Chemical Crystal Structure Model (Unit Cell Model)

Model:

Chemical Crystal Structure Model (Unit Cell Model)

Applicable Scope:

High school chemistry "Structure and Properties of Matter" module, college inorganic chemistry, and crystal chemistry classroom demonstrations and student group experiments. Used to display the spatial lattice structures of crystal unit cells, atomic crystals, ionic crystals, and metallic crystals.Dimensions: 24 × 16.7 × 7 cm; Weight: 1256 g

Principle:

Plastic balls of different colors represent atoms/ions in the crystal, and white connecting rods represent intermolecular forces or covalent bonds. They are detachable and assemblable, visually displaying the arrangement of particles inside the unit cell, coordination number, and unit cell parameters, helping students understand the periodic spatial structure of crystals.

Identification of 4 Unit Cell Models:

Diamond Unit Cell (Atomic Crystal): Black balls represent carbon atoms, displaying the tetrahedral spatial network structure of diamond. Students can observe that the coordination number of carbon atoms is 4, and understand the covalent bond network framework of atomic crystals. Face-Centered Cubic Unit Cell (General Framework for Metallic Crystals/Ionic Crystals): Red balls represent particles, displaying face-centered cubic packing, which is the basic packing form of metallic copper, sodium chloride, and other ionic crystals. Sodium Chloride NaCl Unit Cell (Ionic Crystal): Green and gray balls represent Na+ and Cl- respectively, demonstrating the alternating arrangement of ions, helping students understand that the coordination number of ionic crystals is 6, and the sharing calculation of ions in the unit cell. Graphite Crystal Structure (Mixed-Type Crystal): Black balls are carbon atoms, displaying the planar six-membered ring structure within graphite layers and the gaps between layers, explaining graphite's electrical conductivity and interlayer sliding characteristics.

Product Features:

Plastic atom balls + pluggable connecting rods, easy to assemble and disassemble; balls have multi-directional holes, suitable for three-dimensional spatial arrangement of crystals; One set includes multiple typical unit cells: diamond, graphite, sodium chloride, face-centered cubic, and other classic crystals required by middle school curriculum standards; Equipped with a storage box, each component stored in separate bags; Solves difficulties: Students find it hard to imagine the three-dimensional space of unit cells from two-dimensional planar diagrams. It can be used for teaching knowledge points such as unit cell particle number calculation, packing modes, and coordination number.

Assembly Steps:

Graphite Model: First assemble a single-layer hexagonal carbon ring (6 C atoms + 6 short rods), then stack multiple layers, using long rods to connect between layers (simulating van der Waals forces). Diamond Model: Start with one C atom as the center, connect four C atoms to form a tetrahedron, and repeatedly expand into a three-dimensional network (maintain a bond angle of 109.5°). Sodium Chloride Model: First construct the face-centered cubic unit cell of Cl- (8 vertices + 6 face centers), then insert Na+ at the body center and edge centers (total of 4 Na+ ions). Carbon Dioxide Model: Connect two red O atoms to both sides of the black C atom using double bonds (long rod + spring), forming a linear shape (bond angle 180°).

Teaching Uses:

Classroom demonstration: Explaining the structural differences among ionic crystals, atomic crystals, metallic crystals, and mixed-type crystals; Student experiments: Hands-on construction of unit cells, practicing the sharing method to calculate the number of particles in a unit cell; Understanding core concepts such as close packing, coordination number, crystal lattice, and unit cell.