solid states lab - Chris Stanton Chemistry 216 April 26,...

Info iconThis preview shows pages 1–3. Sign up to view the full content.

View Full Document Right Arrow Icon
Chris Stanton April 26, 2007 Chemistry 216 Solid State Structures I. Introduction This lab allowed for the viewing of specific structures of solids. Specific structures involving elements as well as generalized structures (fcc, bcc, hcp, etc.) were able to be seen first hand. Building these structures made it easy to see the unit cell of each, count the number of atoms within each, determine the coordination number, and calculate the packing efficiency. This lab created the ability to compare different structures and compounds to see both how they are similar in nature and what about them makes them different. II. Part I Questions I. Primitive or Simple Cubic and Body-Centered Cubic A. Primitive or Simple Cubic 1a) corners = 8; faces = 0; edges = 0; inside = 0 1b) total = 1 2a) below = 1; same = 4; above = 1 2b) CN = 6 2c) Spheres are not close packed. 2d) Neither 3a) Packing efficiency = ((4/3)Π)/8 = Π/6 3b) D = M/V, therefore: packing efficiency is directly related to density. B. Body-Centered Cubic 1a) corners = 8; faces = 0; edges = 0; inside = 1 1b) total = 2 2a) below = 4; same = 4; above = 4 2b) CN = 12 2c) Spheres are close packed. 2d) ABA 3a) Packing efficiency = ((8/3)Π)/8 = Π/3 3b) D = M/V, therefore: packing efficiency is directly related to density. 4) Body-Centered Cubic has a full sphere in the center, a higher density, and, therefore, a higher packing efficiency. BCC also has a CN = 12 where Simple Cubic has a CN = 6. 5) BCC has higher packing efficiency. The density of BCC would be higher because it is close-packed and Simple Cubic is not. II. Hexagonal Close-Packing and Cubic Close-Packing A. Hexagonal Close-Packing 1a) corners = 8; faces = 0; edges = 0; inside = 1 1b) total = 2 2a) below = 3; same = 6; above = 3 2b) CN = 12 2c) Spheres are close packed.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
2d) ABA 3a) Packing efficiency = ((8/3)Π)/12 = 2Π/9 3b) D = M/V, therefore: packing efficiency is directly related to density. B. Cubic Close-Packing 1a) corners = 8; faces = 2; edges = 0; inside = 2 1b) total = 4 2a) below = 3; same = 6; above = 3 2b) CN = 12 2c) Spheres are close packed. 2d) ABCA 3a) Packing efficiency = ((16/3)Π)/(12√2) = (2Π√2)/9 3b) D = M/V, therefore: packing efficiency is directly related to density. 4) Cubic Close-Packing has four layers compared to three. It seems to be denser and has a higher packing efficiency. 5) There is a greater density in the Cubic Close-Packing. Copper wire does not break because it is malleable and the structure of it is CCP. When you lift one corner, the entire structure above that corner moves with it, which explains why copper would not break, but bend instead. III. Diamond and Graphite A. Diamond 1a) corners = 8; faces = 0; edges = 2; inside = 1 1b) total = 2 2a) below = 2; same = 0; above = 2 2b) CN = 4 2c) Spheres are not close packed. 2d) Neither
Background image of page 2
Image of page 3
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 7

solid states lab - Chris Stanton Chemistry 216 April 26,...

This preview shows document pages 1 - 3. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online