Simple-cubic sphere packing
= Simple-cubic sphere packing
{title2=$\eta=\pi/6$}
Equal spheres of radius $r$ occupy the sites of a cubic lattice of spacing $2r$. A cell contains one sphere, so its <packing fraction> is $(4\pi r^3/3)/(2r)^3=\pi/6$. This is an ideal arranged deposit rather than a claim about all settling suspensions.