National Institute of Standards and Technology

Computational Chemistry Comparison and Benchmark DataBase
Release 22	May 2022
NIST Standard Reference Database 101

I	Introduction
II	Experimental data
III	Calculated data
IV	Data comparisons
V	Cost comparisons
VI	Input and output files
VII	Tutorials and Units
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IX	Feedback
X	Older CCCBDB versions
XII	Geometries
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XIV	Reaction data
XV	Entropy data
XVI	Bibliographic data
XVII	Ion data
XVIII	Bad calculations
XIX	Index of properties
XX	H-bond dimers
XXI	Oddities

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IV.D.8.

Average Bond Length Differences by Model Chemistry

Calculated at ROHF/6-31+G**

Species	Name	Bond type	Bond Length (Å)
			Experimental	unc.	Calculated	Difference	atom1	atom2
O2	Oxygen diatomic	rO=O	1.208		1.163	-0.045	1	2
SeO	Selenium monoxide	rSeO	1.639	±0.001	1.596	-0.044	1	2
C2H2O2	Ethanedial	rCH	1.132		1.090	-0.042	1	3
O2+	diatomic oxygen cation	rOO	1.116		1.075	-0.041	1	2
SiC	silicon monocarbide	rCSi	1.722		1.683	-0.039	1	2
CP	Carbon monophosphide	rC#P	1.562		1.525	-0.037	1	2
NSe	Nitrogen monoselenide	rN=Se	1.652		1.617	-0.035	1	2
CN	Cyano radical	rC#N	1.172		1.137	-0.034	1	2
BN	boron nitride	rB=N	1.325		1.291	-0.034	1	2
SO+	sulfur monoxide cation	rO=S	1.424		1.391	-0.033	1	2
HS+	sulfur monohydride cation	rSH	1.374		1.341	-0.033	1	2
H2Cl+	dihydrogen monochloride cation	rHCl	1.321	±0.000	1.288	-0.033	1	2
SiN	Silicon nitride	rSiN	1.575		1.543	-0.033	1	2
N3	azide radical	rNN	1.181		1.150	-0.031	1	2
CH3OCl	methyl hypochlorite	rCH	1.111	±0.018	1.081	-0.030	3	4
NO	Nitric oxide	rN=O	1.154	±0.000	1.125	-0.029	1	2
C2H	Ethynyl radical	rC#C	1.217		1.187	-0.029	1	2
CO+	carbon monoxide cation	rC=O	1.115	±0.000	1.087	-0.028	1	2
Se2	Selenium diatomic	rSe=Se	2.166	±0.001	2.139	-0.027	1	2
FO	Oxygen monofluoride	rFO	1.354		1.327	-0.027	1	2
SO	Sulfur monoxide	rS=O	1.481		1.457	-0.024	1	2
SiP	Silicon monophosphide	rSiP	2.078	±0.002	2.054	-0.024	1	2
C2H2+	acetylene cation	rC=C	1.253	±0.001	1.229	-0.023	1	2
HeH+	Helium hydride cation	rHHe	0.790		0.767	-0.023	1	2
HO2	Hydroperoxy radical	rOH	0.971		0.949	-0.021	1	3
PO	Phosphorus monoxide	rP=O	1.476		1.456	-0.020	1	2
HO2	Hydroperoxy radical	rOO	1.331		1.311	-0.020	1	2
NS	Mononitrogen monosulfide	rNS	1.497	±0.000	1.478	-0.019	1	2
BO	boron monoxide	rB=O	1.205		1.186	-0.019	1	2
AlS	Aluminum sulfide	rAlS	2.029		2.010	-0.019	1	2
HCl+	hydrogen chloride cation	rHCl	1.315		1.296	-0.019	1	2
PS	phosphorus sulfide	rP=S	1.900		1.883	-0.017	1	2
CH	Methylidyne	rCH	1.120		1.103	-0.017	1	2
He2+	helium diatomic cation	rHeHe	1.081	±0.001	1.065	-0.016	1	2
DO	Hydroxyl-d	rDO	0.970		0.954	-0.016	1	2
Cl2+	chlorine diatomic cation	rClCl	1.892		1.876	-0.016	1	2
CBrClF2	Methane, bromochlorodifluoro-	rCBr	1.932	±0.004	1.917	-0.015	1	2
OH	Hydroxyl radical	rOH	0.970		0.954	-0.015	1	2
NH	Imidogen	rNH	1.036		1.021	-0.015	1	2
ClF	Chlorine monofluoride	rFCl	1.628	±0.000	1.614	-0.015	1	2
COBr2	Carbonic dibromide	rC=O	1.172	±0.003	1.158	-0.014	1	2
CBr4	Carbon tetrabromide	rCBr	1.942	±0.002	1.928	-0.014	1	2
NO-	nitric oxide anion	rN=O	1.258	±0.010	1.244	-0.014	1	2
CH2	Methylene	rCH	1.085		1.072	-0.013	1	2
S2	Sulfur diatomic	rS=S	1.889		1.876	-0.013	1	2
PH	phosphorus monohydride	rPH	1.422		1.412	-0.011	1	2
CH2CHF	Ethene, fluoro-	rCH	1.082		1.072	-0.010	1	4
HF+	hydrogen fluoride cation	rHF	1.014		1.005	-0.010	1	2
CH3CH2SH	ethanethiol	rCH	1.095		1.085	-0.010	1	4
HS	Mercapto radical	rSH	1.341		1.331	-0.010	1	2
DS	Mercapto-d	rSD	1.341		1.331	-0.009	1	2
NF	nitrogen fluoride	rNF	1.317		1.308	-0.009	1	2
CF	Fluoromethylidyne	rCF	1.276		1.268	-0.008	1	2
CH3CH2SH	ethanethiol	rCH	1.090		1.082	-0.008	2	7
AsH	Arsenic monohydride	rAsH	1.535	±0.001	1.527	-0.008	1	2
HSe	Selenium monohydride	rSeH	1.475	±0.010	1.467	-0.008	1	2
C2H2O2	Ethanedial	rCC	1.526		1.519	-0.007	1	2
CH3CH2SH	ethanethiol	rCH	1.092		1.085	-0.007	1	5
BS	boron sulfide	rBS	1.609		1.602	-0.007	1	2
SiH	Silylidyne	rSiH	1.520		1.514	-0.007	1	2
MgOH	magnesium hydroxide	rOH	0.940		0.934	-0.006	1	3
C2H2+	acetylene cation	rCH	1.077	±0.005	1.071	-0.006	1	3
CH3Br	methyl bromide	rCH	1.082	±0.001	1.077	-0.006	1	3
C2H3	vinyl	rCH	1.085		1.080	-0.005	2	4
SiH3+	Silyl cation	rSiH	1.460	±0.010	1.455	-0.005	1	2
GaAs	Gallium arsenide	rGa#As	2.530	±0.020	2.525	-0.005	1	2
AsF	Arsenic monofluoride	rFAs	1.736	±0.001	1.732	-0.004	1	2
HS-	mercapto anion	rSH	1.343		1.339	-0.004	1	2
CH2CHF	Ethene, fluoro-	rCH	1.077		1.074	-0.003	2	5
CH3OCl	methyl hypochlorite	rCH	1.086	±0.018	1.083	-0.003	3	5
HBr+	hydrogen bromide cation	rHBr	1.448		1.445	-0.003	1	2
CH3CH2O	Ethoxy radical	rCH	1.085		1.085	0.000	1	5
CH3CH2O	Ethoxy radical	rCH	1.088		1.088	0.000	2	7
CH3CH2O	Ethoxy radical	rCH	1.086		1.086	0.000	1	4
BeH	beryllium monohydride	rBeH	1.343		1.344	0.002	1	2
SF	Monosulfur monofluoride	rSF	1.599		1.602	0.003	1	2
H2Se	Hydrogen selenide	rSeH	1.460		1.463	0.003	1	2
HBr	hydrogen bromide	rHBr	1.414	±0.000	1.418	0.004	1	2
SiBr+	Silicon monobromide cation	rSiBr	2.095	±0.000	2.101	0.005	1	2
GeF	Germanium monofluoride	rFGe	1.745		1.751	0.006	1	2
LiO	lithium oxide	rLiO	1.688		1.694	0.006	1	2
GaF	Gallium monofluoride	rFGa	1.774	±0.000	1.781	0.006	1	2
MgH	magnesium monohydride	rMgH	1.730		1.736	0.006	1	2
PF2	Phosphorus difluoride	rPF	1.579		1.588	0.009	1	2
C3H5	Allyl radical	rCH	1.069		1.078	0.009	1	2
MgF	Magnesium monofluoride	rMgF	1.750		1.760	0.010	1	2
C2H	Ethynyl radical	rCH	1.047		1.057	0.011	1	3
GeH	germylidene	rGeH	1.588		1.599	0.011	1	2
SiF	silicon monofluoride	rSiF	1.604		1.616	0.012	1	2
CH3Br	methyl bromide	rCBr	1.934	±0.000	1.946	0.012	1	2
SiF2	Silicon difluoride	rFSi	1.590	±0.000	1.602	0.012	1	2
BeF	Beryllium monofluoride	rBeF	1.361		1.373	0.012	1	2
PF	phosphorus monofluoride	rFP	1.593		1.605	0.013	1	2
MgOH	magnesium hydroxide	rMgO	1.767		1.782	0.015	1	2
BeCl	beryllium monochloride	rBeCl	1.797		1.815	0.018	1	2
ClO	Monochlorine monoxide	rClO	1.596	±0.001	1.620	0.024	1	2
AlC	Aluminum carbide	rC=Al	1.955		1.980	0.025	1	2
CCl	carbon monochloride	rCCl	1.649		1.676	0.027	1	2
SCl	sulfur monochloride	rSCl	1.975		2.003	0.028	1	2
SiCl	Clorosilylidyne	rSiCl	2.061	±0.000	2.090	0.029	1	2
GeCl	Germanium monochloride	rClGe	2.164	±0.000	2.193	0.029	1	2
MgCl	magnesium monochloride	rMgCl	2.199		2.237	0.038	1	2
B2	Boron diatomic	rBB	1.590		1.637	0.047	1	2
BrO	Bromine monoxide	rOBr	1.718		1.766	0.048	1	2
AlN	Aluminum nitride	rN#Al	1.786		1.839	0.053	1	2
NCl	nitrogen monochloride	rNCl	1.611	±0.000	1.663	0.053	1	2
TiCl	Titanium Monochloride	rClTi	2.265	±0.000	2.335	0.071	1	2
CrH	Chromium hydride	rHCr	1.655	±0.001	1.729	0.074	1	2
KH	Potassium hydride	rKH	2.243	±0.001	2.322	0.080	1	2
CuH	Copper monohydride	rCuH	1.463		1.560	0.098	1	2
AlO	Aluminum monoxide	rAlO	1.618		1.716	0.099	1	2
CaH	Calcium monohydride	rCaH	2.003	±0.000	2.124	0.121	1	2
CaBr	Calcium monobromide	rCaBr	2.594	±0.000	2.734	0.140	1	2
CuO	Copper Monoxide	rCuO	1.724	±0.000	1.865	0.141	1	2
CaCl	calcium monochloride	rClCa	2.437		2.589	0.153	1	2

115 molecules.