Announcements

1
Announcements

• To join clicker to class today
• Turn on the Clicker (the red LED comes on).
• Push Join button followed by 20 followed by
  the Send button (switches to flashing green LED
  if successful).

• Exam Friday.
• Review Materials Posted.

• Graded quizzes available outside Dr. Gutow's
  office.
• If you instructor has not previously arranged to
  return your lab notebooks they are outside Dr.
  Gutow's office.

2
Review

• Molecular solidsIsolated molecules held together
  by intermolecular forces.
• Network solids
• diamond continuous network of covalent bonds.
• Silicates networks of SiO4 tetrahedra held
  together by ionic interactions (ex. minerals and
  clays).
• band structure of solids
• Conductors, semiconductors and non-conductors.
• Shift in band gap caused by small amounts of
  impurities (ex. yellow diamond).
• Intro to crystal field splitting in discussion.

3
Some Silicate Gemstonescourtesy of Dr. Wacholtz
4
Tourmalines
(Na,Ca)(Mg, Fe, Al, Mn, Li)3Al6(BO3)3(Si6O18)(OH,F
)4
5
Beryls
Be3Al2-x(Cr, Fe)xSi6O18
6
Absorbance of Emeralds(fig 10.25)
7
Zn2 tetrahedral complexesCourtesy of Dr.
Wacholtz
Wavelength Transmitted/ reflected
580 nm
605 nm
565 nm
Wavelength Absorbed (d-d) transition
640
600
610
(note the ligands absorb in the UV to blue range
350-400 nm
8
The End Finis
9
Review-Chapter 9

• attractive interactions among molecules
• ion-ion (lattice energy Uk(Q1Q2/d), calculation
  of U from a cycle of reactions)
• ion-dipole
• dipole-dipole
• dipole - induced dipole
• Dispersion

10
Review-Chapter 9

• H-bonding
• Generally weaker than ion-ion interactions
• Stronger than other intermolecular interactions.
• Only seen for hydrogens bonded to N, O or F.
• Bond to lone pair on another molecule (usually on
  N, O or F).
• Explain very high boiling points for H2O, NH3 and
  HF
• Solubility
• like dissolves like (polar in polar, nonpolar
  in nonpolar)
• Only soluble if dissolved particles lower energy
  than undissolved solid.

11
Review-Chapter 9

• Raoults law Pvap XsolvPsolv
• Note Xsolvnsolv/(nsolv insolute)
• Reading phase diagrams
• Waters unusual properties explained primarily by
  strong directional hydrogen bonding.
• expansion on freezing formation of a
  meniscus
• surface tension capillary action

12
Review-Chapter 10

• Crystalline solids
• cubic, bcc and fcc lattices
• Volumes of different lattices in terms of radius
  of atoms
• Vcubic 8r3,
• In ionic lattices smaller ion usually fits into
  octahedral or tetrahedral holes
• small () ion lt 44 radius of big ion into
  tetrahedral holes
• if () ion about same size as (-) ion get simple
  cubic, like CsCl.

13
Review Chapter 10

• Molecular solidsIsolated molecules held together
  by intermolecular forces.
• Network solids
• diamond continuous network of covalent bonds.
• Silicates networks of SiO4 tetrahedra held
  together by ionic interactions (ex. minerals and
  clays).
• band structure of solids
• Conductors, semiconductors and non-conductors.
• Shift in band gap caused by small amounts of
  impurities (ex. yellow diamond).

14
Review Chapter 10

• Crystal field theory
• Ligands around a transition metal ion cause the
  d-orbitals to lose their degeneracy.
• You are responsible for two ligand arrangements,
  octahedral tetrahedral
• High spin versus low spin states.