In compounds involving more than one element ionic

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Unformatted text preview: with the typically lower CNs for these structures (CN 4), can result in groups of atoms (molecules) that have fulfilled their primary bond requirements without the establishment of a 3-D primary bond network. In these materials, secondary bonds play a dominant role in determining the engineering properties. It is important to note that the strongest and stiffest directions in covalent solids are ones in which a continuous primary bond structure exists. In these directions covalent solids are every bit as strong and stiff as metallic and ionic solids. It is only in the directions in which primary bonds are absent that the properties are controlled by secondary bonds. The directional dependence of properties in covalent materials is utilized effectively in producing fibers that are very strong along their length direction (i.e., covalent bond direction) from polymeric materials. The high strength and stiffness along the fiber axis are obtained, however, at the expense of properties in the perpendicular directions. 2.8 MIXED BONDING | v v As mentioned previously, the type of primary bond formed in a compound depends on the electronegativities of the atoms involved. In compounds involving more than one element, ionic bonds are favored when the difference in electronegativities, EN, is large, and covalent bonds are favored when EN is small. The transition from pure ionic to pure covalent bonding is gradual, and many compounds display a bond with mixed ionic/ | e-Text Main Menu | Textbook Table of Contents 1-27-98 plm/iq 3-21-98 MP1 51 result from surface deposits of contaminants occurring in ae occurring in some steels. stagnant pools of electrolyte located on horizontal position pof austenite. g052 [V] G2 7-27060 / IRWIN / Schaffer js 1-27-98 plm 3-21-98 sections of metal. %RA) The change in area planar density The number of atoms or ions centered (expressed in percent) of a on a crystallographic plane per unit area of the plane. Part I Fundamentals en fractured. 52 plastic deformation Deformation that is permanent; pg799 ansformation, during cooling, [R] G15 7-27060 / IRWIN / Schaffer covalentfor example, a...
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This note was uploaded on 02/25/2013 for the course PHYS 2202 taught by Professor Sowell during the Spring '10 term at Georgia Institute of Technology.

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