# Halite

## Download the structure for interactive viewing

Choose one of the options below, based on which program you want to view the structure with.For viewing with the demo version of

**CrystalMaker (more info)**,

**CrystalMaker (more info)**,

**XtalDraw (more info)**,

## Questions

- In halite, which element is the cation? Which element is the anion?
- What type of bonding occurs between the cations and anions in halite?
- What is the coordination number of Na?
- Consider a single cation and the anions it is bonded to. If you connect the anions, what type of polyhedron forms around the cations?
- How many cleavages occur in NaCl? What is the angle between them?
- Look down a single row of atoms that are perpendicular to one of the flat faces. What is the rotational symmetry in this direction?
- Rotate so you are looking down the main diagonal fo the cube. (From corner to opposite corner.) What is the symmetry in this direction? (ignore rotoinversion for now and just treat as a simple rotation)
- This structure contains 2-fold, 4-fold and 3-fold rotation axes. How many identical 2-fold axes are there? How many identical 4-fold axes are there? (Warning: counting these rotational axes is quite difficult for the computer visualization)
- How many sets of mirror planes occur in this structure, and what is the angular relation between these planes?