B2, cesium chloride

Structural typeB2
Common namecesium chloride
Definitionbcc lattice of comparable size ions
Pearson symbolcP2
Space group221 Pm-3m Oh1
Chemical formulaAB
Bondingmetallic, ionic
Atomic positions  A (1a)   0    0    0   (marked by C)
 X (1b)  1/2  1/2  1/2  (marked by S)
CoordinationAB, BA – 8cb
SublatticesA, B – sc
PDB filesB2
Superstructuresbcc for A=B
Substanceslate I + early VII (CsCl, RbCl), metal alloys (AlCo, AgZn)

This lattice has the highest Madelung constant, therefore it is preferable for highly ionic solids.