List of tables ................................................. xv
1 Atomic properties: one-electron atoms ........................ 1
Introduction ................................................. 1
1.1 A dash of physics: a particle in motion ................. 1
1.2 A dash of physics: the forces acting between particles
carrying electric charge ................................ 2
1.3 The energies of one-electron atoms ...................... 4
1.4 The introduction of quantum mechanics: atomic orbitals
and orbital energies .................................... 6
1.5 Polar coordinates, the Bohr radius and the Rydberg
energy unit ............................................. 7
1.6 The energy levels of one-electron atoms ................. 8
1.7 The orbital energy diagrams of one-electron atoms:
comparison with experiment .............................. 8
1.8 Ionization energies ..................................... 9
1.9 The size of one-electron atoms ......................... 10
1.10 The ground state wavefunctions of one-electron atoms ... 10
1.11 Probability densities, electron densities and the
shape of Is atomic orbitals ............................ 13
1.12 The wavefunctions, probability densities and shape of
2s atomic orbitals ..................................... 14
1.13 The wavefunctions, probability densities and shape of
2p atomic orbitals ..................................... 15
1.14 The wavefunctions, probability densities and shape of
3d atomic orbitals ..................................... 16
1.15 A final dash of physics: angular momentum .............. 18
1.16 Electron spin and spin orbitals ........................ 20
1.17 Spin-orbit coupling .................................... 22
2 Atomic properties: two-electron atoms ....................... 23
Introduction ................................................ 23
2.1 The energy, the Hamiltonian operator and the
wavefunctions of a two-electron atom ................... 23
2.2 The atomic orbital model ............................... 25
2.3 The ground state of a two-electron atom: calculation
of the energy .......................................... 27
2.4 Atomic size ............................................ 28
2.5 First ionization energies .............................. 29
2.6 Orbital energies and Koopman's theorem ................. 30
2.7 The ground state of a two-electron atom: beginning
the search for an acceptable wavefunction including
the electron spin ...................................... 31
2.2 The search for acceptable wavefunctions including
the electron spin: the Pauli Principle ................. 32
2.9 The Pauli Principle and Slater determinants ............ 34
2.10 The lowest excited states of the helium atom: finding
acceptable wavefunctions ............................... 36
2.11 The lowest excited states of the He atom: calculation
of the energies ........................................ 38
2.12 The rule of maximum spin ............................... 40
3 Atoms with more than two electrons: atomic properties
and periodic trends ......................................... 41
Introduction ................................................ 41
3.1 The ground state of the lithium atom ................... 42
3.2 The beryllium atom ..................................... 43
3.3 Lithium and beryllium: ionization energies and atomic
sizes .................................................. 43
3.4 The p-block elements from boron to neon: average
configuration energies ................................. 44
3.5 The aufbau model and the ground state electron
configuration of the elements .......................... 45
3.6 The ionization energies of the first 20 elements ....... 46
3.7 Valence shell s-electron ionization energies ........... 48
3.8 Configuration-averaged ionization energies and mean
valence shell ionization energies ...................... 48
3.9 Periodic variation of the mean valence electron shell
ionization energies of main group elements ............. 49
3.10 The atomic sizes and bonding radii of main group
elements ............................................... 51
3.11 Electron affinities .................................... 52
3.12 Electronegativity and electronegativity coefficients ... 53
3.13 Net atomic charges and atomic dipoles .................. 54
3.14 Atomic polarizabilities ................................ 55
References .................................................. 56
4 Homonuclear diatomic molecules .............................. 57
Introduction ................................................ 57
4.1 Bond strength .......................................... 57
4.2 The potential energy curve ............................. 59
4.3 The equilibrium bond distance and the dissociation
energy of a diatomic molecule .......................... 59
4.4 Vibrational energy levels .............................. 60
4.5 The standard dissociation energy at zero kelvin ........ 62
4.6 Comparison of the standard dissociation energies at
0 К and 298 К .......................................... 63
4.7 Force constants ........................................ 63
References .................................................. 64
5 Gaseous alkali metal halides: ionic bonds ................... 65
Introduction ................................................ 65
5.1 The electric dipole moments of molecules ............... 65
5.2 The spherical ion model ................................ 67
5.3 The electric dipole moments of the gaseous monomeric
alkali metal halides ................................... 68
5.4 Bond strength .......................................... 69
5.5 Bond distances in alkali metal halide molecules ........ 69
5.6 Force constants ........................................ 71
5.7 The potential energy curve of a spherical ion pair ..... 71
5.8 The dissociation energy of a spherical ion pair at
zero kelvin ............................................ 73
5.9 The potential energy of alkali metal halide dimers ..... 74
5.10 Alkali metal halide dimers: calculation of
equilibrium bond distances and dissociation energies ... 76
5.11 Calculation of the M-X bond distance in crystalline
alkali metal halides ................................... 78
5.12 Ionic radii ............................................ 80
5.13 The polarizable ion model for the monomeric alkali
metal halides .......................................... 81
5.14 The energy of a pair of polarized ions at infinite
distance ............................................... 82
5.15 The Coulomb interaction energy of two polarized ions
at distance R .......................................... 83
5.16 Electrides and alkalides ............................... 85
References .................................................. 86
6 Other heteronuclear diatomic molecules: polar соvalent
bonds ....................................................... 87
Introduction ................................................ 87
6.1 Electric dipole moments and ionic characters ........... 87
6.2 Bond strength and bond polarity ........................ 90
6.3 Bond distances and bond polarities ..................... 92
6.4 Single bond distances in polyatomic molecules .......... 94
6.5 A modified Schomaker-Stevenson rule for the
prediction of single bond distances between p-block
elements ............................................... 94
6.6 Carbon-based bonding radii ............................. 97
References .................................................. 97
7 Lewis' "cubical atom" model. Molecular orbital
calculations on the one-electron molecule H2+ and the two-
electron molecule H2 ........................................ 99
Introduction ................................................ 99
7.1 The electron octet, the "cubical atom," and the
electron pair bond ..................................... 99
7.2 Molecular orbitals: the hydrogen molecule ion ......... 102
7.3 Approximate molecular orbitals obtained by linear
combinations of atomic orbitals ....................... 105
7.4 Improvement of the LCAO MO ............................ 108
7.5 The hydrogen molecule and the molecular orbital
approximation ......................................... 109
7.6 The electric dipole moment of HD: failure of the
Born-Oppenheimer (adiabatic) approximation ............ 112
7.7 The dihelium(+2)ion: the IUPAC definition of
a chemical bond ....................................... 113
References ................................................. 114
8 Molecular orbital calculations on heteronuclear diatomic
molecules, hybridization, and estimation of net atomic
charges from calculated electron densities ................. 115
Introduction ............................................... 115
8.1 The LiH molecule: approximate molecular orbital
calculations .......................................... 115
8.2 Simplified Hiickel calculations ....................... 119
8.3 The importance of the "resonance integral", H1,2 ...... 121
8.4 A more accurate MO calculation for LiH ................ 122
8.5 Hybrid atomic orbitals ................................ 123
8.6 Hybridization energies ................................ 126
8.7 Orthogonal hybrid orbitals ............................ 127
8.8 Equivalent hybrid orbitals ............................ 128
8.9 The estimation of net atomic charges from calculated
electron densities .................................... 129
References ................................................. 133
9 Homonuclear diatomic species of second-period elements
from Li2 to Ne2 ............................................ 135
Introduction ............................................... 135
9.1 The dilithium molecule ................................ 135
9.2 The beryllium dimer ................................... 136
9.3 The diboron molecule .................................. 137
9.4 The dicarbon and dinitrogen molecules ................. 139
9.5 The dioxygen and diflourine molecules ................. 139
9.6 A molecular orbital energy level diagram for the
species from Li2 to Ne2 ............................... 140
9.7 The long-range attraction between neon atoms .......... 141
9.8 The helium dimer ...................................... 144
9.9 van der Waals interactions: dipole-dipole
interactions; dipole-induced dipole interactions;
and dispersion interactions ........................... 144
9.10 van der Waals radii from crystal structures ........... 145
9.11 The crystal structure of chlorine ..................... 147
9.12 The liquid structures of neon and methane ............. 147
References ................................................. 148
10 Structure and bonding in the gaseous dihalides and dialkyl
derivatives of the Group 2 and Group 12 metals ............. 149
Introduction ............................................... 149
10.1 Are the gaseous dihalides of the Group 2 and 12
halides linear? ....................................... 149
10.2 Molecular shapes ...................................... 152
10.3 Bond distances in metal dichlorides ................... 152
10.4 Bond energies of metal dichlorides .................... 153
10.5 The spherical ion model and the mean bond energies
of the Group 2 and 12 metal dichlorides ............... 155
10.6 The polarizable ion model and the shape of the
heavier Group 2 metal halides ......................... 156
10.7 The Valence Shell Electron Pair Repulsion (VSEPR)
model ................................................. 157
10.8 The VSEPR model and the structures of the Group 2
and 12 metal dihalides ................................ 157
10.9 The hybridization model and two-center molecular
orbitals ............................................. 158
10.10 Delocalized molecular orbitals ....................... 160
10.11 Metal dialkyls and dihydrides ........................ 162
10.12 Group variation of bond distances .................... 163
References ................................................. 164
11 Structure and bonding in the gaseous monochlorides,
trichlorides and trimethyl derivatives of the Group 13
elements ................................................... 167
Introduction ............................................... 167
11.1 Mono- and tri-chlorides of the Group 13 elements ...... 167
11.2 The molecular structures of the monomeric
trichlorides .......................................... 168
11.3 Trimethylderivatives of the Group 13 elements ......... 168
11.4 Group variation of M-C and M-Cl bond distances and
bond energies ......................................... 169
11.5 The spherical ion model and the bond energies of the
Group 13 element chlorides ............................ 170
11.6 The Valence Shell Electron Pair Repulsion model ....... 170
11.7 sp2 hybridization and localized molecular orbitals .... 171
11.8 The relative stabilities of the Lewis-valent and
subvalent chlorides ................................... 174
References ................................................. 176
12 Electron deficient molecules: three-center, two-electron
bonds ...................................................... 177
Introduction ............................................... 177
12.1 The trihydrogen cation ................................ 177
12.2 A molecular orbital description of H3+ ................ 177
12.3 Jahn-Teller distortion ................................ 180
12.4 The first electron deficient molecule, diborane ....... 181
12.5 Hexamethyldialane: bridging methyl groups ............. 183
12.6 Comparison of the strength of hydrogen, methyl and
phenyl bridges ........................................ 183
12.7 Nuclear magnetic resonance spectroscopy and bridge-
terminal exchange of methyl groups in (CH3)4Аl2
(μ-СН3)2 .............................................. 184
12.8 Clusters .............................................. 187
12.9 Cage compounds: closoboranes and carboranes ........... 188
12.10 The dimethylberyIlium polymer and the methyllithium
tetramer ............................................. 189
References ................................................. 191
13 Structure and bonding in simple compounds of the Group 14
elements ................................................... 193
Introduction ............................................... 193
13.1 The structures of the subvalent element chlorides ..... 194
13.2 Bonding models for the subvalent element chlorides .... 194
13.1 The structures of the Lewis-valent element chlorides .. 195
13.4 Hydrogen and methyl derivatives of the Lewis-valent
elements .............................................. 196
13.5 Bonding models for tetravalent compounds .............. 196
13.6 Construction of two orthogonal and equivalent hybrid
orbitals spanning an arbitrary valence angle β ........ 198
13.7 Radical species formed by H atom extraction from
methane ............................................... 199
13.8 Heteroleptic compounds: the molecular structures of
fluorinated methanes and methylsilanes ................ 200
13.9 C-F and C-H bond energies in fluorinated methanes ..... 203
13.10 The polarity of C-F bonds in fluorinated methanes .... 204
13.11 The polarity of Si-F and Si-C bonds in fluorinated
methylsilanes ........................................ 205
13.12 The effect of introducing more electronegative
atoms at the most electronegative of two bonded
atoms ................................................ 206
13.13 Inductive versus steric effects ...................... 207
References ................................................. 208
14 Structure and bonding in some simple hydrocarbons and in
ethane and ethene analogues of the heavier Group 14
elements ................................................... 209
Introduction ............................................... 209
14.1 The molecular structures of ethane, ethene, and
ethyne ................................................ 209
14.2 Ethane, ethene, and ethyne: model considerations ...... 211
14.3 Single C-C bond distances and hybridization ........... 213
14.4 Delocalized jt orbitals in benzene .................... 214
14.5 Ethane analogues of the heavier Group 14 elements ..... 216
14.6 The molecular structures of ethene analogues of the
heavier Group 14 elements ............................. 217
14.7 Molecular orbital descriptions of the ethene
analogues of the heavier Group 14 elements ............ 220
14.8 The molecular structure of Si2H2 ...................... 222
References ................................................. 223
15 Structure and bonding in simple compounds of the Group 15
elements ................................................... 225
Introduction ............................................... 225
15.1 Compounds of Lewis-valent elements .................... 225
15.2 Inversion of the N atom in ammonia .................... 227
15.3 Some planar amines .................................... 228
15.4 The gas phase molecular structures of phosphorus
pentafluoride and pentachloride ....................... 230
15.5 The solid state structures of the phosphorus
pentahalides .......................................... 231
15.6 Other homoleptic derivatives of hypervalent Group 15
elements .............................................. 232
15.7 The strength of the hypervalent bonds ................. 233
15.8 The pentaphenyl derivatives of Group 15 elements ...... 234
15.9 Structural non-rigidity and Berry pseudorotation ...... 235
15.10 Pentacoordination and the VSEPR model ................ 236
15.11 Heteroleptic hypervalent compounds ................... 236
15.12 Molecular orbital descriptions of the hypervalent
compounds ............................................ 238
References ................................................. 240
16 Electron donor-acceptor complexes .......................... 241
Introduction ............................................... 241
16.1 Covalent and dative bonds ............................. 242
16.2 N→B bond distances and dissociation energies in
substituted amine borane complexes .................... 243
16.3 Complexes of the electron donors HCN and H3CCN with
the electron acceptor BF3 ............................. 244
16.4 Some complexes of trimethylaluminum ................... 245
16.5 Two complexes containing dative and covalent bond
distances between identical atom pairs ................ 246
16.6 Dative bonds and the VSEPR model ...................... 247
16.7 The molecular structure of (Ме3М)2АlСl3, a complex
with two dative bonds ................................. 249
16.8 Bridge bonds: bonds with equal covalent and dative
contributions ......................................... 250
16.9 Triple bridges and cage compounds ..................... 251
16.10 Dative π-bonding ..................................... 252
16.11 Some complexes of beryllium, zinc and silicon ........ 253
16.12 Electron donor-acceptor complexes with Group 15
acceptor atoms ....................................... 253
References ................................................. 255
17 Structure and bonding in simple compounds of the Group 16
elements ................................................... 257
Introduction ............................................... 257
17.1 Compounds of the Lewis-valent elements ................ 257
17.2 Across angle radii .................................... 258
17.3 MO description of bonding in the Lewis-valent
compounds ............................................. 260
17.4 Ions and radicals formed from H2O ..................... 261
17.5 The molecular structure of hydrogen peroxide, HOOH .... 261
17.6 The peculiar structure of dioxygen difluoride, FOOF:
anomeric derealization ................................ 263
17.7 The molecular structures of compounds of hypervalent
Group 14 elements ..................................... 264
17.8 Compounds of hypervalent Group 16 elements: model
considerations ........................................ 266
17.9 The solid state structure of tellurium tetrachloride .. 268
References ................................................. 269
18 Structure and bonding in simple compounds of the Group 17
elements ................................................... 271
Introduction ............................................... 271
18.1 Compounds of Lewis-valent halogens .................... 271
18.2 Compounds of hypervalent halogens ..................... 272
18.3 Compounds of hypervalent halogens: model
considerations ........................................ 274
18.4 The crystal structure of iodine trichloride ........... 275
18.5 19F NMR spectra of ClF3 and BrF3 ...................... 276
18.6 Some electron donor-acceptor complexes of dihalogens .. 276
18.7 Hydrogen bonded complexes ............................. 279
18.1 The structures of ice and liquid water ................ 281
18.9 Polywater ............................................. 282
References ................................................. 284
19 Structure and bonding in simple compounds of the noble
gases ...................................................... 285
Introduction ............................................... 285
19.1 Hypervalent compounds of the noble gases .............. 285
19.2 Two compounds of Xe+ .................................. 287
References ................................................. 287
20 Structure and bonding in oxides and oxoacids of carbon,
sulfur, nitrogen, phosphorus, and chlorine ................. 289
Introduction ............................................... 289
20.1 Carbon oxides ......................................... 289
20.2 Some sulfur oxides .................................... 291
20.3 Sulfur oxofluorides ................................... 293
20.4 Sulfuric acid and related compounds ................... 294
20.5 Mono-nitrogen oxides and their N-N bonded dimers ...... 295
20.6 Hartree-Fock and configuration interaction
calculations on ONNO and O2NNO2 ....................... 298
20.7 Nitric acid and nitric acid anhydride (N2O5) .......... 299
20.8 Dinitrogen monoxide ................................... 299
20.9 Phosphorus oxides ..................................... 300
20.10 The crystal structure of orthophosphoric acid ........ 302
20.11 Chlorine oxides and perchloric acid .................. 303
20.12 The shape of triatomic molecules formed from
elements in Groups 14 to 18 .......................... 304
References ................................................. 305
Appendix ...................................................... 307
Index ......................................................... 309
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