History of Crystallography in Switzerland
Hans Grimmer, Paul Scherrer Institute
Introduction
Crystallography evolved from the study of the form of mineral crystals and of the anisotropy of their physical properties. After the discovery of X-ray diffraction by Laue (1912), the focus of crystallography shifted to structure analysis; chemists became the main users of crystallographic methods. Crystallographic institutes at universities were established first in Zürich, 1949 in Bern, in the 1970s in Geneva, Lausanne, Neuchâtel and Basel. In the beginning, the main focus in Switzerland was on methods and general principles. Due to the increasing demand of chemistry and biology institutes and the materials sciences, the focus shifted to the determination of ever more complicated structures, to disorder in crystals and to their dynamic properties. Crystallography laboratories were established also in institutes of chemistry and structural biology. The structure analysis of biological macromolecules and their application in drug design, although very successful and of great economic importance, will be mentioned only shortly in this article.
In addition to X-rays, neutrons became in the 1960s important probes to investigate crystals. Synchrotrons became a much more versatile and brilliant source of X-rays than X-ray tubes, especially when synchrotrons dedicated to the production of X-rays were built in the 1980s. Such sources are out of reach of university institutes, they were made available at Paul Scherrer Institute (PSI) in Switzerland and at national and international centres abroad. With the availability of the sources also the development of the corresponding beam-lines and of new applications gradually shifted from the universities to neutron and synchrotron radiation centres. As a consequence, full professors of crystallography who retired after 2000 were either not replaced or replaced at a lower level. On the other hand, joint appointments at PSI and Swiss universities, in particular ETH and EPFL have become common.
Crystallography overlaps with many sciences: mineralogy, solid state physics and chemistry, molecular biology, pharmacy and materials science. Crystallography is increasingly perceived as providing indispensable tools rather than as a science of its own at the crossroads of these disciplines [1].
The beginnings
Crystallography developed from mineralogy in the 17th century, when regularities in the forms of crystals and anisotropies of their physical properties were discovered. The term "Crystallographia" was actually introduced 290 years ago by the Swiss physician and scientist M. A. Kappeler [2]. In the 19th century the mathematical classification of 3-fold periodic structures was developed with the derivation of the 7 crystal systems, the 14 lattice types, the 32 crystal classes and the 230 types of space groups [3].
In 1855, the Polytechnic Institute (called ETH since 1911) was established in Zürich. Systematic crystallographic research started in Switzerland with Gustav Adolf Kenngott, who was Professor of Mineralogy at ETH from 1856 and at the University of Zürich (UZ) from 1857 until his retirement in 1893. The main activities of his successor Ulrich Grubenmann (1893-1920) were in petrography, where he made use of polarisation microscopy and chemical analytic methods. He was succeeded by Paul Niggli (1920-1953). All three were strong personalities and served the ETH as rectors, Niggli became rector also of UZ [4].
When Max von Laue was "Privatdozent" in Munich under Arnold Sommerfeld, he had in the beginning of 1912 the idea that X-rays might show interference effects with crystals. Paul Knipping and Walter Friedrich performed the experiments, showing interference spots compatible with the cubic symmetry of ZnS crystals. Laue's explanation of these spots proved the wave properties of X-rays and, simultaneously, the space group symmetry of crystals, i.e. that crystals are 3-fold periodic. Laue was not interested in determining the structure of crystals. This endeavour was started in England in 1913 by William Lawrence Bragg and his son William Henry Bragg. Laue received the Nobel Prize for physics in 1914, the Braggs in 1915. British crystallographers remained the leaders in structure determination until the 1960s.
The cross-fertilization between crystallography and neighbouring disciplines is shown by the fact that Peter Debye became 1911 Professor of Theoretical Physics at UZ, succeeded by Max von Laue in October 1912.
In 1915 Debye developed in Göttingen together with his PhD-student Paul Scherrer a method to determine the distances between neighbouring lattice planes from the diffraction of X-rays by crystal powders, known as Debye-Scherrer method. In 1920, the ETH appointed Debye and Scherrer as professors of physics and the above-mentioned Paul Niggli as Professor of mineralogy and petrography [4].
The "Zürich school of crystallography" [3]
Niggli made important contributions to mineralogy and petrography, but his main interest was in showing how symmetry considerations can be used to determine the space group and the structure of crystals. In particular, his book "Geometrische Kristallographie des Diskontinuums", published in 1919, became the precursor of the volume "Space-group symmetry" of today's "International Tables of Crystallography" and already contained the concepts and tables that are most important for structure determination. Niggli collaborated with mathematicians as Georg Polya at ETH and Heinrich Heesch at UZ. Using symmetry and modern mathematical methods for the solution of general problems in crystallography is a distinctive feature of the research by Niggli and many of his successful students, often referred to as the "Zürich school of crystallography" [3].
In 1932 Conrad Burri was appointed professor for special mineralogy and petrography, whereas Niggli continued lecturing on crystal structure, crystal physics and crystal chemistry. These courses, named 'general mineralogy', were compulsory for chemists during their first three semesters [4].
In collaboration with EMPA, X-ray equipment was installed. Since 1930 it was run by Ernst Brandenberger, who later became professor of materials science and testing, as well as a director of EMPA [4].
After the sudden death of Niggli at age 64, Fritz Laves, who had finished his thesis under Niggli, succeeded him from 1954 to 1976. He is best known for his work on the crystal structure of metals and alloys, where he was mainly interested in general structural principles from a crystal-chemical point of view, e.g. the 'Laves phases', intermetallic phases with composition AB2 [5].
The "Institute for Crystallography and Petrography" was strengthened by the appointment of two associate professors at UZ and ETH, Alfred Niggli (a pupil of Paul Niggli) in 1960 for crystal structure research and Walter Max Meier in 1966 for crystallography and mineral synthesis. Niggli, best known for his work in mathematical crystallography, was full professor from 1966 to his death in 1985. Meier was full professor 1973-1992; financially supported by Mobil Oil, he and his group determined the structure of many zeolites by powder diffraction.
The chemical institutes created their own chemical crystallography group, led with great success by Jack Dunitz from 1957 to 1990.
Bern
Zürich remained the unique center of crystallography until 1949, when Werner Nowacki [6], who had earned his doctorate under Paul Niggli with work on homogeneous space partitions into domains of influence, became professor in Bern. He founded the Section of Crystallography and Structural Studies. Feeling that the interests of crystallographers were not adequately represented by the "Swiss Society of Mineralogy and Petrology", he initiated the "Swiss Society for Crystallography" in 1968 and became its first president [7].
Nevertheless, Nowacki was very productive also in mineralogy by investigating the sulfosalt minerals found in the Lengenbach deposit in the valley of Binn. In order to determine the chemical composition of these often very small crystals he founded the Laboratory of Electron Microprobe Analysis in 1964.
When Hans-Beat Bürgi succeeded Nowacki in 1979, the Laboratory of Chemical and Mineralogical Crystallography was established. Bürgi's main interests are in static and dynamic structural chemistry, whereas research in mineralogical crystallography was continued by Thomas Armbruster and research in mathematical crystallography by Peter Engel. When Bürgi retired in 2007 (and became permanent academic guest at the organic chemistry institute of UZ) the Laboratory was split into the Laboratory for Mineralogical Crystallography led by Armbruster and the Laboratory for Chemical Crystallography led by Piero Macchi.
Crystallography in the French speaking part of Switzerland
Hans Schmid joined the Battelle Geneva Research Center in 1957, where he worked on the synthesis and potential applications of ferroelectrics, ferromagnetics and ferroelastics for display and data storage. In 1964 he synthesized a variety of boracites, in which he discovered for the first time, in collaboration with Edgar Ascher, the simultaneous occurrence and mutual coupling of ferroelectricity, ferromagnetism and ferroelasticity in the same phase [8]. From 1977 to 1996 Schmid was Professor of Applied Chemistry at the University of Geneva.
In Geneva, a chair of crystallography was created in 1970, headed by Erwin Parthé until his retirement in 1993 [9]. His main interests were alloys and intermetallics. He developed a standard presentation of inorganic crystal-structure data, which helps to recognize similar structures. The results were published in a four volume series "TYPIX Standardized Data and Crystal Chemical Characterization of Inorganic Structure Types”.
Klaus Yvon held a second chair 1982-2009. His main interests were new compounds for energy storage (metal hydrides) and energy conversion (superconductors, ferromagnets).
At present, Radovan Cerný is in charge of teaching crystallography and Céline Besnard runs a service of structure determination.
Dieter Schwarzenbach taught crystallography at the University of Lausanne first as lecturer, then 1973-2001 as professor. He is an expert for the determination of electron densities in crystals. Gervais Chapuis joined him in 1975 and was full professor 1991-2009. He investigated incommensurate structures by diffraction and molecular dynamics. They initiated and led a project for the construction of a beam line at the European Synchrotron Radiation Facility (ESRF) in Grenoble. This effort resulted in the Swiss-Norwegian Beam Lines (SNBL), which started operation in 1995. In 2003 the Institute of Crystallography was transferred from the university to EPFL. Two former members of the institute, Phil Pattison and Kurt Schenk, are now attached to the X-ray diffraction service of the EPFL Institute of Chemical Sciences and Engineering (ISIC).
Helen Stoeckli-Evans taught chemical crystallography at the University of Neuchâtel 1972-2009, moving up from lecturer to professor. From 1997 to 2006 she was responsible for the small molecule crystallography service BENEFRI of the universities of Berne, Neuchâtel and Fribourg. The service was reorganized in 2006 and is now run jointly by the Institute of Microtechnology of the University of Neuchâtel and the Swiss Center for Electronics and Microelectronics (CSEM) under the responsibility of Antonia Neels, a former collaborator of Helen Stoeckli.
At the University in Fribourg, the group of Katharina Fromm grows crystals and determines their structure for its research in the coordination chemistry of nano- and biomaterials.
Basel
Two years after the foundation of the "Biozentrum" of the University of Basel, Johan N. Jansonius started in 1973 as research group leader in the Department of Structure Biology. Prof. Jansonius retired in 1998. In 1997, Tilman Schirmer was promoted to Associate Professor in the above-mentioned department.
The Laboratory for Chemical Crystallography of the University of Basel started in 1980, led by Margareta Zehnder (Neuburger-Zehnder). It is now run by her husband Markus Neuburger, mainly as a service laboratory for structure determination.
Of course, important bio-crystallographic research was done in the pharmaceutical industry, e.g. by Markus Grütter, (a PhD student of Jansonius) at Ciba-Geigy (later Novartis) before he moved to UZ, or by Fritz Winkler at Hoffmann-LaRoche before he moved to ETH.
Newer developments in the Zürich area
When Walter Steurer was appointed Professor at UZ and ETH in 1993 after the retirement of Walter Max Meier, the institute was reorganized as "Laboratory of Crystallography"; it is now attached to the ETH department of materials. Steurer's main research fields are quasicrystals, their structure analysis and description and the interpretation of both Bragg and diffuse scattering. Research on zeolites and powder diffraction continues with Lynne McCusker and Christian Bärlocher.
With the appointment in 2010 of Nicola Spaldin as Professor of Materials Theory and in 2011 of Manfred Fiebig as Professor of Multifunctional Ferroic Materials, the department of materials has considerably strengthened its competence in developing new multifunctional materials.
Structure determination is done also in other departments of ETH. Michael Wörle is responsible for X-ray analysis in the Laboratory of Inorganic Chemistry led by Reinhard Nesper.
Timothy Richmond is 1987-2014 full professor for the Crystallography of Biological Macromolecules, Nenad Ban since 2007 for Molecular Structural Biology. Fritz Winkler (1999-2009) and Gebhart Schertler since 2010 professors for Structural Biology headed simultaneously the Biology Department at Paul Scherrer Institute (PSI).
The leading position in crystallography-related research of ETH in the German speaking area [10] is due to all these contributions.
Also the activities at UZ deserve mentioning: Coming from Novartis, Markus Grütter was 1997-2013 full professor for macromolecular structural biology. Anthony Linden manages the X-ray crystallographic facility at the organic chemistry institute.
In the laboratory of Alex Müller at the IBM Research Center in Rüschlikon, Georg Bednorz synthesized in 1974 perovskites (SrTiO3) for his diploma work. He obtained his doctorate at ETH under the supervision of Heini Gränicher and Alex Müller. Back at IBM, he and Müller synthesized oxides that they considered to be candidates for super¬conductivity. In 1986 they found in La1.85Ba0.15CuO4 a superconducting transition temperature Tc = 35 K, higher than the highest known Tc in metals. For this discovery, they received the Nobel Prize for physics in 1987 [11].
Anke Weidenkaff is head of the Laboratory for Solid State Chemistry and Catalysis at EMPA Dübendorf and teaches at the University of Bern. Alex Dommann, who applied X-ray diffraction to the characterization of coatings for industrial applications first at "Neutechnikum Buchs" and then at CSEM in Neuchâtel is now at EMPA St. Gallen.
The neutron sources at PSI [12]
Walter Hälg, since 1955 at ETH and full professor 1960-1984 started neutron scattering at the nuclear reactors SAPHIR and DIORIT of the Swiss Federal Institute for Reactor Research (EIR) in Würenlingen. The first instrument was a two-axis neutron diffractometer, used for single crystal studies of magnetic phase diagrams in external magnetic fields up to 6 Tesla. Albert Furrer was 1984-2004 head of the Laboratory for Neutron Scattering (LNS). In his period, EIR and the Swiss Institute for Nuclear Research (SIN) merged in 1988 to the Paul Scherrer Institute (PSI), and the Swiss Spallation Neutron Source SINQ was built and started operation in 1996. Successors of Furrer were Joël Mesot 2004-2008, who is now director of PSI and Professor at ETH and EPFL, Andrey Zheludev 2009-2010, now at ETH, and Christian Rüegg since 2011. Crystallographic research at LNS is done mainly in the diffraction group. Using the strong features of neutrons, Peter Fischer, group head until 2002, made important contributions to hydrogen storage in metals, the structure of high temperature superconductors and to magnetism. At present, the diffraction group at SINQ runs a single crystal neutron diffractometer and two powder diffractometers, one using thermal and the other cold neutrons. These instruments allow experiments in a wide range of temperatures, pressures and magnetic fields, e.g. for powders at temperatures between 50 mK and 1800 K, pressures up to 100 kbar, in magnetic fields up to 4 T. Dynamic properties of crystals are investigated in the spectroscopy group. This group operates five spectrometers. Some of its research topics are high temperature superconductors, critical phenomena in ferroelectrics, magnetism and colossal magnetoresistance.
Since 25 years, Switzerland is a member state of the Institut Laue-Langevin (ILL) in Grenoble; it also participates in the planning of the European Spallation Source (ESS) to be built in Lund, Sweden.
The synchrotron radiation source SLS at PSI
Switzerland is a member state also of the European Synchrotron Radiation Facility (ESRF) in Grenoble, which started operation in 1994, and is engaged, in particular, in running the Swiss-Norwegian Beamlines (SNBL), as mentioned above.
In order to satisfy the increasing demand of synchrotron light, the Swiss Light Source (SLS) was constructed at PSI. Research at the SLS started in 2001 under J. Friso van der Veen, who is also Professor of Experimental Physics at ETH 2000-2014. The SLS provides photon beams of high brightness for research in materials science, biology and chemistry. At present, 18 beamlines are in operational mode, using synchrotron radiation at wavelengths ranging from the VUV to the hard X-ray regime.
Four laboratories operate these beamlines, provide user support and do research of their own: "Macromolecules and Bioimaging" runs among others 3 beamlines dedicated to macromolecular crystallography, "Catalysis and Sustainable Chemistry" runs among others the PHOENIX beamline for X-ray microspectroscopic measurements (µ-XAS and µ-XRF), "Micro- and Nanotechnology" runs the X-ray Interference Lithography beamline. The various groups of "Condensed Matter and Materials Science", headed by Frithjof Nolting, operate 11 beamlines. At the MS beamline powder and surface diffraction techniques are used for research in condensed matter and materials science; at the two soft X-ray beamlines SIS and ADRESS the spectroscopy techniques ARPES and RIXS are used to investigate novel materials like high-temperature superconductors and low-dimensional magnets; the soft X-ray beamline SIM serves to study electronic and magnetic properties of thin films, multilayers, and bulk systems of metals and oxides; ultra-fast phenomena in solids are studied at beamline FEMTO using 100 fs X-ray pulses for diffraction or spectroscopy. Even shorter pulses will be available at the X-ray free-electron laser (SwissFEL) under construction at PSI.
The Swiss Society for Crystallography [7]
As mentioned above, the Swiss Society for Crystallography (SSCr) was founded in 1968 with Nowacki as its first president. The society included from its beginning members interested in crystal growth, which formed a section with activities of their own. Already in 1969, the SSCr was admitted as a member society of the 'Schweizerische Naturforschende Gesellschaft', the predecessor of the 'Swiss Academy of Sciences' (SAS). The SSCr is a member society of the International Union of Crystallography (IUCr) and of the European Crystallographic Association (ECA).
With financial support of the SAS, the SSCr produced a copiously illustrated brochure describing fascinating aspects of pure and applied crystallographic research in Switzerland. The German version 'Kristallographie in der Schweiz' appeared in 1999, the French version 'Cristallographie en Suisse' in 2001 [13].
In addition to many national meetings, the SSCr has organized several European meetings: A highlight for the society and its section was the organization of the 3rd European Crystallographic Meeting (ECM-3), immediately followed by the 1st European Conference on Crystal Growth, which both took place in Zürich in 1976. In 2006 the European Powder Diffraction Conference (EPDIC-10) was organized in Geneva and in 2016 ECM-30 will take place in Basel.
Table 1 shows the main officers of the SSCr. Until 2009 the chairman of the section for crystal growth acted as vicepresident of the society, until 1993 the secretary acted also as treasurer.
A majority of the SSCr officers were employed by a university, but also the Basel pharmaceutical industry is well represented with two presidents and with the treasurers from 1993 to 2010. The president Ascher worked at Battelle, the vicepresident Scheel was 1968-1982 at IBM Rüschlikon, 1989-2001 at EPFL, since 2001 self-employed. The growing importance of the neutron and synchrotron sources for crystallography is reflected by the fact that two of the SSCr presidents, the secretaries since 2002 and the editors of the 'SGK/SSCr Newsletter' since 1998, all work at PSI.
References:
[1] W. Steurer, Z. Kristallogr. 217 (2002) 267-272
[2] K. Mieleitner, Moritz Anton Cappelers Prodromus Crystallographiae, Piloty & Loehle, München, 1922
[3] J. J. Burckhardt, Die Symmetrie der Kristalle, Birkhäuser, Basel, 1988
[4] Eidgenössische Technische Hochschule 1855-1955, Buchverlag der NZZ, Zürich, 1955
[5] H. Jagodzinski, Fritz H. Laves 1906-1978, Acta Cryst. A35 (1979) 343
[6] P. Engel, Memorial of Werner Nowacki, March 14, 1909 - March 31, 1988, Am. Mineral. 74 (1989) 1394-1396
[7] V. Gramlich & H. Grimmer, The History of Crystallography in Switzerland, Chimia 55 (2001) 484-486
[8] H. Schmid, The Dice-Stone Der Würfelstein: Some Personal Souvenirs Around the Discovery of the First Ferromagnetic Ferroelectric, Ferroelectrics, 427 (2012) 1-33
[9] S. C. Abrahams & W. Jeitschko, Erwin Parthé (1928-2006), Acta Cryst. B63 (2007) 1-3
[10] U. Schmoch & A. Hullmann, Kristallforschung, Bild der Wissenschaft, 9/1999, 12-13
[11] J. G. Bednorz & K. A. Müller, Perovskite-type oxides - the new approach to high-Tc superconductivity, Nobel lecture (1987)
[12] P. Fischer, J. Schefer, L. Keller, O. Zaharko, V. Pomjakushin, D. Sheptyakov, N. Aliouane & M. Frontzek, 50 Years of Swiss Neutron Diffraction Instrumentation, Swiss Neutron News, 42 (2013) 4-15
[13] SGK-SSCr, Kristallographie in der Schweiz (1999), Cristallographie en Suisse (2001)
[Released: January 2014]