Molecular Orbital Theory for polyatomics--constructing MO ...



Molecular Orbital Theory for polyatomics--constructing MO diagramsDivide into your groups and create a ?-only MO diagram for your assigned molecule. You may want to consider the following points for construction of the MO diagram:1) What is the central atom and how many valence e- does it have?2) What is the correct set of LGO’s for the ligand atoms?3) How many e- does each ligand atom contribute to ?-bonding?4) What are the energies of ?, ?* and n.b. levels?5) Draw each MO (?, ?*, and non-bonding)?I will ask some groups to put their MO diagram up on the board and describe it. GroupMolecule Square Planar CH4 (JACS, 1970, 92, 4992) SnCl2 TeF6XeF2 (hint, descend in symmetry)PF4+PhICl2 (model the Ph group as a Cl!)SnCl42- (with hypothetical C3v structure)XeF4IF7Reminder of the technique for constructing LGO’s:I Draw a Lewis structure and assign VSEPR geometryII Assign a point group to the molecular geometryIII determine the central atom’s VB hybrid orbitals for the electronic geometryIV use the VB hybrid orbitals as generator orbitalsV Generate the LGO’s by taking linear combinations of the ligand ?-orbitals (lobes) to get an orbital with the same symmetry as the generator orbitalVI Assign proper symmetry labels from the character tableReminder of the technique for constructing MO diagrams:I name the MO diagram and its constituentsII place AO's and LGO’s with relative energies on one sidesIII place the correct number of electrons on each sideIV form MO's (bonding, antibonding and non-bonding) and give them symmetry labelsV place electrons in the MO's working from the bottom upVI be able to draw each MOOhE8C36C26C43C42i6S48 S63?h6?dA1g1111111111x2+y2, z2A2g11-1-111-111-1Eg2-100220-120(2z2-x2-y2,x2-y2)T1g30-11-1310-1-1(Rx,Ry,Rz)T2g301-1-13-10-11(xz, yz, xy)A1u11111-1-1-1-1-1A2u11-1-11-11-1-11Eu2-1002-201-20T1u30-11-1-3-1011(x,y,z)T2u301-1-1-3101-1D4hE2C4C22C2'2C2"i2S4?h2?v2?dA1g1111111111x2+y2, z2A2g111-1-1111-1-1RzB1g1-111-11-111-1x2-y2B2g1-11-111-11-11xyEg20-20020-200(Rx,Ry), (xz, yz)A1u11111-1-1-1-1-1A2u111-1-1-1-1-111zB1u1-111-1-11-1-11B2u1-11-11-11-11-1Eu20-200-20200(x, y)D5hE2C52C525C2?h2S52S525?vA1’11111111x2+y2, z2A2’111-1111-1RzE1’22cos72°2cos144°022cos72°2cos144°0(x,y)E2’22cos144°2cos72°022cos144°2cos72°0(x2-y2, xy)A1”1111-1-1-1-1A2”111-1-1-1-11ZE1”22cos72°2cos144°02-2cos72°-2cos144°0(Rx, Ry), (xz,yz)E2”22cos144°2cos72°0-2-2cos144°-2cos72°0D3hE2C33C2?h2S33?vA1’111111x2+y2, z2A2’11-111-1RzE’2-102-10(x,y), (x2-y2, xy)A1”111-1-1-1xyA2”11-1-1-11zE”2-10-210(Rx, Ry), (xz,yz)TdE8C33C26S46?dA111111x2+y2 +z2A2111-1-1E2-1200(2z2-x2-y2, x2-y2)T130-11-1(Rx,Ry,Rz)T230-1-11(x,y,z)(xy,xz,yz)C2vEC2?v(xz)?v’(yz)A11111Z, x2,y2 ,z2A211-1-1Rz, xyB11-11-1x,Ry, xzB21-1-11y,Rx, yzC3vE2C2??vA1111z, x2+y2 ,z2A211-1RzE2-10(x,y)(Rx,Ry)(x2-y2,xy)(xz,yz) ................
................

In order to avoid copyright disputes, this page is only a partial summary.

Google Online Preview   Download