125.2
26 F2O
102.6
F2O
104.7
28 F3-
180.0
29 SCN
180.0
OCS+
180.0
30 Na2O
180.0
Na2O
130.2
MgF2
180.0
SiO2
180.0
PO2+
180.0
OCS
180.0
OCS
180.0
SCN-
180.0
NNS
180.0
ClCN
180.0
ClCN
180.0
31 PO2
136.4
SO2+
137.4
32 SiF2
100.9
SiF2
101.5
PO2-
120.0
SO2
119.8
SO2
121.5
ClNO
114.0
ClNO
115.3
OClO+
122.3
ClOO+
118.2
33 SF2+
101.9
SO2-
117.1
OClO
120.0
OClO
120.6
ClOO
112.8
34 SF2
99.2
SF2
99.6
35 SF2-
80.5
SF2-
180.0
37 CS2+
180.0
38 PPO
180.0
CS2
180.0
BeCl2
180.0
CaF2
180.0
TiO2
106.7
39 CS2-
141.6
CCl2+
135.1
40 SSO
117.9
SSO
119.2
CCl2
109.9
41 CCl2-
104.2
42 Cl2O
110.7
46 MgCl2
180.0
48 S3
117.9
SiCl2
101.7
ZnF2
180.0
GeO2
180.0
OCSe
180.0
OCSe
180.0
BrCN
180.0
49 S3-
115.6
ClS2
110.8
AsO2
133.9
50 SCl2
103.3
SCl2
103.3
SCl2
103.6
GeF2
96.9
SeO2
115.4
SeO2
116.0
BrNO
114.4
51 OBrO
116.5
52 Cl3-
180.0
54 CaCl2
180.0
KrF2
180.0
60 BrOCl
110.7
64 ZnCl2
180.0
GeS2
180.0
66 GeCl2
100.3
78 BrOBr
110.6

Isovalent Triatomics

HAH triatomics (2 hydrogens)
valence electrons molecule
angle
3 BeH2+
180.0
BeH2+
180.0
4 BeH2
180.0
BeH2
180.0
BH2+
180.0
MgH2
180.0
AlH2+
180.0
CaH2
180.0
ZnH2
180.0
5 BH2
127.6
CH2+
139.6
AlH2
118.3
SiH2+
120.1
6 BH2-
123.3
CH2
131.6
CH2
131.6
CH2
180.0
NH2+
150.9
AlH2-
93.8
SiH2
92.5
SiH2
92.6
PH2+
93.4
GeH2
91.6
AsH2+
91.6
7 CH2-
97.9
NH2
103.3
H2O+
109.8
SiH2-
92.3
PH2
92.6
H2S+
94.7
GeH2-
91.5
AsH2
91.2
H2Se+
91.9
8 NH2-
98.4
H2O
104.0
H2O
102.6
H2F+
111.1
PH2-
91.8
H2S
93.4
H2S
93.3
H2Cl+
96.6
H2Se
91.2
H2Se
91.2
9 H2O-
100.8
H2S-
80.8
HAB triatomics (1 hydrogen)
valence electrons molecule
angle
8 C2H+
180.0
LiOH
180.0
LiOH
180.0
NaOH
180.0
9 C2H
180.0
HCN+
180.0
HNB
180.0
BeOH
138.6
MgOH
139.6
CaOH
180.0
10 C2H-
180.0
HCN
180.0
HCN
180.0
HCN
180.0
HNC
180.0
HNC
180.0
NNH+
180.0
HBO
180.0
HCO+
180.0
HCP
180.0
HCP
180.0
HBS
180.0
HBS
180.0
HCS+
180.0
11 NNH
121.2
HCN-
129.8
HCO
123.3
HNO+
134.4
HCS
134.0
12 HNO
107.4
HNO
109.9
HO2+
112.6
HCO-
108.2
HCF
101.9
HPO
105.6
HNS
108.1
HCS-
105.3
HCCl
102.9
CHBr
101.0
13 HNO-
105.2
HO2
104.5
HNS-
104.7
HS2
102.1
HOBr+
110.0
14 HO2-
96.6
HOF
97.2
HOF
99.2
HOCl
102.6
HOCl
103.9
HOBr
101.6
HOBr
101.6
HOBr
103.2
16 FHF-
180.0
ABC triatomics (no hydrogens)
valence electrons molecule
angle
7 Li2O+
180.0
Li2O+
180.0
8 Li2O
180.0
Na2O
180.0
Na2O
130.2
11 C3+
180.0
12 C3
180.0
C3
180.0
C3
180.0
14 NCN
180.0
CN2
62.2
CN2
62.2
CN2
55.6
15 N3
180.0
BO2
180.0
N2O+
180.0
CO2+
180.0
CO2+
180.0
NCO
180.0
NCO
180.0
SCN
180.0
OCS+
180.0
CS2+
180.0
16 N3-
180.0
BO2-
180.0
N2O
180.0
N2O
180.0
NO2+
180.0
CO2
180.0
NCO-
180.0
CNO-
180.0
FCN
180.0
FCN
180.0
BeF2
180.0
MgF2
180.0
SiO2
180.0
PO2+
180.0
PPO
180.0
NNS
180.0
SCN-
180.0
CS2
180.0
OCS
180.0
OCS
180.0
ClCN
180.0
ClCN
180.0
MgCl2
180.0
BeCl2
180.0
CaCl2
180.0
CaF2
180.0
TiO2
106.7
ZnF2
180.0
ZnCl2
180.0
GeO2
180.0
GeS2
180.0
OCSe
180.0
OCSe
180.0
BrCN
180.0
17 CO2-
134.2
NO2
133.7
NO2
134.9
O3+
134.0
CF2+
124.8
PO2
136.4
CS2-
141.6
SO2+
137.4
CCl2+
135.1
AsO2
133.9
18 O3
116.3
O3
118.8
NO2-
115.4
FNO
110.4
FNO
113.2
CF2
104.2
CF2
106.0
NF2+
107.6
SiF2
100.9
SiF2
101.5
PO2-
120.0
S3
117.9
SO2
119.8
SO2
121.5
SSO
117.9
SSO
119.2
ClOO+
118.2
ClNO
114.0
ClNO
115.3
CCl2
109.9
SiCl2
101.7
OClO+
122.3
GeCl2
100.3
GeF2
96.9
SeO2
115.4
SeO2
116.0
BrNO
114.4
19 O3-
114.8
NF2
103.3
CF2-
99.4
FO2
125.2
SO2-
117.1
S3-
115.6
SF2+
101.9
OClO
120.0
OClO
120.6
CCl2-
104.2
ClOO
112.8
ClS2
110.8
OBrO
116.5
20 F2O
102.6
F2O
104.7
SF2
99.2
SF2
99.6
SCl2
103.3
SCl2
103.3
SCl2
103.6
Cl2O
110.7
BrOCl
110.7
BrOBr
110.6
21 SF2-
80.5
SF2-
180.0
22 F3-
180.0
Cl3-
180.0
KrF2
180.0