Crystal and Magnetic Structure of Sr2BIrO6 (B = Sc, Ti, Fe, Co, In) in the Framework of Multivalent Iridium Double Perovskites

• Published in: European journal of inorganic chemistry Vol. 2015; no. 30; pp. 5027 - 5038
• Main Authors: Kayser, Paula, Alonso, Jose A., Mompeán, Federico J., Retuerto, Maria, Croft, Mark, Ignatov, Alexander, Fernández-Díaz, Maria T.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 01.10.2015; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Subjects: 5d elements; Antiferromagnetic ordering; Iridium; Magnetic properties; Perovskite phases
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.201500569

The preparation, crystal structure and magnetic properties of Sr2BIrO6 (B = In, Sc, Fe, Co or Ti) oxides are reported. For B = Sc, Fe, Co or In materials, X‐ray and neutron powder diffraction (NPD) studies confirm the presence of 1:1 B‐ordered perovskite‐like structures crystallizing in the monoclinic I2/m and P21/n space groups, with unit‐cell parameters a ≈ √2a0, b ≈ √2a0, c ≈ 2a0 and β ≈ 90°. Sr2TiIrO6 is described as a disordered perovskite with orthorhombic symmetry in the Pbnm space group. For B = Fe and Co, low‐temperature NPD data and magnetic measurements indicate the existence of an antiferromagnetic structure resulting from the Fe3+/Co3+ magnetic moment interaction. X‐ray absorption spectroscopy corroborates that the oxidation states of B and Ir are 3+ and 5+, respectively. The bond lengths and other structural features are discussed in the framework of other recently reported iridium double perovskites where iridium adopts tetravalent, pentavalent and hexavalent oxidation states, and in the wider context of Sr double perovskites. Selected members of the Sr2BIrO6 family, containing cations of different nature and Ir with oxidation states 4+, 5+ and 6+, have been obtained under synthesis conditions carefully chosen to select the required iridium valence. Additionally, the influence of the Mn+ radius on the internal parameters, obtained from an X‐ray neutron powder diffraction (NPD) analysis, is discussed.