Book Notes-Crystallography

Book Notes-Crystallography - Intro Musthavesymmetry...

Info iconThis preview shows pages 1–4. Sign up to view the full content.

View Full Document Right Arrow Icon
Intro Must have symmetry Repetition through a volume or around a point Translational Symmetry Plane Lattices o Center of each spot at intersection of lattice lines is a lattice node o Unit meshes are the 4 shapes that can make up the 5 plane lattices Space Lattices and Unit Cell o Plane lattices layered to make 3D o Unit cell- volume outlined by lattice nodes o Crystal axes-edges of unit cell Bravais Lattices and Crystal Systems o 14 types in 6 groups divided by unit cell shape Point Symmetry How a motif can be repeated around a point Reflection o Monoclinic crystal system only one mirror plane possible (like  human symmetry) o Triclinic-none o Isometric-up to 9 Rotation
Background image of page 1

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

View Full DocumentRight Arrow Icon
o Noted with A sub #of fold o 1-360, 2-180, 3-120, 4-90, 6-60 o everything has infinite number of 1 fold because it brings it back to  original position Inversion o Any line through origin creates symmetry o Indictated with i Compound Symmetry Operations o Rotoinversion axes- rotation axes with inversion o Symmetry Notation o Ex: i,3A sub2,3m i- center symmetry 3m- 3 mirrored planes 3A sub2- 3 2 fold rotation axes o Hermann- Mauguin: presence of some symmetry implies of others-  more abbreviated Ex: 2/m2/m2/m 3 2 fold axes, each perpendicular to a mirror implies center symmetry 32 Point Groups 2d- mirrors and rotation, inversion only in 3D Steno’s Law
Background image of page 2
o Angles b/w crystal faces are consistent Measurement of Crystal Angles o Goniometer- measures crystal angles Determining Crystal System and crystal Class o Center symmetry?- Identify mirror planes- Identify Rotation axes-  Compile combination of symmetry Space Groups ???????????????? Crystal Faces
Background image of page 3

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

View Full DocumentRight Arrow Icon
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 09/26/2010 for the course GEO 416k taught by Professor Staff during the Fall '08 term at University of Texas.

Page1 / 8

Book Notes-Crystallography - Intro Musthavesymmetry...

This preview shows document pages 1 - 4. Sign up to view the full document.

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