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

NIST policy on privacy, security, and accessibility.

Please rate our products
© 2013 copyright by the U.S. Secretary of Commerce on behalf of the United States of America. All rights reserved.

The National Institute of Standards and Technology (NIST) is an agency of the U.S. Department of Commerce.

Please send questions, comments, corrections, additions and suggestions to cccbdb@nist.gov.

return to home page

III.G.1.a.

Comparison of levels of theory for P-O


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 1.4817
12
PM3 1.5076
12
PM6 1.5309
25
composite G2 1.5045
23
G3 1.5033
23
G3B3 1.5381
25
G3MP2 1.4557
1
G4 1.5135
25
CBS-Q 1.5024
23

average calculated bond lengths (Å)
Methods with standard basis sets
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP Def2TZVPP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pV(D+d)Z cc-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ aug-cc-pCVTZ
hartree fock HF 1.6040
22
1.5748
25
1.5041
25
1.6091
25
1.5000
26
1.4984
25
1.5141
20
1.4913
25
1.4964
23
1.4850
25
1.4279
5
1.5050
26
1.5422
26
1.5161
25
1.4904
25
1.4701
12
1.5196
25
1.4871
19
1.4699
12
1.4447
2
1.5038
12
1.4391
3
1.4678
1
1.4337
2
1.4343
2
ROHF     1.5318
1
1.5477
1
1.4557
1
1.4557
1
1.4557
1
1.4485
1
1.4475
1
  1.4371
1
1.4581
1
  1.4699
1
1.4467
1
1.4395
1
1.4728
1
1.4459
1
1.4393
1
1.4444
2
1.4326
2
1.4332
2
1.4672
1
1.4332
2
1.4338
2
density functional LSDA 1.6380
23
1.5686
14
1.5390
22
1.6381
23
1.5376
23
1.5398
22
1.5425
22
1.5306
23
1.5336
22
1.5225
22
  1.5813
8
  1.5593
22
1.5308
22
1.4641
4
1.5620
22
1.5211
8
1.4616
4
1.4979
1
1.5614
4
1.4793
2
1.5139
1
1.4820
1
1.4817
1
BLYP 1.6674
22
1.6304
25
1.5582
25
1.6641
25
1.5858
26
1.5574
25
1.5608
25
1.5511
25
1.5554
23
1.5432
23
1.4899
2
1.5915
10
1.4829
1
1.5771
25
1.5480
25
  1.5199
5
1.4997
2
  1.5063
2
1.5667
5
1.4924
3
1.5327
1
1.4915
2
1.4922
2
B1B95 1.6047
19
1.4774
1
1.5198
19
1.6191
19
1.5175
19
1.5179
19
1.5191
19
1.5105
19
1.5111
19
1.5035
19
1.4550
1
1.5573
10
1.4570
1
1.5350
19
1.5091
19
1.4541
4
1.5377
19
1.5003
13
1.4521
4
1.4770
2
1.5373
5
1.4663
3
1.5012
1
1.4641
2
1.4646
2
B3LYP 1.6376
25
1.6068
25
1.5367
25
1.6388
25
1.5358
25
1.5355
25
1.5384
25
1.5291
25
1.5433
20
1.5191
25
1.4625
5
1.5407
26
1.5639
26
1.5545
25
1.5268
25
1.5079
12
1.5644
23
1.5309
23
1.5077
12
1.4847
2
1.5358
12
1.4735
3
1.5102
1
1.4714
2
1.4721
2
B3LYPultrafine   1.5626
2
    1.5397
23
1.4889
2
1.4937
5
1.4811
2
  1.4653
1
1.4697
2
1.5724
5
1.4634
1
1.5694
6
1.5114
11
  1.5769
6
1.5238
24
  1.4845
2
1.5462
5
1.4736
3
1.5103
1
1.4714
2
1.4721
2
B3PW91 1.6459
20
1.6042
25
1.5343
25
1.6350
25
1.5326
25
1.5324
25
1.5344
25
1.5257
25
1.5398
20
1.5171
25
1.4676
2
1.5646
10
1.4622
1
1.5513
25
1.5238
25
  1.4976
5
1.4732
2
  1.4826
2
1.5428
5
1.4714
3
1.5075
1
1.4694
2
1.4699
2
mPW1PW91 1.6329
21
1.5994
25
1.5420
20
1.6326
23
1.5283
25
1.5280
25
1.5301
25
1.5213
25
1.5258
23
1.5171
23
1.4637
2
1.5602
10
1.4585
1
1.5467
25
1.5257
23
  1.5566
13
1.5376
6
  1.4785
2
1.5390
5
1.4678
3
1.5029
1
1.4655
2
1.4660
2
M06-2X 1.6311
10
1.6152
10
1.5218
26
1.6555
9
1.5221
24
1.5571
9
1.5598
9
1.5517
9
1.5527
9
1.5357
10
1.4521
1
1.5633
9
1.4540
1
1.5746
9
1.5424
10
  1.5713
10
1.5344
6
  1.4713
2
1.5382
5
1.4654
3
1.4950
1
1.4619
2
1.4624
2
PBEPBE 1.6675
20
1.6272
23
1.5657
20
1.6692
20
1.5559
23
1.5557
23
1.5582
23
1.5490
23
1.5495
23
1.5395
23
1.4783
5
1.5845
10
1.5728
26
1.5752
23
1.5468
23
1.4792
4
1.6013
10
1.5539
7
1.4767
4
1.5032
2
1.5614
5
1.4894
3
1.5285
1
1.4884
2
1.4890
2
PBEPBEultrafine   1.5829
2
    1.5358
11
1.5068
2
1.5073
2
1.4989
2
  1.4832
1
1.4867
2
1.5875
5
1.4808
1
1.5851
6
1.5590
6
  1.5927
6
1.5615
6
  1.5033
2
1.5614
5
1.4894
3
1.5287
1
1.4885
2
1.4891
2
PBE1PBE 1.6176
6
1.4814
1
1.5473
6
1.6655
5
1.5188
22
1.5452
6
1.5599
5
1.5487
5
1.5500
5
1.5302
6
1.4575
1
1.5627
5
1.4594
1
1.5624
6
1.5475
5
  1.5813
5
1.5382
6
  1.4795
2
1.5396
5
1.4687
3
1.5038
1
1.4663
2
1.4669
2
HSEh1PBE 1.6460
10
1.6010
24
1.5543
10
1.6669
9
1.5283
24
1.5553
10
1.5299
24
1.5560
9
1.5571
9
1.5402
10
1.4578
1
1.5617
10
1.4598
1
1.5739
10
1.5194
24
  1.5858
9
1.5505
5
  1.4799
2
1.5402
5
1.4690
3
1.5044
1
1.4667
2
1.4672
2
TPSSh 1.5470
2
1.6476
5
1.5700
5
1.6762
5
1.5781
26
1.5670
5
1.5790
26
1.5607
5
1.4858
2
1.5669
26
1.4743
2
1.5739
5
1.4686
1
1.5852
5
1.5720
26
1.4766
2
1.5926
5
1.5601
5
1.4768
2
1.4897
2
1.5488
5
1.4771
3
1.5147
1
1.4759
2
1.4764
2
wB97X-D 1.5319
2
1.5512
2
1.5720
26
1.5706
2
1.5691
26
1.4797
2
1.5699
26
1.4720
2
1.5646
26
1.4665
2
1.4617
2
1.5721
26
1.4560
1
1.5704
26
1.5635
26
1.4638
2
1.4973
2
1.5638
26
1.4637
2
1.4764
2
1.4624
2
1.4629
2
1.5003
1
1.4634
2
1.4639
2
B97D3 1.5602
2
1.6261
26
1.5127
2
1.6012
2
1.5805
26
1.5022
2
1.5819
26
1.4941
2
1.5762
26
1.4864
2
1.5687
26
1.5044
2
1.4738
1
1.5173
2
1.5745
26
1.4835
2
1.5193
2
1.5366
26
1.4834
2
1.4982
2
1.4814
2
1.4819
2
1.5251
1
1.4825
2
1.4831
2
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP Def2TZVPP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pV(D+d)Z cc-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ aug-cc-pCVTZ
Moller Plesset perturbation MP2 1.6404
20
1.6120
25
1.5421
25
1.6420
25
1.5780
26
1.5403
25
1.5457
25
1.5701
26
1.5328
23
1.5240
25
1.4814
2
1.5374
26
1.5660
26
1.5571
25
1.5328
24
1.5371
7
1.5781
23
1.5168
12
1.5381
7
1.4871
2
1.5293
14
1.4849
3
1.5350
1
1.4822
2
1.4853
2
MP2=FULL 1.6403
20
1.6184
23
1.5490
22
1.6578
22
1.5393
25
1.5388
25
1.5444
25
1.5275
25
1.5415
20
1.5327
20
1.4792
2
1.5665
10
1.4730
1
1.5626
23
1.5306
23
1.5336
7
1.5761
15
1.5224
8
1.5332
7
1.4823
2
1.5253
14
1.4800
3
1.5346
1
1.4800
2
1.4828
2
ROMP2 1.5610
1
1.5310
1
  1.6321
1
1.5169
1
1.5169
1
1.5181
1
1.5035
1
1.5035
1
1.4980
1
1.4913
1
1.5180
1
  1.5318
1
1.5008
1
  1.5397
1
    1.5129
1
1.4927
1
1.4954
1
1.5296
1
1.4931
1
1.4958
1
MP3         1.5290
23
  1.5705
26
      1.4557
2
1.5582
5
1.4516
1
1.5919
4
1.5425
5
        1.4732
2
1.5343
5
1.4630
3
1.4817
1
1.4577
2
1.4598
2
MP3=FULL   1.5532
2
1.4864
2
1.5744
2
1.5692
26
1.4703
2
1.5316
13
1.4604
2
1.4604
2
1.4596
2
1.4539
2
1.5575
5
1.4498
1
1.5686
5
1.5393
5
  1.4975
2
1.4623
2
  1.4726
2
1.5309
5
1.4585
3
1.4817
1
1.4557
2
1.4576
2
MP4   1.6764
19
    1.5655
20
    1.4915
2
1.5573
14
  1.5013
1
1.5919
5
  1.6031
5
1.5449
21
  1.6178
5
1.5731
5
    1.5753
4
1.4962
2
1.5521
1
1.5003
1
1.5031
1
MP4=FULL   1.7216
5
    1.5866
5
      1.5859
4
  1.4993
1
    1.6015
5
1.5639
5
  1.6149
5
1.5681
5
    1.5717
4
1.4918
2
1.5517
1
1.4988
1
1.5015
1
B2PLYP 1.5575
2
1.5652
1
1.5068
2
1.6235
2
1.5134
16
1.4858
1
1.4982
2
1.4753
1
1.4870
2
1.4755
2
1.4759
2
1.4898
1
1.4692
1
1.5009
1
1.5734
18
  1.5171
2
1.4805
2
  1.4927
2
1.4766
2
1.4783
2
1.5206
1
1.4774
2
1.4790
2
B2PLYP=FULL 1.5576
2
1.5594
2
1.5067
2
1.6235
2
1.4893
2
1.4965
2
1.4904
2
1.4868
2
1.4868
2
1.4798
2
1.4753
2
1.4998
2
1.4685
1
1.5119
2
1.4841
2
  1.5166
2
1.4850
2
  1.4925
2
1.4756
2
1.4768
2
1.5205
1
1.4768
2
1.4783
2
B2PLYP=FULLultrafine 1.5576
2
1.5725
2
1.5067
2
1.6234
2
1.4855
5
1.4966
2
1.4980
2
1.4868
2
1.4868
2
1.4798
2
1.4753
2
1.4999
2
1.4686
1
1.5120
2
1.4841
2
  1.5167
2
1.4850
2
  1.4924
2
1.4756
2
1.4768
2
1.5206
1
1.4768
2
1.4783
2
Configuration interaction CID   1.5974
22
1.5277
22
1.6373
20
1.5182
25
    1.5122
23
    1.4510
2
  1.4449
1
1.4768
1
1.4508
1
        1.4695
2
1.5290
5
1.4580
3
1.4814
1
1.4529
2
1.4546
2
CISD   1.6020
22
1.5307
22
1.6423
20
1.5200
25
    1.5156
22
    1.4532
2
  1.4465
1
1.4794
1
1.4524
1
        1.4723
2
1.5308
5
1.4599
3
1.4827
1
1.4552
2
1.4567
2
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP Def2TZVPP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pV(D+d)Z cc-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ aug-cc-pCVTZ
Quadratic configuration interaction QCISD   1.6167
25
1.5450
22
1.6668
22
1.5417
23
1.5431
22
1.5472
22
1.5287
23
1.5285
21
1.5323
18
1.4688
2
1.5648
10
1.4631
1
1.5483
19
1.5239
14
  1.5884
10
1.5411
6
  1.4894
2
1.5431
5
1.4742
3
1.5200
1
1.4708
2
1.4729
2
QCISD(T)         1.5509
22
    1.5002
2
    1.4867
1
1.5798
9
  1.5679
13
1.5240
9
  1.5644
9
1.5267
9
  1.5093
1
1.5702
4
1.4870
2
1.5222
1
1.4894
1
1.4912
1
QCISD(T)=FULL         1.5106
1
  1.5124
1
      1.4843
1
    1.5238
1
1.4938
1
1.4849
1
1.5303
1
1.4933
1
1.4844
1
1.5088
1
1.4855
1
1.4851
1
1.5222
1
1.4872
1
1.4887
1
QCISD(TQ)         1.5273
1
  1.5306
1
      1.4813
1
    1.5411
1
1.4913
1
1.4826
1
1.5515
1
1.4926
1
1.4829
1
           
QCISD(TQ)=FULL         1.5265
1
  1.5296
1
      1.4792
1
    1.5401
1
1.4885
1
1.4796
1
1.5499
1
1.4877
1
             
Coupled Cluster CCD   1.6063
22
1.5355
22
1.6441
22
1.5288
25
1.5354
22
1.5397
22
1.5214
23
1.5323
18
1.5271
18
1.4606
2
1.5576
10
1.4560
1
1.5453
17
1.5181
14
  1.5555
14
1.5052
10
  1.4768
2
1.5374
5
1.4671
3
1.5203
1
1.4624
2
1.4645
2
CCSD         1.5324
25
1.4792
1
1.4815
1
1.4718
3
1.4649
1
1.4682
2
1.4648
2
1.5545
6
1.4595
1
1.5773
10
1.5441
10
1.5408
5
1.5795
6
1.5383
6
1.5155
4
1.4847
2
1.5406
5
1.4707
3
1.5109
1
1.4668
2
1.4688
2
CCSD=FULL         1.5499
6
        1.4654
2
1.4626
2
1.5535
6
1.4574
1
1.5668
6
1.5316
6
1.5373
5
1.5771
6
1.5334
6
1.5541
4
1.4834
2
1.5368
5
1.4658
3
1.5092
1
1.4643
2
1.4660
2
CCSD(T)         1.5430
16
1.5071
2
1.4913
1
1.4881
2
  1.4920
1
1.4847
1
1.5874
8
  1.5669
14
1.5322
15
1.5698
4
1.5653
10
1.5238
11
1.5717
4
  1.5691
4
1.4855
2
  1.4872
1
1.4890
1
CCSD(T)=FULL         1.5615
10
          1.4825
1
1.5750
9
  1.5912
9
1.5554
5
1.5664
4
1.6012
9
1.5582
5
1.5665
4
  1.5651
4
1.4805
2
  1.4850
1
1.4865
1
STO-3G 3-21G 3-21G* 6-31G 6-31G* 6-31G** 6-31+G** 6-311G* 6-311G** 6-31G(2df,p) 6-311+G(3df,2p) TZVP Def2TZVPP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pV(D+d)Z cc-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ aug-cc-pCVTZ

average calculated bond lengths (Å)
Methods with effective core potentials (select basis sets)
daug-cc-pVDZ daug-cc-pVTZ daug-cc-pVQZ Sadlej_pVTZ CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF         1.6142
25
1.5157
25
1.6116
25
1.5147
25
1.5998
25
1.5929
25
density functional B1B95         1.5831
4
1.4948
6
       
B3LYP         1.6478
25
1.5525
25
1.6445
25
1.5527
25
1.6325
25
1.6247
25
wB97X-D         1.5769
2
1.4961
2
1.5727
2
1.4960
2
1.5639
2
1.5529
2
Moller Plesset perturbation MP2         1.6543
25
1.5606
25
1.6504
25
1.5603
25
1.6484
25
1.6308
25
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.