Feature article
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Crystallography in Norway

35 men and women from Norway are listed in the first edition of the World Directory of Crystallographers from 1957. That is a large number coming from a population of about 4 million at that time. The number listed increased to 76 in 1971 and has since decreased to 43 today. In 1957 some working with crystallography were not listed, and in the list to day several have retired. Furthermore, those listed in 1957 were mainly determining crystal structures from X-ray diffraction data. Today, those listed have a wider interest in crystallography.

I will, in this article, concentrate on the work done by Norwegians active in determining crystal structures – mostly the pioneers active in Norway up to about 1990. Two Norwegian crystallographers educated in Norway are included (Zachariasen and Hope), but they went to the USA where they worked for the rest of their lives, but kept contact with colleagues in Norway.

The dominating activity has been in Oslo. I have received information about the history of crystallography in other citiesin Norway from E. Sletten (Bergen, Norway), T. Dahl (Tromsø, Norway) and F. Mo (Trondheim, Norway). I am grateful for their cooperation and contributions.

Classical crystallography

[Peter Waage] Peter Waage

The study of the external shape of crystals, classical crystallography, started in Norway at the Royal Norwegian Mining School at Kongsberg in the 18th century with the Danish Professor M. T. Brünnich (1737-1827), director of the silver mines. He published a book about Norwegian minerals in 1777. P. Waage and H. Mohn wrote the first Norwegian textbook on crystal shapes in 1859. (Waage is known for his contribution to the law of mass action, also called Guldberg and Waage's law.)

[Oslo logo]

Crystallography at the University of Oslo

Department of Physics

[Lars Vegard] Lars Vegard

L. Vegard (1880-1963) was the pioneer in X-ray crystallography in Norway. He graduated with a master's degree from the Royal Frederik's U. (Oslo), then called Kristiania, the only university in Norway up to 1946. He worked as an assistant to K. Birkeland (1867-1917) on research connected with the Aurora Borealis. The spectrum of Northern Light became the main field of interest in his career, but he was also active in X-ray crystallography.

[Oslo campus] Central campus of the University of Oslo, where today only the faculty of law is located. Licensed under CC BY-SA 3.0 via Wikimedia Commons - http://commons.wikimedia.org/wiki/File:Universitetet_i_Oslo_sentrum.jpg#/media/File:Universitetet_i_Oslo_sentrum.jpg

In 1909 Vegard worked in the laboratory of W. Bragg (Leeds) and in 1911-1912 in the laboratory of W. Wien (Würzburg). In early June 1912 he attended a presentation by M. von Laue, who showed the sensational diffraction pictures that had been taken in Munich a few months earlier. Vegard wrote to Bragg and told him about 'certain new curious properties of X-rays' and included a copy of some of the pictures, inspiring the work by L. Bragg and his father W. Bragg.

Following his return to Norway, L. Vegard received his Dr. Philos. degree in 1913 with a dissertation on light emitted from canal rays. In 1918 he became the successor to Birkeland as full professor.

Vegard built his first X-ray diffractometer in 1914 and determined the crystal structure of silver. He started work on mixed crystals; von Laue mentioned this work in his Nobel Prize acceptance address in 1915. Vegard and about fifty of his graduate students worked in X-ray crystallography for thirty years. In 1920 Vegard published what has been called Vegard's law, 'The lattice constants of a mixed crystal vary linearly with the composition'. The law is still quoted in the literature.

Vegard also did pioneering low-temperature (liquid hydrogen) work, resulting in the determination of the crystal structures of a number of small-molecule substances that are gases at room temperature. Noteworthy among these are the structures of N2 and O2.

When a nuclear reactor was built at Kjeller just outside Oslo in the early 1950s, work was started to use neutrons for determining crystal structures. A. F. Andresen (1923-1991) began as a graduate student in physics at Kjeller and continued to work there the rest of his life. He used neutron diffraction to study the structure of magnetic compounds and was a pioneer in the study of the structures and properties of metal hydrides as potential materials for energy storage. For 15 years Andresen was a member of the Commission on Neutron Diffraction of the IUCr, three years as its Chairman. Another active researcher at Kjeller was the physicist Tormod Riste (1925-1996) working in solid-state physics.

None of Vegard's students continued working in crystallography. J. Gjønnes (1931-), who is the best-known Norwegian physicist in crystallography, belongs to a different tradition, from C. Finbak, H. Viervoll and N. Norman with connection to O. Hassel's group in physical chemistry (see below). In the early 1960s Gjønnes spent some time in J. Cowley's group in Melbourne. After returning to the U. of Oslo in 1965, Gjønnes established a group in electron microscopy and electron diffraction crystallography at the Dept. of Physics at the U. of Oslo. The experimental work covered a wide field of materials science. Theoretical studies included various aspects of dynamical electron diffraction: on symmetry, notably the so-called G-M (Gjønnes-Moodie) lines; methods for precise determination of structure factors, as well as the effects of dynamical diffraction on diffuse scattering and spectroscopic signals in electron microscopy. In recent years he has been engaged in developing the novel technique of precession electron diffraction as a practical tool for solving crystal structures. In 2008 his contributions to electron diffraction crystallography were recognized by a medal (named after him), of which he was the first recipient. Groups in Trondheim as well as in Oslo have continued the work in electron microscopy and electron crystallography. Gjønnes has been a member of the IUCr Commission on electron diffraction.

Mineralogy

[Victor Moritz Goldschmidt] Victor Moritz Goldschmidt

V. M. Goldschmidt (1888-1947) is the giant in Norwegian crystallography. He is the father of modern geochemistry and was proposed several times for the Nobel Prize in chemistry.

Goldschmidt was born in Zürich, but came to Norway at the age of thirteen. He learned classical crystallography from T. Hiortdahl (1839-1925) working in his private laboratory at Kristiania U. in 1906. Goldschmidt compared Hiortdahl to P. von Groth (1843-1927) and gave him credit for his systematic experimental work in chemical crystallography from 1862 to 1885, resulting in the introduction of the concept of partial isomorphism. Goldschmidt received his Dr. Philos. degree in 1911 when only 23 years of age. His dissertation was a monumental work on the geology of the Oslo region by showing that Gibbs' phase rule also applied in nature. Goldschmidt was appointed professor of crystallography, mineralogy and petrography and head of the Inst. of Mineralogy in 1914.

[Goldschmidt and Berner] V. M. Goldschmidt (right) teaching E. Q. Berner classical crystallography in 1915. Berner (1893-1983) later became professor of organic chemistry at UiO in 1934.

In 1920 the institute (and museum) moved to a new building at Tøyen on the outskirts of the city. There he formed a research group and started systematic studies of minerals, determining the composition from X-ray spectroscopy and the crystal structure by X-ray crystallography, using equipment built at the museum. The results were published from 1923 to 1938 in nine volumes on 'The geochemical laws of distribution of the elements' (German). A mineral is not a pure chemical compound, and Goldschmidt found that the main ions in a mineral could be substituted with other ions of the same size and charge. He determined the ionic radii (the Goldschmidt radii) that explained the lanthanide contraction.

Goldschmidt also inspired his students to go into X-ray crystallography. The best known of his students who founded their own schools in X-ray crystallography are W. H. Zachariasen (1906-1979), O. Hassel (1897-1981) and H. Haraldsen (1906-2001).

W. (Willie) Zachariasen grew up close to the Langesund fiord, known for its islands with many rare minerals. When he finished high school in 1923 he started his studies at the University and was selected as a member of Goldschmidt's research group. He received his Dr. Philos. degree in 1928 on crystal structure determinations of oxides – the youngest person to obtain a doctor's degree in Norway (only 22). He was a master of interpreting powder diagrams. After a year as a postdoctoral fellow with L. Bragg (Manchester), he joined the faculty of physics at the U. of Chicago. There he stayed for the rest of his life. He contributed significantly to the theory of X-ray diffraction, as reflected in his book, The Theory of X-Ray Diffraction in Crystals. Zachariasen is known for his work on the determination of the structures of many of the radioactive elements and compounds produced during the Manhattan project from 1940 and onwards.

The best known from Goldschmidt's group at Tøyen that continued with mineralogy and geology is T. Barth (1899-1971). He determined the structure of several inorganic compounds. From 1929-1936 he worked as a crystallographer in the Geophysical Laboratory in Washington. He succeeded Goldschmidt in 1937 and was head of the Museum of Geology and Mineralogy from 1949 to 1958.

Physical chemistry (structural chemistry)

[Odd Hassel and students] Odd Hassel (to the left) with a group of students going on an excursion in the summer of 1934.

O. Hassel (1897-1981) started his studies at the University in 1915 with Goldschmidt as his mentor. He wrote his Master's thesis on rates of certain chemical reactions, with H. Goldschmidt (1857-1937), the father of Victor, as his advisor. He went abroad to study at the K. Wilhelm Inst. in Berlin-Dahlem, where he learned X-ray diffraction, and obtained his Doctor's degree in 1924 at the Friedrich Wilhelms U. His closest advisor/colleague was H. Mark (1895-1992), later known as the father of polymer science.

In 1925 Hassel returned to the Laboratory of Chemistry in Oslo where new X-ray equipment awaited him. When Goldschmidt accepted a professorship in Göttingen, Hassel took over the laboratory at Tøyen, where he determined the crystal structure of several inorganic compounds, including graphite and the closely related boron nitride. In 1934 he published the book Kristallchemie in German that was translated into English and Russian. He became a full professor of physical chemistry the same year, the first such professorship in Norway.

[Cyclohexane 1]
[Cyclohexane 2] Illustrations from Odd Hassel's paper 'The Cyclohexane Problem' [Tidsskr. Kjemi. Borgv. Metallurgi, Bd 30, nr 5A, 18, Jun 1970] describing the stereochemistry of cyclohexane based upon his electron diffraction studies, for which he was awarded the Nobel prize in chemistry in 1969.

Hassel became interested in the structures of organic compounds, in particular cyclohexane and its derivatives, but the structures were too complex to be solved by X-ray crystallography in the 1930s. He measured dipole moments that could tell something about the symmetry of molecules and turned to electron diffraction as a method for determining the structure of organic molecules in the gas phase. He established a research group in physics and chemistry. The most prominent members were C. Finbak (1904-1954) and H. Viervoll (1914-2005). Finbak invented the rotating sector and was central in the construction of the first electron diffraction instrument in Oslo. He also used X-ray methods to study the rotation of ions in solids and the structure of liquids. Viervoll refined the computational methods for electron diffraction of gases and built the first electronic computer in Norway. The group in Oslo became a leader in the field of gas electron diffraction.

In the early 1940s Hassel and coworkers published the structures of cyclohexane and cyclohexane derivatives that earned Hassel the Nobel Prize in chemistry in 1969, shared with D. Barton (1918-1998).

In the 1950s, Hassel's group broke up into one group for electron diffraction studies of gases, one for X-ray diffraction of crystalline compounds and one on spectroscopy (IR, UV and Raman).

In his last ten years of active research, together with his students, Hassel began to study charge-transfer compounds. The first structures, compounds of dioxane and bromine and of dioxane and HgCl2, were determined by J. Hvoslef (1926-1986), and compounds of aliphatic amines and halogens were determined by K. Olaf Strømme (1929-). These studies showed that the structures of the charge-transfer compounds are quite different from the structures proposed earlier by the spectroscopist R. Mulliken (1896-1986). Hvoslef received his Dr. Philos. degree in 1972 and went on to use neutron diffraction at Kjeller to determine H-atom positions. Strømme obtained his degree on structural aspects of molecular disorder in 1974. Both worked as lecturers at the department for the rest of their professional lives.

Due to the low melting points of some of the charge-transfer compounds, the X-ray diffraction group in Oslo had to develop methods for collecting data at low temperatures, first using a Weissenberg camera, and later manual and automatic diffractometers.

The best known of Hassel's students working with X-ray crystallography are S. Furberg, C. Rømming, B. Fjærtoft Pedersen, T. Dahl and H. Hope.

[Furberg and student] Sven Furberg showing a student how the diffractometer works.

S. Furberg (1920-1983) is famous for the determination of the structure of cytidine in 1948. He also proposed models for DNA that contributed to the Watson and Crick model in 1953. His best-known students are A. Hordvik (see below) and A. Mostad (1929-), who determined the crystal structures of several organic molecules of biological interest including L-dopa. Mostad worked together with Christian Rømming for many years, and has written a series of popular articles in Norwegian on elements and simple chemicals.

C. Rømming (1928-) introduced new equipment and new methods for handling crystallographic data in Oslo from Hassel's time in the 1950s to long into his own retirement years.

E. Wang Lund (1919-1979), the first to use Fourier methods in Norway, learned about them in Gunnar Hägg's laboratory in Uppsala in 1948. After 1960 he concentrated on teaching and writing textbooks.

[Berit Pedersen et al] Berit Pedersen, Henk Schenk, Peter Paufler, Yvonne Mascarenhas at the 1990 IUCr Congress and General Assembly in Bordeaux, France.

B. Fjærtoft Pedersen (1933-) worked at the Central Inst. of Industrial Research and became the first woman crystallographer in Norway when she was awarded the Dr. Philos. degree for the elucidation of the structure of perhydrates in 1969. She returned to the Dept. of Pharmacy at the university in 1972 where she concentrated on determining the crystal structures of drugs and imaging compounds.

[Hakon Hope] Håkon Hope

H. Hope (1930-), after receiving his Cand. Real. degree in 1958, stayed on as an assistant to O. Hassel, working on charge-transfer compounds. In 1961 he received a Fulbright fellowship and spent two years at UCLA with J. D. McCullough and K. N. Trueblood. In 1965 he accepted a professorship at the Dept. of Chemistry, U. of California, Davis. Hope advanced the accuracy of diffractometry to optimize the information obtainable from diffraction data. He used the anomalous scattering from oxygen to determine the absolute configurations of molecules, and pursued the accurate measurement of electron densities and the determination of molecular geometries free of valence electron distortions. During a visit to the U. of Oslo, he developed equipment and techniques that facilitated diffraction measurements at liquid nitrogen temperatures.

In Davis in 1972, low-temperature measurements became the standard mode of operation for everyday structure determination. An important mission was to advance X-ray crystallography as a rapid, first-choice analytical method. Before area detectors, same-day structure service had become commonplace in Davis. To help study extremely reactive compounds, Hope developed methods that allowed simple, open-air manipulation of reactive or low-melting crystals. He modified these methods for use with biocrystals, first demonstrating their utility with small proteins, and then by showing that low-temperature diffraction data could be obtained from crystals of ribosome particles. The winners of the 2009 Nobel Prize in Chemistry used the methods with advantage. Hope was a coeditor of Acta Crystallographica (1984-1993) and received an honorary degree at the U. of Oslo in 1994.

T. Dahl (1938-) was Hassel's last graduate student. He graduated in 1963 and after some years as Hassel's research assistant he went to the U. of Tromsø, where he was awarded the Dr. Philos. degree in 1976 for his structure determinations of addition compounds between hexafluorobenzene and methylated benzenes. His later work comprises structure determinations of various addition compounds and substituted adeninium compounds.

Inorganic chemistry (solid-state chemistry)

H. Haraldsen established a research tradition that is still active at the Dept. of Chemistry at the U. of Oslo. Haraldsen worked as an assistant to Goldschmidt and wrote his Master's thesis on an X-ray and thermal analysis of two minerals. In 1932 he received his Doctor's degree with W. Biltz (1877-1943) in Göttingen on the thermal analysis of three phosphides. He studied magnetochemistry in Danzig with W. Klemm (1896-1985). Klemm was interested in transition metal chalcognides, an interest that occupied Haraldsen for the rest of his life. (The term chalcognides for the elements in group 16 in the periodic table was coined in Klemm's group in Danzig.)

In 1936 Haraldsen returned to Oslo where he became a full professor, succeeding the radiochemist E. Gleditsch (1879-1968). He established the second X-ray diffraction laboratory at the Dept. of Chemistry. Haraldsen was head of the division of general and inorganic chemistry, which is a section in the department. He built up laboratories for the high-temperature synthesis of chalcogenides, did phase analysis of d-metal/chalcogenide systems, determined the structures of the phases discovered by X-ray diffraction, and measured their magnetic, electric and thermal properties. He and his co-workers, F. Grønvold (1924-) and A. Kjekshus (1932-), guided graduate students who determined a number of crystal structures by X-ray diffraction. Some of these students are still active in the department, now called material or nano sciences. The current leaders are H. Fjellvåg (1954-) and S. Stølen (1960-).

The successor to Haraldsen in 1976 was P. Kofstad (1929-1997) who is known for his work on the defect structures of transition metal oxides. He wrote textbooks and studied high-temperature corrosion and the structure of non-stoichometric compounds. This work is carried forward today by T. Norby(1955-).

Department of Chemistry, UiO today

In 2003 the research in the department was reorganized into two sections: Section A, Life sciences chemistry, and Section B, Functional materials chemistry. Both sections have X-ray diffraction laboratories. The laboratory in A studies single crystals and in B mainly powders.

[Carl Henrik Gorbitz] Carl Henrik Gørbitz

Early attempts by C. Henrik Gørbitz (1961-) to start protein crystallography were not very successful. The activity was expanded when U. Krengel (1964-) joined section A in 2004. She took her PhD in Heidelberg in the group of K. Holmes at the Max-Planck-Inst. for Medical Research (1988-1991; supervisor: E. Pai). As a postdoc she worked in Toronto with Pai and in Groningen with B. Dijkstra. In 1997, Krengel moved to Chalmers U. of Technology in Gothenburg where she established her own group focusing on protein-carbohydrate interactions. In Oslo she has set up an entire production line from gene cloning to final refined structure. Structures solved include those of anti-tumour antibodies, bacterial toxins, mushroom lectins and chorismate mutases, and work is being extended to include membrane proteins and large glycoproteins such as the human mucins. All projects involve international collaborations, with scientists from Sweden, Switzerland (ETH), Cuba and the USA.

Crystallography at the University of Bergen

[Bergen logo]

The U. of Bergen was established in 1946. O. Foss (1918-2007) introduced X-ray crystallography when he was appointed professor of chemistry in 1955. He had used the method in his pioneering work on establishing the un-branched structure of the sulphur chains in polythionates. Later his research also encompassed the chemistry and structure of divalent selenium and tellurium compounds, and he was the first to study the structures of tellurium(II) complexes with ligands like thiourea, thiocyanates etc.

During the first two decades after Foss' arrival in Bergen the group of structural chemists grew steadily, the majority of its members working mainly on compounds of sulphur, selenium and tellurium. A. Hordvik (1928-1995) and his students were scientifically very productive in this group, especially in the study of cyclic dithioles and thiathiophthenes and thiathiophthene analogues. In 1974 Hordvik left Bergen to establish new activity at the U. of Tromsø (see below). S. Husebye (1933-), after obtaining his PhD from Tulane U., returned to Bergen where he studied a variety of chalcogen compounds, with special attention on highly coordinated tellurium(IV) complexes. K. Marøy (1930-) collaborated extensively with Olav Foss for a long period, and in later years worked on salts of selenates and tellurates together with S. Hauge (1932-). K. Maartmann-Moe (1928-) joined the group in 1965 and became the manager of the X-ray laboratory equipment when the first single-crystal diffractometer was purchased in 1968, a responsibility he held until his retirement in 1995.

The scope of structural chemistry in Bergen was gradually broadened to include work on transition metal complexes. In 1967 E. Sletten (1939-) started studies on transition metal complexes of DNA components (nucleobases, nucleosides and nucleotides) and was the first to publish crystal structures of such complexes. He later continued studying this type of compound in solution employing NMR techniques. J. Sletten (1941-), after completing her doctoral work on structure and bonding in higher homologues of thiathiophthenes, turned to the field of transition metal chemistry, with emphasis on the study of di- and polynuclear complexes showing ferro- orantiferromagnetic interaction.

Today the crystallographic facilities at the Dept. of Chemistry are excellent, with modern single-crystal and powder diffractometers. K. W. Törnroos (1956-), who came to Bergen from Stockholm U. in 1996, is presently the sole crystallographer. Törnroos has been engaged in a wide range of crystallographic projects, one of the key subjects being the study of spin-crossover phenomena.

Crystallography at the University of Tromsø

[Tromso logo]
[Hordvik, King] Asbjørn Hordvik and Jim King, then IUCr Executive Secretary.

The University in Tromsø was established in 1968. The pioneer in X-ray crystallography in Tromsø was A. Hordvik, who was a student of Sven Furberg while he was at the U. of Bergen. Hordvik established the first protein crystallography laboratory in Norway. He was Secretary-Treasurer of the IUCr from 1986 until he died. The leadership of the protein crystallography group was later taken over by E. Hough and A. Smalås, and the laboratory now has status as a national centre for structural biology.

Crystallography at the University of Trondheim

[NTNU logo]

In Trondheim, crystallography was studied in the Dept. of Physics at the Technical U. established in 1910 (today called the Norwegian U. of Science and Technology, NTNU). H. Brækken started the first X-ray diffraction studies of crystals in 1926, but it was H. Sørum (1915-1995) who established X-ray crystallography as a field of its own in Trondheim. He learned crystallography in the group of W. L. Bragg in 1947-1949 and received his Doctor's degree in Trondheim in 1952 on a study of some feldspars. He taught crystallography, designed equipment and did research on molecular structure, diffraction physics, disorder, defect structures, interdiffusion in metallic materials and topography at NTNU until his retirement in 1982.

[Fauque, Mo, Frey] Guy Fauque, Frode Mo, Michel Frey at the Lyle H. Jensen Symposium in 1986.

The best known of his students is F. Mo (1937-). He has determined accurately the structure and charge density in small organic S-containing molecules, and the structure of biologically important molecules. He has studied multiple scattering, used synchrotron radiation in materials studies, and studied structural phase transitions and ferroelectric compounds, including epitaxial thin films, under electric fields. A particularly interesting line of research was the development of the physical estimation of structure-factor phases from three-beam interference in non-perfect crystals as a novel method for initiating the determination of macromolecular structure and for studies of subtle structural changes.

In 1989, together with his colleague in the Dept. of Chemistry, D. Nicholson, Mo initiated collaboration with Swiss scientists for the purpose of constructing and operating a joint bending-magnet beamline, which later became the Swiss-Norwegian Beamlines (SNBL) at the ESRF.

In 1972, R. Høier (1938-2009) was appointed Associate Professor in Sørum's group. He was a student of J. Gjønnes in Oslo. A significant part of the work done in Høier's group was devoted to studies of metallic materials and ceramics. His main interests were in dynamic diffraction theory, many-beam effects and electron crystallography.

In 1983, E. J. Samuelsen (1937-) was appointed the successor of H. Sørum. His research has been focused on studies of the structure and properties of materials, including partially disordered materials, low-dimensional systems, in particular organic chains and layers with semiconducting properties, phase transitions, lattice vibrations and magnetism. He has used neutron-, light- and X-ray scattering in his work.

Bjørn Pedersen

The author

[Bjorn Pedersen] Bjørn Pedersen

The author of this article graduated in 1958 from Haraldsen's research group after discovering two new subsulfides of vanadium and determining the crystal structure of them. After graduation he worked for a short time as an assistant to Furberg trying to solve the structure of β-glucose. He then left the field of X-ray crystallography to work with solid-state NMR, where knowledge of crystallography also turned out to be useful, and became a professor of chemistry at UiO from 1970 to 2003 when he retired. Since then he has written articles and contributed to books on the history of chemistry in Norway. (bjornp@kjemi.uio.no).