The new one-dimensional oxide Sr 3 PbNiO 6 contains the first reported example of lead in the 2H hexagonal perovskite-related family of oxides with the formula A 3 A‘BO 6 . The compound can be prepared by conventional high-temperature synthetic routes, or single crystals can be grown from a sodium chloride flux. Sr 3 PbNiO 6 adopts the K 4 CdCl 6 structure type ( R 3̄ c; a = 9.7041(1) Å, c = 11.3128(1) Å, V = 922.59(1) Å 3, Z = 6), comprised of face-sharing polyhedral [PbO 6/2 NiO 6/2 ] chains surrounded by six [Sr 2+ ] chains, both running along [001]. Pb 4+ occupies a slightly distorted trigonal prismatic coordination environment previously unobserved in oxides; Ni 2+ is octahedrally coordinated. The cation distribution in the polyhedral chains (+4 cation in the trigonal prismatic site, +2 in the octahedral site) is the inverse of that normally observed in the A 3 A‘BO 6 oxides. Sr 3 PbNiO 6 is a Curie−Weiss paramagnet with an antiferromagnetic transition at T N = 6 K. Complementary single-crystal and neutron diffraction structure determinations, thermogravimetric analysis, scanning electron microscopy, and magnetic susceptibility measurements are reported.
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Smith et al. (1999) studied this question.