α-Quartz SiO₂

Unit cell

Lattice constants

a = 4.913 Å, b = 4.913 Å, c = 5.404 Å; α = 90°, β = 90°, γ = 120°

Cell volume

113.0 ų

Atoms in the cell

9 (Si 3, O 6)

Formula units Z

3

Calculated density

1.41 g cm⁻³

Shortest contact

1.614 Å

Coordination

Si

CN 4 at 1.61 Å (4 O)

O

CN 2 at 1.61 Å (2 Si)

About the structure

• Corner-sharing SiO₄ tetrahedra wound into 3₁ helices along c — the structure is chiral, which is why quartz rotates polarised light and comes in left- and right-handed crystals.
• Si–O 1.61 Å, Si–O–Si ≈ 144°; the most common mineral of the continental crust and the material of piezoelectric oscillators.
• Coordinates from the Crystallography Open Database, entry 1011097 (open data); hydrogen and water sites with partial occupancy below 0.5 are left out.

Atom positions (fractional, one cell)

Z, coordination numbers, distances, density and packing on this page are computed from these coordinates.