National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 19April 2018
NIST Standard Reference Database 101
IIExperimental data
IIICalculated data
IVData comparisons
VCost comparisons
VIInput and output files
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XOlder CCCBDB versions
XIII Vibrations
XIVReaction data
XVEntropy data
XVIBibliographic data
XVIIIon data
XVIIIBad calculations
XIXIndex of properties
XXH-bond dimers

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Molecules with the most calculations producing poor bond lengths

The following table lists molecules sorted by how many calculations produced bond lengths that differ from experiment by more than 0.050 Å.
Click on a name for a table of bond length comparisons.
molecule name poor calculations bond description
Na2 Sodium diatomic 580 rNaNa
Mg2 Magnesium diatomic 508 rMgMg
He2+ helium dimer cation 496 rHeHe
Cl2 Chlorine diatomic 492 rClCl
Al2Cl6 Aluminum, di-μ-chlorotetrachlorodi- 449 rAlCl
Li2 Lithium diatomic 403 rLiLi
SiP Silicon monophosphide 399 rSiP
Al2 Aluminum diatomic 393 rAlAl
CaH Calcium monohydride 391 rCaH
SCl sulfur monochloride 370 rSCl
Be2 Beryllium diatomic 346 rBeBe
KH Potassium hydride 325 rKH
CaBr Calcium monobromide 309 rCaBr
NCl nitrogen monochloride 307 rNCl
ClOF3 Chlorine trifluoride oxide 300 rFCl
O2 Oxygen diatomic 289 rOO
CaC Calcium monocarbide 280 rCCa
CFCl chlorofluoromethylene 264 rCCl
ClF3 Chlorine trifluoride 259 rFCl
Ne2 Neon dimer 250 rNeNe
PO Phosphorus monoxide 244 rPO
NO Nitric oxide 241 rNO
SOF4 Sulfur tetrafluoride oxide 219 rFS
SCl2 Sulfur dichloride 212 rSCl
NaLi lithium sodium 205 rLiNa
LiH Lithium Hydride 201 rLiH
ClF Chlorine monofluoride 200 rFCl
LiCl lithium chloride 197 rLiCl
LiK Lithium Potassium 194 rLiK
SO Sulfur monoxide 194 rSO
SF Monosulfur monofluoride 191 rSF
PS phosphorus sulfide 187 rPS
OPCl Phosphorus oxychloride 187 rPCl
ClF3 Chlorine trifluoride 186 rFCl
ClOF3 Chlorine trifluoride oxide 184 rFCl
SiF silicon monofluoride 183 rSiF
CaCl calcium monochloride 182 rClCa
HClO4 perchloric acid 180 rOCl
Si2 Silicon diatomic 180 rSiSi
GaAs Gallium arsenide 178 rGaAs
BF Boron monofluoride 176 rBF
O2+ diatomic oxygen cation 171 rOO
LiO lithium oxide 169 rLiO
HClO4 perchloric acid 166 rOCl
ClFO3 Perchloryl fluoride 166 rFCl
SiH2Cl2 dichlorosilane 163 rSiCl
BrO Bromine monoxide 162 rOBr
FO Oxygen monofluoride 161 rFO
CaO Calcium monoxide 158 rOCa
NS Mononitrogen monosulfide 154 rNS
NO- nitric oxide anion 153 rNO
CuH Copper monohydride 151 rCuH
ICl Iodine monochloride 149 rClI
HOBr Hypobromous acid 148 rBrO
FNO2 Nitryl fluoride 147 rNF
F2SO Thionyl Fluoride 147 rFS
AlN Aluminum nitride 145 rNAl
AlO Aluminum monoxide 143 rAlO
AlCl Aluminum monochloride 142 rAlCl
N2 Nitrogen diatomic 142 rNN
HO2 Hydroperoxy radical 137 rOO
IF Iodine monofluoride 137 rFI
CaF Calcium monofluoride 137 rFCa
BrF5 bromine pentafluoride 136 rFBr
NaK Sodium Potassium 136 rNaK
NaF sodium fluoride 135 rNaF
IBr Iodine monobromide 132 rBrI
SOF4 Sulfur tetrafluoride oxide 132 rFS
KCl Potassium Chloride 129 rKCl
CaOH Calcium monohydroxide 123 rOCa
OH- hydroxide anion 120 rOH
CuF Copper monofluoride 119 rCuF
Se2 Selenium diatomic 118 rSeSe
B2 Boron diatomic 116 rBB
HCl Hydrogen chloride 115 rHCl
CCl carbon monochloride 114 rCCl
NaCl Sodium Chloride 114 rNaCl
S2 Sulfur diatomic 113 rSS
SiC silicon monocarbide 111 rCSi
P2 Phosphorus diatomic 110 rPP
GeF+ Germanium monofluoride cation 110 rFGe
CF Fluoromethylidyne 109 rCF
CrH Chromium hydride 108 rHCr
PF+ phosphorus monofluoride cation 105 rFP
HClO4 perchloric acid 103 rOCl
CO Carbon monoxide 103 rCO
CuO Copper Monoxide 103 rCuO
TiCl Titanium Monochloride 101 rClTi
ClO Monochlorine monoxide 99 rClO
C2H6O2S Dimethyl sulfone 98 rSO
SF4 Sulfur tetrafluoride 97 rSF
BrF3 Bromine trifluoride 95 rFBr
Cl2+ chlorine diatomic cation 95 rClCl
CuCl Copper monochloride 94 rCuCl
KBr Potassium Bromide 93 rKBr
Cu2 Copper dimer 90 rCuCu
P2+ phosphorus dimer cation 88 rPP
OPCl Phosphorus oxychloride 87 rPO
NO+ nitric oxide cation 87 rNO
NF nitrogen fluoride 87 rNF
AlS Aluminum sulfide 87 rAlS
GeCl Germanium monochloride 86 rClGe
F2SO Thionyl Fluoride 85 rOS
ClFO3 Perchloryl fluoride 85 rClO
C2H6O2S Dimethyl sulfone 85 rCS
AlC Aluminum carbide 84 rCAl
CH3ONO Methyl nitrite 84 rNO
SO+ sulfur monoxide cation 84 rOS
CHF2Cl difluorochloromethane 81 rCCl
BrCl Bromine monochloride 81 rClBr
AsF Arsenic monofluoride 80 rFAs
SiF2 Silicon difluoride 79 rFSi
PO- phosphorus monoxide anion 79 rOP
SO Sulfur monoxide 78 rOS
SF4 Sulfur tetrafluoride 77 rSF
CCl2 dichloromethylene 76 rCCl
CH3NO3 Methyl nitrate 75 rNO
NSe Nitrogen monoselenide 75 rNSe
LiCl- lithium chloride anion 75 rLiCl
As4 Arsenic tetramer 74 rAsAs
BF3 Borane, trifluoro- 74 rBF
C5H10 2-Pentene, (E)- 73 rCC
CH2O2 Dioxirane 73 rOO
PCl5 Phosphorus pentachloride 73 rPCl
SiF4 Silicon tetrafluoride 73 rSiF
BeCl beryllium monochloride 71 rBeCl
Br2 Bromine diatomic 70 rBrBr
NS+ nitrogen sulfide cation 70 rNS
PCl5 Phosphorus pentachloride 69 rPCl
SSO Disulfur monoxide 68 rSS
NaH sodium hydride 67 rNaH
CH2FCl fluorochloromethane 67 rCCl
CH3SCH2CH3 Ethane, (methylthio)- 67 rCS
S2+ sulfur dimer cation 66 rSS
SeO Selenium monoxide 66 rSeO
PF phosphorus monofluoride 66 rFP
HOCl hypochlorous acid 65 rClO
HNO3 Nitric acid 64 rNO
KF Potassium Fluoride 63 rKF
NaBr Sodium Bromide 63 rNaBr
PF5 Phosphorus pentafluoride 63 rPF
SSO Disulfur monoxide 63 rSO
SiCl Clorosilylidyne 62 rSiCl
HS- mercapto anion 62 rSH
BrF Bromine monofluoride 62 rFBr
BrF3 Bromine trifluoride 60 rFBr
FNO2 Nitryl fluoride 60 rNO
H2CS Thioformaldehyde 60 rCS
CH2O2 Dioxirane 60 rCO
CH3SCH2CH3 Ethane, (methylthio)- 59 rCS
ArH+ Argon hydride cation 59 rArH
HF Hydrogen fluoride 59 rHF
LiBr Lithium Bromide 59 rLiBr
SeO2 Selenium dioxide 59 rSeO
SeS Selenium monosulfide 59 rSSe
As2 Arsenic diatomic 57 rAsAs
C3H6 Cyclopropane 56 rCC
PCl phosphorus chloride 56 rPCl
SiH Silylidyne 56 rSiH
SOCl2 thionyl chloride 55 rSO
F2O Difluorine monoxide 55 rFO
HCl+ hydrogen chloride cation 54 rHCl
CH3COCl Acetyl Chloride 54 rCCl
CH3OC2H5 Ethane, methoxy- 54 rCO
SiH3F monofluorosilane 54 rSiF
PO2 Phosphorus dioxide 54 rPO
MgOH magnesium hydroxide 54 rMgO
MgCl magnesium monochloride 53 rMgCl
GeF Germanium monofluoride 53 rFGe
C2Cl2 dichloroacetylene 53 rCCl
BrF5 bromine pentafluoride 52 rFBr
CH3Br methyl bromide 52 rCBr
C4H10O Ethoxy ethane 51 rCO
OH Hydroxyl radical 51 rOH
SiHCl3 Trichlorosilane 51 rSiCl
NO3 Nitrogen trioxide 49 rNO
C(CH3)3NH2 2-Propanamine, 2-methyl- 49 rCC
C(CH3)3NH2 2-Propanamine, 2-methyl- 48 rCH
CCl2O Phosgene 48 rCCl
PF5 Phosphorus pentafluoride 47 rFP
I2 Iodine diatomic 45 rII
CS carbon monosulfide 45 rCS
AlF Aluminum monofluoride 45 rAlF
C5H6 Bicyclo[2.1.0]pent-2-ene 45 rCC
CH2ClCH2Cl Ethane, 1,2-dichloro- 44 rCCl
N2O3 Dinitrogen trioxide 44 rNO
LiF lithium fluoride 43 rLiF
SiH3Cl chlorosilane 43 rSiCl
CP Carbon monophosphide 43 rCP
BeO beryllium oxide 42 rBeO
GaF Gallium monofluoride 41 rFGa
SiS silicon monosulfide 41 rSiS
HOBr Hypobromous acid 41 rOH
HF+ hydrogen fluoride cation 41 rHF
N3 azide radical 41 rNN
MgS magnesium sulfide 40 rMgS
AlH+ aluminum monohydride cation 40 rAlH
BCl boron monochloride 39 rBCl
ClCN chlorocyanogen 39 rCCl
CFCl3 Trichloromonofluoromethane 39 rCCl
N2O3 Dinitrogen trioxide 39 rNO
SiH+ silicon monohydride cation 39 rSiH
CH2Br2 dibromomethane 38 rCBr
CHClCCl2 Trichloroethylene 38 rCCl
CHClCCl2 Trichloroethylene 38 rCCl
CO+ carbon monoxide cation 38 rCO
H2O Water 38 rOH
GeH germylidene 37 rGeH
C4H8O2 1,3-Dioxane 37 rCO
SiO Silicon monoxide 37 rSiO
BeF Beryllium monofluoride 36 rBeF
CH3I methyl iodide 36 rCI
CHBr3 bromoform 35 rCBr
ScH Scandium monohydride 35 rScH
MgH+ magnesium monohydride cation 34 rMgH
HO2 Hydroperoxy radical 34 rOH
C2H2 Acetylene 33 rCC
C2Cl2 dichloroacetylene 33 rCC
C2 Carbon diatomic 32 rCC
HClO4 perchloric acid 32 rOH
AlH aluminum monohydride 31 rAlH
HS Mercapto radical 30 rSH
CH3ONO Methyl nitrite 29 rNO
CBr4 Carbon tetrabromide 28 rCBr
C5H8 Bicyclo[2.1.0]pentane 28 rCC
C5H8O Cyclopentanone 28 rCC
N2O3 Dinitrogen trioxide 28 rNO
PN Phosphorus mononitride 27 rPN
BS boron sulfide 27 rBS
CH2C(CH3)OCH3 1-Propene, 2-methoxy- 26 rCO
CSe Carbon monoselenide 24 rCSe
CaOH Calcium monohydroxide 24 rOH
NH Imidogen 24 rNH
MgOH magnesium hydroxide 23 rOH
SiN Silicon nitride 23 rSiN
C2HF3 Trifluoroethylene 23 rCF
CH3ONO Methyl nitrite 23 rCO
C6H6 Fulvene 22 rCH
C4H8O2 Ethyl acetate 22 rCO
C3H8O2 Methane, dimethoxy- 22 rCO
MgO magnesium oxide 21 rMgO
C4H5N Cyclopropanecarbonitrile 20 rCC
CN Cyano radical 20 rCN
CH3OC2H5 Ethane, methoxy- 20 rCO
CF3COOH trifluoroacetic acid 19 rCO
C4H10O Propane, 2-methoxy- 19 rCO
C2H3N3 1H-1,2,4-Triazole 19 rCN
MgH magnesium monohydride 19 rMgH
Si(CH3)4 tetramethylsilane 18 rSiC
C3O2 Carbon suboxide 18 rCO
C4 Carbon tetramer 18 rCC
C4H8O2 1,3-Dioxolane, 2-methyl- 18 rCO
CF3COOH trifluoroacetic acid 18 rOH
CH3OCHO methyl formate 18 rCO
DF Hydrofluoric acid-d 18 rDF
DCl Hydrochloric acid-d 17 rDCl
LiOH lithium hydroxide 17 rLiO
NH+ imidogen cation 16 rNH
CH2C(CH3)OCH3 1-Propene, 2-methoxy- 16 rCO
CH2NN diazomethane 16 rNN
C2H3N3 1H-1,2,4-Triazole 16 rCN
BeS beryllium sulfide 16 rBeS
C2H5F fluoroethane 15 rCF
C6H5OCH3 Anisole 15 rCO
MgF Magnesium monofluoride 15 rMgF
HNCO Isocyanic acid 14 rCO
NH2CONH2 Urea 14 rNH
PH phosphorus monohydride 14 rPH
C2H3N3 1H-1,2,4-Triazole 14 rCN
C3H3NO Oxazole 14 rCO
CH3OCH3 Dimethyl ether 14 rCO
CF3COOH trifluoroacetic acid 14 rCC
DS Mercapto-d 14 rSD
CH3OCHO methyl formate 14 rCO
C6H8 Bicyclo[2.1.1]hex-2-ene 13 rCC
C4H5N Cyclopropanecarbonitrile 13 rCC
C4H5N (E)-2-Butenenitrile 13 rCC
OCSe Carbonyl selenide 13 rCO
AsH Arsenic monohydride 12 rAsH
C2H5F fluoroethane 11 rCC
DO Hydroxyl-d 11 rDO
HI Hydrogen iodide 11 rHI
HBr+ hydrogen bromide cation 10 rHBr
CFCl3 Trichloromonofluoromethane 10 rCF
C3H4 cyclopropene 10 rCH
C3H4 cyclopropene 10 rCH
C2H Ethynyl radical 10 rCC
C2- carbon diatomic anion 10 rCC
C5H12O Butane, 1-methoxy- 10 rCO
C3H6O 2-Propen-1-ol 9 rCH
C3H6O 2-Propen-1-ol 9 rCH
C3H6O 2-Propen-1-ol 9 rCH
C3H6O 2-Propen-1-ol 9 rCH
C3H6O 2-Propen-1-ol 9 rCH
CH2FCl fluorochloromethane 9 rCF
HS+ sulfur monohydride cation 9 rSH
OCSe Carbonyl selenide 9 rCSe
CH2CO Ketene 8 rCO
CH2CHCHO Acrolein 8 rCC
CH2CHCHO Acrolein 8 rCO
CHF2Cl difluorochloromethane 8 rCF
CN- cyanide anion 8 rCN
C3H4O Cyclopropanone 8 rCC
C4H4N2 1,3-Diazine 8 rCN
C4H5NO 3-Methylisoxazole 8 rCC
BN boron nitride 8 rBN
C3H3NO Oxazole 7 rCO
CSe2 Carbon diselenide 7 rCSe
CH2 Methylene 7 rCH
CH3NC methyl isocyanide 7 rCN
PH+ phosphorus monohydride cation 7 rPH
SiH4 Silane 7 rSiH
CH3CH2CHO Propanal 6 rCC
CH2NN diazomethane 6 rCN
ClCN chlorocyanogen 6 rCN
C3H2N2 Malononitrile 6 rCC
C5H10 2-Pentene, (E)- 6 rCC
C3O2 Carbon suboxide 6 rCC
C6H5OH phenol 6 rCO
C3H8O2 Methane, dimethoxy- 5 rCO
C4H6 Methylenecyclopropane 5 rCC
C4H6O Cyclobutanone 5 rCC
C3H3NO Oxazole 5 rCH
C3H3NO Oxazole 5 rCH
C3H3NO Oxazole 5 rCH
BeH beryllium monohydride 5 rBeH
CH3CH(NH2)COOH Alanine 5 rCC
CH3NC methyl isocyanide 5 rCN
CH3NHCH3 Dimethylamine 5 rCH
HNCNH diiminomethane 5 rCN
LiOH lithium hydroxide 4 rOH
CH3CH2CHO Propanal 4 rCC
CH3NH2 methyl amine 4 rCN
CH3NH2 methyl amine 4 rNH
CH3CH2CHO Propanal 4 rCH
CH3CH2CHO Propanal 4 rCH
CH3CH2CHO Propanal 4 rCH
CH3CH2CHO Propanal 4 rCH
CH3CHClCH3 Propane, 2-chloro- 4 rCH
CH Methylidyne 4 rCH
CCl2O Phosgene 4 rCO
HBr hydrogen bromide 4 rHBr
Fe(CO)5 Iron pentacarbonyl 4 rCO
AsH3 Arsine 4 rAsH
C4H6 Bicyclo[1.1.0]butane 4 rCC
C5H10S 2H-Thiopyran, tetrahydro- 4 rCC
C5H6 Bicyclo[2.1.0]pent-2-ene 4 rCC
C5H7N Cyclobutanecarbonitrile 4 rCC
C6H12 (E)-3-methylpent-2-ene 4 rCC
C5H8 Cyclopentene 3 rCC
C5H8 Spiropentane 3 rCC
C4H6S Thiophene, 2,5-dihydro- 3 rCH
C3H8O2 1,3-Propanediol 3 rOH
BO boron monoxide 3 rBO
C2H2O2 Ethanedial 3 rCH
CH3ONO Methyl nitrite 3 rCH
CH3ONO Methyl nitrite 3 rCH
CH3COCH2CH3 2-Butanone 3 rCC
CH3CH2NH2 Ethylamine 3 rCH
CH3COCl Acetyl Chloride 3 rCO
CH3CH2O Ethoxy radical 2 rCH
CH3CH2SH ethanethiol 2 rCH
CH3CH2SH ethanethiol 2 rCH
CH3COCH2CH3 2-Butanone 2 rCC
CH3COCH2CH3 2-Butanone 2 rCH
CH3COCH2CH3 2-Butanone 2 rCH
CH3COCH2CH3 2-Butanone 2 rCH
CH3COCH2CH3 2-Butanone 2 rCH
CH3COCH2CH3 2-Butanone 2 rCH
CH2BrCl Methane, bromochloro- 2 rHC
CH3CH(NH2)COOH Alanine 2 rCC
CH2CCHCH3 1,2-Butadiene 2 rCC
F2 Fluorine diatomic 2 rFF
H2Se Hydrogen selenide 2 rSeH
C10H8 naphthalene 2 rCC
C4H5NO Isoxazole, 5-methyl- 2 rCC
C5H10 2-Pentene, (Z)- 2 rCC
C5H8 Cyclobutane, methylene- 2 rCC
C5H8 Cyclobutane, methylene- 2 rCH
C5H8 Bicyclo[2.1.0]pentane 2 rCC
C6H6 Fulvene 2 rCC
C6H5OCH3 Anisole 2 rCO
HSe Selenium monohydride 2 rSeH
SiH2Cl2 dichlorosilane 2 rSiH
P2H4 H2PPH2 2 rPH
P2H4 H2PPH2 2 rPH
SiH3Cl chlorosilane 1 rSiH
C6H6 Fulvene 1 rCC
C8H8 cyclooctatetraene 1 rCC
C6H8 (Z)-hexa-1,3,5-triene 1 rCC
C5H8 Bicyclo[2.1.0]pentane 1 rCC
C5H5N Pyridine 1 rCC
C5H8O 2H-Pyran, 3,4-dihydro- 1 rCC
C6H12 Cyclohexane 1 rCH
C6H5NH2 aniline 1 rCC
C5H9N Pentanenitrile 1 rCC
C5H10 2-Pentene, (Z)- 1 rCH
C5H10O 2-Butanone, 3-methyl- 1 rCC
C5H10O 2-Butanone, 3-methyl- 1 rCH
C4H6 Cyclobutene 1 rCC
C3H5ClO Oxirane, (chloromethyl)- 1 rCC
C4H4N2 1,3-Diazine 1 rCN
C4H10O Ethoxy ethane 1 rCC
C4H10O Propane, 2-methoxy- 1 rCH
C2H3N3 1H-1,2,4-Triazole 1 rCN
C2H2O2 Ethanedial 1 rCC
C2H4F2 1,2-difluoroethane 1 rCC
C2H5N Aziridine 1 rCH
C2H5N Aziridine 1 rCH
C3H4N2 1H-Pyrazole 1 rCH
C3H4N2 1H-Pyrazole 1 rCH
C3H4N2 1H-Pyrazole 1 rCH
BH Boron monohydride 1 rBH
BH+ boron monohydride cation 1 rBH
H2 Hydrogen diatomic 1 rHH
HD Deuterium hydride 1 rDH
D2 Deuterium diatomic 1 rDD
CHF2Cl difluorochloromethane 1 rCH
CH2CHCH2CH3 1-Butene 1 rCC
CH2ClCHCHCH3 2-Butene, 1-chloro- 1 rCC
CH2CHOCHCH2 Vinyl ether 1 rCH
CH2CHOCHCH2 Vinyl ether 1 rCO
CH2C(CH3)OCH3 1-Propene, 2-methoxy- 1 rCH
CH3COCl Acetyl Chloride 1 rCC
CH3OCHO methyl formate 1 rCH
CH3OCHO methyl formate 1 rCH