CHEM 1410 Lecture Notes - Lecture 36: Amorphous Solid, Covalent Bond, Ionic Compound
25 Nov 2016
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Crystalline solids - most organized, long range repeating structure. Polycrystalline solids - solid is composed of many small crystals with varying orientation. Amorphous solid - no long or short range structure, aka glasses . Solids composed of covalent molecules: molecular solids - individual molecules are oriented in a regular structure to optimize/maximize imf, tend to have low melting points, tend to be soft , e. g. All carbons are trigonal planar: carbon has 3 bonds and contributes 1 p orbital to an extended - bonding network, graphite has many layers of graphene. Ions arranged to maximize coulombic attractions (g) + cl- (g) Lattice energy - energy needed to break an ionic solid into gas phase ions. Example: rank from high to low lattice energy (*lattice energy correlates to m. p) (based on size) highest. Example: rank from high to low lattice energy. *if elements are in the same row, differences in charge are more important than differences in size.
