National Institute of Standards and Technology
Computational Chemistry Comparison and Benchmark DataBase
Release 21August 2020
NIST Standard Reference Database 101
IIExperimental data
IIICalculated data
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VCost comparisons
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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 786 rNaNa
NaLi lithium sodium 524 rLiNa
Mg2 Magnesium diatomic 510 rMgMg
Cl2 Chlorine diatomic 504 rClCl
C4H8O2 Ethyl acetate 501 rCO
He2+ helium diatomic cation 496 rHeHe
CaO Calcium monoxide 461 rOCa
Al2Cl6 Aluminum, di-μ-chlorotetrachlorodi- 451 rAlCl
Li2 Lithium diatomic 405 rLiLi
SiP Silicon monophosphide 401 rSiP
Al2 Aluminum diatomic 395 rAlAl
CaH Calcium monohydride 392 rCaH
SCl sulfur monochloride 371 rSCl
HSSSH trisulfane 367 rHS
O2 Oxygen diatomic 366 rOO
Be2 Beryllium diatomic 348 rBeBe
KH Potassium hydride 325 rKH
CaBr Calcium monobromide 309 rCaBr
NCl nitrogen monochloride 307 rNCl
ClOF3 Chlorine trifluoride oxide 301 rFCl
Cl2+ chlorine diatomic cation 280 rClCl
CaC Calcium monocarbide 280 rCCa
CFCl chlorofluoromethylene 264 rCCl
ClF3 Chlorine trifluoride 261 rFCl
BrCl Bromine monochloride 258 rClBr
Ne2 Neon diatomic 252 rNeNe
LiCl lithium chloride 246 rLiCl
PO Phosphorus monoxide 244 rPO
NO Nitric oxide 241 rNO
BF Boron monofluoride 237 rBF
PS phosphorus sulfide 227 rPS
C2H6O2S Dimethyl sulfone 224 rSO
ClF Chlorine monofluoride 224 rFCl
F2 Fluorine diatomic 223 rFF
IF Iodine monofluoride 223 rFI
ClO Monochlorine monoxide 222 rClO
Br2 Bromine diatomic 222 rBrBr
SOF4 Sulfur tetrafluoride oxide 219 rFS
SCl2 Sulfur dichloride 213 rSCl
HOCl hypochlorous acid 212 rClO
LiH Lithium Hydride 201 rLiH
SO Sulfur monoxide 197 rSO
SO+ sulfur monoxide cation 196 rOS
PF2 Phosphorus difluoride 196 rPF
LiK Lithium Potassium 194 rLiK
S2 Sulfur diatomic 193 rSS
SF Monosulfur monofluoride 192 rSF
OPCl Phosphorus oxychloride 187 rPCl
LiBr Lithium Bromide 187 rLiBr
ClF3 Chlorine trifluoride 187 rFCl
ClOF3 Chlorine trifluoride oxide 185 rFCl
SiF silicon monofluoride 184 rSiF
CaCl calcium monochloride 183 rClCa
Si2 Silicon diatomic 182 rSiSi
HClO4 perchloric acid 182 rOCl
SeO Selenium monoxide 181 rSeO
GaAs Gallium arsenide 180 rGaAs
BrF Bromine monofluoride 178 rFBr
O2+ diatomic oxygen cation 172 rOO
N2 Nitrogen diatomic 171 rNN
LiO lithium oxide 170 rLiO
ClFO3 Perchloryl fluoride 168 rFCl
HClO4 perchloric acid 167 rOCl
SeO2 Selenium dioxide 167 rSeO
SiH2Cl2 dichlorosilane 163 rSiCl
BrO Bromine monoxide 162 rOBr
AlBr Aluminum monobromide 161 rAlBr
FO Oxygen monofluoride 161 rFO
ICl Iodine monochloride 161 rClI
SiH3Cl chlorosilane 158 rSiCl
C2H6O2S Dimethyl sulfone 158 rCS
NS Mononitrogen monosulfide 154 rNS
NO- nitric oxide anion 153 rNO
CuH Copper monohydride 152 rCuH
HOBr Hypobromous acid 149 rBrO
F2SO Thionyl Fluoride 148 rFS
FNO2 Nitryl fluoride 148 rNF
AlN Aluminum nitride 145 rNAl
AlO Aluminum monoxide 144 rAlO
AlCl Aluminum monochloride 143 rAlCl
CaF Calcium monofluoride 138 rFCa
BrF5 bromine pentafluoride 137 rFBr
HO2 Hydroperoxy radical 137 rOO
NaF sodium fluoride 136 rNaF
NaK Sodium Potassium 136 rNaK
CH3Br methyl bromide 135 rCBr
IBr Iodine monobromide 132 rBrI
SOF4 Sulfur tetrafluoride oxide 132 rFS
KCl Potassium Chloride 129 rKCl
CaOH Calcium monohydroxide 124 rOCa
CuF Copper monofluoride 120 rCuF
OH- hydroxide anion 120 rOH
Se2 Selenium diatomic 118 rSeSe
B2 Boron diatomic 117 rBB
HCl Hydrogen chloride 115 rHCl
NaCl Sodium Chloride 115 rNaCl
SiBr+ Silicon monobromide cation 114 rSiBr
CCl carbon monochloride 114 rCCl
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 106 rFP
HClO4 perchloric acid 104 rOCl
CuO Copper Monoxide 104 rCuO
CO Carbon monoxide 103 rCO
C5H6 Propellane 102 rCC
TiCl Titanium Monochloride 102 rClTi
SF4 Sulfur tetrafluoride 98 rSF
BrF3 Bromine trifluoride 97 rFBr
CuCl Copper monochloride 96 rCuCl
KBr Potassium Bromide 93 rKBr
Cu2 Copper diatomic 91 rCuCu
I2 Iodine diatomic 90 rII
P2+ phosphorus diatomic cation 89 rPP
GeCl Germanium monochloride 88 rClGe
AlS Aluminum sulfide 87 rAlS
OPCl Phosphorus oxychloride 87 rPO
NO+ nitric oxide cation 87 rNO
NF nitrogen fluoride 87 rNF
ClFO3 Perchloryl fluoride 86 rClO
CH3ONO Methyl nitrite 86 rNO
F2SO Thionyl Fluoride 85 rOS
AlC Aluminum carbide 84 rCAl
ArH+ Argon hydride cation 83 rArH
CHF2Cl difluorochloromethane 82 rCCl
HSSSH trisulfane 82 rSS
SiF2 Silicon difluoride 80 rFSi
PO- phosphorus monoxide anion 80 rOP
AsF Arsenic monofluoride 80 rFAs
SO Sulfur monoxide 79 rOS
SF4 Sulfur tetrafluoride 78 rSF
HCCl Chloromethylene 78 rCCl
CCl2 dichloromethylene 77 rCCl
CH3NO3 Methyl nitrate 77 rNO
MgH magnesium monohydride 76 rMgH
LiCl- lithium chloride anion 76 rLiCl
NSe Nitrogen monoselenide 75 rNSe
PCl5 Phosphorus pentachloride 74 rPCl
CH3I methyl iodide 74 rCI
CH2O2 Dioxirane 74 rOO
As4 Arsenic tetramer 74 rAsAs
BF3 Borane, trifluoro- 74 rBF
C5H10 2-Pentene, (E)- 74 rCC
SiF4 Silicon tetrafluoride 73 rSiF
LiI Lithium Iodide 72 rLiI
BeCl beryllium monochloride 71 rBeCl
IO Iodine monoxide 70 rIO
PCl5 Phosphorus pentachloride 70 rPCl
NS+ nitrogen sulfide cation 70 rNS
XeF2 Xenon difluoride 70 rFXe
SSO Disulfur monoxide 69 rSS
HF Hydrogen fluoride 69 rHF
NaH sodium hydride 67 rNaH
PF phosphorus monofluoride 67 rFP
CH2FCl fluorochloromethane 67 rCCl
CH3SCH2CH3 Ethane, (methylthio)- 67 rCS
C3O2 Carbon suboxide 66 rCO
S2+ sulfur diatomic cation 66 rSS
HNO3 Nitric acid 66 rNO
XeF4 Xenon tetrafluoride 65 rFXe
CH3CSNH2 Ethanethioamide 65 rCS
SSO Disulfur monoxide 64 rSO
NaBr Sodium Bromide 64 rNaBr
PF5 Phosphorus pentafluoride 64 rPF
SiCl Clorosilylidyne 63 rSiCl
KF Potassium Fluoride 63 rKF
H2Cl+ dihydrogen monochloride cation 63 rHCl
H2CS Thioformaldehyde 62 rCS
HS- mercapto anion 62 rSH
HeH+ Helium hydride cation 61 rHHe
BrF3 Bromine trifluoride 61 rFBr
FNO2 Nitryl fluoride 60 rNO
CH2O2 Dioxirane 60 rCO
OH Hydroxyl radical 60 rOH
SeS Selenium monosulfide 59 rSSe
CH3SCH2CH3 Ethane, (methylthio)- 59 rCS
CI4 tetraiodomethane 59 rCI
H2O Water 57 rOH
As2 Arsenic diatomic 57 rAsAs
PCl phosphorus chloride 57 rPCl
SiH Silylidyne 56 rSiH
C3H6 Cyclopropane 56 rCC
F2O Difluorine monoxide 56 rFO
CH3COCl Acetyl Chloride 55 rCCl
MgOH magnesium hydroxide 55 rMgO
SOCl2 thionyl chloride 55 rSO
MgCl magnesium monochloride 54 rMgCl
SiH3F monofluorosilane 54 rSiF
PO2 Phosphorus dioxide 54 rPO
CH3OC2H5 Ethane, methoxy- 54 rCO
HCl+ hydrogen chloride cation 54 rHCl
BrF5 bromine pentafluoride 54 rFBr
C2Cl2 dichloroacetylene 53 rCCl
GeF Germanium monofluoride 53 rFGe
LiF lithium fluoride 53 rLiF
SiHCl3 Trichlorosilane 51 rSiCl
C4H10O Ethoxy ethane 51 rCO
NO3 Nitrogen trioxide 50 rNO
LiOH lithium hydroxide 49 rLiO
CCl2O Phosgene 48 rCCl
CO+ carbon monoxide cation 47 rCO
NH2F monofluoroamine 47 rNF
PF5 Phosphorus pentafluoride 47 rFP
C5H6 Bicyclo[2.1.0]pent-2-ene 46 rCC
AlF Aluminum monofluoride 46 rAlF
CS carbon monosulfide 45 rCS
CH2ClCH2Cl Ethane, 1,2-dichloro- 44 rCCl
N2O3 Dinitrogen trioxide 44 rNO
CP Carbon monophosphide 43 rCP
BeO beryllium oxide 42 rBeO
HF+ hydrogen fluoride cation 42 rHF
HOBr Hypobromous acid 41 rOH
N3 azide radical 41 rNN
SiS silicon monosulfide 41 rSiS
GaF Gallium monofluoride 41 rFGa
CH3OCH3 Dimethyl ether 41 rCO
AlH+ aluminum monohydride cation 40 rAlH
MgS magnesium sulfide 40 rMgS
N2O3 Dinitrogen trioxide 39 rNO
SiH+ silicon monohydride cation 39 rSiH
BCl boron monochloride 39 rBCl
CFCl3 Trichloromonofluoromethane 39 rCCl
ClCN chlorocyanogen 39 rCCl
CHClCCl2 Trichloroethylene 38 rCCl
CHClCCl2 Trichloroethylene 38 rCCl
CH2Br2 dibromomethane 38 rCBr
C4H8O2 Ethyl acetate 38 rCO
C4H8O2 1,3-Dioxane 37 rCO
GeH germylidene 37 rGeH
KrH+ Protonated Krypton 37 rHKr
SiO Silicon monoxide 37 rSiO
BeF Beryllium monofluoride 36 rBeF
C2H2 Acetylene 35 rCC
CHBr3 bromoform 35 rCBr
ScH Scandium monohydride 35 rScH
PH phosphorus monohydride 35 rPH
MgH+ magnesium monohydride cation 34 rMgH
HO2 Hydroperoxy radical 34 rOH
C2Cl2 dichloroacetylene 34 rCC
C2 Carbon diatomic 33 rCC
AsH Arsenic monohydride 32 rAsH
HClO4 perchloric acid 32 rOH
OCSe Carbonyl selenide 32 rCO
SCSe Carbon sulfide selenide 32 rCS
AlH aluminum monohydride 31 rAlH
CBrClF2 Methane, bromochlorodifluoro- 30 rCBr
HS Mercapto radical 30 rSH
CH3ONO Methyl nitrite 29 rNO
CN Cyano radical 28 rCN
CBr4 Carbon tetrabromide 28 rCBr
CH2CO Ketene 28 rCO
C5H8 Bicyclo[2.1.0]pentane 28 rCC
C5H8O Cyclopentanone 28 rCC
ICN Cyanogen iodide 28 rCI
N2O3 Dinitrogen trioxide 28 rNO
PN Phosphorus mononitride 27 rPN
BS boron sulfide 27 rBS
CH2C(CH3)OCH3 1-Propene, 2-methoxy- 26 rCO
LiNH2 lithium amide 26 rLiN
NH Imidogen 24 rNH
SiN Silicon nitride 24 rSiN
CaOH Calcium monohydroxide 24 rOH
CSe Carbon monoselenide 24 rCSe
CH3ONO Methyl nitrite 23 rCO
C2HF3 Trifluoroethylene 23 rCF
C6H6 Fulvene 23 rCH
MgOH magnesium hydroxide 23 rOH
HBr+ hydrogen bromide cation 23 rHBr
OCSe Carbonyl selenide 23 rCSe
HI Hydrogen iodide 22 rHI
C3H8O2 Methane, dimethoxy- 22 rCO
MgO magnesium oxide 21 rMgO
C4H5N Cyclopropanecarbonitrile 20 rCC
CH3OC2H5 Ethane, methoxy- 20 rCO
CF3COOH trifluoroacetic acid 19 rCO
C4H10O Propane, 2-methoxy- 19 rCO
C2H3N3 1H-1,2,4-Triazole 19 rCN
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
Si(CH3)4 tetramethylsilane 18 rSiC
DCl Hydrochloric acid-d 17 rDCl
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
MgF Magnesium monofluoride 16 rMgF
NH+ imidogen cation 16 rNH
HNCNH diiminomethane 15 rCN
C2H3N3 1H-1,2,4-Triazole 15 rCN
C2H5F fluoroethane 15 rCF
C6H5OCH3 Anisole 15 rCO
C3H3NO Oxazole 14 rCO
CF3COOH trifluoroacetic acid 14 rCC
DS Mercapto-d 14 rSD
CH3OCHO methyl formate 14 rCO
HNCO Isocyanic acid 14 rCO
NH2CONH2 Urea 14 rNH
COBr2 Carbonic dibromide 13 rCO
C6H8 Bicyclo[2.1.1]hex-2-ene 13 rCC
C4H5N (E)-2-Butenenitrile 13 rCC
C4H5N Cyclopropanecarbonitrile 13 rCC
C3O2 Carbon suboxide 12 rCC
C2H Ethynyl radical 12 rCC
CH3CH2CHO Propanal 12 rCC
DO Hydroxyl-d 11 rDO
C2H5F fluoroethane 11 rCC
C2- carbon diatomic anion 10 rCC
C4H8O2 Ethyl acetate 10 rCC
C4H8O2 Ethyl acetate 10 rCO
C5H12O Butane, 1-methoxy- 10 rCO
HBr hydrogen bromide 10 rHBr
CFCl3 Trichloromonofluoromethane 10 rCF
ICN Cyanogen iodide 10 rCN
HS+ sulfur monohydride cation 9 rSH
CH2FCl fluorochloromethane 9 rCF
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
C3H4O Cyclopropanone 8 rCC
C4H4N2 1,3-Diazine 8 rCN
C4H5NO 3-Methylisoxazole 8 rCC
BN boron nitride 8 rBN
CN- cyanide anion 8 rCN
CHF2Cl difluorochloromethane 8 rCF
SiH4 Silane 8 rSiH
PH+ phosphorus monohydride cation 8 rPH
LiOH lithium hydroxide 7 rOH
CSe2 Carbon diselenide 7 rCSe
CH2 Methylene 7 rCH
CH3NC methyl isocyanide 7 rCN
C3H3NO Oxazole 7 rCO
C3F6 hexafluoropropene 7 rCF
C5H6 Propellane 7 rCC
C6H5OH phenol 6 rCO
C5H10 2-Pentene, (E)- 6 rCC
C3H2N2 Malononitrile 6 rCC
CH2NN diazomethane 6 rCN
ClCN chlorocyanogen 6 rCN
CH3NC methyl isocyanide 5 rCN
CH3CH(NH2)COOH Alanine 5 rCC
CH3NHCH3 Dimethylamine 5 rCH
C3H3NO Oxazole 5 rCH
C3H3NO Oxazole 5 rCH
C3H3NO Oxazole 5 rCH
C3F6 hexafluoropropene 5 rCC
BeH beryllium monohydride 5 rBeH
C4H6 Methylenecyclopropane 5 rCC
C4H6O Cyclobutanone 5 rCC
C3H8O2 Methane, dimethoxy- 5 rCO
NH2SH Thiohydroxylamine 5 rSH
C4H6 Bicyclo[1.1.0]butane 4 rCC
C6H12 (E)-3-methylpent-2-ene 4 rCC
C5H7N Cyclobutanecarbonitrile 4 rCC
C5H10S 2H-Thiopyran, tetrahydro- 4 rCC
AsH3 Arsine 4 rAsH
CH3NH2 methyl amine 4 rCN
CH3NH2 methyl amine 4 rNH
CH3CHClCH3 Propane, 2-chloro- 4 rCH
CH Methylidyne 4 rCH
C5H6 Bicyclo[2.1.0]pent-2-ene 4 rCC
CCl2O Phosgene 4 rCO
Fe(CO)5 Iron pentacarbonyl 4 rCO
HCCl Chloromethylene 3 rCH
CH3ONO Methyl nitrite 3 rCH
CH3ONO Methyl nitrite 3 rCH
CH2BrCl Methane, bromochloro- 3 rHC
CH3COCH2CH3 2-Butanone 3 rCC
CH3CH2NH2 Ethylamine 3 rCH
CH3COCl Acetyl Chloride 3 rCO
BO boron monoxide 3 rBO
C2H2O2 Ethanedial 3 rCH
C5H8 Cyclopentene 3 rCC
C4H6S Thiophene, 2,5-dihydro- 3 rCH
C3H8O2 1,3-Propanediol 3 rOH
SCSe Carbon sulfide selenide 3 rCSe
SiH3Cl chlorosilane 2 rSiH
SiH2Cl2 dichlorosilane 2 rSiH
P2H4 H2PPH2 2 rPH
P2H4 H2PPH2 2 rPH
HSe Selenium monohydride 2 rSeH
C4H5NO Isoxazole, 5-methyl- 2 rCC
C6H5OCH3 Anisole 2 rCO
C6H6 Fulvene 2 rCC
C5H10 2-Pentene, (Z)- 2 rCC
C5H8 Bicyclo[2.1.0]pentane 2 rCC
C5H8 Cyclobutane, methylene- 2 rCC
C5H8 Cyclobutane, methylene- 2 rCH
C10H8 naphthalene 2 rCC
C2H2+ acetylene cation 2 rCC
C2H2+ acetylene cation 2 rCH
BH Boron monohydride 2 rBH
B2H6 Diborane 2 rBH
B2H6 Diborane 2 rBH
CH3CH(NH2)COOH Alanine 2 rCC
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
CH2CCHCH3 1,2-Butadiene 2 rCC
CH2CHCH2CH3 1-Butene 2 rCC
H2Se Hydrogen selenide 2 rSeH
H2 Hydrogen diatomic 1 rHH
D2 Deuterium diatomic 1 rDD
CHF2Cl difluorochloromethane 1 rCH
CH2CHOCHCH2 Vinyl ether 1 rCH
CH2CHOCHCH2 Vinyl ether 1 rCO
CH2ClCHCHCH3 2-Butene, 1-chloro- 1 rCC
CH2C(CH3)OCH3 1-Propene, 2-methoxy- 1 rCH
C8H8 cyclooctatetraene 1 rCC
CH3COCl Acetyl Chloride 1 rCC
CH3OCHO methyl formate 1 rCH
CH3OCHO methyl formate 1 rCH
BH+ boron monohydride cation 1 rBH
C2H2O2 Ethanedial 1 rCC
C2H3N3 1H-1,2,4-Triazole 1 rCN
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
C5H8 Bicyclo[2.1.0]pentane 1 rCC
C5H10 2-Pentene, (Z)- 1 rCH
C5H10O 2-Butanone, 3-methyl- 1 rCC
C5H10O 2-Butanone, 3-methyl- 1 rCH
C5H5N Pyridine 1 rCC
C6H6 Fulvene 1 rCC
C6H8 (Z)-hexa-1,3,5-triene 1 rCC
C6H12 Cyclohexane 1 rCH
C6H5NH2 aniline 1 rCC
C5H8O 2H-Pyran, 3,4-dihydro- 1 rCC
C5H9N Pentanenitrile 1 rCC
C4H6 Cyclobutene 1 rCC
C4H8O2 Ethyl acetate 1 rCC
C3H5ClO Oxirane, (chloromethyl)- 1 rCC
C4H4N2 1,3-Diazine 1 rCN
C4H10O Propane, 2-methoxy- 1 rCH
C4H10O Ethoxy ethane 1 rCC
HD Deuterium hydride 1 rDH