84 mol C atoms are in the unit cell of the diamond with the lowest density.
A unit cell is the most minor portion of a crystal lattice that suggests the three-dimensional sample of the complete crystal. A crystal may be the notion of because the equal unit cellular is repeated in 3 dimensions.
A unit cell is the smallest repeating part of a crystal lattice. Unit cells occur in wide extraordinary varieties. As one example, the cubic crystal device is composed of three exceptional sorts of unit cells : (1) easy cubic, (2) face-centered cubic, and (3)body-focused cubic.
Learn more about unit cell here: https://brainly.com/question/10816130
#SPJ4