Holes + elements

• occupied space in hcp arrangement is 74%
• occupied space in ccp arrangement is 74%
• occupied space in bcc structure is 68%
• occupied space in primitive cubic is 52%
• The radius of a tetrahedral hole is 0.225r
• The radius of an octahedral hole is 0.414r
• number of atoms in unit cell of hcp is 6
• number of atoms in unit cell of ccp is 4
• number of atoms in unit cell for bcc is 2
• number of atoms in primitive cubic is 1
• structure of group 1 metals is bcc
• structure of group 2 elements is hcp (Be, Mg) - ccp (Ca, Sr) - bcc (Ba)
• structure of group 3 + 4 is hcp
• structure of group 5 + 6 is bcc
• determining element structure: bcc is faboured by metals with small valence electrons per orbital. metals that are close packed have low directional covalent character, high densities
• coordination of relative radius 1 is 12 (Goldschmidt)
• coordination of realtive radius 0.97 is 8 (Goldschmidt)
• coordination of relative radius 0.96 is 6 (Goldschmidt)
• coordination of relative radius 0.88 is 4 (Goldschmidt)
• Radius ratio 0.225-0.414 has CN 4:4
• Radius ratio 0.414-0.732 has CN: 6:6 or 6:3
• radius ratio of 0.732-1 has CN 8:8 or 8:4