title: Thermal expansion in BaRuO3perovskites - an unusual case of bond strengthening at high temperatures.
abstract: The temperature dependences of the structures of three polytypes of BaRuO3have been investigated between room temperature and 1000 °C using high resolution synchrotron X-ray diffraction. The structural studies reveal a systematic decrease of the Ru-Ru distance as the pressure required to prepare the polytype increases. The O-O distance across the shared face increases as the Ru-Ru separation decreases. The 9R and 4H polytypes undergo unexceptional changes with increasing temperature. In 6H-BaRuO3there is an apparent increase in the Ru-Ru interaction at around 650 °C and a concurrent reduction in the O-O distance, indicating an anomalous strengthening of the Ru-Ru interactions upon heating.
authors.affiliation: School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia. Brendan.Kennedy@Sydney.edu.au.
authors.forename: Paula
authors.initials: P
authors.lastname: Kayser
authors.affiliation: School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia. Brendan.Kennedy@Sydney.edu.au.
authors.forename: Sean
authors.initials: S
authors.lastname: Injac
authors.affiliation: School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia. Brendan.Kennedy@Sydney.edu.au.
authors.forename: Brendan J
authors.identifier: http://orcid.org/0000-0002-7187-4579
authors.initials: BJ
authors.lastname: Kennedy
authors.affiliation: School of Chemistry, The University of Sydney, Sydney, NSW 2006, Australia. Brendan.Kennedy@Sydney.edu.au.
authors.forename: Andre L
authors.initials: AL
authors.lastname: Menezes de Oliveira
authors.affiliation: Department of Crystalline Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Shirako
authors.affiliation: Department of Crystalline Materials Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan.
authors.forename: Masashi
authors.initials: M
authors.lastname: Hasegawa