Structure of Cu₆PbO₈

First-principles quantum mechanical calculations based on density functional theory were performed for CuPbO, hexacopper lead octaoxide, murdochite. The computed lattice parameter, density and bond lengths at ambient pressure are in good agreement with experimental data for murdochite. At about 18 GPa a phase transition is predicted, when a polymorph with a Suzuki-type structure, i.e. a close-packed structure with ordered vacancies, is proposed to become stable. The pressure dependence of the structural parameters has been calculated for the two polymorphs and their bulk moduli have been predicted. It is argued that the incorporation of halogen atoms is not a precondition for the stability of murdochite.

Computing details

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Crystal data

Cu6O8Pb	V = 807.99 Å^3
Mr = 716.5	Z = 4
Cubic, Fm3m	Dx = 5.9 Mg m^−3
Hall symbol: -F 4 2 3	Mo radiation, λ = 0.710 Å
a = 9.314 Å

Data collection

h = →	l = →
k = →

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Biso*/Beq
Pb	0	0	0
Cu	0	0.25	0.25
O	0.145	0.145	0.145

(thisHPstudy)

Crystal data

Cu6O8Pb	V = 641.2 Å^3
Mr = 716.5	Z = 4
Cubic, Fm3m	Dx = 7.4 Mg m^−3
Hall symbol: -F 4 2 3	Mo radiation, λ = 0.710 Å
a = 8.623 Å

Data collection

h = →	l = →
k = →

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Biso*/Beq
Pb	0	0	0
O2	0.252	0	0
O1	0.25	0.25	0.25
Cu1	0	0.25	0.25