Ionic Crystal Lattices Laboratory

Crystal evidenceLive observation

Grow an ordered lattice of alternating positive and negative ions.

CrystalNaCl

Assembled ions8 / 64

Coordination6

Lattice energy−98 kJ/mol

Ionic Crystal LaboratoryPaused

ModeStudent

How does an ionic lattice form?

Oppositely charged ions repeat in three dimensions. Many electrostatic attractions stabilize the solid; each structure has a characteristic coordination.

Ions occupy alternating sites.
Order grows layer by layer.
Collective attraction lowers energy.

Crystal growth chamber

Sound

Crystal structure

Assembly progress13%

Temperature300 K

Vacancy defects0%

Layer displacement0%

Observation lens

Simulation speed1×

Structure evidence

Cation charge+1

Anion charge−1

Nearest spacing281 pm

StateOrdered solid

3D view and ion focus

Drag the crystal to orbit it. Switch to Pan when you want to reposition the full view.

Energy history

Teacher demonstrations

Guided visual lecture

Chapter 1 of 80%

Ready. Clear embedded audio is synchronized to the crystal model.

Language

Narrator

Playback speed1×

External recording: share this browser tab with tab audio enabled. No microphone is used.

1. Repeating ionic order

Watch: Alternating ions assemble into a 3D solid.

Chapters

Electrostatic lattice model

Coulomb attraction: F = k|q₊q₋| / r²

Born–Landé model: U = −[N_AM|z₊z₋|e² / (4πε₀r₀)](1 − 1/n)

Greater charge product and smaller nearest-neighbor distance usually increase the magnitude of lattice energy.

Values are educational reference magnitudes. A real lattice sums long-range interactions over the entire crystal and includes short-range quantum repulsion.

Learning objectives

Describe an ionic solid as a repeating 3D lattice.
Identify alternating charges and coordination number.
Connect charge, spacing, and lattice energy.
Explain vacancies, ionic conduction, and brittleness.

Suggested investigations

Complete NaCl growth and focus a central ion.
Compare NaCl and MgO with the energy lens.
Add vacancies and inspect broken coordination links.
Displace a layer until the crystal fractures.

Questions for exploration

Why is an ionic crystal not described as separate NaCl molecules?
Why does MgO have larger lattice energy than NaCl?
Why can molten ionic material conduct electricity?

Teacher whiteboard

Use a finger, stylus, mouse, Android device, or smart board. Ten full-size pages keep their own drawings.

Pen color

Line width4

Upload image

Knowledge check

Seven questions0 / 7

Choose an answer for instant feedback.