High-pressure behaviour of Prussian blue analogues: interplay of hydration, Jahn-Teller distortions and vacancies. Issue 5 (14th December 2018)

• Record Type: Journal Article
• Authors: Boström, Hanna L. B.; Collings, Ines E.; Cairns, Andrew B.; Romao, Carl P.; Goodwin, Andrew L.
• Is Part Of: Dalton transactions. Volume 48:Issue 5(2019)
• Page Start: 1647
• Page End: 1655
• Publication Date: 2018-12-14
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c8dt04463e
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Compression of Mn[Pt(CN)6 ] and its defective analogue Mn[Co(CN)6 ]0.67 leads to tilting, whereas no transition occurs for the orbitally disordered Cu[Co(CN)6 ]0.67 . Abstract : We report a high-pressure crystallographic study of four hydrated Prussian blue analogues: M[Pt(CN)6 ] and M[Co(CN)6 ]0.67 (M = Mn 2+, Cu 2+ ) in the range 0–3 GPa. Mn[Co(CN)6 ]0.67 was studied by single-crystal X-ray diffraction, whereas the other systems were only available in polycrystalline form. The Mn-containing compounds undergo pressure-induced phase transitions from Fm 3̄ m to R 3̄ at ∼1.0–1.5 GPa driven by cooperative tilting of the octahedral units. No phase transition was found for the orbitally disordered Cu[Co(CN)6 ]0.67 up to 3 GPa. Mn[Co(CN)6 ]0.67 is significantly softer than the other samples, with a bulk modulus of ∼14 GPa compared to ∼35 GPa of the powdered samples. The discrepant pressure responses are discussed in terms of the presence of structural defects, Jahn-Teller distortions, and hydration. The implications for the development of polar systems are reviewed based upon our high-pressure study.