Mn(I) in an extended oxide: the synthesis and characterization of La(1-x)Ca(x)MnO(2+δ) (0.6 ≤ x ≤ 1)

Edward Dixon; Joke Hadermann; Silvia Ramos; Andrew L Goodwin; Michael A Hayward

doi:10.1021/ja207616c

Mn(I) in an extended oxide: the synthesis and characterization of La(1-x)Ca(x)MnO(2+δ) (0.6 ≤ x ≤ 1)

J Am Chem Soc. 2011 Nov 16;133(45):18397-405. doi: 10.1021/ja207616c. Epub 2011 Oct 25.

Authors

Edward Dixon¹, Joke Hadermann, Silvia Ramos, Andrew L Goodwin, Michael A Hayward

Affiliation

¹ Department of Chemistry, University of Oxford, Inorganic Chemistry Laboratory, South Parks Road, Oxford, OX1 3QR, United Kingdom.

PMID: 21999167
DOI: 10.1021/ja207616c

Abstract

Reduction of La(1-x)Ca(x)MnO(3) (0.6 ≤ x ≤ 1) perovskite phases with sodium hydride yields materials of composition La(1-x)Ca(x)MnO(2+δ). The calcium-rich phases (x = 0.9, 1) adopt (La(0.9)Ca(0.1))(0.5)Mn(0.5)O disordered rocksalt structures. However local structure analysis using reverse Monte Carlo refinement of models against pair distribution functions obtained from neutron total scattering data reveals lanthanum-rich La(1-x)Ca(x)MnO(2+δ) (x = 0.6, 0.67, 0.7) phases adopt disordered structures consisting of an intergrowth of sheets of MnO(6) octahedra and sheets of MnO(4) tetrahedra. X-ray absorption data confirm the presence of Mn(I) centers in La(1-x)Ca(x)MnO(2+δ) phases with x < 1. Low-temperature neutron diffraction data reveal La(1-x)Ca(x)MnO(2+δ) (x = 0.6, 0.67, 0.7) phases become antiferromagnetically ordered at low temperature.