Crystal Models

Equipment: A crystal model.

What it does: The models demonstrate various crystal structures.

Concepts Demonstrated: Crystal structures.

Available crystal models:

• Bravais lattices (L):
  
  Simple Cubic, body-centered Cubic, face-centered Cubic (2 models)
  
  Tetragonal, body-centered Tetragonal
  
  Orthorhombic, body-centered Orthorhombic, base-centered Orthorhombic, face-centered
  Orthorhombic
  
  Monoclinic, base-centered Monoclinic
  
  Triclinic
  
  Trigonal
  
  Hexagonal close packed (L)

  Crystal Structures Limited, scale 2.5 cm to 1 Angstrom:
  

  Copper - FCC (18 atoms, showing conventional cell and coordination).
  

  Potassium - BCC (9 atoms),
  

  Zinc - HCP (15 atoms, showing conventional cell and coordination)

  Graphite (L) in layer C-C distance 1.42A

  Diamond with cubic cell shown (L)

  Buckminsterfullerene (C60) (K)
  

  C-C distance: average 1.44A
  

  Single bonds (pentagon edges) 1.46A
  

  Double bonds (hexagon edges) 1.40A
  

  Mean ball diameter (C atoms treated as points) 6.83 A
  

  Inner/outer ball diameter 6.83-/+ 3.35A
  

  FCC lattice constant 14.17A

  Cadmium Chloride (CSL)

  Cadmium Iodide (CSL)

  Cadmium Sulphide (CSL)

  Calcium chloride (calcite) (L)

  Carbon dioxide (L)

  Cesium chloride (L)

  Germanium (CSL)

  Molybdenum Disulphide (CSL)

  Sodium chloride (L)

  Wurtzite (L)

Cautions: None.

Setup Time: Short.

Difficulty: Straightforward.

Visibility: Medium. The models may be hard to see from the back of a large lecture hall.

Related demonstrations:

References: PIRA 1R50.20

Original Construction: Purchased.