The space lattice of graphite is

Explain the concept of a two-dimensional lattice and a hypothetical two-dimensional crystal.

In a face-centred cubic $(FCC)$ unit cell,the edge length $(a)$ in terms of atomic radius $(r)$ is:

The body-centered unit cell is found in which of the following crystal systems?

$SrO$ has a $NaCl$ structure. If the lattice constant $a = 0.514 \ nm$ and the ionic radius of $Sr^{2+} = 0.113 \ nm$,what is the radius of the $O^{2-}$ ion?

Which of the following does $NOT$ have a triclinic structure?