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

Chem 103 Textbook Team; Chem 104 Textbook Team

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

Average Bond Enthalpy

In kJ/mol

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.
	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

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	141
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		118	C≡O		113
						O=O in O₂		121	N≡O		108

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	71
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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