Atomic arrangement determines how much volume atoms fill.
Atomic packing factor APF=(atoms per cell × atom volume)/cell volume: SC 0.52, BCC 0.68, FCC and HCP 0.74. Density ρ=nA/(V_cN_A). Theoretical density calculations check structure assumptions and detect porosity.
Copper (FCC, a=0.361 nm, A=63.5) has theoretical density about 8.9 g/cm³.
Packing determines how dense a metal is and how many atoms touch each other, which sets properties such as density and slip.
Atomic arrangement determines how much volume atoms fill.
Packing determines how dense a metal is and how many atoms touch each other, which sets properties such as density and slip.
The fraction of volume occupied by atoms in the unit cell, which is about 0.74 for FCC and HCP and about 0.68 for BCC.
No. Packing affects density and slip systems, but strength also depends on defects, alloying and processing.
Typical applications include comparing the density of FCC and BCC metals of similar atomic mass, estimating the volume of an alloy from its crystal structure and explaining why close-packed structures tend to be ductile.
Study "Miller indices" first (topic 4 of 100 in Materials & Chemical). It covers the groundwork this topic builds on.
FCC has 4 atoms per cell. BCC has 2. Theoretical density.
Copper (FCC, a=0.361 nm, A=63.5) has theoretical density about 8.9 g/cm³.
The next topic is "Crystal defects", which builds directly on this one.
It is classed as Beginner in Materials & Chemical (topic 5 of 100). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.
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