return to home page Computational Chemistry Comparison and Benchmark DataBase Release 22 (May 2022) Standard Reference Database 101 National Institute of Standards and Technology
You are here: Calculated > Geometry > Calculated geometry > One type of bond

Comparison of levels of theory for I-P


Click on an entry for a histogram of the values.
The subscript refers to how many bonds of that type have been calculated.
average calculated bond lengths (Å)
Methods with predefined basis sets
semi-empirical AM1 2.2523
3
PM3 2.3624
3
PM6 2.5197
3

average calculated bond lengths (Å)
Methods with standard basis sets
STO-3G 3-21G 3-21G* 6-311G*
hartree fock HF 2.4690
3
2.6269
3
2.4724
3
2.4836
3
density functional LSDA       2.4783
3
BLYP 2.5521
3
2.6939
3
2.5362
3
2.5625
3
B1B95 2.4956
3
2.4606
3
2.4606
3
2.4781
3
B3LYP 2.5224
3
2.6576
3
2.5014
3
2.5228
3
B3LYPultrafine   2.6576
3
  2.5228
3
B3PW91 2.5094
3
2.6343
3
2.4775
3
2.4959
3
mPW1PW91 2.5012
3
2.6256
3
2.4693
3
2.4868
3
M06-2X 2.4852
3
2.6131
3
2.4642
3
2.4794
3
PBEPBE 2.5269
3
2.6560
3
2.4961
3
2.5189
3
PBEPBEultrafine   2.6560
3
  2.5189
3
PBE1PBE 2.4979
3
2.4666
3
2.4666
3
2.4841
3
HSEh1PBE 2.5002
3
2.6299
3
2.4714
3
2.4904
3
TPSSh 2.5161
3
2.6440
3
2.4830
3
2.5012
3
wB97X-D 2.4953
3
2.6148
3
2.4682
3
2.4860
3
B97D3 2.5413
3
2.6715
3
2.5103
3
2.5355
3
STO-3G 3-21G 3-21G* 6-311G*
Moller Plesset perturbation MP2 2.5097
3
2.6872
3
2.4808
3
2.4919
3
MP2=FULL 2.5094
3
2.6875
3
2.4793
3
2.4935
3
MP3=FULL       2.5035
3
MP4       2.5115
3
B2PLYP 2.5143
3
2.6669
3
2.4912
3
2.5092
3
B2PLYP=FULL 2.5142
3
2.6669
3
2.4906
3
2.5097
3
B2PLYP=FULLultrafine 2.5142
3
2.6669
3
2.4906
3
2.5097
3
Configuration interaction CID   2.6727
3
2.4762
3
2.4818
3
CISD   2.6750
3
2.4769
3
2.4824
3
STO-3G 3-21G 3-21G* 6-311G*
Quadratic configuration interaction QCISD   2.7054
3
2.4937
3
2.5056
3
QCISD(T)       2.5134
3
Coupled Cluster CCD   2.6991
3
2.4903
3
2.5015
3
CCSD       2.5042
3
CCSD=FULL       2.5048
3
CCSD(T)       2.5124
3
STO-3G 3-21G 3-21G* 6-311G*

average calculated bond lengths (Å)
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD cc-pVTZ-PP aug-cc-pVTZ-PP Def2TZVPP
hartree fock HF 2.5678
3
  2.5692
3
  2.6053
3
2.6050
3
2.4604
3
  2.4528
3
density functional LSDA             2.4495
3
   
BLYP             2.5316
3
  2.5210
3
B1B95             2.4523
3
  2.4431
3
B3LYP 2.6232
3
  2.6220
3
  2.6497
3
2.6439
3
2.4947
3
  2.4847
3
B3LYPultrafine             2.4947
3
  2.4847
3
B3PW91             2.4691
3
  2.4591
3
mPW1PW91             2.4602
3
  2.4509
3
M06-2X             2.4543
3
  2.4463
3
PBEPBE             2.4894
3
  2.4793
3
PBEPBEultrafine             2.4894
3
  2.4793
3
PBE1PBE             2.4575
3
  2.4483
3
HSEh1PBE             2.4631
3
  2.4537
3
TPSSh             2.4737
3
  2.4637
3
wB97X-D 2.5804
3
  2.5805
3
  2.6057
3
2.5952
3
2.4598
3
  2.4507
3
B97D3             2.5070
3
  2.4965
3
Moller Plesset perturbation MP2 2.6389
3
  2.6392
3
  2.6713
3
2.6727
3
2.4486
3
  2.4335
3
MP2=FULL             2.4433
3
  2.4289
3
MP3             2.4618
3
   
MP3=FULL             2.4572
3
   
MP4             2.4679
3
   
MP4=FULL             2.4624
3
   
B2PLYP             2.4766
3
  2.4651
3
B2PLYP=FULL             2.4750
3
  2.4638
3
B2PLYP=FULLultrafine             2.4750
3
  2.4638
3
Configuration interaction CID             2.4450
3
  2.4304
3
CISD             2.4453
3
  2.4307
3
Quadratic configuration interaction QCISD             2.4621
3
  2.4512
3
QCISD(T)             2.4698
3
  2.4594
3
QCISD(T)=FULL                 2.4550
3
Coupled Cluster CCD             2.4590
3
  2.4476
3
CCSD             2.4611
3
  2.4503
3
CCSD=FULL             2.4557
3
  2.4459
3
CCSD(T)             2.4690
3
  2.4586
3
CCSD(T)=FULL             2.4634
3
  2.4543
3
For descriptions of the methods (AM1, HF, MP2, ...) and basis sets (3-21G, 3-21G*, 6-31G, ...) see the glossary in section I.C. Predefined means the basis set used is determined by the method.