10 - Chemistry 1000 Lecture 10: Crystal structures...

Info iconThis preview shows pages 1–5. Sign up to view the full content.

View Full Document Right Arrow Icon

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

View Full DocumentRight Arrow Icon

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

View Full DocumentRight Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Chemistry 1000 Lecture 10: Crystal structures (continued) Marc R. Roussel Packing fraction I Recall: For rectangular lattices I A corner atom is shared between 8 unit cells 1 8 of an atom is inside any given cell. I A facial atom is shared between 2 unit cells 1 2 of an atom is inside any given cell. I For the bcc lattice, we have 8 1 8 + 1 = 2 atoms. I The diagonal of the bcc unit cell = 4 r . D a a a 4 r x C B A I In the triangle ABC, x 2 = a 2 + a 2 = 2 a 2 . I In the triangle ACD, x 2 = (4 r ) 2- a 2 . I Combining the two equations, we get 2 a 2 = 16 r 2- a 2 , or r = 3 4 a . I The atoms occupy 2 atoms 4 3 r 3 = 3 8 a 3 . I Since the total volume of the unit cell is a 3 , the fraction of the unit cell occupied by atoms is 3 8 = 0 . 68. Examples 1. Silver has an fcc lattice with a unit cell whose lattice constant is 4 . 0862 10- 10 m. Calculate (a) the metallic radius, and (b) the density....
View Full Document

This note was uploaded on 03/03/2012 for the course CHEM 1000 taught by Professor Marc during the Fall '06 term at Lethbridge College.

Page1 / 10

10 - Chemistry 1000 Lecture 10: Crystal structures...

This preview shows document pages 1 - 5. Sign up to view the full document.

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