What is defined as the number of atoms surrounding an atom in a crystal lattice?

coordination number

Explanation:

Coordination number -

In a crystal lattice , the number of atoms that are surrounded to a particular atom , is referred to as the coordination number of the crystal.

In the field of crystallography and chemistry , it is also called the ligancy.

In coordination chemistry , the number of ligands attached to the central metal atom is also known as the coordination number of the coordination compound.

Hence, from the given statement of the question,

The correct term is coordination number.

? you expect us to answer this? ? this is your schoolwork, i don't think we can with this, i think it would considering being