CHEM 001C Lecture Notes - Lecture 10: Crystal Field Theory
CHEM 001C Lecture 10: Coordination Chemistry
●Introduction
○Transitions among d-orbitals provide metal colors
●d-Orbitals
○Atom considered by itself: 5 orbitals are degenerate (each has same energy)
■Electrons from other atoms surrounding metal atom causes d-orbitals to
split in regards to their energy (crystal field splitting)
●Orbitals oriented toward other atoms have a higher energy
●Holes
○The type of hole the metal atom occupies determines how the d-orbitals split
■In a face-centered cubic crystal, there a two available holes for metals to
occupy
■Tetrahedral hole: surrounded by four atoms
■Octahedral hole: surrounded by six atoms
●Tetrahedral Holes
○The d-orbitals in an atom occupying a tetrahedral hole interact with four
surrounding atoms
■The dz2 orbital points above and below the atom and does not come into
contact with electrons from the surrounding atoms
■The dx2 - y2 orbital is aligned along the x - y axis from the metal atom and
does not come into contact with electrons from surrounding atoms
■The dxy, dxz, and dyz orbitals are aligned between axes of the metal atom
●These orbitals are pointed toward the surrounding atoms and
therefore have higher energies than dz2, dx2 - y2 orbitals
●Octahedral Holes
○The d-orbitals in an atom occupying an octahedral hole interact with six
surrounding atoms
Document Summary
Atom considered by itself: 5 orbitals are degenerate (each has same energy) Electrons from other atoms surrounding metal atom causes d-orbitals to split in regards to their energy ( crystal field splitting ) Orbitals oriented toward other atoms have a higher energy. The type of hole the metal atom occupies determines how the d-orbitals split. In a face-centered cubic crystal, there a two available holes for metals to occupy. The d-orbitals in an atom occupying a tetrahedral hole interact with four surrounding atoms. The dz 2 orbital points above and below the atom and does not come into contact with electrons from the surrounding atoms. The dx 2 - y 2 orbital is aligned along the x - y axis from the metal atom and does not come into contact with electrons from surrounding atoms. The dxy, dxz, and dyz orbitals are aligned between axes of the metal atom.
