Magnesium hydride MgH₂

Unit cell

Lattice constants

a = 4.517 Å, b = 4.517 Å, c = 3.021 Å; α = 90°, β = 90°, γ = 90°

Cell volume

61.6 ų

Atoms in the cell

6 (H 4, Mg 2)

Formula units Z

2

Calculated density

1.42 g cm⁻³

Shortest contact

1.954 Å

Coordination

H

CN 3 at 1.95 Å (3 Mg)

Mg

CN 6 at 1.95 Å (6 H)

About the structure

• Rutile structure: each Mg²⁺ is surrounded by six H⁻ in an octahedron, each H⁻ by three Mg²⁺.
• Stores 7.6 wt % hydrogen, the highest of the simple metal hydrides, but releases it only above ~300 °C — the central problem of Mg-based storage.
• Compare with TiO₂ rutile: same framework, hydride in place of oxide.
• Coordinates from the Crystallography Open Database, entry 4124639 (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.