Cubic systems: simple cubic, BCC, FCC
Solid State · Chemistry
Study notes
Copper is FCC with atomic radius 128 pm. Calculate its density. Step 1: FCC: 4 atoms/cell; a = 2√2 r = 2 × 1.414 × 128 = 362 pm. Step 2: Cell volume = (362 × 10⁻¹⁰ cm)³ = 4.74 × 10⁻²³ cm³. Step 3: Mass per cell = 4 × 63.5 / 6.022 × 10²³ = 4.22 × 10⁻²² g. Step 4: Density = 4.22 × 10⁻²² / 4.74 × 10⁻²³ = 8.9 g/cm³ ✓ (real Cu: 8.96). Counting shared atoms correctly is the whole trick.