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III.G.1.a.

Comparison of levels of theory for O-C


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 1.3210
148
PM3 1.3286
378
PM6 1.3710
468
composite G2 1.3316
405
G3 1.3366
425
G3B3 1.3276
484
G4 1.3215
458
CBS-Q 1.3343
326
molecular mechanics DREIDING 1.2635
3

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) 6-311+G(3df,2pd) TZVP cc-pVDZ cc-pVTZ cc-pVQZ aug-cc-pVDZ aug-cc-pVTZ aug-cc-pVQZ cc-pV(T+d)Z cc-pCVDZ cc-pCVTZ Sadlej_pVTZ
hartree fock HF 1.3613
438
1.3399
472
1.3420
444
1.3400
443
1.3222
1085
1.3106
445
1.3242
463
1.3046
450
1.3086
434
1.3169
439
1.3105
272
1.2647
18
1.3310
516
1.3096
442
1.3054
436
1.2486
96
1.3116
417
1.3070
398
1.2373
64
1.1461
3
1.4011
2
1.3979
2
1.2535
12
ROHF 1.2797
18
1.2921
50
1.2928
50
1.2937
49
1.2576
55
1.2625
51
1.2628
51
1.2591
51
1.2614
46
1.2142
20
    1.2660
10
1.2601
51
1.2564
51
1.1912
27
1.2373
40
1.2302
39
1.1791
24
       
density functional LSDA 1.3684
448
1.3430
459
1.3428
463
1.3413
456
1.3153
452
1.3139
457
1.3170
453
1.3107
452
1.3099
454
1.3062
446
1.1608
4
1.1608
4
1.3077
82
1.3131
453
1.3100
450
1.2032
23
1.3155
426
1.2772
97
1.1907
20
       
SVWN 1.2257
4
1.3810
437
1.1874
4
1.1915
4
1.3569
432
1.3115
82
1.3595
436
1.3066
82
1.3071
82
1.3066
82
1.1608
4
1.1608
4
1.1630
4
1.3106
82
1.3064
82
1.1607
4
1.3125
71
1.3054
57
1.1609
4
       
BLYP 1.4152
434
1.3786
444
1.3659
354
1.3791
436
1.3523
435
1.3482
440
1.3523
436
1.3329
349
1.3465
428
1.3539
433
1.1728
4
1.1728
4
1.3341
82
1.3479
435
1.3443
433
1.1723
4
1.3707
215
1.1743
4
1.1726
4
       
B1B95 1.3740
429
1.3530
443
1.3536
441
1.3515
441
1.3239
426
1.3225
440
1.3281
448
1.3190
436
1.3200
435
1.3146
420
1.1558
4
1.1559
4
1.3078
82
1.3214
436
1.3179
433
1.1982
25
1.3170
391
1.2756
122
1.1988
24
  1.4169
2
1.4148
2
 
B3LYP 1.3936
441
1.3602
475
1.3633
445
1.3627
443
1.3272
476
1.3332
442
1.3339
470
1.3253
453
1.3164
229
1.3264
428
1.3654
207
1.2879
18
1.3523
512
1.3315
431
1.3292
429
1.2561
76
1.3093
277
1.3085
220
1.2582
63
1.1700
3
1.4298
2
1.4271
2
1.2772
12
B3LYPultrafine 1.2870
7
1.3141
22
1.1866
4
1.1909
4
1.3287
417
1.1707
4
1.3143
69
1.1618
4
1.1619
4
1.1641
4
1.1603
4
1.2726
16
1.2883
16
1.3156
59
1.3400
171
1.1598
4
1.3162
54
1.3200
433
1.1600
4
       
B3PW91 1.3691
229
1.3596
448
1.3601
445
1.3585
443
1.3240
435
1.3286
444
1.3197
354
1.3249
444
1.3112
225
1.3345
433
1.1591
4
1.1591
4
1.3132
82
1.3281
443
1.3246
441
1.1587
4
1.3476
215
1.1606
4
1.1589
4
       
mPW1PW91 1.3636
231
1.3563
438
1.3426
264
1.3554
439
1.3209
436
1.3253
439
1.3270
438
1.3214
439
1.3227
429
1.3312
433
1.1567
4
1.1567
4
1.3094
82
1.3234
432
1.3057
300
1.1563
4
1.3345
305
1.2963
78
1.1565
4
       
M06-2X 1.3697
95
1.3506
95
1.3508
95
1.3473
95
1.3561
436
1.3220
95
1.3230
95
1.3184
95
1.3187
95
1.3176
95
1.1554
4
1.1553
4
1.3101
82
1.3208
95
1.3185
95
1.1552
4
1.3155
77
1.3068
66
1.1554
4
       
PBEPBE 1.3830
232
1.3805
448
1.3522
237
1.3535
231
1.3460
443
1.3501
434
1.3516
446
1.3462
438
1.3384
429
1.3362
419
1.3743
212
1.4636
18
1.3263
82
1.3482
424
1.3462
432
1.2162
25
1.3205
104
1.3170
150
1.2027
24
1.1694
1
    1.2854
12
PBEPBEultrafine 1.2349
4
1.3161
16
1.1987
4
1.2022
4
1.3642
425
1.1812
4
1.3014
23
1.1726
4
1.1727
4
1.1752
4
1.1712
4
1.2820
16
1.2982
16
1.3241
59
1.3208
59
1.1708
4
1.3255
54
1.3196
62
1.1711
4
       
PBE1PBE 1.3669
76
1.3418
76
1.3418
76
1.3406
76
1.3529
448
1.3139
76
1.3154
76
1.3095
76
1.3100
76
1.3096
76
1.1575
4
1.1575
4
1.3105
76
1.3126
76
1.3094
76
1.1571
4
1.3143
65
1.3058
53
1.1573
4
       
HSEh1PBE 1.3757
95
1.3504
95
1.3506
95
1.3494
95
1.3582
430
1.3220
95
1.3236
95
1.3180
95
1.3184
95
1.3177
95
1.1573
4
1.1573
4
1.3097
82
1.3209
95
1.3178
95
1.1568
4
1.3151
77
1.3058
66
1.1570
4
       
TPSSh   1.3668
15
1.3668
15
1.3662
15
1.3462
489
1.3340
15
1.3466
491
1.3308
15
        1.3329
12
1.3331
15
1.3415
491
  1.3363
15
1.3385
13
         
Moller Plesset perturbation MP2 1.3718
232
1.3750
473
1.3774
439
1.3816
438
1.3321
555
1.3381
441
1.3554
914
1.3241
434
1.3313
431
1.3227
325
1.1695
4
1.2564
17
1.3529
512
1.3348
441
1.3292
440
1.2563
34
1.3211
257
1.3076
120
1.2628
27
1.1810
3
1.2662
10
1.2576
6
1.2867
12
MP2=FULL 1.3666
227
1.3583
304
1.3568
267
1.3618
265
1.3358
525
1.3256
342
1.3297
349
1.3243
443
1.3154
224
1.3092
229
1.1672
4
1.1671
4
1.3088
91
1.3185
304
1.3279
359
1.2517
30
1.3056
116
1.2832
86
1.2503
27
1.1778
3
1.2653
10
1.2554
6
 
ROMP2 1.3687
33
1.3464
31
1.3466
31
1.3458
32
1.3038
32
1.3033
32
1.3134
30
1.3022
30
1.2928
32
1.2893
32
    1.2638
9
1.3058
30
1.2991
29
1.1478
7
1.2643
29
1.2218
13
1.1914
10
       
MP3 1.2152
4
1.1837
4
1.1837
4
1.1900
4
1.3323
416
1.1682
4
1.3416
498
1.1573
4
1.1570
4
1.1580
4
1.1546
4
1.1545
4
1.2804
16
1.2853
16
1.2784
16
1.1533
4
1.1682
4
1.1575
4
1.1538
4
       
MP3=FULL         1.3414
492
  1.3397
466
          1.3207
12
1.3246
12
1.3149
12
               
MP4 1.3623
11
1.3496
164
1.2844
9
1.2809
9
1.3233
204
1.1915
5
1.1932
5
1.2365
8
1.3036
130
1.2920
11
1.1753
4
1.1754
4
1.3177
43
1.3268
47
1.2782
91
1.1744
4
1.3219
36
1.3018
30
1.1751
4
       
MP4=FULL 1.2664
3
1.3676
54
1.2251
3
1.2325
3
1.3331
47
1.1974
3
1.1996
3
1.1884
3
1.3170
44
1.1838
3
1.1839
3
1.1838
3
1.1891
3
1.3328
51
1.2975
33
1.1827
3
1.3271
39
1.2972
32
1.1834
3
       
B2PLYP 1.4074
18
1.3862
18
1.3862
18
1.3880
18
1.3757
375
1.3561
18
1.3585
18
1.3525
18
1.3529
18
1.3507
18
    1.3540
18
1.3558
18
1.3476
401
  1.3709
16
1.3756
14
         
B2PLYP=FULL 1.4073
18
1.3862
18
1.3862
18
1.3879
18
1.3561
18
1.3557
18
1.3581
18
1.3521
18
1.3525
18
1.3497
18
    1.3537
18
1.3555
18
1.3505
18
  1.3706
16
1.3742
14
         
B2PLYP=FULLultrafine         1.3639
237
                                   
Configuration interaction CID 1.2771
7
1.3426
239
1.3408
224
1.3435
223
1.3128
335
1.3635
6
1.3644
6
1.3033
231
1.2546
15
1.2672
11
1.1507
4
1.1507
4
1.1542
4
1.1647
5
1.1560
5
1.1493
4
1.1643
4
1.1534
4
1.1497
4
       
CISD 1.2714
9
1.3475
240
1.3435
227
1.3454
225
1.3146
335
1.4374
7
1.1768
6
1.3021
228
1.2557
15
1.2650
10
1.1523
4
1.1523
4
1.1563
4
1.3633
6
1.1577
5
1.1509
4
1.1662
4
1.1550
4
1.1512
4
       
Quadratic configuration interaction QCISD 1.4215
41
1.3788
384
1.3587
234
1.3649
241
1.3303
309
1.3269
246
1.3268
249
1.3147
276
1.3157
239
1.3148
167
1.1622
4
1.1622
4
1.3196
81
1.3193
234
1.2981
147
1.1607
4
1.3189
89
1.2973
63
1.1611
4
1.1554
1
     
QCISD(T) 1.2343
4
1.2787
12
1.2688
8
1.2691
8
1.3139
182
1.2245
9
1.2832
17
1.3233
15
1.3084
18
1.2313
7
1.1679
4
1.1679
4
1.3159
56
1.3015
124
1.2926
99
1.1667
4
1.2889
75
1.2627
52
1.1673
4
       
QCISD(TQ) 1.2260
4
1.1973
4
1.1973
4
1.2041
4
1.1787
4
1.1785
4
1.1797
4
1.1684
4
1.1682
4
1.1681
4
1.1653
4
1.1653
4
1.1683
4
1.1757
4
1.1677
4
1.1641
4
1.1795
4
1.1685
4
1.1296
1
       
Coupled Cluster CCD 1.4192
41
1.3531
244
1.3497
225
1.3550
234
1.3359
345
1.3130
235
1.3188
235
1.3072
231
1.3100
166
1.3083
166
1.1575
4
1.1575
4
1.3130
76
1.3133
228
1.2903
130
1.1562
4
1.2932
109
1.2562
72
1.1567
4
  1.4256
2
1.4197
2
 
CCSD 1.2370
3
1.2792
11
1.2589
8
1.2605
8
1.3177
194
1.2177
9
1.2768
17
1.3072
15
1.3896
21
1.2397
6
1.1716
3
1.1602
4
1.3118
48
1.3209
94
1.3256
83
1.2319
14
1.3184
41
1.3068
36
1.1943
7
       
CCSD=FULL 1.2232
4
1.1928
4
1.1928
4
1.2003
4
1.3171
55
1.1734
4
1.1743
4
1.1630
4
1.1627
4
1.1605
4
1.1580
4
1.1580
4
1.3069
49
1.3153
51
1.2919
43
1.2289
14
1.3127
42
1.2778
26
1.1861
9
       
CCSD(T) 1.2325
4
1.2685
17
1.2666
8
1.2672
8
1.3313
181
1.2856
22
1.2732
24
1.2456
17
1.2871
19
1.2161
9
1.2334
7
1.2335
7
1.3198
55
1.3037
120
1.2878
114
1.2343
23
1.2957
104
1.2586
62
1.2461
18
1.1622
1
1.2629
6
1.1684
4
 
CCSD(T)=FULL 1.2325
4
1.2007
4
1.2007
4
1.2073
4
1.3194
114
1.1793
4
1.1805
4
1.1694
4
1.1692
4
1.1665
4
1.1649
4
1.1648
4
1.3205
62
1.3203
80
1.2808
51
1.2392
20
1.3085
63
1.2671
35
1.2237
14
  1.2620
6
1.2541
6
 

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 1.3496
445
1.3231
426
1.3480
445
1.3200
430
1.3432
446
1.3425
444
density functional LSDA 1.2169
4
1.1939
4
1.2130
4
1.1858
4
1.1991
4
1.1990
4
SVWN 1.2169
4
1.1939
4
1.2130
4
1.1858
4
1.1991
4
1.1990
4
BLYP 1.2217
4
1.1968
4
1.2183
4
1.1889
4
1.2132
4
1.2135
4
B1B95 1.3794
266
1.3493
263
1.2323
7
1.2060
7
1.2269
7
1.2270
7
B3LYP 1.3767
445
1.3480
425
1.3743
441
1.3449
427
1.3667
443
1.3664
441
B3LYPultrafine 1.2081
4
1.1847
4
1.2049
4
1.1768
4
1.2083
5
1.1988
4
B3PW91 1.2051
4
1.1825
4
1.2017
4
1.1748
4
1.1961
4
1.1962
4
mPW1PW91 1.2020
4
1.1797
4
1.1987
4
1.1721
4
1.1932
4
1.1934
4
M06-2X 1.1948
4
1.1748
4
1.1905
4
1.1652
4
1.1907
4
1.1908
4
PBEPBE 1.2178
4
1.1940
4
1.2142
4
1.1864
4
1.2097
4
1.2099
4
PBEPBEultrafine 1.2178
4
1.1940
4
1.2142
4
1.1864
4
1.2097
4
1.2100
4
PBE1PBE 1.2024
4
1.1801
4
1.1990
4
1.1726
4
1.1938
4
1.1940
4
HSEh1PBE 1.2030
4
1.1806
4
1.1998
4
1.1731
4
1.1939
4
1.1941
4
Moller Plesset perturbation MP2 1.3956
450
1.3531
423
1.3902
445
1.3501
425
1.3876
453
1.3879
449
MP2=FULL 1.2320
4
1.1971
4
1.2256
4
1.1895
4
1.2210
4
1.2209
4
MP3 1.2110
4
1.1828
4
1.2033
4
1.1744
4
1.1983
4
1.1981
4
MP4 1.2440
4
1.2019
4
1.2388
4
1.1956
4
1.2331
4
1.2333
4
MP4=FULL 1.2525
3
1.2114
3
1.2481
3
1.2062
3
1.2412
3
1.2412
3
Configuration interaction CID 1.2095
4
1.1791
4
1.2025
4
1.1706
4
1.1977
4
1.1975
4
CISD 1.2130
4
1.1811
4
1.2058
4
1.1726
4
1.2009
4
1.2007
4
Quadratic configuration interaction QCISD 1.2254
4
1.1912
4
1.2183
4
1.1833
4
1.2133
4
1.2131
4
QCISD(T) 1.2293
4
1.1951
4
1.2227
4
1.1878
4
1.2171
4
1.2170
4
QCISD(TQ) 1.2246
4
1.1928
4
1.2176
4
1.1851
4
1.2125
4
1.2123
4
Coupled Cluster CCD 1.2170
4
1.1857
4
1.2100
4
1.1777
4
1.2051
4
1.2049
4
CCSD 1.2334
3
1.1991
3
1.2270
3
1.1921
3
1.2210
3
1.2209
3
CCSD=FULL 1.2213
4
1.1887
4
1.2142
4
1.1807
4
1.2091
4
1.2088
4
CCSD(T) 1.2282
4
1.1943
4
1.2215
4
1.1868
4
1.2160
4
1.2159
4
CCSD(T)=FULL 1.2282
4
1.1943
4
1.2215
4
1.1868
4
1.2159
4
1.2156
4
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.