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University of Western Australia

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The University Of Western Australia - September 1997

The recent passing of E.N. Maslen, the foundation Director of the UWA Crystallography Centre, provides an appropriate occasion for a thumbnail sketch of crystallographic activities at UWA over the past forty years.

Crystallography has a number of independent roots in Western Australia. The first single crystal studies at UWA were under the direction of C. J. B. Clews, who came as Professor of Physics in 1952 from the Cavendish Laboratory, Cambridge. Two pyrimidine structures were determined with Noel E. White, D.E. Jukes and E.N. Maslen in 1956, the latter in his Honours year. Ted proceeded to Oxford as a Rhodes scholar to work with Dorothy Hodgkin on penicillin and cephalosporin derivatives for his Ph.D. which he received in 1960, returning to the UWA Physics Department as lecturer in that year. He took over the diffraction group of Clews, who became Deputy and Acting Vice-Chancellor. In this period, electron diffraction studies were also introduced.

A reflection electron diffraction camera was constructed and used by P.B. Sewell, J.H. Chute and A.E.C Spargo for epitaxy studies under the supervision of L.N.D. Lucas, subsequently Director of the Electron Microscopy Centre established in 1970. His third research student was a later Director, A.W.S. Johnson, who worked on lead films and surfaces. Powder diffraction studies on soil colloids were undertaken by J. Graham in 1953 under the supervision of J. Shearer. In the Chemistry Department, D.J.M. Bevan was appointed in the late fifties followed by B.N. Figgis, B.G. Hyde and A.H. White in the early and middle sixties, together with, subsequently, one of Bevan's Ph.D. graduates, F.J. Lincoln.

The study of crystallography with electrons flourished in the Chemistry Department in the early 1960s with Hyde, Bevan and L. Bursill’s acquisition of a Siemens transmission electron microscope which was used to elucidate the structures of refractory oxides. The Centre for Microscopy and Microanalysis currently houses a Philips 430 analytical transmission electron microscope (AEM) with a Gatan Image Filter, an X-ray energy dispersive spectrometer and computer analysis system (EDS) acquired in 1985, a JEOL 2000FX II STEM, a 200kV instrument with an integrated EDS system (1990) plus a variety of scanning electron microscopes.

Maslen brought with him from Oxford a keen interest in the application of computers to diffraction studies, first of all in accessing SILLIAC at Sydney, then locally in 1963, an IBM 1620 followed by a DEC PDP-6 in 1967. The latter was used to control one of the first four-circle diffractometers in Australia, a Hilger and Watts Y-231. In this decade, Ted's interests were directed at the elucidation of organic structures by direct methods, with developing interest in precise diffraction studies and their potential for the study of electron density distributions, while the study of inorganic and coordination compounds was developing solidly in the Chemistry Department. A number of graduates of this era subsequently became influential in initiating structural work in other venues: S.R. Hall, G.B. Robertson, K.J. Watson, in single crystal studies, and B.H. O'Connor and H.M. Rietveld in powder work.

A purchase of another four-circle diffractometer by the Chemistry Department in 1970 (a Syntex -1 led to the formation of the Crystallography Centre with Maslen as Director and White as deputy. In 1975 S.R. Hall joined the Centre, and in 1993 became Director when Maslen became Head of UWA Physics. A further diffractometer was purchased in 1978 (Syntex P21), followed by two Enraf-Nonius Turbo CAD-4 instruments, one with a rotating-anode generator, in 1987 and 1992. These acquisitions were with ARC support in cognisance of collaborative structural activities with other campuses, such grants also funding the initial appointments of C.L. Raston, and, later B.W. Skelton.

In the late 70's, the Centre's involvement in the development of the XRAY system, and subsequently the XTAL package, together with the precision density and structural chemistry studies, led to the acquisition of an Interdata microcomputer, and a separation from the UWA central computing facility. Subsequent generations of machines have led to the present complement of workstations that include Sun, SGI and DEC machines.

Research activities at UWA have also encompassed single-crystal neutron diffraction experiments, primarily in respect of X-N electron distribution studies, and more recently the use of synchrotron X-ray sources at Tsukuba, and polarized neutron spin density studies at Grenoble, the latter being coupled with the successful local construction of a helium-temperature instrument by B.N. Figgis.

In 1991 the Research Centre for Advanced Mineral and Material Processing (RCAMMP) acquired a powder diffractometer (Siemens D500) with a high temperature attachment. F.J Lincoln's solid state chemistry group's research includes detailed systematic structural and chemical studies of crystalline Western Australian minerals such as the Fe/Ni, Cu/Ag and Au/Ag sulphides and Pd/Pt and Cu/Ag selenides, the altered beach sand minerals ilmenite and zircon, the rare earth beach sand monazites and xenotimes, and the carbonatite-laterite monazites. This work is being carried out by the combination of X-ray/electron diffraction (principally, convergent beam electron diffraction) and electron microprobe analysis. Profile fitting (Rietveld) refinement methods are used for structure analysis and the quantitative analysis of mineral suites, such as the mineral sands and bauxites, from powder data. Synthesised materials, such as rare earth metal solid electrolytes, magneto-resistive lanthanum manganates, and synthesised mineral-like phases, such as the rare earth substituted monazites and apatite-based ceramic waste forms are also subjected to crystal structure analysis.

Current research activity in the Crystallography Centre includes electron density studies by V. Streltsov and D. du Boulay with synchrotron data collected at the Photon Factory, software development for the XTAL package and the improved scientific data handling methods using the STAR and CIF formats (Hall and du Boulay).

Small molecule X-ray studies (B.W. Skelton and A.H. White) at UWA are diverse, originating in part from collaboration with local, national and international chemists without facilities for this type of work. These include organic, natural products, organometallic, coordination, inorganic and mineral structures ranging in size to 'supramolecular’i' n scale. This work is closely supported by the XTAL software development. With the recent appointment of Bill Harrison to the Chemistry department structural studies also encompass the synthesis and characterisation of new inorganic phases including porous solids related to aluminosilicate zeolite and the solid-state chemistry of vanadium.

 


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Please feel free to send any queries, comments or suggestions to: bws@crystal.uwa.edu.au