1 / 11

Bonding in Solids

Bonding in Solids. Valentin Panyushenko Chris Zheng. Molecular Solids. Held together by intermolecular forces Forces are weak; solid soft; low melting points Typically gas or liquid in room temperature Ex. Ar, H 2 O, CO 2. Benzene Toluene Phenol

benoit
Download Presentation

Bonding in Solids

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Bonding in Solids Valentin Panyushenko Chris Zheng

  2. Molecular Solids • Held together by intermolecular forces • Forces are weak; solidsoft; low melting points • Typically gas or liquid inroom temperature • Ex. Ar, H2O, CO2

  3. Benzene Toluene Phenol Melting point (˚C) 5 -95 43 Boiling point (˚C) 80 111 182 CH3 OH Molecular Solids • Property of molecular solids depend on: • Strength of the forces • Abilities of molecules to pack efficiently in 3D

  4. Intermolecular Forces • London dispersion: weakest;result from attractions betweendipoles • Dipole-dipole: attraction between the + end of one molecule and the – end of another • H Bonding: strongest; molecules containing H bond to an electro-negative element

  5. Diamond Melting point: 3550 ˚C Covalent-Network Solids • Held together by covalent bonds • Compared to molecular solids: harder and higher melting points • In diamond: • Each C is bonded to four other C

  6. Graphite Melting point: 3652 – 3697 ˚C Covalent-Network Solids • Graphite: • C atoms arranged in hexagonal ring • Each C is bonded to three others in the layer • Good conductor of electricity b/c delocalized π bonds • Used as lubricant and the “lead” in pencils

  7. Gray: Na. Green: Cl Ionic Solids • Ions held together by ionic bonds • Strength of ionic bonds depend on the charges • Structure depend on charges and sizes of ions • NaCl: each Na+ ion is surrounded by 6 Cl- ions

  8. Blue: S. Yellow: Zn Gray: Ca. Green: F Gray: Cs. Green: Cl Ionic Solid Structures • ZnS: Zn2+ ions surround tetrahedrally by four S2- ions • CaF2: There are twice as many F- ions as Ca2+ ions • CsCl: each Cs+ ion is surrounded by eight Cl- ions

  9. Metallic Solids • Consist entirely of metal atoms • Each atom has 8 or 12 adjacent atoms • Bonding due to delocalized valence e- • Strength of bonding ↑ as # of valence e- ↑ • Good conductors b/c of the mobility of e-

  10. Face-Center-Cubic (FCC): atoms on each corner & center of each face • Atoms: Al, Au, Ag, Ni, Pt, etc. • Hexagonal Close-Packed (HCP): 3 layers – top and bottom with 7 e-, and middle with 3 e- • Atoms: Mg, Zn, Ti, Be, etc. Metallic Bond Structures • Body Center-Cubic (BCC): atoms on each corner • Atoms: Li, Na, K, Cr, Ba, etc.

  11. Additional Sources • http://www.science.uwaterloo.ca/~cchieh/cact/c123/intermol.html • https://edocs.uis.edu/kdung1/www/Gemini/crystal_structure_visualization.htm • http://www.elmhurst.edu/~ksagarin/color/discussion6.html • http://www.ndt-ed.org/EducationResources/CommunityCollege/Materials/Structure/metallic_structures.htm

More Related