BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Talks.cam//talks.cam.ac.uk//
X-WR-CALNAME:Talks.cam
BEGIN:VEVENT
SUMMARY:Structures and Phase Transitions of Perovskite Oxides and Hybrids 
 Inorganic-Organic Frameworks - Paul Saines (University of Cambridge\, Depa
 rtment of Materials  Science and Metallurgy
DTSTART:20091123T160000Z
DTEND:20091123T170000Z
UID:TALK20361@talks.cam.ac.uk
CONTACT:Ian Farnan
DESCRIPTION: The structures adopted by inorganic materials play a crucial 
 role in determining the properties of these compounds making structural st
 udies of these compounds a fascinating and important area of study. This i
 s particularly the case for both perovskites and hybrid inorganic-organic 
 frameworks. Perovskites are a family of metal oxides well known for the su
 btle variations in the structures they adopt with small variations in thes
 e having a large effect on their magnetic and electrical properties. Hybri
 d frameworks\, including the well known metal-organic frameworks\, are als
 o the focus of a large amount of research mostly due to their catalytic an
 d gas absorbing properties. They tend to exhibit more obvious variation in
  their structures and stoichiometry with their structures being heavily in
 fluenced by both the cation and ligand used.\n\n The work discussed in thi
 s presentation will encompass both of these areas. It will start with disc
 ussing the subtle structural variations found in the double perovskite ser
 ies Ba2LnBO6 (Ln = lanthanide (III) and B’ = Nb5+\, Ta5+ or Sb5+). A sys
 tematic study of this series has been conducted\, using a combination of s
 ynchrotron X-ray and neutron diffraction\, to probe changes in structures 
 caused by variations in composition and temperature. This reveals the role
  of π-bonding and ionic radii in stabilising different octahedral tilting
  systems in the similar seeming compounds in this series. The second part 
 of this talk will examine more recent work examining a very unusual struct
 ure adopted by the manganese succinate hybrid framework [Mn(CO2(CH2)2CO2)]
 . The composition and structure of this phase is unusual compared to that 
 of other transition metal succinates as it consists of sheets of face shar
 ing MnO6 octahedra chains alternating with corner-sharing octahedra pillar
 ed together by succinate ligands. The role of the Mn2+ cation in stabilisi
 ng this structure will be discussed and magnetic susceptibility and heat c
 apacity data will be used to describe the four magnetic phases adopted by 
 this compound at low temperature. Neutron diffraction patterns of this com
 pound have been collected and preliminary analysis of this data will be di
 scussed.\n
LOCATION:Harker 2 lecture room\, Department of Earth Sciences\, Downing Si
 te
END:VEVENT
END:VCALENDAR