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Crystal Lab4AB · ABC Chemistry
Drag to rotate · click an atom for its coordination
Building the cell…

How to read a unit cell

  1. Count the atoms: a corner atom is shared by 8 cells (⅛ each), an edge atom by 4, a face atom by 2, an interior atom belongs wholly to the cell.
  2. Find Z: the number of formula units in the cell. The viewer counts the atoms for you and divides.
  3. Coordination number: click any atom — its nearest neighbours light up and the polyhedron they form is drawn.
  4. Holes: in close-packed arrays every atom brings one octahedral and two tetrahedral holes; switch them on in fcc, hcp and simple cubic to see where ions go.
  5. Density: ρ = Z·M / (NA·V). The Calculator tab does it for the cell shown, or for numbers you type.

All structures

Each structure has its own page with the cell, coordination and notes:

Elements & packing: Simple cubic (Po) · Body-centred cubic (W) · Face-centred cubic (ccp) (Cu) · Hexagonal close-packed (Mg) · Diamond (C) · Graphite (C)

AB structures: Caesium chloride (CsCl) · Rock salt (halite) (NaCl) · Nickel arsenide (NiAs) · Zinc blende (sphalerite) (ZnS) · Wurtzite (ZnS)

AB₂ and A₂B: Fluorite (CaF₂) · Antifluorite (Na₂O) · Rutile (TiO₂) · Anatase (TiO₂) · Cadmium iodide (CdI₂) · Cadmium chloride (CdCl₂)

Oxides & frameworks: Perovskite (ideal cubic) (SrTiO₃) · Rhenium trioxide (ReO₃) · Spinel (MgAl₂O₄) · Corundum (Al₂O₃) · Cuprite (Cu₂O) · Pyrite (FeS₂) · Calcite (CaCO₃) · Molybdenite (MoS₂) · Scheelite (CaWO₄) · Magnetite (inverse spinel) (Fe₃O₄) · Ice Ih (oxygen framework) (H₂O)

Ion conductors & batteries: Lithium cobalt oxide (layered) (LiCoO₂) · Lithium manganese oxide (spinel) (LiMn₂O₄) · Lithium nitride (Li₃N) · α-Silver iodide (superionic) (AgI) · Silver chloride (Frenkel defects) (AgCl) · Lithium iron phosphate (olivine) (LiFePO₄) · NASICON (Na₃Zr₂Si₂PO₁₂)

Frameworks & porous solids: MOF-5 (IRMOF-1) (Zn₄O(BDC)₃) · HKUST-1 (Cu-BTC) (Cu₃(BTC)₂) · Sodalite (Na₈(Al₆Si₆O₂₄)Cl₂) · Faujasite (zeolite X/Y) (Na₅₆(Al,Si)₁₉₂O₃₈₄) · ZSM-5 (silicalite framework) (SiO₂ (MFI))

Hydrides & storage: Magnesium hydride (MgH₂) · Sodium alanate (NaAlH₄)

Pigments & minerals: Egyptian blue (cuprorivaite) (CaCuSi₄O₁₀)