210 likes | 538 Views
Chapter #16 – Liquids and Solids. 16.1) Intermolecular Forces 16.2) The Liquid State 16.3) An Introduction to Structures and Types of Solids 16.4) Structure and Bonding of Metals 16.5) Carbon and Silicon: Network Atomic Solids 16.6) Molecular Solids 16.7) Ionic Solids
E N D
Chapter #16 – Liquids and Solids 16.1) Intermolecular Forces 16.2) The Liquid State 16.3) An Introduction to Structures and Types of Solids 16.4) Structure and Bonding of Metals 16.5) Carbon and Silicon: Network Atomic Solids 16.6) Molecular Solids 16.7) Ionic Solids 16.8) Structures of Actual Ionic Solids 16.9) Lattice Defects 16.10) Vapor Pressure and Changes of State 16.11) Phase Diagrams
SiO Bond Network in Quartz Ring structures Tetrahedral geometry
Two-dimensional reprentations of (a) a quartz crystal and (b) a quartz glass
Figure 16.35: Sulfur crystals (yellow) contain S8 molecules. (right) White phosphorous contains P4 molecules. It is so reactive with the oxygen in air that it must be stored under water.
Examples of silicate anions, all of which are based on SiO44-tetrahedra
n-dopant (electron rich) p-dopant (electron deficient)
(a)-(h) The steps for forming a transistor in a crystal of initially pure silicon.
Ionic Solids Trigonal Holes: r = x R = (2/3 1)R r R x r = 0.1547 R
r = R3/2 – R = 0.225 R Radius of a tetrahedral hole Tetrahedral holes
Octahedral Holes e = 2R d = R + 2r + R r = R2 – R = 0.414 R d2 = (2R)2 + (2R)2 Radius of a octahedral hole d = 2R2
The locations (gray x) of the octahedral holes in the face-centered cubic unit cell
(a) A simple cubic array with X- ions, with an M+ ion in the center (in the cubic hole). r = R3 – R = 0.732 R Radius of a cubic hole
If 0.225 R—< r+ < 0.414 R— If 0.414 R—< r+ < 0.732 R— If 0.732 R—< r+ : Fill r+ intetrahedral holes : Fill r+ inoctahedral holes : Fill r+ incubic holes Filling Holes in Ionic Crystals Guidelines: R— : anion X— radius r+ : cation M+ radius
(a)The location (x) of a tetrahedral hole in the face centered cubic unit cell.(b) one of the tetrahedral holes(c) the unit cell for ZnS, S2- are closest packed,Zn2+ fill alternate tetrahedral holes.(d) the unit cell for CaF2, Ca2+ are closest packed, F– fill tetrahedral holes.