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Computational Chemistry Comparison and Benchmark DataBase
Release 17bSeptember 2015
NIST Standard Reference Database 101
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III.G.1.a.

Comparison of levels of theory for Mg-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 2.2634
4
PM3 1.7805
5
PM6 1.7679
6
composite G2 1.7877
8
G3 1.7876
8
G3B3 1.8003
10
G3MP2 1.7691
1
G4 1.7921
8
CBS-Q 1.7895
9

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 cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pCVDZ cc-pCVTZ
hartree fock HF 1.7503
10
1.8352
8
1.7609
8
1.9014
8
1.7831
10
1.7799
8
1.8122
8
1.7811
10
1.7880
8
1.7687
8
1.7386
2
1.8150
8
1.7862
8
1.7783
7
1.7513
6
1.8063
8
1.7833
10
1.7549
5
1.7426
1
1.7159
1
ROHF   1.7269
1
1.7248
1
  1.7515
2
1.7621
1
1.7821
1
1.7655
1
                       
density functional LSDA 1.7345
10
1.7652
10
1.7623
10
1.8103
8
1.7942
10
1.7931
10
1.8039
10
1.7985
10
1.7989
10
1.7772
10
  1.7933
6
1.7979
10
1.7844
10
1.7933
2
1.7934
10
1.7890
8
1.7935
2
   
SVWN   1.7852
8
    1.7942
10
1.7978
6
1.8013
10
1.8013
6
1.8012
6
1.7810
6
  1.7908
4
1.8018
6
1.7884
6
  1.7972
6
1.7858
6
     
BLYP 1.7609
10
1.8050
10
1.7850
10
1.8373
8
1.8029
12
1.8227
10
1.8368
10
1.8275
10
1.8286
10
1.8087
10
  1.8262
6
1.8325
8
1.8237
8
  1.8442
4
1.8761
2
     
B1B95 1.7391
10
1.7678
10
1.7653
10
1.8172
8
1.7988
10
1.7988
10
1.8078
10
1.8014
10
1.8021
10
1.7839
10
  1.8116
4
1.7974
10
1.7886
10
1.8027
2
1.8016
6
1.7939
7
1.8036
2
1.7442
1
1.7306
1
B3LYP 1.7462
10
1.7926
8
1.7760
8
1.8063
10
1.8060
9
1.8036
10
1.8158
10
1.8095
10
1.8169
9
1.7892
10
1.7563
2
1.8205
8
1.8061
10
1.8036
8
1.7750
7
1.8122
8
1.7966
10
1.7754
8
1.7474
1
1.7349
1
B3LYPultrafine   1.8699
2
    1.8052
10
1.8619
2
1.8704
2
1.8718
2
      1.8727
2
1.8680
2
1.8498
2
  1.8599
2
1.7986
8
     
B3PW91 1.7524
9
1.8006
7
1.7773
8
1.8198
8
1.8034
10
1.8018
10
1.8127
10
1.8067
10
1.8141
9
1.7881
9
  1.7993
6
1.8132
8
1.8008
8
  1.8171
4
1.8462
2
     
mPW1PW91 1.7489
9
1.7893
8
1.7705
9
1.8167
8
1.7999
10
1.7981
10
1.8087
10
1.8024
10
1.8033
10
1.7846
10
  1.7991
6
1.8095
8
1.7969
8
  1.7960
8
1.7919
6
     
M06-2X 1.7304
6
1.7848
4
1.7795
12
1.8140
4
1.7924
10
1.7945
6
1.8019
6
1.7970
6
1.7981
6
1.7820
6
  1.8065
4
1.7915
6
1.7855
6
  1.7971
6
1.7822
6
     
PBEPBE 1.7646
9
1.8009
10
1.7934
8
1.8522
6
1.8208
10
1.8197
10
1.8299
10
1.8261
10
1.8236
10
1.8058
10
1.7841
2
1.8209
6
1.8242
10
1.8129
10
1.8226
2
1.8194
6
1.8152
6
1.8238
2
   
PBEPBEultrafine   1.8918
2
    1.8397
4
1.8812
2
1.8891
2
1.8903
2
      1.8917
2
1.8877
2
1.8666
2
  1.8776
2
1.8681
2
     
PBE1PBE 1.7373
6
1.7668
6
1.7668
6
1.8222
4
1.8009
10
1.8046
6
1.8114
6
1.8050
6
1.8067
6
1.7881
6
  1.8124
4
1.8052
6
1.7942
6
  1.8034
6
1.7924
6
     
HSEh1PBE 1.7376
6
1.7973
7
1.7668
6
1.8227
4
1.7996
10
1.8027
6
1.8101
10
1.8054
6
1.8071
6
1.7880
6
  1.8133
4
1.8052
6
1.7919
10
  1.8037
6
1.7930
6
     
TPSSh 1.7956
2
1.8781
2
1.8524
2
1.9071
2
1.8007
8
1.8667
2
1.8117
8
1.8750
2
1.8750
2
1.7887
12
  1.8749
2
1.8729
2
1.7947
8
  1.8627
2
1.8523
2
     
wB97X-D 1.7866
2
1.8654
2
1.7629
12
1.8942
2
1.7878
12
1.8548
2
1.8629
2
1.8641
2
1.7951
12
1.8383
2
  1.8640
2
1.8607
2
1.7854
12
  1.8525
2
1.7868
12
     
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 cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pCVDZ cc-pCVTZ
Moller Plesset perturbation MP2 1.7365
9
1.7844
8
1.7815
8
1.8186
8
1.8031
12
1.8091
10
1.8352
10
1.8044
12
1.8119
10
1.7969
10
  1.8194
10
1.8080
10
1.8020
10
1.7814
7
1.8314
9
1.8067
10
1.7960
7
1.7346
1
1.7371
1
MP2=FULL 1.7250
9
1.7850
8
1.8006
6
1.8417
6
1.8086
10
1.8047
10
1.8344
8
1.8061
10
1.8189
9
1.7977
8
  1.8095
6
1.8122
9
1.7936
9
1.7736
5
1.8068
8
1.7835
7
1.7968
4
1.7345
1
1.7348
1
MP3         1.8050
10
  1.8039
8
        1.8618
2
1.8641
2
1.8405
2
           
MP3=FULL   1.8627
2
1.8429
2
1.8997
2
1.8006
8
1.8583
2
1.8186
8
1.8599
2
1.8599
2
1.8331
2
  1.8602
2
1.8641
2
1.8302
2
  1.8502
2
1.8349
2
     
MP4   1.7882
8
    1.8143
10
    1.7516
2
1.8315
8
    1.8817
2
1.8810
2
1.8059
10
  1.8819
2
1.8654
2
     
MP4=FULL   1.8849
2
    1.8740
2
      1.8775
2
      1.8809
2
1.8457
2
  1.8703
2
1.8534
2
     
B2PLYP 1.7863
2
1.8714
2
1.8469
2
1.9064
2
1.8177
6
1.8643
2
1.8554
3
1.8721
2
1.8721
2
1.8475
2
  1.8735
2
1.8702
2
1.7963
6
  1.8649
2
1.8541
2
     
B2PLYP=FULL 1.7867
2
1.8291
3
1.8471
2
1.9066
2
1.8335
3
1.8638
2
1.8457
3
1.8718
2
1.8718
2
1.8442
2
  1.8730
2
1.8702
2
1.8472
2
  1.8612
2
1.8507
2
     
B2PLYP=FULLultrafine 1.7868
2
1.8717
2
1.8471
2
1.9065
2
1.8487
3
1.8638
2
1.8729
2
1.8717
2
1.8717
2
1.8442
2
  1.8729
2
1.8702
2
1.8472
2
  1.8612
2
1.8507
2
     
Configuration interaction CID   1.7991
6
1.7866
6
1.8284
6
1.7982
10
    1.7939
10
                       
CISD   1.8028
6
1.7898
6
1.8327
6
1.8008
10
1.7736
1
  1.8019
8
                       
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 cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pCVDZ cc-pCVTZ
Quadratic configuration interaction QCISD   1.8238
8
1.8025
5
1.8523
5
1.8170
9
1.8183
7
1.8237
9
1.8118
9
1.8184
8
1.8018
7
  1.8072
6
1.8165
10
1.7999
9
  1.8213
6
1.8004
6
     
QCISD(T)         1.8166
10
    1.8350
4
      1.8105
6
1.8240
8
1.8132
6
  1.8292
7
1.8109
7
     
QCISD(T)=FULL         1.8718
2
  1.8803
2
          1.8791
2
1.8421
2
  1.8650
2
1.8484
2
     
Coupled Cluster CCD   1.8030
6
1.7904
6
1.8335
6
1.8044
10
1.8075
8
1.8348
8
1.8017
10
1.8093
8
1.7915
8
  1.8037
6
1.8070
9
1.7930
9
  1.8322
8
1.8260
6
  1.7851
1
1.7643
1
CCSD         1.8114
10
    1.7914
2
  1.8485
2
  1.8693
2
1.8113
6
1.7987
6
  1.8679
2
1.8512
2
     
CCSD=FULL         1.8649
2
        1.8383
2
  1.8679
2
1.8713
2
1.8355
2
  1.8567
2
1.8403
2
     
CCSD(T)   1.7751
1
    1.8104
8
1.8297
4
1.7909
1
1.8290
4
1.7754
1
  1.7603
1
1.8099
6
1.8237
8
1.8035
8
1.7645
2
1.8282
7
1.8044
8
1.7680
2
1.7721
1
1.7526
1
CCSD(T)=FULL         1.8074
7
            1.8080
6
1.8104
7
1.7904
5
1.7578
2
1.8131
6
1.8012
4
1.7468
2
1.7693
1
1.7430
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 cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pCVDZ cc-pCVTZ

average calculated bond lengths (Å)
Methods with effective core potentials (select basis sets)
CEP-31G CEP-31G* CEP-121G CEP-121G* LANL2DZ SDD
hartree fock HF 1.8248
7
1.7907
8
1.7995
7
1.7802
8
1.7858
10
1.8940
8
density functional B1B95 1.8010
2
1.7792
2
       
B3LYP 1.8475
8
1.8114
10
1.8299
8
1.8068
10
1.8067
8
1.8269
8
wB97X-D 1.9060
2
1.8591
2
1.8983
2
1.8567
2
1.8746
2
1.8983
2
Moller Plesset perturbation MP2 1.8445
8
1.8081
10
1.8220
8
1.8061
10
1.8157
8
1.8277
8
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.