General chemistryLesson 1 of 1 in the course Liquids and Solids

Crystal Structures: Lattices, Ionic Solids, and X-Ray Diffraction

5 flashcards · 5 quiz questions · 5 match pairs · 4 fill-in sentences · English

Save course
Lesson progress
0 / 5

Your progress is kept in this browser only.Sign up to save it

Summary

Crystalline solids have particles arranged in an orderly, repeating pattern. This lesson introduces why crystals form, how unit cells represent repeating structures, and how to count atoms in a simple cubic cell.

More than 90% of naturally occurring and manufactured solids are crystalline. In many solids, particles adopt regular arrangements because efficient packing maximizes attractive interactions and minimizes the system's intermolecular energy. The regular arrangement at the atomic scale can produce visible features at larger scales, such as well-defined crystal faces.

All flashcards

Unit cell
A repeating building block whose repetition in three dimensions describes a crystal structure.
Coordination number
The number of nearest neighboring particles that a particle contacts in a structure.
Tetrahedral hole
A site surrounded by four anions arranged at the corners of a tetrahedron.
Bragg's equation
The condition for constructive diffraction from crystal planes: nλ=2dsin⁡θn\lambda=2d\sin\theta.
Closest-packed layer sequences
HCP layers repeat ABAB; CCP/FCC layers repeat ABCABC.

Quiz questions

  1. How many atoms belong to a body-centered cubic unit cell?Answer: Two: one from the corners and one at the center.
  2. Along which direction do atoms touch in a face-centered cubic structure?Answer: Along a face diagonal.
  3. What distinguishes the layer stacking in HCP and CCP structures?Answer: HCP repeats AB layers; CCP repeats ABC layers.
  4. In the NaCl structure, where are sodium ions located relative to the FCC chloride-ion array?Answer: In the octahedral holes.
  5. What does Bragg's equation describe for X-rays scattered by crystal planes?Answer: The condition for constructive interference at specific angles.

Based on Chemistry 2e by Paul Flowers, Klaus Theopold, Richard Langley, William R. Robinson, PhD (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.

More in General chemistry

All General chemistry lessons
General chemistryChemical Equations: Balancing, State Symbols, and Ionic Equations5 flashcards · 5 quiz questions · 4 gamesPlay free →General chemistryOxidation Numbers and Redox Half-Reaction Balancing5 flashcards · 5 quiz questions · 4 gamesPlay free →General chemistryMatter, Atomic Structure, Isotopes, and Chemical Bonding5 flashcards · 5 quiz questions · 4 gamesPlay free →General chemistryElectron States, Periodic Patterns, and Chemical Bonding5 flashcards · 5 quiz questions · 4 gamesPlay free →General chemistryIon Formation, Ionic Formulas, and Molecular Compound Properties5 flashcards · 5 quiz questions · 4 gamesPlay free →