Appendix G: Bond Enthalpy, Bond Length, Atomic Radii, and Ionic Radii

Average Bond Enthalpy

In kJ/mol

I Br Cl S P Si F O N C H
H 299 366 431 347 322 323 566 467 391 416 436
C 213 285 327 272 264 301 485 358 285 346
N - - 193 - ~200 335 272 201 160
O 201 - 205 - ~340 368 190 146
F - 238 255 326 490 582 158
Si 234 310 391 226 - 226
P 184 264 319 - 209
S - 213 255 226 Multiple Bonds Multiple Bonds
Cl 209 217 242 N=N 418 C=C 598
Br 180 193 N≡N 946 C≡C 813
I 151 C=N 616 C=O in CO2 803
C≡N 866 C=O carbonyl 695
N=O 607 C≡O 1073
O=O in O2 498 N≡O 632
Data from Cotton, F.A., Wilkinson, G. and Gaus, P.L., Basic Inorganic Chemistry, 3rd ed., New York: Wiley, 1995.
Corrected values for C-C and C-O from Cottrell, T.L., The Strengths of Chemical Bonds, 2ed., London:Butterworths, 1958.

 

Average Bond Length

In picometers, (pm)

I Br Cl S P Si F O N C H
H 161 142 127 132 138 145 92 94 98 110 74
C 210 191 176 181 187 194 141 143 147 154
N 203 184 169 174 180 187 134 136 140
O 199 180 165 170 176 183 130 148
F 197 178 163 168 174 181 128
Si 250 231 216 221 227 234
P 243 224 209 214 220
S 237 218 203 208 Multiple Bonds Multiple Bonds
Cl 232 213 200 N=N 120 C=C 134
Br 247 228 N≡N 110 C≡C 121
I 266 C=N 127 C=O in CO2 116
C≡N 115 C=O carbonyl 121
N=O 115 C≡O 113
O=O in O2 121 N≡O 115

 

Atomic-Radii

Atom Atomic No. Atomic Radius (pm)
H 1 37
He 2 31
Li 3 157
Be 4 112
B 5 86
C 6 77
N 7 74
O 8 74
F 9 72
Ne 10 68
Na 11 191
Mg 12 160
Al 13 143
Si 14 117
P 15 110
S 16 104
Cl 17 99
Ar 18 91
K 19 235
Ca 20 197
Sc 21 164
Ti 22 147
V 23 135
Cr 24 129
Mn 25 137
Fe 26 126
Co 27 125
Ni 28 125
Cu 29 126
Zn 30 137
Ga 31 153
Ge 32 130.5
As 33 121
Se 34 117
Br 35 114
Kr 36 108
Rb 37 250
Sr 38 215
Y 39 182
Zr 40 160
Nb 41 147
Mo 42 140
Tc 43 135
Ru 44 134
Rh 45 134
Pd 46 137
Ag 47 144
Cd 48 152
In 49 167
Sn 50 149
Sb 51 151
Te 52 137
I 53 133
Xe 54 126
Cs 55 272
Ba 56 224
La 57 188
Ce 58 182
Pr 59 181
Nd 60 180
Pm 61 179
Sm 62 179
Eu 63 206
Gd 64 178
Tb 65 177
Dy 66 176
Ho 67 175
Er 68 174
Tm 69 173
Yb 70 194
Lu 71 172
Hf 72 159
Ta 73 147
W 74 141
Re 75 137
Os 76 135
Ir 77 136
Pt 78 139
Au 79 144
Hg 80 155
Tl 81 171
Pb 82 175
Bi 83 182
Po 84 174
At 85 166
Rn 86 159
Fr 87
Ra 88
Ac 89
Th 90 180
Pa 91 163
U 92 156
Np 93 156
Pu 94 164
Am 95 173
Cm 96 155
Bk 97 170
Cf 98
Es 99
Fm 100
Md 101
No 102
Lr 103
Wells, A. F. Structural Inorganic Chemistry, 5th ed., Clarendon: Oxford, 1984, p 289 and 1288.
Slater, J. C. J. Chem. Phys. 1964, 41, 3199.
Clementi, E; Raimondi, D. L.; Reinhardt, W. P. J. Chem. Phys. 1967, 47(4), 1300-1307.

 

Ionic-Radii

Ion Species Atomic No. Ionic Radius (pm)
H +1 1
He 2
Li +1 3 90
Be +2 4 59
B +3 5 41
C +4 6 30
N -3 7
N +3 7 30
N +5 7 27
O -2 8 126
F -1 9 119
F +7 9 22
Ne 10
Na +1 11 116
Mg +2 12 86
Al +3 13 67.5
Si +4 14 54
P +3 15 58
P +5 15 52
S -2 16 170
S +4 16 51
S +6 16 43
Cl -1 17 167
Cl +5 17
Cl +7 17 41
Ar 18
K +1 19 152
Ca +2 20 114
Sc +3 21 88.5
Ti +2 22 100
Ti +3 22 81
Ti +4 22 74.5
V +2 23 93
V +3 23 78
V +4 23 72
V +5 23 68
Cr +2 24 94
Cr +3 24 75.5
Cr +4 24 69
Cr +5 24 63
Cr +6 24 58
Mn +2 25 97
Mn +3 25 78.5
Mn +4 25 67
Mn +5 25
Mn +6 25
Mn +7 25 60
Fe +2 26 92
Fe +3 26 78.5
Fe +4 26 72.5
Fe +6 26
Co +2 27 88.5
Co +3 27 75
Co +4 27 67
Ni +2 28 83
Ni +3 28 74
Ni +4 28 62
Cu +1 29 91
Cu +2 29 87
Cu +3 29 68
Zn +2 30 88
Ga +3 31 76
Ge +2 32 87
Ge +4 32 67
As +3 33 72
As +5 33 60
Se -2 34 184
Se +4 34 64
Se +6 34 56
Br -1 35 182
Br +3 35
Br +5 35
Br +7 35 53
Kr 36
Rb +1 37 166
Sr +2 38 132
Y +3 39 104
Zr +4 40 86
Nb +3 41 86
Nb +4 41 82
Nb +5 41 78
Mo +3 42 83
Mo +4 42 79
Mo +5 42 75
Mo +6 42 73
Tc +4 43 78.5
Tc +5 43 74
Tc +7 43 70
Ru +3 44 82
Ru +4 44 76
Ru +5 44 70.5
Ru +7 44
Ru +8 44
Rh +3 45 80.5
Rh +4 45 74
Rh +5 45 69
Pd +1 46
Pd +2 46 100
Pd +3 46 90
Pd +4 46 75.5
Ag +1 47 129
Ag +2 47 108
Ag +3 47 89
Cd +2 48 109
In +3 49 94
Sn +4 50 83
Sb +3 51 90
Sb +5 51 74
Te -2 52 207
Te +4 52 111
Te +6 52 70
I -1 53 206
I +5 53
I +7 53 67
Xe +8 54 62
Cs +1 55 181
Ba +2 56 149
La +3 57 117.2
Ce +3 58 115
Ce +4 58 101
Pr +3 59 113
Pr +4 59 99
Nd +2 60
Nd +3 60 112.3
Pm +3 61 111
Sm +2 62
Sm +3 62 109.8
Eu +2 63 131
Eu +3 63 108.7
Gd +3 64 107.8
Tb +3 65 106.3
Tb +4 65 90
Dy +2 66 121
Dy +3 66 105.2
Ho +3 67 104.1
Er +3 68 103
Tm +2 69 117
Tm +3 69 102
Yb +2 70 116
Yb +3 70 100.8
Lu +3 71 100.1
Hf +4 72 85
Ta +3 73 86
Ta +4 73 82
Ta +5 73 78
W +4 74 80
W +5 74 76
W +6 74 74
Re +4 75 77
Re +5 75 72
Re +6 75 69
Re +7 75 67
Os +4 76 77
Os +5 76 71.5
Os +6 76 68.5
Os +7 76 66.5
Os +8 76
Ir +3 77 82
Ir +4 77 76.5
Ir +5 77 71
Pt +2 78 94
Pt +4 78 76.5
Pt +5 78 71
Au +1 79 151
Au +3 79 99
Au +5 79 71
Hg +1 80 133
Hg +2 80 116
Tl +1 81 164
Tl +3 81 102.5
Pb +2 82 133
Pb +4 82 91.5
Bi +3 83 117
Bi +5 83 90
Po +4 84 108
Po +6 84 81
At +7 85 76
Rn 86
Fr +1 87 194
Ra +2 88
Ac+3 89 126
Th +4 90 108
Pa +3 91 118
Pa +4 91 104
Pa +5 91 92
U +3 92 116.5
U +4 92 103
U +5 92 90
U +6 92 87
Np +2 93 124
Np +3 93 115
Np +4 93 101
Np +5 93 89
Np +6 93 86
Np +7 93 85
Pu +3 94 114
Pu +4 94 100
Pu +5 94 88
Pu +6 94 85
Am +2 95
Am +3 95 111.5
Am +4 95 99
Cm +3 96 111
Cm +4 96 99
Bk +3 97 110
Bk +4 97 97
Cf +3 98 109
Cf +4 98 96.1
Es 99
Fm 100
Md 101
No +2 102 124
Lr 103
Shannon, R. D. Acta Cryst. 1976, A32, 751-767.
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