CHEM 1120 1nd Edition Lecture 24Outline of Last Lecture I. Isomerisma. Structural isomersi. Coordination-sphereii. Linkageb. Stereoisomersi. Geometricii. OpticalOutline of Current Lecture I. 5 d-orbitals-Octahedralsa. Magnitude of d-orbital splittingb. Spectrochemical seriesc. Crystal-Field theoryd. MagnetismII. D-orbitals in tetrahedral fieldsIII. D-orbital electronic configurations give rise to colorCurrent LectureI. 5 d-orbitals - Octahedralsa. Putting the electron in the orbital where there are already ligands, it will take a higher energyb. Splitting of energies occursc. Magnitude of d-Orbital splittingi. Small splitting = weak field small energy differenceii. Energy gap between the 2 sets of orbitals depends on the metal and the ligandiii. Strong-field ligands more likely to lead to a low-spin complexd. Spectrochemical seriesi. Ligands can be arranged in an order based on ligand field strength. This series was empirically derived using visible light absorption spectroscopy ii. See power point or textbook to see the seriese. Crystal-Field Theoryi. Energy gap between d orbitals often corresponds to the energy in a photon of visible light These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.f. Magnetismi. Number of unpaired electrons determines whether the complex is paramagnetic or diamagnetic g. Ligand effect on splitting energyi. Since ligands affect whether a complex is high or low spin, ligands affect #of unpaired electronsii. Since more unpaired electrons correlates to a greater magnetic moment, ligands have dramatic effects on magnetic propertiesh. Ligand field stabilization: energy gained by putting electrons in lower energy orbitalsi. Complexes which undergo rapid ligand exchange are labile, slow = inertII. D-Orbitals in tetrahedral fieldsa. No change for square planar complexesIII. D-orbital electronic transitions give rise to colora. Colors come from impuritiesb. Move an electron to a higher energyc. Metal complex can absorb a particular wavelength of light, which leads to an excitation of an electron from one orbital d. Calculating the energy gap: E=hc/wavelengthe. Sample is irridated by light of various wavelengths: absorption spectroscopy f. Each set of ligands results in a slightly different d-orbital splitting, with different wavelength (color) of light absorbedg. Use color wheel! Is yellow light is absorbed, solution is
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