ABSTRACT
As(3)–C X2-As-Csp3 1 .963 1 .965 0 .017 1 .948 1 .978 6 X2-As-Car 1 .956 1 .956 0 .015 1 .944 1 .964 41
As(3)–Cl X2-As-Cl 2 .268 2 .256 0 .039 2 .247 2 .281 10 As(6)–F in AsF6-1 .678 1 .676 0 .020 1 .659 1 .695 36 As(3)–I see OPIMAS (2 .579, 2 .590) As(3)–N(3) X2-As-N-X2 1 .858 1 .858 0 .029 1 .839 1 .873 19 As(4)=N(2) see TPASSN (1 .837) As(4)–O (X)2(O=)As-OH 1 .710 1 .712 0 .017 1 .695 1 .726 6 As(3)–O see ASAZOC, PHASOC01 (1 .787-1 .845) As(4)=O X3-As=O 1 .661 1 .661 0 .016 1 .652 1 .667 9 As(3)=P(3) see BELNIP (2 .350, 2 .362) † As(3)–P(3) see BUTHAZ10 (2 .124) † As(3)–S X2-As-S 2 .275 2 .266 0 .032 2 .247 2 .298 14 As(4)=S X3-As=S 2 .083 2 .082 0 .004 2 .080 2 .086 9 As(3)–Se(2) see COSDIX, ESEARS (2 .355-2 .401) † As(3)–Si(4) see BICGEZ, MESIAD (2 .351-2 .365) † As(3)–Te(2) see ETEARS (2 .571, 2 .576) † B(n)–B(n) n = 5-7 in boron cages 1 .775 1 .773 0 .031 1 .763 1 .786 688 B(4)–B(4) see CETTAW (2 .041) B(4)–B(3) see COFVOI (1 .698) B(3)–B(3) X2-B-B-X2 1 .701 1 .700 0 .014 1 .691 1 .712 8 B(6)–BR 1 .967 1 .971 0 .014 1 .954 1 .979 7 † B(4)–BR 2 .017 2 .008 0 .031 1 .990 2 .044 15 † B(n)–C n = 5-7: B-C in cages 1 .716 1 .717 0 .020 1 .707 1 .728 96
n = 3-4: B-Csp3 not cages 1 .597 1 .599 0 .022 1 .585 1 .611 29 1 n = 4: B-Car 1 .606 1 .607 0 .012 1 .596 1 .615 41 n = 4: B-Car in Ph4B-1 .643 1 .643 0 .006 1 .641 1 .645 16
B(n)–C n = 3: B-Car 1 .556 1 .552 0 .015 1 .546 1 .566 24 B(n)–Cl B(5)–Cl and B(3)–Cl 1 .751 1 .751 0 .011 1 .743 1 .761 14
1 u B(4)–Cl 1 .833 1 .833 0 .013 1 .821 1 .843 22
B(4)–F B-F (B neutral) 1 .366 1 .368 0 .017 1 .356 1 .375 25 B-–F in BF4-1 .365 1 .372 0 .029 1 .352 1 .390 84
B(4)–I see TMPBTI (2 .220, 2 .253) B(4)–N(3) X3-B-N(=C)(X) 1 .611 1 .617 0 .013 1 .601 1 .625 8
in pyrazaboles 1 .549 1 .552 0 .015 1 .536 1 .560 10 B(3)–N(3) X2-B-N-C2: all coplanar 1 .404 1 .404 0 .014 1 .389 1 .408 40 2
for τ(BN) > 30º see BOGSUL, BUSHAY, CILRUK (1 .434-1 .530)
S2-B-N-X2 1 .447 1 .443 0 .013 1 .435 1 .470 14 B(4)–O B-–O in BO-4 1 .468 1 .468 0 .022 1 .453 1 .479 24
for neutral B-O see Note 3 3 B(3)–O(2) X2-B-O-X 1 .367 1 .367 0 .024 1 .349 1 .382 35 B(n)–P n = 4: B-P 1 .922 1 .927 0 .027 1 .900 1 .954 10
n = 3: see BUPSIB10 (1 .892, 1 .893) B(4)–S B(4)–S(3) 1 .930 1 .927 0 .009 1 .925 1 .934 10
B(4)–S(2) 1 .896 1 .896 0 .004 1 .893 1 .899 6 B(3)–S N-B-S2 1 .806 1 .806 0 .010 1 .799 1 .816 28
(=X-)(N-)B-S 1 .851 1 .854 0 .013 1 .842 1 .859 10 Br-Br see BEPZEB, TPASTB 2 .542 2 .548 0 .015 2 .526 2 .551 4 Br-C Br-C* 1 .966 1 .967 0 .029 1 .951 1 .983 100 4
Br-Csp3 (cyclopropane) 1 .910 1 .910 0 .010 1 .900 1 .914 8 Br-Csp2 1 .883 1 .881 0 .015 1 .874 1 .894 31 4 Br-Car (mono-Br + m.p-Br2) 1 .899 1 .899 0 .012 1 .892 1 .906 119 4 Br-Car (o-Br2) 1 .875 1 .872 0 .011 1 .864 1 .884 8 4
–Br(2)–Cl see TEACBR (2 .362-2 .402) † Br-I see DTHIBR10 (2 .646), TPHOSI (2 .695) Br-N see NBBZAM (1 .843) Br-O see CIYFOF 1 .581 1 .581 0 .007 1 .574 1 .587 4 Br-P see CISTED (2 .366) Br-S(2) see BEMLIO (2 .206) † Br-S(3) see CIWYIQ (2 .435, 2 .453) † Br-S(3)+ see THINBR (2 .321) † Br-SE see CIFZUM (2 .508, 2 .619) Br-Si see BIZJAV (2 .284) Br-Te In Br6Te2-see CUGBAH (2 .692-2 .716)
Br-Te(4) see BETUTE10 (3 .079, 3 .015) Br-Te(3) see BTUPTE (2 .835)
Csp3-Csp3 C#–CH2-CH3 1 .513 1 .514 0 .014 1 .507 1 .523 192 (C#)2-CH-CH3 1 .524 1 .526 0 .015 1 .518 1 .534 226 (C#)3-C-CH3 1 .534 1 .534 0 .011 1 .527 1 .541 825 C#–CH2-CH2-C# 1 .524 1 .524 0 .014 1 .516 1 .532 2459 (C#)2-CH-CH2-C# 1 .531 1 .531 0 .012 1 .524 1 .538 1217 (C#)3-C-CH2-C# 1 .538 1 .539 0 .010 1 .533 1 .544 330 (C#)2-CH-CH-(C#)2 1 .542 1 .542 0 .011 1 .536 1 .549 321 (C#)3-C-CH-(C#)2 1 .556 1 .556 0 .011 1 .549 1 .562 215 (C#)3-C-C-(C#)3 1 .588 1 .580 0 .025 1 .566 1 .610 21 C*–C* (overall) 1 .530 1 .530 0 .015 1 .521 1 .539 5777 5,6 in cyclopropane (any subst .) 1 .510 1 .509 0 .026 1 .497 1 .523 888 7 in cyclobutane (any subst .) 1 .554 1 .553 0 .021 1 .540 1 .567 679 8 in cyclopentane (C,H-subst .) 1 .543 1 .543 0 .018 1 .532 1 .554 1641 in cyclohexane (C,H-subst .) 1 .535 1 .535 0 .016 1 .525 1 .545 2814 cyclopropyl-C* (exocyclic) 1 .518 1 .518 0 .019 1 .505 1 .531 366 7 cyclobutyl-C* (exocyclic) 1 .529 1 .529 0 .016 1 .519 1 .539 376 8 cyclopentyl-C* (exocyclic) 1 .540 1 .541 0 .017 1 .527 1 .549 956 cyclohexyl-C* (exocyclic) 1 .539 1 .538 0 .016 1 .529 1 .549 2682 in cyclobutene (any subst .) 1 .573 1 .574 0 .017 1 .566 1 .586 25 8 in cyclopentene (C,H-subst .) 1 .541 1 .539 0 .015 1 .532 1 .549 208 in cyclohexene (C,H-subst .) 1 .541 1 .541 0 .020 1 .528 1 .554 586 in oxirane (epoxide) 1 .466 1 .466 0 .015 1 .458 1 .474 249 9 in aziridine 1 .480 1 .481 0 .021 1 .465 1 .496 67 9
1 u in oxetane 1 .541 1 .541 0 .019 1 .527 1 .557 16 in azetidine 1 .548 1 .543 0 .018 1 .536 1 .558 22 oxiranyl-C* (exocyclic) 1 .509 1 .507 0 .018 1 .497 1 .519 333 9 aziridinyl-C* (exocyclic) 1 .512 1 .512 0 .018 1 .496 1 .526 13 9
Csp3-Csp2 CH3-C=C 1 .503 1 .504 0 .011 1 .497 1 .509 215 C#–CH2-C=C 1 .502 1 .502 0 .013 1 .494 1 .510 483 (C#)2-CH-C=C 1 .510 1 .510 0 .014 1 .501 1 .518 564 (C#)3-C-C=C 1 .522 1 .522 0 .016 1 .511 1 .533 193
Csp3-Csp2 C*–C=C (overall) 1 .507 1 .507 0 .015 1 .499 1 .517 1456 5 C*–C=C (endocyclic) in cyclopropene 1 .509 1 .508 0 .016 1 .500 1 .516 20 10 in cyclobutene 1 .513 1 .512 0 .018 1 .500 1 .525 50 8 in cyclopentene 1 .512 1 .512 0 .014 1 .502 1 .521 208 in cyclohexene 1 .506 1 .505 0 .016 1 .495 1 .516 391 in cyclopentadiene 1 .502 1 .503 0 .019 1 .490 1 .515 18 in cyclohexa-1,3-diene 1 .504 1 .504 0 .017 1 .491 1 .517 56 C*–C=C (exocyclic): cyclopropenyl-C* 1 .478 1 .475 0 .012 1 .470 1 .485 7 10 cyclobutenyl-C* 1 .489 1 .483 0 .015 1 .479 1 .496 11 8 cyclopentenyl-C* 1 .504 1 .506 0 .012 1 .495 1 .512 115 cyclohexenyl-C* 1 .511 1 .511 0 .013 1 .502 1 .519 292 C*CH=O in aldehydes 1 .510 1 .510 0 .008 1 .501 1 .518 7 (C*)2-C=O in ketones 1 .511 1 .511 0 .015 1 .501 1 .521 952 11 in cyclobutanone 1 .529 1 .530 0 .016 1 .514 1 .545 18 in cyclopentanone 1 .514 1 .514 0 .016 1 .505 1 .523 312 acyclic and 6 + rings 1 .509 1 .509 0 .016 1 .499 1 .519 626 C*–COOH in carboxylic acids 1 .502 1 .502 0 .014 1 .495 1 .510 176 C*–COO-in carboxylate anions 1 .520 1 .521 0 .011 1 .516 1 .528 57 C*–C(=O)(–OC*) in acyclic esters 1 .497 1 .496 0 .018 1 .484 1 .509 553 12 in β-lactones 1 .519 1 .519 0 .020 1 .500 1 .538 4 13 in γ-lactones 1 .512 1 .512 0 .015 1 .501 1 .521 110 12 in δ-lactones 1 .504 1 .502 0 .013 1 .495 1 .517 27 12 cyclopropyl (C)–C=O in ketones, acids and esters 1 .486 1 .485 0 .018 1 .474 1 .497 105 7 C*–C(=O)(–NH2) in acyclic amides 1 .514 1 .512 0 .016 1 .506 1 .526 32 14 C*–C(=O)(–NHC*) in acyclic amides 1 .506 1 .505 0 .012 1 .498 1 .515 78 14 C*–C(=O)[–N(C*)2] in acyclic amides 1 .505 1 .505 0 .011 1 .496 1 .517 15 14
Csp3-Car CH3-Car 1 .506 1 .507 0 .011 1 .501 1 .513 454 C#–CH2-Car 1 .510 1 .510 0 .009 1 .505 1 .516 674 (C#)2-CH-Car 1 .515 1 .515 0 .011 1 .508 1 .522 363 (C#)3-C-Car 1 .527 1 .530 0 .016 1 .517 1 .539 308 C*–Car (overall) 1 .513 1 .513 0 .014 1 .505 1 .521 1813 cyclopropyl (C)–Car 1 .490 1 .490 0 .015 1 .479 1 .503 90 7
Csp3-Csp1 C*–C≡C 1 .466 1 .465 0 .010 1 .460 1 .469 21 15 C#–C≡C 1 .472 1 .472 0 .012 1 .464 1 .481 88 15 C*–C≡N 1 .470 1 .469 0 .013 1 .463 1 .479 106 7b cyclopropyl (C)–C≡N 1 .444 1 .447 0 .010 1 .436 1 .451 38 7
Csp2-Csp2 C=C-C=C (conjugated) 1 .455 1 .455 0 .011 1 .447 1 .463 30 16,18 (unconjugated) 1 .478 1 .476 0 .012 1 .470 1 .479 8 17,18 (overall) 1 .460 1 .460 0 .015 1 .450 1 .470 38 C=C-C=C-C=C 1 .443 1 .445 0 .013 1 .431 1 .454 29 18 C=C-C=C (endocyclic in TCNQ) 1 .432 1 .433 0 .012 1 .424 1 .441 280 19 C=C-C(=O)(–C*) (conjugated) 1 .464 1 .462 0 .018 1 .453 1 .476 211 16,18 (unconjugated) 1 .484 1 .486 0 .017 1 .475 1 .497 14 17,18 (overall) 1 .465 1 .462 0 .018 1 .453 1 .478 226 C=C-C(=O)–C=C in benzoquinone (C,H-subst . only) 1 .478 1 .476 0 .011 1 .469 1 .488 28 in benzoquinone (any subst .) 1 .478 1 .478 0 .031 1 .464 1 .498 172
1 u non-quinonoid 1 .456 1 .455 0 .012 1 .447 1 .464 28 C=C-COOH 1 .475 1 .476 0 .015 1 .461 1 .488 22 C=C-COOC* 1 .488 1 .489 0 .014 1 .478 1 .497 113 C=C-COO-1 .502 1 .499 0 .017 1 .488 1 .510 11 HOOC-COOH 1 .538 1 .537 0 .007 1 .535 1 .541 9 HOOC-COO-1 .549 1 .552 0 .009 1 .546 1 .553 13 –OOC-COO-1 .564 1 .559 0 .022 1 .554 1 .568 9 formal Csp2-Csp2 single bond in selected
non-fused heterocycles: in 1H-pyrrole (C3-C4) 1 .412 1 .410 0 .016 1 .401 1 .427 29 in furan (C3-C4) 1 .423 1 .423 0 .016 1 .412 1 .433 62 in thiophene (C3-C4) 1 .424 1 .425 0 .015 1 .415 1 .433 40 in pyrazole (C3-C4) 1 .410 1 .412 0 .016 1 .400 1 .418 20 in isoxazole (C3-C4) 1 .425 1 .425 0 .016 1 .413 1 .438 9 in furazan (C3-C4) 1 .428 1 .427 0 .007 1 .422 1 .435 6 in furoxan (C3-C4) 1 .417 1 .417 0 .006 1 .412 1 .422 14
Csp2-Car C=C-Car (conjugated) 1 .470 1 .470 0 .015 1 .463 1 .480 37 16,18
Csp2-Car 1 .488 1 .490 0 .012 1 .480 1 .496 87 17,18 (overall) 1 .483 1 .483 0 .015 1 .472 1 .494 124 cyclopropenyl (C=C)–Car 1 .447 1 .448 0 .006 1 .441 1 .452 8 10 Car-C(=O)–C* 1 .488 1 .489 0 .016 1 .478 1 .500 84 Car-C(=O)–Car 1 .480 1 .481 0 .017 1 .468 1 .494 58 Car-COOH 1 .484 1 .485 0 .014 1 .474 1 .491 75 Car-C(=O)(–OC*) 1 .487 1 .487 0 .012 1 .480 1 .494 218 Car-COO-1 .504 1 .509 0 .014 1 .495 1 .512 26 Car-C(–O)–NH2 1 .500 1 .503 0 .020 1 .498 1 .510 19 Car-C=N-C# (conjugated) 1 .476 1 .478 0 .014 1 .466 1 .486 27 16 (unconjugated) 1 .491 1 .490 0 .008 1 .485 1 .496 48 17 (overall) 1 .485 1 .487 0 .013 1 .481 1 .493 75 in indole (C3-C3a) 1 .434 1 .434 0 .011 1 .428 1 .439 40
Csp2-Csp1 C=C-C≡C 1 .431 1 .427 0 .014 1 .425 1 .441 11 7b C=C-C≡N in TCNQ 1 .427 1 .427 0 .010 1 .420 1 .433 280 19
Car-Car in biphenyls (ortho subst . all H) 1 .487 1 .488 0 .007 1 .484 1 .493 30 (≥1 non-H ortho-subst .) 1 .490 1 .491 0 .010 1 .486 1 .495 212
Car-Csp1 Car-C≡C 1 .434 1 .436 0 .006 1 .430 1 .437 37 Car-C≡N 1 .443 1 .444 0 .008 1 .436 1 .448 31
Csp1-Csp1 C≡C-C=C 1 .377 1 .378 0 .012 1 .374 1 .384 21 Csp2=Csp2 C*–CH=CH2 1 .299 1 .300 0 .027 1 .280 1 .311 42
(C*)2-C=CH2 1 .321 1 .321 0 .013 1 .313 1 .328 77 C*–CH=CH-C* (cis) 1 .317 1 .318 0 .013 1 .310 1 .323 106 (trans) 1 .312 1 .311 0 .011 1 .304 1 .320 19 (overall) 1 .316 1 .317 0 .015 1 .309 1 .323 127 (C*)2-C=CH-C* 1 .326 1 .328 0 .011 1 .319 1 .334 168 (C*2-C=C-(C*)2 1 .331 1 .330 0 .009 1 .326 1 .334 89 (C*,H)2-C=C-(C*,H)2 (overall) 1 .322 1 .323 0 .014 1 .315 1 .331 493 5 in cyclopropene (any subst .) 1 .294 1 .288 0 .017 1 .284 1 .302 10 10 in cyclobutene (any subst .) 1 .335 1 .335 0 .019 1 .324 1 .347 25 8 in cyclopentene (C,H-subst .) 1 .323 1 .324 0 .013 1 .314 1 .331 104 in cyclohexene (C,H-subst .) 1 .326 1 .325 0 .012 1 .318 1 .334 196 C=C=C (allenes, any subst .) 1 .307 1 .307 0 .005 1 .303 1 .310 18 C=C-C=C (C,H subst ., conjugated) 1 .330 1 .330 0 .014 1 .322 1 .338 76 16 C=C-C=C-C=C (C,H subst ., conjugated) 1 .345 1 .345 0 .012 1 .337 1 .350 58 16 C=C-Car (C,H subst ., conjugated) 1 .339 1 .340 0 .011 1 .334 1 .346 124 16 C=C in cyclopenta-1,3-diene (any subst .) 1 .341 1 .341 0 .017 1 .328 1 .356 18 C=C in cyclohexa-1,3-diene (any subst .) 1 .332 1 .332 0 .013 1 .323 1 .341 56 in C=C-C=O (C,H subst ., conjugated) 1 .340 1 .340 0 .013 1 .332 1 .348 211 16,18 (C,H subst ., unconjugated) 1 .331 1 .330 0 .008 1 .326 1 .339 14 17,18
1 u (C,H subst ., overall) 1 .340 1 .339 0 .013 1 .332 1 .348 226 in cyclohexa-2,5-dien-1-ones 1 .329 1 .327 0 .011 1 .321 1 .335 28 in p-benzoquinones (C*,H subst .) 1 .333 1 .337 0 .011 1 .325 1 .338 14 (any subst .) 1 .349 1 .339 0 .030 1 .330 1 .364 86 in TCNQ (endocyclic) 1 .352 1 .353 0 .010 1 .345 1 .358 142 19 (exocyclic) 1 .392 1 .391 0 .017 1 .379 1 .405 139 19 C=C-OH in enol tautomers 1 .362 1 .360 0 .020 1 .349 1 .370 54 in heterocycles (any subst .): 1H-pyrrole (C2-C3, C4-C5) 1 .375 1 .377 0 .018 1 .361 1 .388 58 furan (C2-C3, C4-C5) 1 .341 1 .342 0 .021 1 .329 1 .351 125 thiophene (C2-C3, C4-C5) 1 .362 1 .359 0 .025 1 .346 1 .377 60 pyrazole (C4-C5) 1 .369 1 .372 0 .019 1 .362 1 .383 20 imidazole (C4-C5) 1 .360 1 .361 0 .014 1 .352 1 .367 44 isoxazole (C4-C5) 1 .341 1 .336 0 .012 1 .331 1 .355 9 indole (C2-C3) 1 .364 1 .363 0 .012 1 .355 1 .371 40
Car ≃ Car in phenyl rings with C*, H subst . only H-C ≃ C-H 1 .380 1 .381 0 .013 1 .372 1 .388 2191 C*–C ≃ C-H 1 .387 1 .388 0 .010 1 .382 1 .393 891 C*–C ≃ C-C* 1 .397 1 .397 0 .009 1 .392 1 .403 182 C ≃ C (overall) 1 .384 1 .384 0 .013 1 .375 1 .391 3264 F-C ≃ C-F 1 .372 1 .374 0 .011 1 .366 1 .380 84 4 Cl-C ≃ C-Cl 1 .388 1 .389 0 .014 1 .380 1 .398 152 4 in naphthalene (D2h, any subst .) C1-C2 1 .364 1 .364 0 .014 1 .356 1 .373 440 C2-C3 1 .406 1 .406 0 .014 1 .397 1 .415 218 C1-C8a 1 .420 1 .419 0 .012 1 .412 1 .426 440 C4a-C8a 1 .422 1 .424 0 .011 1 .417 1 .429 109
Car ≃ Car in anthracene (D2h, any subst .) C1-C2 1 .356 1 .356 0 .009 1 .350 1 .360 56 C2-C3 1 .410 1 .410 0 .010 1 .401 1 .416 34 C1-C9a 1 .430 1 .430 0 .006 1 .426 1 .434 56 C4a-C9a 1 .435 1 .436 0 .007 1 .429 1 .440 34 C9-C9a 1 .400 1 .402 0 .009 1 .395 1 .406 68 in pyridine (C,H subst .) 1 .379 1 .381 0 .012 1 .371 1 .387 276 20 (any subst .) 1 .380 1 .380 0 .015 1 .371 1 .389 537 20 in pyridinium cation (N+ –H; C,H subst . on C) C2-C3 1 .373 1 .375 0 .012 1 .368 1 .380 30 C3-C4 1 .379 1 .380 0 .011 1 .371 1 .388 30 (N+ –X; C,H subst . on C) C2-C3 1 .373 1 .372 0 .019 1 .362 1 .382 151 C3-C4 1 .383 1 .385 0 .019 1 .372 1 .394 151 in pyrazine (H subst . on C) 1 .379 1 .377 0 .010 1 .370 1 .388 10 (any subst . on C) 1 .405 1 .405 0 .024 1 .388 1 .420 60 in pyrimidine (C,H subst . on C) 1 .387 1 .389 0 .018 1 .379 1 .400 28
Csp1≡Csp1 X-C≡C-X 1 .183 1 .183 0 .014 1 .174 1 .193 119 15 C,H-C≡C-C,H 1 .181 1 .181 0 .014 1 .173 1 .192 104 15 in C≡C-C(sp2,ar) 1 .189 1 .193 0 .010 1 .181 1 .195 38 15 in C≡C-C≡C 1 .192 1 .192 0 .010 1 .187 1 .197 42 15 in CH≡C-C# 1 .174 1 .174 0 .011 1 .167 1 .180 42 15
Csp3-Cl Omitting 1,2-dichlorides: C-CH2-Cl 1 .790 1 .790 0 .007 1 .783 1 .795 13 4 C2-CH-Cl 1 .803 1 .802 0 .003 1 .800 1 .807 8 4 C3-C-Cl 1 .849 1 .856 0 .011 1 .837 1 .858 5 4 X-CH2-Cl (X = C,H,N,O) 1 .790 1 .791 0 .011 1 .783 1 .797 37 4 X2-CH-Cl (X = C,H,N,O) 1 .805 1 .803 0 .014 1 .800 1 .812 26 4 X3-C-Cl (X = C,H,N,O) 1 .843 1 .838 0 .014 1 .835 1 .858 7 4 X2-C-Cl2 (X = C,H,N,O) 1 .779 1 .776 0 .015 1 .769 1 .790 18 4
1 u X-C-Cl3 (X = C,H,N,O) 1 .768 1 .765 0 .011 1 .761 1 .776 33 4 Cl-CH(–C)–CH(–C)–Cl 1 .793 1 .793 0 .013 1 .786 1 .800 66 4 Cl-C(–C2)–C(–C2)–Cl 1 .762 1 .760 0 .010 1 .757 1 .765 54 4 cyclopropyl-Cl 1 .755 1 .756 0 .011 1 .749 1 .763 64
Csp2-Cl C=C-Cl (C,H,N,O subst . on C) 1 .734 1 .729 0 .019 1 .719 1 .748 63 4 C=C-Cl2 (C,H,N,O subst . on C) 1 .720 1 .716 0 .013 1 .708 1 .729 20 4 Cl-C=C-Cl 1 .713 1 .711 0 .011 1 .705 1 .720 80 4
Car-Cl Car-Cl (mono-Cl + m,p-Cl2) 1 .739 1 .741 0 .010 1 .734 1 .745 340 4 Car-Cl (o-Cl2) 1 .720 1 .720 0 .010 1 .713 1 .717 364 4
Csp1Cl see HCLENE10 (1 .634, 1 .646) Csp3-F Omitting 1,2-difluorides
C-CH2-F and C2-CH-F 1 .399 1 .399 0 .017 1 .389 1 .408 25 4 C3-C-F 1 .428 1 .431 0 .009 1 .421 1 .435 11 4 (C*,H)2-C-F2 1 .349 1 .347 0 .012 1 .342 1 .356 58 4 C*–C-F3 1 .336 1 .334 0 .007 1 .330 1 .344 12 4 F-C*–C*–F 1 .371 1 .374 0 .007 1 .362 1 .375 26 4 X3-C-F (X = C,H,N,O) 1 .386 1 .389 0 .033 1 .373 1 .408 70 4 X2-C-F2 (X = C,H,N,O) 1 .351 1 .349 0 .013 1 .342 1 .356 58 4 X-C-F3 (X = C,H,N,O) 1 .322 1 .323 0 .015 1 .314 1 .332 309 4 F-C(–X)2-C(–X)2-F (X = C,H,N,O) 1 .373 1 .374 0 .009 1 .362 1 .377 30 4 F-C(–X)2-NO2 (X = any subst .) 1 .320 1 .319 0 .009 1 .312 1 .327 18
Csp2-F C=C-F (C,H,N,O subst . on C) 1 .340 1 .340 0 .013 1 .334 1 .346 34 4 Car-F Car-F (mono-F + m,p-F2) 1 .363 1 .362 0 .008 1 .357 1 .368 38 4
Car-F (o-F2) 1 .340 1 .340 0 .009 1 .336 1 .344 167 4 Csp3-H C-C-H3 (methyl) 1 .059 1 .061 0 .030 1 .039 1 .083 83 21
C2-C-H2 (primary) 1 .092 1 .095 0 .013 1 .088 1 .099 100 21 C3-C-H (secondary) 1 .099 1 .097 0 .004 1 .095 1 .103 14 21 C2,3-C-H (primary and secondary) 1 .093 1 .095 0 .012 1 .089 1 .100 118 21 X-C-H3 (methyl) 1 .066 1 .074 0 .028 1 .049 1 .087 160 21 X2-C-H2 (primary) 1 .092 1 .095 0 .012 1 .088 1 .099 230 21 X3-C-H (secondary) 1 .099 1 .099 0 .007 1 .095 1 .103 117 21 X2,3-C-H (primary and secondary) 1 .094 1 .096 0 .011 1 .091 1 .100 348 21
Csp2-H C-C=C-H 1 .077 1 .079 0 .012 1 .074 1 .085 14 21 Car-H Car-H 1 .083 1 .083 0 .011 1 .080 1 .087 218 21 Csp3-I C*–I 2 .162 2 .159 0 .015 2 .149 2 .179 15 4 Car-I Car-I 2 .095 2 .095 0 .015 2 .089 2 .104 51 4 Csp3-N(4) C*–NH3+ 1 .488 1 .488 0 .013 1 .482 1 .495 298
(C*)2-NH2+ 1 .494 1 .493 0 .016 1 .484 1 .503 249 (C*)3-NH+ 1 .502 1 .502 0 .015 1 .491 1 .512 509 (C*)4-N+ 1 .510 1 .509 0 .020 1 .496 1 .523 319 C*–N+ (overall) 1 .499 1 .498 0 .018 1 .488 1 .510 1370
Csp3-N(3) C*–N+ in N-subst . pyridinium 1 .485 1 .484 0 .009 1 .477 1 .490 32 C*–NH2 (Nsp3: pyramidal) 1 .469 1 .470 0 .010 1 .462 1 .474 19 22 (C*)2-NH (Nsp3: pyramidal) 1 .469 1 .467 0 .012 1 .461 1 .477 152 5,22 (C*)3-N (Nsp3: pyramidal) 1 .469 1 .468 0 .014 1 .460 1 .476 1042 5,22 C*–Nsp3 (overall) 1 .469 1 .468 0 .014 1 .460 1 .476 1201 Csp3-Nsp3 in aziridine 1 .472 1 .471 0 .016 1 .464 1 .482 134 in azetidine 1 .484 1 .481 0 .018 1 .472 1 .495 21 in tetrahydropyrrole 1 .475 1 .473 0 .016 1 .464 1 .483 66 in piperidine 1 .473 1 .473 0 .013 1 .460 1 .479 240 Csp3-Nsp2 (N planar) in: 23 acyclic amides C*–NH-C=O 1 .454 1 .451 0 .011 1 .446 1 .461 78 14 β-lactams C*–N(–X)–C=O (endo) 1 .464 1 .465 0 .012 1 .458 1 .475 23 13 γ-lactams C*–NH-C=O (endo) 1 .457 1 .458 0 .011 1 .449 1 .465 20 13 C*–N(–C*)–C=O (endo) 1 .462 1 .461 0 .010 1 .453 1 .466 15 13 C*–N(–C*)–C=O (exo) 1 .458 1 .456 0 .014 1 .448 1 .465 15 13 δ-lactams C*–NH-C=O (endo) 1 .478 1 .472 0 .016 1 .467 1 .491 6 14 C*–N(–C*)–C=O (endo) 1 .479 1 .476 0 .007 1 .475 1 .482 15 14
1 u C*–N(–C*)–C=O (exo) 1 .468 1 .471 0 .009 1 .462 1 .477 15 14 nitro compounds (1,2-dinitro omitted): C-CH2-NO2 1 .485 1 .483 0 .020 1 .478 1 .502 8 C2-CH-NO2 1 .509 1 .509 0 .011 1 .502 1 .511 12 C3-C-NO2 1 .533 1 .533 0 .013 1 .530 1 .539 17 C2-C-(NO2)2 1 .537 1 .536 0 .016 1 .525 1 .550 19 1,2-dinitro: NO2-C*–C*–NO2 1 .552 1 .550 0 .023 1 .536 1 .572 32
Csp3-N(2) C#–N=N 1 .493 1 .493 0 .020 1 .477 1 .506 54 C*–N=C-Car 1 .465 1 .468 0 .011 1 .461 1 .472 75
Csp2-N(3) C=C-NH2 Nsp2 planar 1 .336 1 .344 0 .017 1 .317 1 .348 10 23 C=C-NH-C# Nsp2 planar 1 .339 1 .340 0 .016 1 .327 1 .351 17 23 C=C-N-(C#)2 Nsp2 planar 1 .355 1 .358 0 .014 1 .341 1 .363 22 23 Nsp3 pyramidal 1 .416 1 .418 0 .018 1 .397 1 .432 18 22 Csp2-Nsp2 (N planar) in: 23 acyclic amides NH2-C=O 1 .325 1 .323 0 .009 1 .318 1 .331 32 14 C*–NH-C=O 1 .334 1 .333 0 .011 1 .326 1 .343 78 14 (C*)2-N-C=O 1 .346 1 .342 0 .011 1 .339 1 .356 5 14 β-lactams C*–NH-C=O 1 .385 1 .388 0 .019 1 .374 1 .396 23 13 γ-lactams C*–NH-C=O 1 .331 1 .331 0 .011 1 .326 1 .337 20 13 C*–N(–C*)–C=O 1 .347 1 .344 0 .014 1 .335 1 .359 15 13 δ-lactams C*–NH-C=O 1 .334 1 .334 0 .006 1 .330 1 .339 6 14 (C*)–N(–C*)–C=O 1 .352 1 .353 0 .010 1 .344 1 .356 15 14 peptides C#–N(–X)–C(–C#)(=O) 1 .333 1 .334 0 .013 1 .326 1 .340 380 24 ureas (NH2)2-C=O 1 .334 1 .334 0 .008 1 .329 1 .339 48 25,26 (C#–NH)2-C=O 1 .347 1 .345 0 .010 1 .341 1 .354 26 25 [(C#)n-N]2-C=O 1 .363 1 .359 0 .014 1 .354 1 .370 40 25,27 thioureas 1 .346 1 .343 0 .023 1 .328 1 .361 192 (X2N)2-C=S imides [C#–C(=O)]2-NH 1 .376 1 .377 0 .012 1 .369 1 .383 64 [C#–C(=O)]2-N-C# 1 .389 1 .383 0 .017 1 .376 1 .404 38 [Csp2-C(=O)]2-N-C# 1 .396 1 .396 0 .010 1 .389 1 .403 46 [Csp2-C(=O)]2-N-Csp2 1 .409 1 .406 0 .020 1 .391 1 .419 28 guanidinium [C-(NH2)3]+ (unsubst .) 1 .321 1 .320 0 .008 1 .314 1 .327 39 (any subst .) 1 .328 1 .325 0 .015 1 .317 1 .333 140 in heterocyclic systems (any subst .) 1H-pyrrole (N1-C2, N1-C5) 1 .372 1 .374 0 .016 1 .363 1 .384 58 indole (N1-C2) 1 .370 1 .370 0 .012 1 .364 1 .377 40 pyrazole (N1-C5) 1 .357 1 .359 0 .012 1 .347 1 .365 20 imidazole (N1-C2) 1 .349 1 .349 0 .018 1 .338 1 .358 44 imidazole (N1-C5) 1 .370 1 .370 0 .010 1 .365 1 .377 44
Csp2-N(2) in imidazole (N3-C4) 1 .376 1 .377 0 .011 1 .369 1 .384 44 Car-N(4) Car-N+–(C,H)3 1 .465 1 .466 0 .007 1 .461 1 .470 23 Car-N(3) Car-NH2
(Nsp2: planar) 1 .355 1 .360 0 .020 1 .340 1 .372 33 23 (Nsp3: pyramidal) 1 .394 1 .396 0 .011 1 .385 1 .403 25 22 (overall) 1 .375 1 .377 0 .025 1 .363 1 .394 98 28
Car-N(3) Car-NH-C# (Nsp2: planar) 1 .353 1 .353 0 .007 1 .347 1 .359 16 23 (Nsp3: pyramidal) 1 .419 1 .423 0 .017 1 .412 1 .432 8 22 (overall) 1 .380 1 .364 0 .032 1 .353 1 .412 31 28 Car-N-(C#)2 (Nsp2: planar) 1 .371 1 .370 0 .016 1 .363 1 .382 41 23 (Nsp3: pyramidal) 1 .426 1 .425 0 .011 1 .421 1 .431 22 22 (overall) 1 .390 1 .385 0 .030 1 .366 1 .420 69 28 in indole (N1-C7a) 1 .372 1 .372 0 .007 1 .367 1 .376 40
1 u Car-NO2 1 .468 1 .469 0 .014 1 .460 1 .476 556
Car-N(2) Car-N=N 1 .431 1 .435 0 .020 1 .422 1 .442 26 Csp2=N(3) in furoxan (+N2=C3) 1 .316 1 .316 0 .009 1 .311 1 .324 14 Csp2=N(2) Car-C=N-C# 1 .279 1 .279 0 .008 1 .275 1 .285 75
(C,H)2-C=N-OH in oximes 1 .281 1 .280 0 .013 1 .273 1 .288 67 S-C=N-X 1 .302 1 .302 0 .021 1 .285 1 .319 36 in pyrazole (N2=C3) 1 .329 1 .331 0 .014 1 .315 1 .339 20 in imidazole (C2=N3) 1 .313 1 .314 0 .011 1 .307 1 .319 44 in isoxazole (N2=C3) 1 .314 1 .315 0 .009 1 .305 1 .320 9 in furazan (N2=C3, C4=N5) 1 .298 1 .299 0 .006 1 .294 1 .303 12 in furoxan (C4=N5) 1 .304 1 .306 0 .008 1 .300 1 .308 14
Car ≃ N(3) C ≃ N+–H (pyrimidinium) 1 .335 1 .334 0 .015 1 .325 1 .342 30 C ≃ N+–C* (pyrimidinium) 1 .346 1 .346 0 .010 1 .340 1 .352 64 C ≃ N+–O-(pyrimidinium) 1 .362 1 .359 0 .013 1 .353 1 .369 56
Car ≃ N(2) C ≃ N (pyridine) 1 .337 1 .338 0 .012 1 .330 1 .344 269 C ≃ N (pyrazine) 1 .336 1 .335 0 .022 1 .319 1 .347 120 C ≃ N ≃ C (pyrimidine) 1 .339 1 .338 0 .015 1 .333 1 .342 28 N ≃ C ≃ N (pyrimidine) 1 .333 1 .335 0 .013 1 .326 1 .337 28 C ≃ N (pyrimidine) (overall) in any 6-membered N-containing aromatic ring:
1 .336 1 .337 0 .014 1 .331 1 .339 56
H-C ≃ N ≃ C-H 1 .334 1 .334 0 .014 1 .327 1 .341 146 H-C ≃ N ≃ C-C* 1 .339 1 .341 0 .013 1 .336 1 .345 38 C*–C ≃ N ≃ C-C* 1 .345 1 .345 0 .008 1 .342 1 .348 24 C ≃ N ≃ C (overall) 1 .336 1 .337 0 .014 1 .329 1 .344 204
Csp1≡N(2) X-S-N≡C-(isothiocyanide) 1 .144 1 .147 0 .006 1 .140 1 .148 6 Csp1≡N(1) C*–C≡N 1 .136 1 .137 0 .010 1 .131 1 .142 140
C=C-C≡N in TCNQ 1 .144 1 .144 0 .008 1 .139 1 .149 284 19 Car-C≡N 1 .138 1 .138 0 .007 1 .133 1 .143 31 X-C≡N 1 .144 1 .141 0 .012 1 .138 1 .151 10 (S-C≡N)– 1 .155 1 .156 0 .012 1 .147 1 .165 14
Csp3-O(2) in alcohols CH3-OH 1 .413 1 .414 0 .018 1 .395 1 .425 17 C-CH2-OH 1 .426 1 .426 0 .011 1 .420 1 .431 75 C2-CH-OH 1 .432 1 .431 0 .011 1 .425 1 .439 266 C3-C-OH 1 .440 1 .440 0 .012 1 .432 1 .449 106 C*–OH (overall) 1 .432 1 .431 0 .013 1 .424 1 .441 464 in dialkyl ethers 29 CH3-O-C* 1 .416 1 .418 0 .016 1 .405 1 .426 110 C-CH2-O-C* 1 .426 1 .424 0 .011 1 .418 1 .435 34 C2-CH-O-C* 1 .429 1 .430 0 .010 1 .420 1 .437 53 C3-C-O-C* 1 .452 1 .450 0 .011 1 .445 1 .458 39 C*–O-C* (overall) 1 .426 1 .425 0 .019 1 .414 1 .437 236 5 in aryl alkyl ethers 29 CH3-O-Car 1 .424 1 .424 0 .012 1 .417 1 .431 616 C-CH2-O-Car 1 .431 1 .430 0 .013 1 .422 1 .438 188 C2-CH-O-Car 1 .447 1 .446 0 .020 1 .435 1 .466 58 C3-C-O-Car 1 .470 1 .469 0 .018 1 .456 1 .483 55 C*–O-Car (overall) 1 .429 1 .427 0 .018 1 .419 1 .436 917 in alkyl esters of carboxylic acids 12,29 CH3-O-C(=O)–C* 1 .448 1 .449 0 .010 1 .442 1 .455 200 C-CH2-O-C(=O)–C* 1 .452 1 .453 0 .009 1 .445 1 .458 32 C2-CH-O-C(=O)–C* 1 .460 1 .460 0 .010 1 .454 1 .465 78 C3-C-O-C(=O)–C* 1 .477 1 .475 0 .008 1 .472 1 .484 6 C*–O-C(=O)–C* (overall) 1 .450 1 .451 0 .014 1 .442 1 .459 314 in alkyl esters of α,β-unsaturated acids: C*–O-C(=O)–C=C (overall) 1 .453 1 .452 0 .013 1 .444 1 .459 112 in alkyl esters of benzoic acid C*–O-C(=O)–C(phenyl) (overall) 1 .454 1 .454 0 .012 1 .446 1 .463 219 in ring systems oxirane (epoxides) (any subst .) 1 .446 1 .446 0 .014 1 .438 1 .456 498 9
1 u oxetane (any subst .) 1 .463 1 .460 0 .015 1 .451 1 .474 16 tetrahydrofuran (C,H subst .) 1 .442 1 .441 0 .017 1 .430 1 .451 154
Csp3-O(2) tetrahydropyran (C,H subst .) 1 .441 1 .442 0 .015 1 .431 1 .451 22 β-lactones: C*–O-C(=O) 1 .492 1 .494 0 .010 1 .481 1 .501 4 16 γ-lactones: C*–O-C(=O) 1 .464 1 .464 0 .012 1 .455 1 .473 110 12 δ-lactones: C*–O-C(=O) 1 .461 1 .464 0 .017 1 .452 1 .473 27 12 O-C-O system in gem-diols, and pyranose and
furanose sugars: 30,31
HO-C*–OH 1 .397 1 .401 0 .012 1 .388 1 .405 18 C5-O5-C1-O1H in pyranoses O1 axial (α): C5-O5 1 .439 1 .440 0 .008 1 .432 1 .445 29 O5-C1 1 .427 1 .426 0 .012 1 .421 1 .432 29 C1-O1 1 .403 1 .400 0 .012 1 .391 1 .412 29 O1 equatorial (β): C5-O5 1 .435 1 .436 0 .008 1 .429 1 .440 17 O5-C1 1 .430 1 .431 0 .010 1 .424 1 .436 17 C1-O1 1 .393 1 .393 0 .007 1 .386 1 .399 17 α + β (overall): C5-O5 1 .439 1 .440 0 .008 1 .432 1 .446 60 O5-C1 1 .430 1 .429 0 .012 1 .421 1 .436 60 C1-O1 1 .401 1 .399 0 .011 1 .392 1 .407 60 C4-O4-C1-O1H in furanoses (overall values) C4-O4 1 .442 1 .446 0 .012 1 .436 1 .449 18 O4-C1 1 .432 1 .432 0 .012 1 .421 1 .443 18 C1-O1 1 .404 1 .405 0 .013 1 .397 1 .409 18 C5-O5-C1-O1-C* in pyranoses O1 axial (α): C5-O5 1 .439 1 .438 0 .010 1 .433 1 .446 67 O5-C1 1 .417 1 .417 0 .009 1 .410 1 .424 67 C1-O1 1 .409 1 .409 0 .014 1 .401 1 .417 67 O1-C* 1 .435 1 .435 0 .013 1 .427 1 .443 67 O1 equatorial (β): C5-O5 1 .434 1 .435 0 .006 1 .429 1 .439 39 O5-C1 1 .424 1 .424 0 .008 1 .418 1 .431 39 C1-O1 1 .390 1 .390 0 .011 1 .381 1 .400 39 O1-C* 1 .437 1 .438 0 .013 1 .428 1 .445 39 α + β (overall): C5-O5 1 .436 1 .436 0 .009 1 .431 1 .442 126 O5-C1 1 .419 1 .419 0 .011 1 .412 1 .426 126 C1-O1 1 .402 1 .403 0 .016 1 .391 1 .413 126 O1-C* 1 .436 1 .436 0 .013 1 .428 1 .445 126 C4-O4-C1-O1-C* in furanoses (overall values) C4-O4 1 .443 1 .445 0 .013 1 .429 1 .453 23 O4-C1 1 .421 1 .418 0 .012 1 .413 1 .431 23 C1-O1 1 .410 1 .409 0 .014 1 .401 1 .420 23 O1-C* 1 .439 1 .437 0 .014 1 .429 1 .449 23 Miscellaneous: C#–O-SiX3 1 .416 1 .416 0 .017 1 .405 1 .428 29 C*–O-SO2-C 1 .465 1 .461 0 .014 1 .454 1 .475 33
Csp2-O(2) in enols: C=C-OH 1 .333 1 .331 0 .017 1 .324 1 .342 53 in enol esters: C=C-O-C* 1 .354 1 .353 0 .016 1 .341 1 .363 40 in acids: C*–C(=O)–OH 1 .308 1 .311 0 .019 1 .298 1 .320 174 C=C-C(=O)–OH 1 .293 1 .295 0 .019 1 .279 1 .307 22 Car-C(=O)–OH 1 .305 1 .311 0 .020 1 .291 1 .317 75 in esters: C*–C(=O)–O-C* 1 .336 1 .337 0 .014 1 .328 1 .346 551 12,29 C=C-C(=O)–O-C* 1 .332 1 .331 0 .011 1 .324 1 .339 112
1 u Car-C(=O)–O-C* 1 .337 1 .335 0 .013 1 .329 1 .344 219 12 C*–C(=O)–O-C=C 1 .362 1 .359 0 .018 1 .351 1 .374 26 C*–C(=O)–O-C=C 1 .407 1 .405 0 .017 1 .394 1 .420 26 C*–C(=O)–O-Car 1 .360 1 .359 0 .011 1 .355 1 .367 40 12 in anhydrides: O=C-O-C=O 1 .386 1 .386 0 .011 1 .379 1 .393 70 in ring systems: furan (O1-C2, O1-C5) 1 .368 1 .369 0 .015 1 .359 1 .377 125 isoxazole (O1-C5) 1 .354 1 .354 0 .010 1 .345 1 .360 9 β-lactones: C*–C(=O)–O-C* 1 .359 1 .359 0 .013 1 .348 1 .371 4 13 γ-lactones: C*–C(=O)–O-C* 1 .350 1 .349 0 .012 1 .342 1 .359 110 12 δ-lactones: C*–C(=O)–O-C* 1 .339 1 .339 0 .016 1 .332 1 .347 27 12
Car-O(2) in phenols: Car-OH 1 .362 1 .364 0 .015 1 .353 1 .373 551 in aryl alkyl ethers: Car-O-C* 1 .370 1 .370 0 .011 1 .363 1 .377 920 29,32
Car-O(2) in diaryl ethers: Car-O-Car 1 .384 1 .381 0 .014 1 .375 1 .391 132 in esters: Car-O-C(=O)–C* 1 .401 1 .401 0 .010 1 .394 1 .408 40 12
Csp2=O(1) in aldehydes and ketones: C*–CH=O 1 .192 1 .192 0 .005 1 .188 1 .197 7 (C*)2-C=O 1 .210 1 .210 0 .008 1 .206 1 .215 474 5 (C#)2-C=O in cyclobutanones 1 .198 1 .198 0 .007 1 .194 1 .204 12 in cyclopentanones 1 .208 1 .208 0 .007 1 .203 1 .212 155 in cyclohexanones 1 .211 1 .211 0 .009 1 .207 1 .216 312 C=C-C=O 1 .222 1 .222 0 .010 1 .216 1 .229 225 (C=C)2-C=O 1 .233 1 .229 0 .010 1 .226 1 .242 28 Car-C=O 1 .221 1 .218 0 .014 1 .212 1 .229 85 (Car)2-C=O 1 .230 1 .226 0 .015 1 .220 1 .238 66 C=O in benzoquinones 1 .222 1 .220 0 .013 1 .211 1 .231 86 delocalized double bonds in carboxylate anions: H-C ≃ O2-(formate) 1 .242 1 .243 0 .012 1 .234 1 .252 24 C*–C ≃ O2-1 .254 1 .253 0 .010 1 .247 1 .261 114 C=C-C ≃ O2-1 .250 1 .248 0 .017 1 .238 1 .261 52 Car-C ≃ O2-1 .255 1 .253 0 .010 1 .249 1 .262 22 HOOC-C ≃ O2-(hydrogen oxalate) 1 .243 1 .247 0 .015 1 .232 1 .256 26 –O2 ≃ C-C ≃ O2-(oxalate) 1 .251 1 .251 0 .007 1 .248 1 .254 18 in carboxylic acids (X-COOH) C*–C(=O)–OH 1 .214 1 .214 0 .019 1 .203 1 .224 175 C=C-C(=O)–OH 1 .229 1 .226 0 .017 1 .218 1 .237 22 Car-C(=O)–OH 1 .226 1 .223 0 .020 1 .211 1 .241 75 in esters: C*–C(=O)–O-C* 1 .196 1 .196 0 .010 1 .190 1 .202 551 12 C=C-C(=O)–O-C* 1 .199 1 .198 0 .009 1 .193 1 .203 113 Car-C(=O)–O-C* 1 .202 1 .201 0 .009 1 .196 1 .207 218 12 C*–C(=O)–O-C=C 1 .190 1 .190 0 .014 1 .184 1 .198 26 C*–C(=O)–O-Car 1 .187 1 .188 0 .011 1 .181 1 .195 40 12 in anhydrides: O=C-O-C=O 1 .187 1 .187 0 .010 1 .184 1 .193 70 in β-lactones: C*–C(=O)–O-C* 1 .193 1 .193 0 .006 1 .187 1 .198 4 13 γ-lactones: C*–C(=O)–O-C* 1 .201 1 .202 0 .009 1 .196 1 .206 109 12 δ-lactones: C*–C(=O)–O-C* 1 .205 1 .207 0 .008 1 .201 1 .209 27 12 in amides: NH2-C(–C*)=O 1 .234 1 .233 0 .012 1 .225 1 .243 32 14 (C*–)(C*,H-)N-C(–C*)=O 1 .231 1 .231 0 .012 1 .224 1 .238 378 14 β-lactams: C*–NH-C=O 1 .198 1 .200 0 .012 1 .193 1 .204 23 13 γ-lactams: C*–NH-C=O 1 .235 1 .235 0 .008 1 .232 1 .240 20 13 C*–N(–C*)–C=O 1 .225 1 .226 0 .011 1 .217 1 .233 15 13 δ-lactams: C*–NH-C=O 1 .240 1 .241 0 .003 1 .237 1 .243 6 14 C*–N(–C*)–C=O 1 .233 1 .233 0 .007 1 .229 1 .239 15 14 in ureas: (NH)2)2-C=O 1 .256 1 .256 0 .007 1 .249 1 .261 24 25,26 (C#–NH)2-C=O 1 .241 1 .237 0 .011 1 .235 1 .245 13 25
1 u [(C#)n-N]2-C=O 1 .230 1 .230 0 .007 1 .224 1 .234 20 25,27
Csp3-P(4) C3-P+–C* 1 .800 1 .802 0 .015 1 .790 1 .812 35 33 C2-P(=O)–CH3 1 .791 1 .790 0 .006 1 .786 1 .795 10 C2-P(=O)–CH2-C 1 .806 1 .806 0 .009 1 .801 1 .813 45 C2-P(=O)–CH-C2 1 .821 1 .821 0 .009 1 .815 1 .828 15 C2-P(=O)–C-C3 1 .841 1 .842 0 .008 1 .835 1 .847 14 C2-P(=O)–C* (overall) 1 .813 1 .811 0 .017 1 .800 1 .822 84
Csp3-P(3) C2-P-C* 1 .855 1 .857 0 .019 1 .840 1 .870 23 Car-P(4) C3-P+–Car 1 .793 1 .792 0 .011 1 .786 1 .800 276
C2-P(=O)–Car 1 .801 1 .802 0 .011 1 .796 1 .807 98 Ph3-P=N+=P-Ph3 1 .795 1 .795 0 .008 1 .789 1 .800 197
Car-P(3) C2-P-Car 1 .836 1 .837 0 .010 1 .830 1 .844 102 (N≃)2P-Car(P ≃ N aromatic) 1 .795 1 .793 0 .011 1 .788 1 .803 43
Csp3-S(4) C*–SO2-C (C* = CH3 excluded) 1 .786 1 .782 0 .018 1 .774 1 .797 75 C*–SO2-C (overall) 1 .779 1 .778 0 .020 1 .764 1 .790 94 C*–SO2-O-X 1 .745 1 .744 0 .009 1 .738 1 .754 7 34 C*–SO2-N-X2 1 .758 1 .756 0 .018 1 .746 1 .773 17 34
Csp3-S(3) C*–S(=O)–C (C* = CH3 excluded) 1 .818 1 .814 0 .024 1 .802 1 .829 69 C*–S(=O)–C (overall) 1 .809 1 .806 0 .025 1 .793 1 .820 88 CH3-S+–X2 1 .786 1 .787 0 .007 1 .779 1 .792 21 C*–S+–X2 (C* = CH3 excluded) 1 .823 1 .820 0 .016 1 .812 1 .834 18 C*–S+–X2 (overall) 1 .804 1 .794 0 .025 1 .788 1 .820 41
Csp3-S(2) C*–SH 1 .808 1 .805 0 .010 1 .800 1 .819 6 CH3-S-C* 1 .789 1 .787 0 .008 1 .784 1 .794 9
Csp3-S(2) C-CH2-S-C* 1 .817 1 .816 0 .013 1 .808 1 .824 92 C2-CH-S-C* 1 .819 1 .819 0 .011 1 .811 1 .825 32 C3-C-S-C* 1 .856 1 .860 0 .011 1 .854 1 .863 26 C*–S-C* (overall) 1 .819 1 .817 0 .019 1 .809 1 .827 242 in thiirane 1 .834 1 .835 0 .025 1 .810 1 .858 4 9 in thiirane: see ZCMXSP (1 .817, 1 .844) in tetrahydrothiophene 1 .827 1 .826 0 .018 1 .811 1 .837 20 in tetrahydrothiopyran 1 .823 1 .821 0 .014 1 .812 1 .832 24 C-CH2-S-S-X 1 .823 1 .820 0 .014 1 .813 1 .832 41 C3-C-S-S-X 1 .863 1 .865 0 .015 1 .848 1 .878 11 C*–S-S-X (overall) 1 .833 1 .828 0 .022 1 .818 1 .848 59
Csp2-S(2) C=C-S-C* 1 .751 1 .755 0 .017 1 .740 1 .764 61 C=C-S-C=C (in tetrathiafulvalene) 1 .741 1 .741 0 .011 1 .733 1 .750 88 C=C-S-C=C (in thiophene) 1 .712 1 .712 0 .013 1 .703 1 .722 60 O=C-S-C# 1 .762 1 .759 0 .018 1 .747 1 .778 20
Car-S(4) Car-SO2-C 1 .763 1 .764 0 .009 1 .756 1 .769 96 Car-SO2-O-X 1 .752 1 .750 0 .008 1 .749 1 .756 27 Car-SO2-N-X2 1 .758 1 .759 0 .013 1 .749 1 .765 106 35
Car-S(3) Car-S(=O)–C 1 .790 1 .790 0 .010 1 .783 1 .798 41 Car-S+–X2 1 .778 1 .779 0 .010 1 .771 1 .787 10
Car-S(2) Car-S-C* 1 .773 1 .774 0 .009 1 .765 1 .779 44 Car-S-Car 1 .768 1 .767 0 .010 1 .762 1 .774 158 Car-S-Car (in phenothiazine) 1 .764 1 .764 0 .008 1 .760 1 .769 48 Car-S-S-X 1 .777 1 .777 0 .012 1 .767 1 .785 47
Csp1-S(2) N≡C-S-X 1 .679 1 .683 0 .026 1 .645 1 .698 10 Csp1-S(1) (N≡C-S)– 1 .630 1 .630 0 .014 1 .619 1 .641 14 Csp2=S(1) (C*)2-C=S: see IPMUDS (1 .599)
(Car)2-C=S: see CELDOM (1 .611) (X)2-C=S (X = C,N,O,S) 1 .671 1 .675 0 .024 1 .656 1 .689 245 X2N-C(=S)–S-X 1 .660 1 .660 0 .016 1 .648 1 .674 38 (X2N)2-C=S (thioureas) 1 .681 1 .684 0 .020 1 .669 1 .693 96 N-C(≃S)2 1 .720 1 .721 0 .012 1 .709 1 .731 20
Csp3-Se C#–Se 1 .970 1 .967 0 .032 1 .948 1 .998 21 Csp2-Se(2) C=C-Se-C=C (in tetraselenafulvalene) 1 .893 1 .895 0 .013 1 .882 1 .902 32 Car-Se(3) Ph3-Se+ 1 .930 1 .929 0 .006 1 .924 1 .936 13 Csp3-Si(5) C#–Si-–X4 1 .874 1 .876 0 .015 1 .859 1 .884 9 Csp3-Si(4) CH3-Si-X3 1 .857 1 .857 0 .018 1 .848 1 .869 552
1 u C*–Si-X3 (C* = CH3 excluded) 1 .888 1 .887 0 .023 1 .872 1 .905 124 C*–Si-X3 (overall) 1 .863 1 .861 0 .024 1 .850 1 .875 681
Car-Si(4) Car-Si-X3 1 .868 1 .868 0 .014 1 .857 1 .878 178 Csp1-Si(4) C≡C-Si-X3 1 .837 1 .840 0 .012 1 .824 1 .849 8 Csp3-Te C#–Te 2 .158 2 .159 0 .030 2 .128 2 .177 13 Car-Te Car-Te 2 .116 2 .115 0 .020 2 .104 2 .130 72 Csp2=Te see CEDCUJ (2 .044) Cl-Cl see PHASCL (2 .306, 2 .227) Cl-I see CMBIDZ (2 .563), HXPASC (2 .541, 2 .513),
METAMM (2 .552), BQUINI (2 .416, 2 .718)
Cl-N see BECTAE (1 .743-1 .757), BOGPOC (1 .705) Cl-O(1) in CIO-4 1 .414 1 .419 0 .026 1 .403 1 .431 252 Cl-P (N≃)2P-Cl (N ≃ P aromatic) 1 .997 1 .994 0 .015 1 .989 2 .004 46
Cl-P (overall) 2 .008 2 .001 0 .035 1 .986 2 .028 111 Cl-S Cl-S (overall) 2 .072 2 .079 0 .023 2 .047 2 .091 6
see also longer bonds in CILSAR (2 .283), BIHXIZ (2 .357), CANLUY (2 .749)
Cl-Se see BIRGUE10, BIRHAL10, CTCNSE (2 .234-2 .851)
Cl-Si(4) Cl-Si-X3 (monochloro) 2 .072 2 .075 0 .009 2 .066 2 .078 5 Cl2-Si-X2 and Cl3-Si-X 2 .020 2 .012 0 .015 2 .007 2 .036 5
Cl-Te Cl-Te in range 2 .34-2 .60 2 .520 2 .515 0 .034 2 .493 2 .537 22 36 see also longer bonds in BARRIV, BOJPUL, CETUTE,
EPHTEA, OPNTEC10 (2 .73-2 .94)
F-N(3) F-N-C2 and F2-N-C 1 .406 1 .404 0 .016 1 .395 1 .416 9 F-P(6) in hexafluorophosphate, PF-6 1 .579 1 .587 0 .025 1 .563 1 .598 72 F-P(3) (N≃)2P-F(N ≃ P aromatic) 1 .495 1 .497 0 .016 1 .481 1 .510 10 F-S 43 observations in range 1 .409-1 .770 in a wide variety
of environments; F-S(6) in F2-SO2-C2 (see FPSULF10, BETJOZ)
1 .640 1 .646 0 .011 1 .626 1 .649 6
F-S(4) in F2-S(=O)–N (see BUDTEZ) 1 .527 1 .528 0 .004 1 .524 1 .530 24 37 F-Si(6) in SiF26 – 1 .694 1 .701 0 .013 1 .677 1 .703 6 F-Si(5) F-Si-–X4 1 .636 1 .639 0 .035 1 .602 1 .657 10 F-Si(4) F-Si-X3 1 .588 1 .587 0 .014 1 .581 1 .599 24 F-Te see CUCPlZ (F-Te(6) = 1 .942, 1 .937), FPHTEL(F-
Te(4) = 2 .006) H-N(4) X3-N+–H 1 .033 1 .036 0 .022 1 .026 1 .045 87 21 H-N(3) X3-N-H 1 .009 1 .010 0 .019 0 .997 1 .023 95 21 H-O(2) in alcohols C*–O-H 0 .967 0 .969 0 .010 0 .959 0 .974 63 21
C#–O-H 0 .967 0 .970 0 .010 0 .959 0 .974 73 21 in acids O=C-O-H 1 .015 1 .017 0 .017 1 .001 1 .031 16 21,38
I-I in I-3 2 .917 2 .918 0 .011 2 .907 2 .927 6 I-N see BZPRIB, CMBIDZ, HMTITI, HMTNTI,
IFORAM, IODMAM (2 .042-2 .475) I-O X-I-O(see BZPRIB, CAJMAB, IBZDAC11) 2 .144 2 .144 0 .028 2 .127 2 .164 6
for IO-6 see BOVMEE (1 .829-1 .912) I-P(3) see CEHKAB (2 .490-2 .493) † I-S sec DTHIBR10 (2 .687), ISUREA10 (2 .629), BZTPPI
(3 .251) I-Te(4) I-Te-X3 2 .926 2 .928 0 .026 2 .902 2 .944 8 N(4)–N(3) X3-N+–N0-X2 (N0 planar) 1 .414 1 .414 0 .005 1 .412 1 .418 13 N(3)–N(3) (C)(C,H)–Na-Nb(C)(C,H) 5,39
Na, Nb pyramidal 1 .454 1 .452 0 .021 1 .444 1 .457 44 40 Na pyramidal, Nb planar 1 .420 1 .420 0 .015 1 .407 1 .433 68 40 Na, Nb planar 1 .401 1 .401 0 .018 1 .384 1 .418 40 40 overall 1 .425 1 .425 0 .027 1 .407 1 .443 139
N(3)–N(2) in pyrazole (N1-N2) 1 .366 1 .366 0 .019 1 .350 1 .375 20 in pyridaznium (Nl+≃N2) 1 .350 1 .349 0 .010 1 .345 1 .361 7
N(2) ≃ N(2) N ≃ N (aromatic) in pyridazine with C,H as ortho substituents 1 .304 1 .300 0 .019 1 .287 1 .326 6
1 u with N,Cl as ortho substituents 1 .368 1 .373 0 .011 1 .362 1 .375 9
N(2)=N(2) C#–N=N-C# cis 1 .245 1 .244 0 .009 1 .239 1 .252 21 trans 1 .222 1 .222 0 .006 1 .218 1 .227 6 (overall) 1 .240 1 .241 0 .012 1 .230 1 .251 27 Car-N=N-Car 1 .255 1 .253 0 .016 1 .247 1 .262 13 X-N=N=N (azides) 1 .216 1 .226 0 .028 1 .202 1 .237 19
N(2)=N(1) X-N=N=N (azides) 1 .124 1 .128 0 .015 1 .114 1 .137 19 N(3)–O(2) (C,H)2-N-OH (Nsp2: planar) 1 .396 1 .394 0 .012 1 .390 1 .401 28
C2-N-O-C (Nsp3: pyramidal) 1 .463 1 .465 0 .012 1 .457 1 .468 22 (Nsp2: planar) 1 .397 1 .394 0 .011 1 .388 1 .409 12 in furoxan (N2-O1) 1 .438 1 .436 0 .009 1 .430 1 .447 14
N(3)–O(1) (C≃)2N+–O-in pyridine N-oxides 1 .304 1 .299 0 .015 1 .291 1 .316 11 in furoxan (+N2-O6-) 1 .234 1 .234 0 .008 1 .228 1 .240 14
N(2)–O(2) in oximes (C#)2-C=N-OH 1 .416 1 .418 0 .006 1 .416 1 .420 7 (H)(Csp2)–C=N-OH 1 .390 1 .390 0 .011 1 .380 1 .401 20 (C#)(Csp2)–C=N-OH 1 .402 1 .403 0 .010 1 .393 1 .410 18 (Csp2)2-C=N-OH 1 .378 1 .377 0 .017 1 .365 1 .393 16 (C,H)2-C=N-OH (overall) 1 .394 1 .395 0 .018 1 .379 1 .408 67 in furazan (O1-N2, O1-N5) 1 .385 1 .383 0 .013 1 .378 1 .392 12 in furoxan (O1-N5) 1 .380 1 .380 0 .011 1 .370 1 .388 14 in isoxazole (O1-N2) 1 .425 1 .425 0 .010 1 .417 1 .434 9
N(3)=O(1) in nitrate ions NO3-1 .239 1 .240 0 .020 1 .227 1 .251 105 in nitro groups C*–NO2 1 .212 1 .214 0 .012 1 .206 1 .221 84 C#–NO2 1 .210 1 .210 0 .011 1 .203 1 .218 251 Car-NO2 1 .217 1 .218 0 .011 1 .211 1 .215 1116 C-NO2 (overall) 1 .218 1 .219 0 .013 1 .210 1 .226 1733
N(3)–P(4) X2-P(=X)–NX2 Nsp2: planar 1 .652 1 .651 0 .024 1 .634 1 .670 205 Nsp3: pyramidal 1 .683 1 .683 0 .005 1 .680 1 .686 6 (overall) 1 .662 1 .662 0 .029 1 .639 1 .682 358 subsets of this group are: O2-P(=S)–NX2 1 .628 1 .624 0 .015 1 .615 1 .634 9 C-P(=S)–(NX2)2 1 .691 1 .694 0 .018 1 .678 1 .703 28 O-P(=S)–(NX2)2 1 .652 1 .654 0 .014 1 .642 1 .664 28 P(=O)–(NX2)3 1 .663 1 .668 0 .026 1 .640 1 .679 78
N(3)–P(3) –NX-P(–X)–NX-P(–X)–(P2N2 ring) 1 .730 1 .721 0 .017 1 .716 1 .748 20 –NX-P(=S)–NX-P(=S)–(P2N2 ring) 1 .697 1 .697 0 .015 1 .690 1 .703 44 in P-substituted phosphazenes: (N≃)2P-N (amino)
(aziridinyl) 1 .637 1 .638 0 .014 1 .625 1 .651 16 1 .672 1 .674 0 .010 1 .665 1 .676 15
N(2)=P(4) Ph3-P=N+=P-Ph3 1 .571 1 .573 0 .013 1 .563 1 .580 66 N(2)=P(3) Ph3-P=N-C,S 1 .599 1 .597 0 .018 1 .580 1 .615 7 N(2) ≃ P(3) N ≃ P aromatic
in phosphazenes 1 .582 1 .582 0 .019 1 .571 1 .594 126 in P ≃ N ≃ S 1 .604 1 .606 0 .009 1 .594 1 .612 36
N(3)–S(4) C-SO2-NH2 1 .600 1 .601 0 .012 1 .591 1 .610 14 35 C-SO2-NH-C# 1 .633 1 .633 0 .019 1 .615 1 .652 47 35 C-SO2-N-C(#)2 1 .642 1 .641 0 .024 1 .623 1 .659 38 35
N(3)–S(2) C-S-NX2 Nsp2: planar 1 .710 1 .707 0 .019 1 .698 1 .722 22 23 (for Nsp3 pyramidal see MODIAZ: 1 .765) X-S-NX2 Nsp2: planar 1 .707 1 .705 0 .012 1 .699 1 .715 30 23
N(2)–S(2) C=N-S-X 1 .656 1 .663 0 .027 1 .632 1 .677 36 N(2) ≃ S(2) N ≃ S aromatic in P ≃ N ≃ S 1 .560 1 .558 0 .011 1 .554 1 .563 37 N(2)=S(2) N=S in N=S=N and N=S=S 1 .541 1 .546 0 .022 1 .521 1 .558 37 N(3)–SE see COJCUZ (1 .830), DSEMOR10 (1 .846, 1 .852),
MORTRS10 (1 .841) N(2)–Se see SEBZQI (1 .805), NAPSEZ10 (1 .809, 1 .820)
1 u N(2)=Se see CISMUM (1 .790, 1 .791) N(3)–Si(5) see DMESIP01, BOJLER, CASSAQ, CASYOK,
CECXEN, CINTEY, CIPBUY, FMESIB, MNPSIL, PNPOSI (1 .973-2 .344)
N(3)–Si(4) X3-Si-NX2 (overall) 1 .748 1 .746 0 .022 1 .735 1 .757 170 subsets of this group are: X3-Si-NHX 1 .714 1 .719 0 .014 1 .702 1 .727 16 X3-Si-NX-Si-X3 acyclic 1 .743 1 .744 0 .016 1 .731 1 .755 45 N-Si-N in 4-membered rings 1 .742 1 .742 0 .009 1 .735 1 .748 53 N-Si-N in 5-membered rings 1 .741 1 .742 0 .019 1 .726 1 .749 33
N(2)–Si(4) X3-Si-N-–Si-X3 1 .711 1 .712 0 .019 1 .693 1 .729 15 N-Te see ACLTEP (2 .402), BIBLAZ (1 .980), CESSAU
(2 .023) O(2)–O(2) C*–O-O-C*,H
τ(OO) = 70-85º 1 .464 1 .464 0 .009 1 .458 1 .472 12 τ(OO) ca. 180º 1 .482 1 .480 0 .005 1 .478 1 .486 5 overall 1 .469 1 .471 0 .012 1 .461 1 .478 17 O=C-O-O-C=O see ACBZPO01 (1 .446), CEYLUN
(1 .452), CIMHIP (1 .454) Si-O-O-Si 1 .496 1 .499 0 .005 1 .490 1 .499 10
O(2)–P(5) X-P-(OX)4 41 trigonal bipyramidal: axial 1 .689 1 .685 0 .024 1 .675 1 .712 20 equatorial 1 .619 1 .622 0 .024 1 .604 1 .628 20 square pyramidal 1 .662 1 .661 0 .020 1 .649 1 .673 28
O(2)–P(4) C-O-P(≃ O)32 – 1 .621 1 .622 0 .007 1 .615 1 .628 12 (H-O)2-P(≃ O)2-1 .560 1 .561 0 .009 1 .555 1 .566 16 (C-O)2-P(≃ O)2-1 .608 1 .607 0 .013 1 .599 1 .615 16 (C#–O)3-P=O 1 .558 1 .554 0 .011 1 .550 1 .564 30 (Car-O)3-P=O 1 .587 1 .588 0 .014 1 .572 1 .599 19 X-O-P(=O)–(C,N)2 1 .590 1 .585 0 .016 1 .577 1 .601 33 (X-O)2-P(=O)–(C,N) 1 .571 1 .572 0 .013 1 .563 1 .579 70
O(2)–P(3) (N≃)2P-O-C (N ≃ P aromatic) 1 .573 1 .573 0 .011 1 .563 1 .584 16 O(1)=P(4) C-O-P(≃ O)32-(delocalized) 1 .513 1 .512 0 .008 1 .508 1 .518 42
(H-O)2-P(≃ O)2-(delocalized) 1 .503 1 .503 0 .005 1 .499 1 .508 16 (C-O)2-P(≃ O)2-(delocalized) 1 .483 1 .485 0 .008 1 .474 1 .490 16 (C-O)3-P=O 1 .449 1 .448 0 .007 1 .446 1 .452 18 C3-P=O 1 .489 1 .486 0 .010 1 .481 1 .496 72 N3-P=O 1 .461 1 .462 0 .014 1 .449 1 .470 26 (C)2(N)–P=O 1 .487 1 .489 0 .007 1 .479 1 .493 5 (C,N)2(O)–P=O 1 .467 1 .462 0 .007 1 .462 1 .472 33 (C,N)(O)2-P=O 1 .457 1 .458 0 .009 1 .454 1 .462 35
O(2)–S(4) C-O-SO2-C 1 .577 1 .576 0 .015 1 .566 1 .584 41 C-O-SO2-CH3 1 .569 1 .569 0 .013 1 .556 1 .582 7 C-O-SO2-Car 1 .580 1 .578 0 .015 1 .571 1 .588 27
O(1)=S(4) C-SO2-C 1 .436 1 .437 0 .010 1 .431 1 .442 316 42 X-SO2-NX2 1 .428 1 .428 0 .010 1 .422 1 .434 326 C-SO2-N-(C,H)2 1 .430 1 .430 0 .009 1 .425 1 .435 206 C-SO2-O-C 1 .423 1 .423 0 .008 1 .418 1 .428 82 in SO42-1 .472 1 .473 0 .013 1 .463 1 .481 104
O(1)=S(3) C-S(=O)–C 1 .497 1 .498 0 .013 1 .489 1 .505 90 5 O-Se see BAPPAJ, BIRGUE10, BIRHAL10, CXMSEO,
DGLYSE, SPSEBU (1 .597 for O=Se to 1 .974 for O-Se)
O(2)–Si(5) (X-O)3-Si-(N)(C) 1 .663 1 .658 0 .023 1 .650 1 .665 21 O(2)–Si(4) X3-Si-O-X (overall) 1 .631 1 .630 0 .022 1 .617 1 .646 191 O(2)–Si(4) subsets of this group are:
X3-Si-O-C# 1 .645 1 .647 0 .012 1 .634 1 .652 29 X3-Si-O-Si-X3 1 .622 1 .625 0 .014 1 .614 1 .631 70 X3-Si-O-O-Si-X3 1 .680 1 .676 0 .008 1 .673 1 .688 10
O(2)–Te(6) (X-O)6-Te 1 .927 1 .927 0 .020 1 .908 1 .942 16
1 u O(2)–Te(4) (X-O)2-Te-X2 2 .133 2 .136 0 .054 2 .078 2 .177 12 P(4)–P(4) X3-P-P-X3 2 .256 2 .259 0 .025 2 .243 2 .277 6 P(4)–P(3) see CECHEX (2 .197), COZPIQ (2 .249) P(3)–P(3) X2-P-P-X2 2 .214 2 .210 0 .022 2 .200 2 .224 41 P(4)=P(4) see BUTSUE (2 .054) P(3)=P(3) see BALXOB (2 .034) P(4)=S(1) C3-P=S 1 .954 1 .952 0 .005 1 .950 1 .957 13
(N,O)2(C)–P=S 1 .922 1 .924 0 .014 1 .913 1 .927 26 (N,O)3-P=S 1 .913 1 .914 0 .014 1 .906 1 .921 50
P(4)=Se(1) X3-P=Se 2 .093 2 .099 0 .019 2 .075 2 .108 12 P(3)–Si(4) X2-P-Si-X3: 3-and 4-rings 2 .264 2 .260 0 .019 2 .249 2 .283 22
excluded (see BOPFER, BOPFIV, CASTOF10, COZVIW: 2 .201-2 .317)
P(4)=Te(1) see MOPHTE (2 .356), TTEBPZ (2 .327) S(2)–S(2) C-S-S-C
τ(SS) = 75-105º 2 .031 2 .029 0 .015 2 .021 2 .038 46 τ(SS) = 0-20º 2 .070 2 .068 0 .022 2 .057 2 .077 28 (overall) 2 .048 2 .045 0 .026 2 .028 2 .068 99 in polysulphide chain-S-S-S-2 .051 2 .050 0 .022 2 .037 2 .065 126
S(2)–S(1) X-N=S-S 1 .897 1 .896 0 .012 1 .887 1 .908 5 S-Se(4) see BUWZUO (2 .264, 2 .269) S-Se(2) X-Se-S (any) 2 .193 2 .195 0 .015 2 .174 2 .207 9 S(2)–Si(4) X3-Si-S-X 2 .145 2 .138 0 .020 2 .130 2 .158 19 S(2)–Te X-S-Te (any) 2 .405 2 .406 0 .022 2 .383 2 .424 10
X=S-Te (any) 2 .682 2 .686 0 .035 2 .673 2 .694 28 Se(2)–Se(2) X-Se-Se-X 2 .340 2 .340 0 .024 2 .315 2 .361 15 Se(2)–Te(2) see BAWFUA, BAWGAH (2 .524-2 .561) † Si(4)–Si(4) X3-Si-Si-X3 3-membered rings excluded:
see CIHRAM (2 .511) 2 .359 2 .359 0 .012 2 .349 2 .366 42
Te-Te see CAHJOK (2 .751, 2 .704)
Appendix 1. (Footnotes to Table) 1 . Sample dominated by B-CH3 . For longer bonds in B-–CH3 see
LITMEB10 [B(4)–CH3 = 1 .621-1 .644Å] . 2 . p(π)–p(π) Bonding with Bsp2 and Nsp2 coplanar (τBN = 0 ± 15º) pre-
dominates . See G . Schmidt, R . Boese, and D . Bläser, Z. Naturforsch ., 1982, 37b, 1230 .
