Chemistry · Mini Lab

NH3 vs. NI3

Same central atom. Very different behavior.

Mini Lab: NH3 vs. NI3

Model note: The demonstration material commonly called nitrogen triiodide is usually the ammonia adduct NI3·NH3. Use the simplified NI3 unit for this comparison.

1. Draw

  1. Draw Lewis structures for NH3 and NI3, including lone pairs.
  2. Record two similarities and two differences.
  3. Get teacher approval before continuing.

2. Observe

Watch the demonstration until it pauses. Record exactly what triggers the change and what you observe.

3. Hypothesize

  1. Compare how electron groups are arranged around nitrogen.
  2. Identify where repulsion could occur.
  3. Write why dry nitrogen triiodide responds to touch while ammonia does not.

4. Check

Watch the explanation. Mark what your hypothesis got right, revise what it missed, and be ready to share with the class.

Safety: This demonstration stays on video. Nitrogen triiodide is never made or handled in class. Video: The Royal Institution, "Slow Motion Contact Explosive - Nitrogen Triiodide."

Mini Lab: NH3 vs. NI3 by Ramsey Musallam