Question

3. (9 points) Sketch the frontier orbitals involved in bonding the H2 to W. a. (3 points) Start by considering the orbitals of the free H2 molecule. Draw the MO diagram for H2 and fill in the electrons. What is the HOMO? LUMO? Draw the shape of these orbitals. b. (4 points) Consider the metal orbitals which would have the appropriate symmetry to interact with each H2 orbital. Draw these interactions. Be sure to indicate the direction of electron donation. C. (2 points) How would the bound H2 bond length compare to the free H2 bond length? Explain.

The molecule is

Answer 1

3.a. Morbital are formed by the Linear Combination of Atomic Orbitals (LCAO). In hydrogen molecule, the two hydrogen atoms undergo LCAO to form two molecular orbital (MO). The orbital that is formed by the positive interaction of the atomic orbitals (Bonding Moleclar Orbital) is lower in energy than tha orbital formed by negative interaction of the atomic orbitals (Antibonding Molecular Orbital).

HOMO is the highest occupied molecular orbital that is completely filled with the electrons. LUMO is the lowest unoccupied molecular orbital and corresponds to the Antibonding Molecular Orbital.

3. a an electronic configuration of H 182 90 Alomic orbitar (AO) orbital Molecular (Mo) Alornic orbital (AO 64,(LUMO) 16 62 CHOMO) molecular orbital electronic configuration : 66 6 Bonding molecular mo orbital (Homo). 6 Antibanding molecular erfital (LUMO) shape of orbitals HOMO formed by orbitals positive overlap of calore (но мр) 615 LOMD formed by negaline everlap of calornic Arbiláls. Kumo)
b.
b. The structure of the confien wie PP) It is: PR2 ov H PR (octahedral (on gearnetry) the donates its 6-election density dey orbital of the metal atorn can be represented as: to the vacant (w). This O Gus PR du²y2 . Because FR is a 6-donating ligand with lone pair of electrons on P , it donates electron density to w and in turn, the election density on w is denated to 6t of the modicule. (615
c. The bond length of the bound hydrogen will be greater than the free one. PR_{​​​​​3} is a sigma donating ligand. It donates it's extra electron density to the vacant orbital of W. Because of this W donates the extra electron density to Antibonding Molecular Orbital of hydrogen molecule. As the electron density on the Antibonding orbital of hydrogen molecule increases, the bond length increases. Thus bound hydrogen has greater bond length than the free hydrogen molecule.