Synthesis and crystal structure of a new hexagonal perovskite 7H-Ba7Li1.75Mn3.5O15.75 with Mn4+/Mn5+ charge distribution. Issue 42 (7th October 2015)

• Record Type: Journal Article
• Authors: Tarakina, N. V.; Tyutyunnik, A. P.; Bazuev, G. V.; Vasilev, A. D.; Gould, C.; Nikolaenko, I. V.; Berger, I. F.
• Is Part Of: Dalton transactions. Volume 44:Issue 42(2015)
• Page Start: 18527
• Page End: 18535
• Publication Date: 2015-10-07
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Chemistry, Inorganic -- Periodicals; 546.05
• DOI: 10.1039/c5dt01528f
• Languages: English
• ISSNs: 1477-9226

Abstract

Abstract : Our work describes the synthesis and crystal structure of a new hexagonal perovskite 7H-Ba7 Li1.75 Mn3.5 O15.75 with Mn 4+ /Mn 5+ charge distribution. Abstract : Ba7 Li1.75 Mn3.5 O15.75 is a new hexagonal perovskite whose crystal structure has elements typical for the layered hexagonal perovskites and quasi-one-dimensional oxides, hence representing a new polytype. It has been synthesized via a solid-state microwave route. The crystal structure was solved using a combination of X-ray and neutron diffraction data, which show that Ba7 Li1.75 Mn3.5 O15.75 crystallizes in a hexagonal unit cell with parameters a = 5.66274(2) Å and c = 16.7467(1) Å ( V = 465.063(4) Å 3 ), with one formula unit, and can be described as columns of face-shared octahedra occupied by Mn 4+ and Li + cations and vacancies along the c axis separated in the ab plane by barium atoms. Every sixth layer, the coordination of Mn 5+ and Li + changes to tetrahedral. Additional local ordering of manganese and lithium atoms among cationic sites leading to the formation of a rhombohedral supercell has been observed by scanning transmission electron microscopy.