Ab initio LCAO-MO-SCF calculations for several typical molecules containing phosphorus have been undertaken to study the role of phosphorus 3d orbitals in the bonding.It is emphasized that the discussion about the 3d ...Ab initio LCAO-MO-SCF calculations for several typical molecules containing phosphorus have been undertaken to study the role of phosphorus 3d orbitals in the bonding.It is emphasized that the discussion about the 3d orbital participation in bonding should be based on a reasonable choice of basis sets and it seems suitable to choose the atomic orbitals in proper molecular environment as the basis set.As an approximation,the optimized minimal STO-NG basis sets have been adopted in the present paper.The results obtained well exhibit the model of 3d orbital participation in bonding. It is shown that under the influence of highly electronegative ligands the phosphorus 3d orbitals con- tract greatly,their energy levels drop considerably,and thus they can effectively participate in bond- ing.The presence of highly electronegative ligands seems necessary.The contribution of 3d orbitals to bonding is achieved mainly through the concertedformation of σ bonds and p-d backbonds,though the contribution to σ bonding is minor.The three-center,four-electron bond modelis only approxi- mately correct.The results of the present paper demonstrate that the model of 3d orbital participation in bonding favoured by experimental chemists is reasonable and possesses sound ground.展开更多
The role of the sulfur 3d orbitals in bond formation is discussed by taking into account the influence of the environment on the orbitals of the sulfur atom in the molecules. The ca cula- tion results of a series of p...The role of the sulfur 3d orbitals in bond formation is discussed by taking into account the influence of the environment on the orbitals of the sulfur atom in the molecules. The ca cula- tion results of a series of prototype molecules containing sulfur such as SF_2, SF_4, NSF_3, SF_1, H_2S are reported. It is convincingly shown that in highly electronegative environment the energy levels of the sulfur 3d orbitals are reduced to the vicinity of those of the ligand valence orbitals and their spatial distributions are contracted to the bonding area, and therefore they can participate in bond formation to a certain extent, which is enhanced by the formation of the d-p π back bonds. It seems that the result reported in this paper is helpful for the solution of the long-standing debate about the sulfur 3d orbital participation in bond formation.展开更多
基金The National Natural Science Foundation of China.
文摘Ab initio LCAO-MO-SCF calculations for several typical molecules containing phosphorus have been undertaken to study the role of phosphorus 3d orbitals in the bonding.It is emphasized that the discussion about the 3d orbital participation in bonding should be based on a reasonable choice of basis sets and it seems suitable to choose the atomic orbitals in proper molecular environment as the basis set.As an approximation,the optimized minimal STO-NG basis sets have been adopted in the present paper.The results obtained well exhibit the model of 3d orbital participation in bonding. It is shown that under the influence of highly electronegative ligands the phosphorus 3d orbitals con- tract greatly,their energy levels drop considerably,and thus they can effectively participate in bond- ing.The presence of highly electronegative ligands seems necessary.The contribution of 3d orbitals to bonding is achieved mainly through the concertedformation of σ bonds and p-d backbonds,though the contribution to σ bonding is minor.The three-center,four-electron bond modelis only approxi- mately correct.The results of the present paper demonstrate that the model of 3d orbital participation in bonding favoured by experimental chemists is reasonable and possesses sound ground.
文摘The role of the sulfur 3d orbitals in bond formation is discussed by taking into account the influence of the environment on the orbitals of the sulfur atom in the molecules. The ca cula- tion results of a series of prototype molecules containing sulfur such as SF_2, SF_4, NSF_3, SF_1, H_2S are reported. It is convincingly shown that in highly electronegative environment the energy levels of the sulfur 3d orbitals are reduced to the vicinity of those of the ligand valence orbitals and their spatial distributions are contracted to the bonding area, and therefore they can participate in bond formation to a certain extent, which is enhanced by the formation of the d-p π back bonds. It seems that the result reported in this paper is helpful for the solution of the long-standing debate about the sulfur 3d orbital participation in bond formation.
