Solid State Inorganic Chemistry Professor Ray Withers and Professor A David Rae

We aim to understand and exploit the factors that determine structure and function in crystalline inorganic solids. Our interest is in understanding the fine details of structure at a local scale and relating this to overall structure and physicochemical properties.

The principal experimental tools used are synthesis, transmission electron microscopy and scanning electron microscopy in combination with powder and single crystal X-ray diffraction.

We study a wide range of crystalline inorganic materials including solid electrolytes (eg. for use in solid-state batteries), ferroic materials, displacively flexible framework structures and tough ceramics.

Current research activities

Displacively flexible framework structures and their underlying crystal chemistry

The inherent displacive flexibility of many framework structures plays a crucial role in many of their useful physical properties, for example, low thermal expansion, easy ion exchange and catalytic activity. The 'average' structure is fixed, but at the local level, molecules are vibrating, rotating or bending at bonds with neighbouring molecules. We are investigating the nature of this flexibility and the consequences for the physical properties of the material.

The effect of local strain on crystal chemistry

When one kind of atom is substituted for another in a crystal structure it alters the local chemistry and introduces strain into the crystal lattice. We aim to characterise this substitutional strain and apply it to understand the geological history of rocks, improve metal recovery from ores and design and synthesise new materials.

Oxygen/fluorine ordering and transition metal oxyfluorides

We are synthesising new metal oxyfluoride compounds which have ferroelectric (can be polarised in one direction by applying an electric field) and ferroelastic (can be polarised under mechanical stress) properties. We are examining the importance of local oxygen/fluorine ordering in determining the properties of these materials.

Annual Research Report   (PDF format)

Group members

Academic Staff:
Professor Ray Withers (Leader)   |   Professor David Rae   |   Dr Lasse Norén   |   Dr Yun Liu

PhD Students:
Frank Brink   |   Valeska Ting

Key publications

1. R.L.Withers and H.Rossell. A TEM study of “Rhombohedral” β type solid solutions in the Bi₂O₃-SrO and Bi₂O₃-CaO systems. J. SolidState Chem. 118, 1995, 66-73.
2. R.L.Withers, S.Schmid and J.G.Thompson. Compositionally and/or displacively flexible systems and their underlying crystal chemistry. Prog. in SolidState Chemistry 26, 1- 96, 1998.
3. R.L.Withers, Y.Tabira, Y.Liu and T.Höche. A TEM and RUM study of the inherent displacive flexibility of the fresnoite framework structure type. Phys. Chem. Minerals 29, 624-632, 2002.
4. R.L.Withers. An analytical solution for the zero frequency hyperbolic RUM modes of distortion of SiO₂–tridymite. SolidState Sciences 5, 115-123, 2003.
5. R.L. Withers, T.R. Welberry, F.J. Brink and L. Norén. Oxygen/fluorine ordering, structured diffuse scattering and the local crystal chemistry of K₃MoO₃F₃. J. SolidState Chem. 170, 211-220, 2003.

>>more publications

private web page:   Ray Withers group photos

Professor R L Withers Research School of Chemistry, Building 35 Australian National University Canberra ACT 0200 AUSTRALIA Ph: +61 2 6125 3714 Fx: +61 2 6125 0750 E-mail: withers@rsc.anu.edu.au Professor A D Rae Research School of Chemistry, Building 35 Australian National University Canberra ACT 0200 AUSTRALIA Ph: +61 2 6125 3895 Fx: +61 2 6125 0750 E-mail: rae@rsc.anu.edu.au

David Rae came to the RSC in 1993 after over 20 years at the University of New South Wales. He has taken study leave at Oak Ridge National Laboratory, University of Wisconsin-Madison and the ANU.