Exsolution of SrO during the Topochemical Conversion of LaSr3CoRuO8 to the Oxyhydride LaSr3CoRuO4H4

Lun Jin; Maria Batuk; Franziska K K Kirschner; Franz Lang; Stephen J Blundell; Joke Hadermann; Michael A Hayward

doi:10.1021/acs.inorgchem.9b02552

Exsolution of SrO during the Topochemical Conversion of LaSr₃CoRuO₈ to the Oxyhydride LaSr₃CoRuO₄H₄

Inorg Chem. 2019 Nov 4;58(21):14863-14870. doi: 10.1021/acs.inorgchem.9b02552. Epub 2019 Oct 22.

Authors

Lun Jin¹, Maria Batuk², Franziska K K Kirschner³, Franz Lang³, Stephen J Blundell³, Joke Hadermann², Michael A Hayward¹

Affiliations

¹ Department of Chemistry , University of Oxford , Inorganic Chemistry Laboratory, South Parks Road , Oxford OX1 3QR , U.K.
² EMAT , University of Antwerp , Groenenborgerlaan 171 , Antwerp B-2020 , Belgium.
³ Department of Physics, Clarendon Laboratory , University of Oxford , Parks Road , Oxford OX1 3PU , U.K.

PMID: 31638780
DOI: 10.1021/acs.inorgchem.9b02552

Abstract

Reaction of the n = 1 Ruddlesden-Popper oxide LaSr₃CoRuO₈ with CaH₂ yields the oxyhydride phase LaSr₃CoRuO₄H₄ via a topochemical anion exchange. Close inspection of the X-ray and neutron powder diffraction data in combination with HAADF-STEM images reveals that the nanoparticles of SrO are exsolved from the system during the reaction, with the change in cation stoichiometry accommodated by the inclusion of n > 1 (Co/Ru)_nO_n+1H_2n "perovskite" layers into the Ruddlesden-Popper stacking sequence. This novel pseudotopochemical process offers a new route for the formation of n > 1 Ruddlesden-Popper structured materials. Magnetization data are consistent with a LaSr₃Co⁺Ru²⁺O₄H₄ (Co⁺, d⁸, S = 1; Ru²⁺, d⁶, S = 0) oxidation/spin state combination. Neutron diffraction and μ⁺SR data show no evidence for long-range magnetic order down to 2 K, suggesting the diamagnetic Ru²⁺ centers impede the Co-Co magnetic-exchange interactions.