research papers The structure of denisovite, a fibrous IUCrJ nanocrystalline polytypic disordered ‘very complex’ ISSN 2052-2525 silicate, studied by a synergistic multi-disciplinary MATERIALSjCOMPUTATION approach employing methods of electron crystallography and X-ray powder diffraction Received 20 October 2016 Ira V. Rozhdestvenskaya,a Enrico Mugnaioli,b,c* Marco Schowalter,d Martin U. Accepted 14 February 2017 Schmidt,e Michael Czank,f Wulf Depmeierf* and Andreas Rosenauerd a Edited by A. Fitch, ESRF, France Department of Crystallography, Institute of Earth Science, Saint Petersburg State University, University emb. 7/9, St Petersburg 199034, Russian Federation, bDepartment of Physical Sciences, Earth and Environment, University of Siena, Via Laterino 8, Siena 53100, Italy, cCenter for Nanotechnology Innovation@NEST, Istituto Italiano di Tecnologia, Piazza Keywords: denisovite; minerals; fibrous San Silvestro 12, Pisa 56127, Italy, dInstitute of Solid State Physics, University of Bremen, Otto-Hahn-Allee 1, Bremen materials; nanocrystalline materials; electron D-28359, Germany, eInstitut fu¨r Anorganische und Analytische Chemie, Goethe-Universita¨t, Max-von-Laue-Strasse 7, crystallography; electron diffraction Frankfurt am Main D-60438, Germany, and fInstitute of Geosciences, Kiel University, Olshausenstrasse 40, Kiel tomography; X-ray powder diffraction; D-24098, Germany. *Correspondence e-mail:
[email protected],
[email protected] modularity; disorder; polytypism; OD approach; complexity; framework-structured solids; inorganic materials; nanostructure; Denisovite is a rare mineral occurring as aggregates of fibres typically 200– nanoscience. 500 nm diameter. It was confirmed as a new mineral in 1984, but important facts about its chemical formula, lattice parameters, symmetry and structure have CCDC references: 1532655; 1532656 remained incompletely known since then.