3.3.Arrangement of Atoms (Crystallography) 33 Simple Cubic Face-Centered Body-Centered (SC) Cubic (FCC) Cubic (BCC) Simple Body-Centered Tetragonal Tetragonal Simple Body-Centered Base-Centered Face-Centered Orthorhombic Orthorhombic Orthorhombic Orthorhombic Simple Base-Centered Hexagonal Rhombohedral Monoclinic Triclinic Monoclinic FIGURE 3.8.The 14 Bravais lattices grouped into seven crystal systems: First row:a=b=c,a=B=y=90(cubic); Second row:a=b≠c,a=B=y=90°(tetragonal); Third row:a≠b≠c,a=B=y=90°(orthorhombic: Fourth row:at least one angle is 90.Specifically: Hexagonal:a=B=90°，y=120°a=b≠c(the unit cell is the shaded part of the structure); Rhombohedral:a=b=c,a=B=y≠90°≠60°≠109.5°； Monoclinic:a=y=90°，B≠90°，a≠b≠c; Triclinic:a≠B≠y≠90°，a≠b≠c.FIGURE 3.8. The 14 Bravais lattices grouped into seven crystal systems: First row: a
b
c, 


90° (cubic); Second row: a
b  c, 


90° (tetragonal); Third row: a  b  c, 


90° (orthorhombic); Fourth row: at least one angle is  90°. Specifically: Hexagonal: 

90°, 
120° a
b  c (the unit cell is the shaded part of the structure); Rhombohedral: a
b
c, 

  90°  60°  109.5°; Monoclinic: 

90°,   90°, a  b  c; Triclinic:       90°, a  b  c. 3.3 • Arrangement of Atoms (Crystallography) 33 Simple Cubic (SC) Face-Centered Cubic (FCC) Body-Centered Cubic (BCC) Simple Tetragonal Body-Centered Tetragonal Simple Orthorhombic Body-Centered Orthorhombic Base-Centered Orthorhombic Face-Centered Orthorhombic Hexagonal Rhombohedral Simple Monoclinic Base-Centered Monoclinic Triclinic