270
14 Principles: Bond-Band-Barrier Correlation
14.2.2.2 Intrinsic sp-Orbital Hybridization of Oxygen
The sp-orbital hybridization is intrinsic to oxygen, which generates four tetrahedrally
directional orbits. The sp-orbital hybridization is more stable than the original 2s, 2p x ,
2p y and 2p z orbital configurations though the hybridization requires a small amount
of energy. The hybridization of sp orbitals is fairly insensitive to its partners that
donate electrons. The geometrical arrangement of the electron pairs in the valence
shell of the central atom A for any molecule AB n [28].
The AB 2 molecule is a common structure for the element A, like oxygen, possessing two lone-pair nonbonding orbitals and two bonding orbitals. In the H 2 O
molecule, the 2s and 2p orbits of an oxygen atom hybridize to form sp
3 -type orbits.
There are two electron pairs “−” in the bonding orbits (BP) and two lone pairs “:”
in the non-bonding orbits (LP). The interaction system consisting of lone pair and
polar-covalent bond is widely known as hydrogen bond (O
−2 : H
+ –O
−2 ) being the
key element to water and ice [29].
Hypothesis can be made that the interaction of oxygen atom with metal atoms
arranges in the general AB 2 structure and then the bond configuration is M 2 O tetrahedron. Similar to a H 2 O molecule, the charge cloud in the lone-pair orbit is under
the influence of only one (oxygen) nucleus, so this orbital is larger than a bonding
orbital occupied by sharing pair of electrons between two positive nuclei (O and H).
The repulsion between the lone pairs (H
+ : O
−2 :H
+ ) occupied orbits, increases the
angle between them to 109°28
or more.
One needs to note that one oxygen atom can never capture two electrons simultaneously from a certain atom because of the directional nature of the sp
3 -hybrided
bond geometry [30]. Meanwhile, their repulsions towards the electron pairs in the
bonding orbitals push the bonding orbitals (H
+ –O
−2 –H
+ ) closer together, thereby
reducing the H
+ –O
−2 –H
+ bond angle from the standard tetrahedral value to 104.5°
or less. The repulsion energies between the tetrahedral orbits are in the order of
LP ↔ LP > BP ↔ BP > LP ↔ BP.
14.2.2.3 Surface Bond Contraction
Atomic radii are no longer constant when atoms alter their states from metallic to
either ionic or polarized. For instance, the radius of Cu reduces from 1.27 to 0.53 Å
when the Cu becomes Cu
+ while the radius of O increases from 0.64 to 1.32 Å when
the O turns to be O
−2 [31].
On the other hand, atomic radius is not constant but changes with the coordination environment. The BOLS correlation [28] described in Part 1 applies to the
chemisorbed surfaces and also to the intramolecular H–O bond of H 2 O molecules,
which results in the supersolid phase of nanoclusters, nanodroplets, nanobubbles and
the skins of water and ice [29].
According to Pauling, the Cu radius will change from 1.276 to 1.173 Å (about 8%
contraction) if the CN changes from 12 to one (only one neighbor). Jorgensen [32]
and Kamimura and Suwa [33] noticed that the Cu-apical oxygen (at the apex of the
14 Principles: Bond-Band-Barrier Correlation
14.2.2.2 Intrinsic sp-Orbital Hybridization of Oxygen
The sp-orbital hybridization is intrinsic to oxygen, which generates four tetrahedrally
directional orbits. The sp-orbital hybridization is more stable than the original 2s, 2p x ,
2p y and 2p z orbital configurations though the hybridization requires a small amount
of energy. The hybridization of sp orbitals is fairly insensitive to its partners that
donate electrons. The geometrical arrangement of the electron pairs in the valence
shell of the central atom A for any molecule AB n [28].
The AB 2 molecule is a common structure for the element A, like oxygen, possessing two lone-pair nonbonding orbitals and two bonding orbitals. In the H 2 O
molecule, the 2s and 2p orbits of an oxygen atom hybridize to form sp
3 -type orbits.
There are two electron pairs “−” in the bonding orbits (BP) and two lone pairs “:”
in the non-bonding orbits (LP). The interaction system consisting of lone pair and
polar-covalent bond is widely known as hydrogen bond (O
−2 : H
+ –O
−2 ) being the
key element to water and ice [29].
Hypothesis can be made that the interaction of oxygen atom with metal atoms
arranges in the general AB 2 structure and then the bond configuration is M 2 O tetrahedron. Similar to a H 2 O molecule, the charge cloud in the lone-pair orbit is under
the influence of only one (oxygen) nucleus, so this orbital is larger than a bonding
orbital occupied by sharing pair of electrons between two positive nuclei (O and H).
The repulsion between the lone pairs (H
+ : O
−2 :H
+ ) occupied orbits, increases the
angle between them to 109°28
or more.
One needs to note that one oxygen atom can never capture two electrons simultaneously from a certain atom because of the directional nature of the sp
3 -hybrided
bond geometry [30]. Meanwhile, their repulsions towards the electron pairs in the
bonding orbitals push the bonding orbitals (H
+ –O
−2 –H
+ ) closer together, thereby
reducing the H
+ –O
−2 –H
+ bond angle from the standard tetrahedral value to 104.5°
or less. The repulsion energies between the tetrahedral orbits are in the order of
LP ↔ LP > BP ↔ BP > LP ↔ BP.
14.2.2.3 Surface Bond Contraction
Atomic radii are no longer constant when atoms alter their states from metallic to
either ionic or polarized. For instance, the radius of Cu reduces from 1.27 to 0.53 Å
when the Cu becomes Cu
+ while the radius of O increases from 0.64 to 1.32 Å when
the O turns to be O
−2 [31].
On the other hand, atomic radius is not constant but changes with the coordination environment. The BOLS correlation [28] described in Part 1 applies to the
chemisorbed surfaces and also to the intramolecular H–O bond of H 2 O molecules,
which results in the supersolid phase of nanoclusters, nanodroplets, nanobubbles and
the skins of water and ice [29].
According to Pauling, the Cu radius will change from 1.276 to 1.173 Å (about 8%
contraction) if the CN changes from 12 to one (only one neighbor). Jorgensen [32]
and Kamimura and Suwa [33] noticed that the Cu-apical oxygen (at the apex of the