Free browser-based 3D crystal and molecular lattice viewer for common materials structures and custom unit cells. Inspect SC, BCC, FCC, HCP, diamond, ionic, semiconductor, ceramic, graphene, and…
Engineering reference
The interactive workspace is paired with its published engineering context: core equations, assumptions, design boundaries, and source references. Worked examples, validation cases, and editorial review dates are displayed only where that supporting evidence has been published for the tool.
Visualize common crystal structures and molecular bases in a rotatable, zoomable three-dimensional projection directly in the browser.
Edit lattice constants, angles, fractional atomic coordinates, replication counts, neighbor cutoffs, and display options to turn a preset into a custom material or molecule.
Overlay a Miller plane (hkl) and a crystallographic direction [uvw], select atoms to inspect their coordinates and nearest neighbors, and export unit-cell or supercell geometry.
The lattice defines the translational symmetry through three vectors a⃗, b⃗, and c⃗. The basis specifies one or more atoms or molecular sites in fractional coordinates. Replicating the basis by integer translations builds the extended crystal structure.
Conventional cells such as FCC or diamond contain several basis positions because the chosen cell emphasizes symmetry rather than minimizing the number of lattice points.
A fractional coordinate such as (1/2, 1/2, 1/2) remains at the body center even if the lattice constants or cell angles change. Cartesian positions are obtained from the linear combination x a⃗ + y b⃗ + z c⃗.
This is why the custom editor uses fractional coordinates: the same atomic basis can be explored under different lattice parameters without manually recalculating XYZ coordinates.
For the simplified plane drawn here, the fractional-coordinate equation is hx + ky + lz = 1. The visual overlay clips that plane to the first unit cell so the orientation can be compared with the atoms and cell edges.
A crystallographic direction [uvw] is constructed as u a⃗ + v b⃗ + w c⃗. In non-cubic cells, a plane normal and a direction with the same integer indices are not generally parallel in Cartesian space.
Lengths a, b, and c of the crystallographic cell.
Angles α, β, and γ between lattice vectors.
Element symbol and fractional x, y, z coordinates for each atomic or molecular site.
Number of cells shown along each lattice-vector direction.
Distance used for selected-atom coordination inspection.
Integer (hkl) and [uvw] indices for crystallographic overlays.
Interactive projected positions of atoms, bonds, unit-cell edges, planes, and directions.
Scalar triple product of the three lattice vectors.
Mass represented by the entered basis divided by unit-cell volume.
Atoms within the selected distance cutoff and their Cartesian separation.
Cartesian coordinates for the currently replicated supercell.
Simple unit-cell CIF containing lattice parameters and fractional atomic positions.
r = x a⃗ + y b⃗ + z c⃗V = a⃗ · (b⃗ × c⃗)ρ = m_cell /(N_A V_cell)Miller plane: hx + ky + lz = 1direction [uvw] = u a⃗ + v b⃗ + w c⃗Load the FCC copper preset and inspect a 2 × 2 × 2 supercell.
Result: The conventional cell contains four Cu sites and the ideal density is approximately 8.9 g/cm³ using the entered lattice constant.
Interpretation: The nearest-neighbor distance is a/√2 for the ideal FCC geometry.
Load BCC iron and select the atom at fractional (1/2, 1/2, 1/2).
Result: The selected site sits at the center of the cubic cell and has eight nearest corner-site neighbors in an extended crystal.
Interpretation: Increase replication or choose an interior supercell atom to avoid boundary truncation when counting coordination.
A fractional coordinate of 0.5 means half a lattice vector, not 0.5 Å.
Better approach: Use fractional coordinates in the custom basis; read Cartesian coordinates from the selected-atom panel.
A finite displayed supercell truncates neighbors at its boundaries.
Better approach: Replicate more cells and select an interior atom before interpreting coordination counts.
The viewer uses only a distance threshold based on approximate covalent radii.
Better approach: Treat bonds as visual guides; use validated chemistry or electronic-structure methods for bond-order analysis.
Construct crystallographic lattice vectors from a, b, c, α, β, and γ.
Convert each fractional basis coordinate to Cartesian position and translate it through the requested supercell replication.
Project the Cartesian geometry through user-controlled rotations and either perspective or orthographic projection.
Infer optional visual bonds from covalent-radius distance thresholds and calculate selected-atom neighbors from the explicit cutoff.
Generate plane and direction overlays from the entered crystallographic integer indices.
These checks document how representative calculations are cross-checked against analytic or reference results.
Primary sources are preferred for ratings, standards, manufacturer data, and externally defined constants.