Chap 11C - Chap 11C Wang Bonding in Solids Chapter 11.8...

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Unformatted text preview: Chap 11C / Wang Bonding in Solids Chapter 11.8 Bonding in Solids 11.1 A Molecular Comparison of Gases, Liquids, Solids. 11.2 Intermolecular Forces 11.3 Some Properties of Liquids 11.4 Phase Changes 11.5 Vapor Pressure 11.6 Phase Diagrams 11.8 11.8 Bonding in Solids The solid state At room temperature, solids: • are not compressible • commonly have regular repeating units Two types are observed Crystalline solids have a definite melting point. - ionic - covalent - molecular - metallic Crystalline vs. Amorphous solids vs. Crystalline Structure: particles ordered in well-defined arrays particles wellAppearance: flat surfaces with definite angles flat Composition/M.P: pure with sharp melting points pure Examples: quartz, diamond quartz, http://www.tuspirits.c om/images/Arkansas Crystal867.jpg Amorphous solids do not have a definite melting point or regular repeating units. Crystalline vs. Amorphous solids vs. s/e/ec/Moldavite_Besednice.jpg Crystal lattice Crystal lattice refers to the 3dimetional array of points, each points representing an identical environment within a crystalline solid. amorphous or non crystalline : Structure: no orderly structure no Appearance: surfaces lack definite faces / angles surfaces Composition/M.P: mixtures with broad range of mixtures melting temperature Examples: glass, rubber, some plastics glass, Four Four Types of Crystalline Solids: I. Molecular solids (A) Molecular Particles: Atoms Particles: Atoms Force between units: London dispersion London Properties: soft/brittle, lower MP, poor soft/brittle, conductor QYI0pnq0tsq7xikXw4pP2o1_400 .gif Four Types of Crystalline Solids: I. Molecular solids (B) Molecular Particles: Molecules Particles: Molecules Force between units: Intermolecular forces. Intermolecular (London dispersion, dipole-dipole, hydrogen bonding) dipole- Properties: soft/brittle, lower MP, poor conductor soft/brittle, Examples: Ice (H2O) Example: solid Helium crystals lium/crystal_structure.html Fall 2009 UM=SJTU JI Efficient Efficient packing in Crystalline Solids • A crystalline solid usually adopts a particular crystal structure so to maximize the attractive forces between the particles (atoms or ions) occupying the lattice points. • Crystalline structure of pure metallic most solids usually occurs with most efficient packing with minimum empty space. minimum Four Types of Crystalline Solids: II. Ionic solids Ionic Particles: Ions Particles: Ions (+ and - ) Force between units : ionic bond ionic Properties: Hard/brittle High MP Poor conductor Example: NaCl dry Ice (CO2) 88070521_b0a7e4eb6d.jpg?v=0 _quilt_gallery/quilt/quilt_icecrystals.jpg /images/uesc_03_img0170.jpg Page 1 Chap 11C / Wang Bonding in Solids Four Types of Crystalline Solids: Metallic III. Metallic solids Particles: metal Particles: metal atoms Force between units: metallic bond metallic Properties: soft / hard, low / high MP, soft excellent conductor, ductile, malleable Four Types of Crystalline Solids: IV. Covalent Network solids Covalent Particles: atoms Particles: atoms in a network of covalent bonds Force between units: covalent bonds covalent Properties: very hard, high MP, poor conductor very (except graphite) purified Examples: diamond & graphite Classify this crystalline solid: sulfur sulfur stry/1/0/6/R/sulfur1.jpg Physical Phase Density Density Density Liquid density at m.p. Melting point Boiling point Critical point Heat of fusion Heat of vaporization Specific heat capacity Ionic Ti(IV) and O-2 ions ordered in arrays to maximize ionic attractions. Natural mineral Rhenium metal crystals ElectronElectron-sea model: Free-floating Freevalence electrons form the ‘sea’ in which metal cations are immersed. Classify this crystalline solid: TiO2 TiO properties solid (alpha) 2.07 g·cm−3 (beta) 1.96 g·cm−3 (gamma) 1.92 g·cm−3 1.819 g·cm−3 388.36 K, 115.21 ° C, 239.38 ° F 717.8 K, 444.6 ° 832.3 ° C, F 1314 K, 20.7 MPa (mono) 1.727 kJ·mol−1 (mono) 45 kJ·mol−1 (25 ° 22.75 J·mol−1·K−1 C) Molecular S8 molecules ordered in arrays to maximize molecules intermolecular attractions. Fall 2009 UM=SJTU JI ages/070379.gif szczak/Photos/40-34.jpg Classify this crystalline solid: Buckyball Buckyball (text page 474) nium%20dioxide-250_tcm1846284.jpg onamicros/1/f0006-Brookite-LosBlancos,.jpg4 Classify this solid: Fullerenes Fullerenes • Molecular C60 molecules ordered in arrays to molecules maximize intermolecular attractions. • • a/commons/8/85/C60-Fullerenkristallin.JPG ScienceDaily (July 21, 2008) — University of Surrey researchers have found a way to make ultraultra-small pure carbon crystals entirely formed from the spherical carbon ‘buckyball’ ‘buckyball’ molecule known as C60. The method used involves mixing two liquids together, one of which contains C60, at low temperature. ompounds/Ti/O1Ti1-12137201.jpg A fullerene is any molecule composed entirely of carbon, in the form of a hollow sphere, ellipsoid, or tube. Spherical fullerenes are also called buckyballs, buckyballs, and cylindrical ones are called carbon nanotubes … Fullerenes are similar in structure to graphite, which is composed of stacked graphene sheets of linked hexagonal rings; but they may also contain pentagonal (or sometimes heptagonal) rings. rings. Page 2 ...
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This note was uploaded on 07/30/2011 for the course CHEM 210 taught by Professor Zhang during the Spring '09 term at Shanghai Jiao Tong University.

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