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 C-Si


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 1.6983
10
PM3 1.8044
8
PM6 1.8133
19
composite G2 1.7895
8
G3 1.7895
8
G3B3 1.7828
15
G3MP2 1.7184
1
G4 1.7846
18
CBS-Q 1.7901
8

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-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVTZ aug-cc-pCVTZ daug-cc-pVDZ daug-cc-pVTZ
hartree fock HF 1.7960
15
1.8668
15
1.8340
15
1.8686
15
1.8317
16
1.8365
15
1.8376
15
1.8328
15
1.8327
15
1.8301
15
1.8685
7
1.8455
19
1.8447
15
1.8342
15
1.7672
7
1.8456
15
1.8341
15
1.7673
7
1.8562
13
1.7680
3
1.7596
1
1.8373
2
1.8607
2
1.8262
17
ROHF 1.5408
1
1.7062
2
1.6601
2
1.7046
2
1.6590
2
1.6590
2
1.6647
2
1.6588
2
1.6588
2
1.6310
1
  1.6862
1
1.6703
2
1.6602
2
1.6564
2
1.6756
2
1.6632
2
1.6578
2
1.6768
1
1.6776
1
1.7596
1
1.8373
2
   
density functional LSDA 1.7567
8
1.7823
7
1.7805
8
1.8112
8
1.7878
9
1.7875
9
1.7889
9
1.7832
9
1.7836
9
1.7793
9
  1.7565
3
1.7951
9
1.7821
9
1.6661
1
1.7948
9
1.7825
7
1.6671
1
1.7452
3
1.7453
3
1.7127
1
1.8317
2
   
BLYP 1.8296
15
1.8823
15
1.8468
15
1.8849
15
1.7868
19
1.8484
15
1.8509
15
1.8450
15
1.8452
15
1.8401
15
1.8607
2
1.8305
6
1.8554
15
1.8444
15
  1.8946
3
1.8683
2
  1.7729
3
1.7735
3
1.7336
1
1.8635
2
1.8880
2
1.8682
2
B1B95 1.7794
11
1.8391
2
1.8003
11
1.8406
11
1.8015
11
1.8014
11
1.8248
15
1.7977
11
1.7981
11
1.7945
11
1.8312
2
1.8030
6
1.8095
11
1.7981
11
1.6703
3
1.8103
11
1.7982
11
1.6709
3
1.7502
3
1.7506
3
1.7105
1
1.8341
2
1.8566
2
1.8386
2
B3LYP 1.8135
15
1.8679
15
1.8321
15
1.8697
15
1.8340
15
1.8335
15
1.8355
15
1.8298
15
1.8262
14
1.8354
18
1.8550
3
1.8402
19
1.8405
15
1.8296
15
1.7564
7
1.8410
15
1.7970
18
1.7568
7
1.8545
13
1.7587
3
1.7152
1
1.8467
2
1.8707
2
1.8514
2
B3LYPultrafine   1.9221
2
    1.8340
15
1.8524
2
1.8580
2
1.8492
2
  1.8441
2
1.8439
2
1.8055
5
1.8212
6
1.8077
6
  1.8223
6
1.8224
16
      1.7152
1
1.8467
2
1.8707
2
1.8514
2
B3PW91 1.8051
14
1.8646
15
1.8293
15
1.8656
15
1.8304
15
1.8298
15
1.8311
15
1.8257
15
1.8221
14
1.8226
15
1.8379
2
1.8098
6
1.8367
15
1.8258
15
  1.8728
3
1.8634
4
  1.7551
3
1.7554
3
1.7135
1
1.8404
2
1.8643
2
1.8454
2
mPW1PW91 1.8010
14
1.8614
15
1.8222
14
1.8624
15
1.8271
15
1.8266
15
1.8279
15
1.8225
15
1.8228
15
1.8196
15
1.8350
2
1.8067
6
1.8335
15
1.8228
15
  1.8248
7
1.8005
6
  1.7521
3
1.7525
3
1.7103
1
1.8380
2
1.8611
2
1.8423
2
M06-2X 1.7795
6
1.8413
6
1.8245
19
1.8477
6
1.8274
19
1.8003
6
1.8028
6
1.7983
6
1.7984
6
1.8140
8
1.8214
21
1.8041
6
1.8106
6
1.8184
8
  1.8122
6
1.8185
8
  1.7508
3
1.7511
3
1.7046
1
1.8393
2
1.8601
2
1.8431
2
PBEPBE 1.8165
14
1.8745
15
1.8364
14
1.8727
14
1.8410
15
1.8405
15
1.8421
15
1.8364
15
1.8367
15
1.8331
15
1.8610
3
1.8219
6
1.8474
15
1.8365
15
1.6875
3
1.8468
8
1.8400
9
1.6881
3
1.7669
3
1.7674
3
1.7301
1
1.8534
2
1.8772
2
1.8580
2
PBEPBEultrafine   1.8520
3
    1.8439
9
1.7918
3
1.7957
3
1.7887
3
  1.8511
2
1.8504
2
1.8133
5
1.8286
6
1.8151
6
  1.8295
6
1.8154
6
      1.7301
1
1.8534
2
1.8772
2
1.8580
2
PBE1PBE 1.7860
6
1.8438
2
1.8016
6
1.8525
6
1.8303
19
1.8031
6
1.8053
6
1.7995
6
1.7996
6
1.7961
6
1.8352
2
1.8071
6
1.8136
6
1.8006
6
  1.8147
6
1.8010
6
  1.9120
1
1.9127
1
1.7114
1
1.8379
2
1.8612
2
1.8427
2
HSEh1PBE 1.7870
6
1.8608
19
1.8018
6
1.8535
6
1.8307
19
1.8035
6
1.8313
19
1.7999
6
1.8001
6
1.7964
6
1.8354
2
1.8076
6
1.8142
6
1.8226
19
  1.8152
6
1.8013
6
  1.7531
3
1.7535
3
1.7118
1
1.8381
2
1.8618
2
1.8430
2
TPSSh 1.8466
2
1.8512
5
1.8002
5
1.8540
5
1.7763
18
1.7995
5
1.7767
18
1.7964
5
1.8459
2
1.7729
19
1.8400
2
1.8039
5
1.8114
5
1.7733
18
1.8410
2
1.8129
5
1.7967
5
1.8413
2
1.9149
1
1.9155
1
1.7177
1
1.8430
2
1.8671
2
1.8477
2
wB97X-D 1.8343
2
1.9068
2
1.7727
19
1.9142
2
1.7733
19
1.8390
2
1.7737
19
1.8369
2
1.7705
19
1.8344
2
1.8329
2
1.7748
19
1.7749
19
1.7705
19
1.8333
2
1.8600
2
1.7703
19
1.8336
2
      1.8356
2
1.8597
2
1.8400
2
B97D3 1.8631
2
1.8057
19
1.8663
2
1.9460
2
1.7889
19
1.8624
2
1.7894
19
1.8598
2
1.7867
19
1.8541
2
1.7920
20
1.8653
18
1.8774
2
1.7867
18
1.8542
2
1.8811
2
1.8578
18
1.8544
2
      1.8560
2
1.8807
2
1.8588
21
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-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVTZ aug-cc-pCVTZ daug-cc-pVDZ daug-cc-pVTZ
Moller Plesset perturbation MP2 1.8152
14
1.8855
15
1.8375
15
1.8899
15
1.7773
19
1.8336
15
1.8352
15
1.7704
19
1.8293
15
1.8234
14
1.8351
2
1.8355
19
1.8465
15
1.8308
15
1.7571
4
1.8504
15
1.8234
10
1.7577
4
1.8499
13
1.7611
3
1.6904
1
1.8409
2
1.8739
2
1.8459
2
MP2=FULL 1.8148
14
1.8851
15
1.8324
14
1.8864
14
1.8315
15
1.8304
15
1.8321
15
1.8276
15
1.8237
14
1.8161
14
1.8296
2
1.8110
6
1.8439
15
1.8229
15
1.7473
4
1.8110
7
1.7891
10
1.7456
4
1.8401
13
1.7477
3
1.6848
1
1.8354
2
1.8695
2
1.8345
2
ROMP2 1.6724
3
1.7213
2
1.7188
3
1.7694
3
1.7170
3
1.7165
3
1.7193
3
1.7143
3
1.7141
3
1.7110
3
  1.7303
1
1.7334
3
1.7164
3
1.7050
1
1.7392
3
1.7175
1
1.7073
1
1.8169
2
1.8182
2
1.7207
1
1.8409
2
   
MP3         1.8289
13
  1.7605
16
        1.7656
3
1.7806
3
1.7571
3
        1.7521
3
1.7529
3
1.6947
1
1.8391
2
   
MP3=FULL         1.7592
16
  1.7578
16
        1.7644
3
1.7787
3
1.7495
3
        1.9020
1
1.8998
1
1.6907
1
1.8351
2
   
MP4   1.8881
11
    1.8459
12
    1.8833
1
1.8171
10
    1.7987
4
1.8120
4
1.7575
6
  1.7965
3
1.6968
2
  1.6904
2
1.6909
2
1.6952
1
1.8496
2
   
MP4=FULL   1.8460
4
    1.7939
4
      1.7881
4
      1.8098
4
1.7828
4
  1.7923
3
1.7596
3
      1.6902
1
1.8448
2
   
B2PLYP 1.7738
5
1.8500
5
1.7953
5
1.8567
5
1.8308
18
1.7977
5
1.8013
5
1.7955
5
1.7957
5
1.8164
7
1.8410
2
1.8036
5
1.8123
5
1.7703
18
  1.8156
5
1.8291
8
  1.7579
3
1.7588
3
1.7035
1
1.8450
2
1.8719
2
1.8499
2
B2PLYP=FULL 1.7737
5
1.8499
5
1.7948
5
1.8566
5
1.7967
5
1.7967
5
1.8005
5
1.7950
5
1.7951
5
1.7887
5
1.8394
2
1.8031
5
1.8116
5
1.7946
5
  1.8145
5
1.7948
5
  1.9121
1
1.9124
1
1.7023
1
1.8435
2
1.8705
2
1.8465
2
B2PLYP=FULLultrafine 1.8382
2
1.9216
2
1.8453
2
1.9317
2
1.8493
22
1.8451
2
1.8518
2
1.8447
2
1.8447
2
1.8379
2
1.8394
2
1.8565
2
1.8571
22
1.8307
22
  1.8709
2
1.8273
22
        1.8435
2
1.8705
2
1.8465
2
Configuration interaction CID   1.8727
14
1.8259
14
1.8771
14
1.8276
15
    1.8233
15
    1.8286
2
  1.8594
2
1.8370
2
        1.9102
1
1.9103
1
1.7056
1
1.8333
2
1.8669
2
1.8384
2
CISD   1.8785
14
1.8260
14
1.8757
14
1.8277
15
    1.8195
14
    1.8297
2
  1.8609
2
1.8381
2
        1.9102
1
1.9102
1
1.7100
1
1.8344
2
1.8681
2
1.8390
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 cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVTZ aug-cc-pCVTZ daug-cc-pVDZ daug-cc-pVTZ
Quadratic configuration interaction QCISD 1.8855
2
1.8831
15
1.8313
14
1.8845
14
1.8325
15
1.8278
14
1.8291
14
1.8278
15
1.8356
14
1.8297
13
1.8362
2
1.8143
6
1.8262
11
1.8100
9
  1.8312
6
1.8259
8
  1.7619
3
1.7626
3
1.7195
1
1.8412
2
1.8775
2
1.8466
2
QCISD(T)         1.8281
13
    1.8598
3
    1.8433
2
1.8194
6
1.8164
7
1.7957
7
  1.8211
7
1.7879
6
  1.7681
3
1.7693
3
1.7259
1
1.8490
2
1.8862
2
1.8541
2
QCISD(T)=FULL         1.8439
2
  1.8507
2
      1.8381
2
  1.8739
2
1.8443
2
1.8334
2
1.8821
2
1.8431
2
1.8321
2
      1.8443
2
1.8815
2
1.8426
2
Coupled Cluster CCD 1.8854
2
1.8803
14
1.8314
14
1.8857
14
1.8326
15
1.8278
14
1.8296
14
1.8280
15
1.8327
13
1.8303
13
1.8325
2
1.8112
6
1.8268
11
1.8112
9
  1.8166
7
1.8038
6
  1.7574
3
1.7581
3
1.7000
1
1.8376
2
1.8726
2
1.8425
2
CCSD         1.8322
15
1.8389
2
1.8451
2
1.8540
3
1.8401
2
1.8582
4
1.8351
2
1.8138
6
1.8269
6
1.8252
8
1.7579
4
1.8308
6
1.8225
7
1.7584
4
1.7624
3
1.7632
3
1.7193
1
1.8400
2
1.8758
2
1.8455
2
CCSD=FULL         1.8251
8
        1.8508
4
1.8301
2
1.8124
6
1.8246
6
1.8174
8
1.7490
4
1.8208
5
1.7968
6
1.7473
4
1.9037
1
1.9013
1
1.7147
1
1.8356
2
1.8715
2
1.8343
2
CCSD(T)         1.8462
14
1.8598
3
1.8527
2
1.8591
3
1.8468
2
1.8427
2
1.8425
2
1.8192
6
1.8063
8
1.7864
8
1.7659
4
1.8110
8
1.7912
6
1.7667
4
1.7682
3
1.7694
3
1.7258
1
1.8481
2
1.8851
2
1.8534
2
CCSD(T)=FULL         1.8049
6
          1.8373
2
1.8179
6
1.8304
6
1.8041
6
1.7396
5
1.8332
6
1.7667
4
1.7385
5
1.7587
3
1.6844
2
1.7208
1
1.8434
2
1.8805
2
1.8418
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 cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pV(T+d)Z aug-cc-pV(T+d)Z cc-pCVTZ aug-cc-pCVTZ daug-cc-pVDZ daug-cc-pVTZ

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 1.8729
15
1.8441
15
1.8726
15
1.8470
15
1.8482
15
1.8584
15
    1.7809
21
density functional BLYP                 1.8605
2
B1B95 1.9153
7
1.8988
7
1.9157
2
1.8938
2
1.8941
2
1.8973
2
    1.8319
2
B3LYP 1.8776
15
1.8486
15
1.8776
15
1.8462
15
1.8646
15
1.8600
15
    1.7816
21
B3LYPultrafine                 1.8442
2
B3PW91                 1.8384
2
mPW1PW91                 1.8356
2
M06-2X                 1.8361
2
PBEPBE                 1.7916
21
PBEPBEultrafine                 1.8510
2
PBE1PBE                 1.8365
2
HSEh1PBE                 1.8367
2
TPSSh                 1.8405
2
wB97X-D 1.9357
2
1.8737
2
1.9338
2
1.8664
2
1.8935
2
1.8991
2
    1.8335
2
B97D3                 1.8540
2
Moller Plesset perturbation MP2 1.9004
15
1.8525
15
1.8956
15
1.8446
15
1.8730
15
1.8805
15
    1.7775
21
MP2=FULL                 1.8335
2
B2PLYP                 1.8424
2
B2PLYP=FULL                 1.8408
2
B2PLYP=FULLultrafine                 1.8408
2
Configuration interaction CID                 1.8315
2
CISD                 1.8326
2
Quadratic configuration interaction QCISD                 1.8395
2
QCISD(T)                 1.8467
2
QCISD(T)=FULL                 1.8423
2
Coupled Cluster CCD                 1.8356
2
CCSD                 1.8380
2
CCSD=FULL                 1.8341
2
CCSD(T)                 1.8459
2
CCSD(T)=FULL                 1.8415
2
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.