Magnesium nickel hydride (high-temperature form) Mg₂NiH₄

Unit cell

Lattice constants

a = 6.507 Å, b = 6.507 Å, c = 6.507 Å; α = 90°, β = 90°, γ = 90°

Cell volume

275.5 ų

Atoms in the cell

12 (Mg 8, Ni 4)

Formula units Z

4

Calculated density

2.59 g cm⁻³

Shortest contact

2.818 Å

Coordination

Mg

CN 4 at 2.82 Å (4 Ni)

Ni

CN 8 at 2.82 Å (8 Mg)

About the structure

• Isolated [NiH₄]⁴⁻ tetrahedra with Mg²⁺ between them in an antifluorite-like cubic arrangement — the hydrogen is bound to Ni, not to Mg, unlike MgH₂.
• Stores 3.6 wt % hydrogen and releases it near 250 °C; the ordered low-temperature form is monoclinic, this is the cubic phase above 235 °C.
• Coordinates from the Crystallography Open Database, entry 1521145 (open data); hydrogen and water sites with partial occupancy below 0.5 are left out. Some sites are partially occupied in the real crystal.

Atom positions (fractional, one cell)

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