Why cant the shape of an electrovalent or ionic compound be determined?

Question

We can find a definite geometry of covalent compounds by VSEPR theory or by hybridization. Why cant ionic compounds' shapes be found?

Answer 1

Ionic compounds actually have a shape that are much more interesting than covalent compounds. But instead of a molecule as a unit as is the case in covalent, the basic unit is a stack of atoms. This is your crystal structure. And substances mostly ionic that are capable of forming crystal structures are given the distinction of being "true solids."
The science of crystallography was at first concerned only with this crystal in ionic compounds. But in X-ray diffraction crystallography you study stacking of molecules to identify properties of that molecule. (This technique was used to discover the shape of the DNA molecule.)

Answer 2

In covalent bonding, the atoms are in definite position since they share a pair of electrons. In ionic compounds there is only electrostatic attraction. The only need for the atoms is to keep at a given distance but the orientation are random