Direct- and reciprocal space structure modelling: Contributions to the advanced understanding of inclusion compounds
Keywords:
space structure modelling, thiourea-ferrocene inclusion compound, TFIC, crystallographySynopsis
The main content of this thesis falls naturally into one of two parts. The chapters come in an order which follows the research development, but encapsulates single topics enough to allow the reader some flexibility. In short, this work concerns the study of one particular inclusion compound, and all the programming utilities that have been developed in an attempt to tackle this structure as well as others like it. We have sought to gather more details about what happens to the structure in the midst of a chaotic phase transition. This has been done by a non-standard approach of diligent entity construction, seeking to bring a model to perfection by invoking direct space modelling with reciprocal space validation. The idea is simple, but has proven more difficult to conduct to an end.
Part I comprises the structural information and data analysis of the central analysis subject: the thiourea-ferrocene inclusion compound (TFIC). It is divided into chapters with a logical progression: starting with a background on host–guest inclusion complexes and details on the TFIC from the literature in Chapter 1. Then, our experimental details and qualitative investigation is compiled in Chapter 2. The next step is data reduction and structure solutions, covered in Chapter 3. Some background theory and information on twinning is covered in Appendix A.
Part II starts off with a presentation of the developed Mathematica package in Chapter 4. The reader will learn what it is and how it may serve as a utility in the field of crystallo- graphy. Its origin, functionality and purpose will be examined in a summary of its two articles. The subject of model construction will be emphasised, and the thesis will cul- minate with demonstrations of its capability in Chapter 5 where models are tailored to the specific TFIC system. The associated simulations of the diffraction patterns are com- pared with experimental counterparts in order to ascertain what characteristics may be ascribed to the structure during the prominent phase transition; discussions that bring the separate topics together are made in the concluding Chapter 6, which summarises the most important findings on the TFIC.
The following work (published, or to be published) comprises this thesis, listed chronologically:
- Stian Ramsnes, Helge Bøvik Larsen and Gunnar Thorkildsen. ‘Using Mathematica as a platform for crystallographic computing’. In: Journal of Applied Crystallography 1 (Feb. 2019), pp. 214–218. doi: 10.1107/S1600576718018071 (see page 156)
- Stian Penev Ramsnes, Helge Bøvik Larsen and Gunnar Thorkildsen. ‘MaXrd up- dated with emphasis on model construction and reciprocal-space simulations’. In: Journal of Applied Crystallography 53.6 (Dec. 2020), pp. 1620–1624. doi: 10 . 1107/ S160057672001328X (see page 161)
- Stian Penev Ramsnes et al. ‘Complementary Synchrotron Diffraction and Simula- tion Studies on a Ferrocene:Thiourea Inclusion Compound’. To be 2022
The first paper concerns the release of the Mathematica X-ray diffraction package (MaXrd). In essence, it contains point- and space group information from the International Tables for Crystallography and tabulated data on scattering factors and cross sections, required for calculations related to X-ray physics. Included are also functions to utilise this data, with a documentation demonstrating their usage. Highlighted functionality includes ex- traction of symmetry data, data import from cif files, calculations of structure factors, linear absorption coefficients and unit cell transformations.
The second article was submitted once a practical structure modelling extension had been sufficiently generalised. The imported cif data could now be employed to create and visualise crystal structures. Many additions depended on the original symmetry-related foundation, but a few brought novel concepts into the package, such as the function for making domains. The focus on model construction was motivated by the study of a host– guest complex, hence the ability to embed one crystal entity into another. With the possibility to simulate the diffraction patterns (reciprocal space maps), a way of comparing a customised structure with experimental data was realised.
The third article conveys our findings on the thiourea–ferrocene inclusion compound. Complementary studies have been conducted in three areas: qualitative exploration of reciprocal space, quantitative structure solutions of synchrotron data and various model investigations with the MaXrd utility package in Mathematica. We discuss both support- ing evidence and shortcomings of the prevalent high- and low-temperature phases of the TFIC structure.
It is said that if you’re unable to provide a clean and short explanation on a subject, you don’t understand it well enough. In any case, capturing the thesis in a single sentence is a good exercise. Since the first part is about method development, a conclusive remark does not fit as much as for the second part, for which a fitting and simplistic one-liner conclusion for the layman may be:
The cold makes the guest molecules inside the honeycomb network halt their motion and shatters the neat pattern, but heating it makes everything fine again, even if the crystal was a twin to begin with.
References
[2] Takanao Asahi, Katsuhiko Hasebe and Akira Onodera. 'Crystal Structure of the High Pressure Phase VI of Thiourea'. In: Journal of The Physical Society of Japan - J PHYS SOC JPN 69 (Sept. 2000), pp. 2895-2899. doi: 10.1143/JPSJ.69.2895 (cit. on p. 23).
https://doi.org/10.1143/JPSJ.69.2895
[3] Jerry L. Atwood and Jonathan W. Steed, eds. Encyclopedia of Supramolecular Chemistry. Marcel Dekker Inc, 2004 (cit. on pp. 22-24).
https://doi.org/10.1081/E-ESMC
[4] S. W. Bailey et al. 'Report of the International Mineralogical Association (IMA)-International Union of Crystallography (IUCr) Joint Committee on Nomenclature'. In: Acta Crystallographica Section A 33.4 ( July 1977), pp. 681-684. (cit. on p. 143).
https://doi.org/10.1107/S0567739477001703
[5] Jean-François Berár et al. 'New low-temperature crystalline phase of ferrocene: Isomorphous to orthorhombic ruthenocene'. In: The Journal of Chemical Physics 73.1 ( July 1980), pp. 438-441. (cit. on p. 21).
https://doi.org/10.1063/1.439894
[6] J.S. Bodenheimer and W. Low. 'An experimental study of the phase transition in ferrocene'. In: Physics Letters A 36.4 (1971), pp. 253-254. (cit. on p. 20).
https://doi.org/10.1016/0375-9601(71)90494-4
[7] Robert K. Bohn and Arne Haaland. 'On the molecular structure of ferrocene, Fe(C5H5)2'. In: Journal of Organometallic Chemistry 5.5 (1966), pp. 470-476. (cit. on p. 21).
https://doi.org/10.1016/S0022-328X(00)82382-7
[8] Robert W. Cahn and Peter Haasen, eds. Physical Metallurgy. 4th ed. Amsterdam: Elsevier Science, 1996 (cit. on p. 142).
[9] Stuart Cantrill. An iron-clad structure. July 2014. doi: https://doi.org/10.1038/nature13357. url: http://www.nature.com/milestones/milecrystal/full/milecrystal10.html (visited on 24/04/2016) (cit. on p. 19).
[10] S. Carter and J.N. Murrell. 'The barrier to internal rotation in metallocenes'. In: Journal of Organometallic Chemistry 192.3 (1980), pp. 399-408. (cit. on p. 20).
https://doi.org/10.1016/S0022-328X(00)81232-2
[11] M. Catti and G. Ferraris. 'Twinning by merohedry and X-ray crystal structure determination'. In: Acta Crystallographica Section A 32.1 ( Jan. 1976), pp. 163- 165. (cit. on p. 140).
https://doi.org/10.1107/S0567739476000326
[12] E. J. Chan and D. J. Goossens. 'A method to perform modulated structure studies using the program ZMC'. In: Journal of Applied Crystallography 50.6 (Dec. 2017), pp. 1834-1843. (cit. on pp. 88, 91).
https://doi.org/10.1107/S1600576717015023
[13] Y. Chatani, Y. Taki and H. Tadokoro. 'Low-temperature form of urea adducts with n-paraffins'. In: Acta Crystallographica Section B 33.1 ( Jan. 1977), pp. 309-311. (cit. on p. 110).
https://doi.org/10.1107/S0567740877003501
[14] Rene Clement, Renee Claude and Charles Mazieres. 'Clathration of ferrocene and nickelocene in a thiourea host lattice'. In: J. Chem. Soc., Chem. Commun. (16 1974), pp. 654-655. (cit. on pp. 23, 27, 28).
https://doi.org/10.1039/c39740000654
[15] R. Clément et al. 'Phase changes and molecular motion in the thiourea‐cyclohexane inclusion compound'. In: The Journal of Chemical Physics 67.11 (1977), pp. 5381-5385. (cit. on pp. 28, 29, 73, 132).
https://doi.org/10.1063/1.434645
[16] A. Desmedt et al. 'Phase transitions and molecular dynamics in the cyclohexane/thiourea inclusion compound'. In: Phys. Rev. B 64 (5 July 2001), p. 054106. (cit. on pp. 29, 30, 132).
https://doi.org/10.1103/PhysRevB.64.054106
[17] Oleg V. Dolomanov et al. 'OLEX2: a complete structure solution, refinement and analysis program'. In: Journal of Applied Crystallography 42.2 (Apr. 2009), pp. 339-341. (cit. on pp. 57, 60).
https://doi.org/10.1107/S0021889808042726
[18] Michael G. B. Drew, Astrid Lund and David G. Nicholson. 'Molecular Modelling Studies on the Thiourea/ Ferrocene Clathrate'. In: Supramolecular Chemistry 8.3 (1997), pp. 197-212. (cit. on pp. 23, 26, 28, 97).
https://doi.org/10.1080/10610279708034937
[19] Jack David Dunitz and L. E. Orgel. 'Bis-cyclopentadienyl Iron: a Molecular Sandwich'. In: Nature 171.4342 (1953), pp. 121-122 (cit. on p. 19).
https://doi.org/10.1038/171121a0
[20] Jack David Dunitz, L. E. Orgel and A. Rich. 'The crystal structure of ferrocene'. In: Acta Crystallographica 9.4 (Apr. 1956), pp. 373-375. (cit. on pp. 19, 20).
https://doi.org/10.1107/S0365110X56001091
[21] S. Durovic, P. Krishna and D. Pandey. 'Layer stacking'. In: Mathematical, Physical and Chemical Tables. Ed. by Edward Prince. 3rd ed. Vol. C. International Tables for Crystallography. Springer, 2004. Chap. 9.2, pp. 752-773. (cit. on p. 142).
https://doi.org/10.1107/97809553602060000103
[22] Vadim Dyadkin et al. 'A new multipurpose diffractometer PILATUS@SNBL'. In: Journal of Synchrotron Radiation 23.3 (May 2016), pp. 825-829. (cit. on p. 34).
https://doi.org/10.1107/S1600577516002411
[23] J. W. Edwards, G. L. Kington and R. Mason. 'The thermodynamic properties of ferrocene. Part 1.-The low-temperature transition in ferrocene crystals'. In: Trans. Faraday Soc. 56 (0 1960), pp. 660-667. (cit. on p. 20).
https://doi.org/10.1039/TF9605600660
[24] Philip Frank Eiland and Ray Pepinsky. 'X-Ray Examination of Iron Biscyclopentadienyl'. In: Journal of the American Chemical Society 74.19 (Oct. 1952), pp. 4971-4971. (cit. on p. 19).
https://doi.org/10.1021/ja01139a527
[25] Helmut Föll. Defects in Crystals. url: https://www.tf.uni-kiel.de/matwis/amat/def_en/index.html (visited on 10/2019) (cit. on pp. 142, 143).
[26] Georges Friedel. Leçons de Cristallographie. Paris: Berger-Levrault, 1926 (cit. on p. 139).
[27] T C Gibb. 'Anisotropic relaxation of the electric field gradient tensor in the 57 Fe Mossbauer spectra of a thiourea-ferrocene clathrate'. In: Journal of Physics C: Solid State Physics 9.13 ( July 1976), pp. 2627-2642. (cit. on pp. 25-27, 127).
https://doi.org/10.1088/0022-3719/9/13/022
[28] D. J. Goossens et al. 'Monte Carlo Modelling of Diffuse Scattering from Single Crystals: The Program ZMC'. In: Metallurgical and Materials Transactions A 42 (2011), pp. 23-31. (cit. on p. 115).
https://doi.org/10.1007/s11661-010-0199-1
[29] Arne Haaland and J.E. Nilsson. 'The Determination of Barriers to Internal Rotation by Means of Electron Diffraction. Ferrocene and Ruthenocene'. In: Acta Chemica Scandinavica 22 (1968), pp. 2653-2670. (cit. on p. 21).
https://doi.org/10.3891/acta.chem.scand.22-2653
[30] Theo Hahn, ed. Space-Group Symmetry. 5th. Vol. A. International Tables for Crystallography. Kluwer Academic Publishers, 2002 (cit. on p. 73).
[31] Theo Hahn and H. Klapper. 'Twinning of crystals'. In: Physical Properties of Crystals. Ed. by Edward Prince. 2nd ed. Vol. D. International Tables for Crystallography. Wiley, 2013. Chap. 3.3, pp. 413-483. (cit. on pp. 138, 139, 141, 143).
https://doi.org/10.1107/97809553602060000113
[32] Kenneth D. M. Harris. 'Towards a Fundamental Understanding of Urea and Thiourea inclusion Compounds'. In: Journal of the Chinese Chemical Society 46.1 (1999), pp. 5-22. (cit. on pp. 24, 27, 72, 91, 132).
https://doi.org/10.1002/jccs.199900002
[33] Kenneth D.M. Harris. 'Investigation of a time-dependent "nondiscrete" component of X-ray scattering from monohalocyclohexane/thiourea inclusion compounds'. In: Journal of Solid State Chemistry 84.2 (1990), pp. 280-288. (cit. on p. 30).
https://doi.org/10.1016/0022-4596(90)90326-S
[34] Frank H. Herbstein. Crystalline Molecular Complexes and Compounds: Structures and Principles. Oxford University Press, 2005 (cit. on pp. 22-24).
[35] Stephen J. Heyes, Nigel J. Clayden and Christopher M. Dobson. 'Ferrocene molecular reorientation in the (thiourea)3-ferrocene inclusion compound as studied by deuteron NMR spectroscopy'. In: The Journal of Physical Chemistry 95 (Feb. 1991), pp. 1547-1554. (cit. on pp. 23, 26, 27, 97, 127).
https://doi.org/10.1021/j100157a009
[36] Mark D. Hollingsworth et al. 'Memory and Perfection in Ferroelastic Inclusion Compounds'. In: Crystal Growth & Design 5.6 (Nov. 2005), pp. 2100-2116. (cit. on p. 114).
https://doi.org/10.1021/cg050347j
[37] Edward Hough and David G. Nicholson. 'X-Ray crystallographic studies on ferrocene included in a thiourea host lattice'. In: J. Chem. Soc., Dalton Trans. (1 1978), pp. 15-18. (cit. on pp. 22, 26-28, 34, 98, 110, 132).
https://doi.org/10.1039/dt9780000015
[38] Jürg Hulliger, Olaf König and Ralf Hoss. 'Polar inclusion compounds of perhydrotriphenylene (phtp) and efficient nonlinear optical molecules**'. In: Advanced Materials 7.8 (1995), pp. 719-721. (cit. on p. 23).
https://doi.org/10.1002/adma.19950070807
[39] Matthew J. Jones, Ian J. Shannon and Kenneth D. M. Harris. 'Temperature-dependent structural properties of the chlorocyclohexane/thiourea inclusion compound investigated by synchrotron X-ray powder diffraction'. In: J. Chem. Soc., Faraday Trans. 92 (2 1996), pp. 273-279. (cit. on pp. 28, 29, 73, 132).
https://doi.org/10.1039/ft9969200273
[40] Thomas J. Kealy and Peter L. Pauson. 'A New Type of Organo-Iron Compound'. In: Nature 168.4285 (1951), pp. 1039-1040. (cit. on p. 19).
https://doi.org/10.1038/1681039b0
[41] H. Klapper and Th. Hahn. 'The application of eigensymmetries of face forms to X-ray diffraction intensities of crystals twinned by 'reticular merohedry''. In: Acta Crystallographica Section A 68.1 ( Jan. 2012), pp. 82-109. (cit. on pp. 48, 49, 141, 142).
https://doi.org/10.1107/S0108767311032454
[42] Thomas Kluyver et al. 'Jupyter Notebooks - a publishing format for reproducible computational workflows'. In: Positioning and Power in Academic Pub- lishing: Players, Agents and Agendas. Ed. by Fernando Loizides and Birgit Scmidt. Netherlands: IOS Press, 2016, pp. 87-90 (cit. on p. 79).
[43] Donald E. Knuth. 'Computer Programming as an Art'. In: Commun. ACM 17.12 (Dec. 1974), pp. 667-673. (cit. on p. viii).
https://doi.org/10.1145/361604.361612
[44] E. Koch. 'Twinning'. In: Mathematical, Physical and Chemical Tables. Ed. by Edward Prince. 3rd ed. Vol. C. International Tables for Crystallography. Springer, 2004. Chap. 1.3, pp. 10-14. (cit. on pp. 139, 140, 142).
https://doi.org/10.1107/97809553602060000103
[45] N. R. Kunchur and Mary R. Truter. '517. A detailed refinement of the crystal and molecular structure of thiourea'. In: J. Chem. Soc. (0 1958), pp. 2551-2557. (cit. on p. 23).
https://doi.org/10.1039/jr9580002551
[46] Logan C. Lorson, Onkei Tai and Bruce M. Foxman. 'Use of Topotactic Phase Transformations To Obtain Solutions of the Crystal Structures of Highly Disordered Materials'. In: Crystal Growth & Design 18.1 (2018), pp. 409-415. (cit. on pp. 24-28, 64-66, 71, 72, 97, 110, 131).
https://doi.org/10.1021/acs.cgd.7b01406
[47] Michael D. Lowery et al. 'Dynamics of ferrocene in a thiourea inclusion matrix'. In: Journal of the American Chemical Society 112.11 (May 1990), pp. 4214- 4225. (cit. on pp. 25-27, 91, 97).
https://doi.org/10.1021/ja00167a017
[48] T. Maris et al. 'Investigations of the Phase Transitions in Thiourea Inclusion Compounds with Cycloheptane, Cyclooctane, and Cyclooctanone'. In: Chemistry of Materials 13.8 ( July 2001), pp. 2483-2492. (cit. on pp. 28, 29, 100, 132).
https://doi.org/10.1021/cm991173u
[49] Samuel A. Miller, John A. Tebboth and John F. Tremaine. '114. Dicyclopentadienyliron'. In: J. Chem. Soc. (0 1952), pp. 632-635. (cit. on p. 19).
https://doi.org/10.1039/jr9520000632
[50] Annibale Mottana et al., eds. Micas: Crystal Chemistry & Metamorphic Petrology. Berlin, Boston: De Gruyter, 2018. doi: https : //doi.org/10.1515/9781501509070 (cit. on pp. 48, 139, 140, 142).
[51] Peter Müller et al. Crystal Structure Refinement: A Crystallographer's Guide to SHELXL. Ed. by Peter Müller. Oxford University Press, 2010 (cit. on p. 61).
[52] T. Nakai et al. 'A 13C NMR study of the dynamic structure of the thiourea-ferrocene inclusion compound'. In: Chemical Physics Letters 132.6 (1986), pp. 554-557. (cit. on pp. 26, 27, 97).
https://doi.org/10.1016/0009-2614(86)87123-8
[53] M. Nespolo, T. Kogure and G. Ferraris. 'Allotwinning: oriented crystal association of polytypes - some warnings on consequences'. In: Zeitschrift für Kristallographie - Crystalline Materials 214.1 (1Jan. 1999), pp. 5-8. (cit. on pp. 140, 142, 143).
https://doi.org/10.1524/zkri.1999.214.1.5
[54] M. Nespolo et al. 'Plesiotwinning: oriented crystal associations based on a large coincidence-site lattice'. In: Zeitschrift für Kristallographie - Crystalline Materials 214.7 (1Jul. 1999), pp. 378-382. (cit. on pp. 48, 140, 143).
https://doi.org/10.1524/zkri.1999.214.7.378
[55] Massimo Nespolo. MaThCryst: Crystal twinning - International Union of Crystallography, Commission on Mathematical and Theoretical Crystallography. url: http://www.crystallography.fr/mathcryst/twins.htm (visited on 03/02/2009) (cit. on p. 142).
[56] Massimo Nespolo. 'Plesiotwins versus diperiodic twins'. In: Acta Crystallographica Section A 74.4 ( July 2018), pp. 332-344. (cit. on pp. 138, 140, 143).
https://doi.org/10.1107/S2053273318005351
[57] Massimo Nespolo and Giovanni Ferraris. 'Overlooked problems in manifold twins: twin misfit in zero-obliquity TLQS twinning and twin index calcu- lation'. In: Acta Crystallographica Section A 63.3 (May 2007), pp. 278-286. (cit. on p. 139).
https://doi.org/10.1107/S0108767307012135
[58] Massimo Nespolo and Giovanni Ferraris. 'The derivation of twin laws in non-merohedric twins. Application to the analysis of hybrid twins'. In: Acta Crystallographica Section A 62.5 (Sept. 2006), pp. 336-349. (cit. on p. 141).
https://doi.org/10.1107/S0108767306023774
[59] Fischer E. O. and Pfab W. 'Cyclopentadien-Metallkomplexe, ein neuer Typ metallorganischer Verbindungen'. In: Zeitschrift für Naturforschung B 7 (1952), pp. 377-379. (cit. on p. 19).
https://doi.org/10.1515/znb-1952-0701
[60] Kouji Ogasahara, Michio Sorai and Hiroshi Suga. 'New finding of a stable low-temperature phase in ferrocene crystal'. In: Chemical Physics Letters 68.2 (Dec. 1979), pp. 457-460. (cit. on pp. 20, 21).
https://doi.org/10.1016/0009-2614(79)87237-1
[61] Jun Okuda. 'Ferrocene - 65 Years After'. In: European Journal of Inorganic Chemistry 2017.2 (2017), pp. 217-219. (cit. on p. 19).
https://doi.org/10.1002/ejic.201601323
[62] P. Seiler and J. D. Dunitz. 'Low-temperature crystallization of orthorhombic ferrocene: structure analysis at 98 K'. In: Acta Crystallographica Section B 38.6 ( June 1982), pp. 1741-1745. (cit. on pp. 20, 21).
https://doi.org/10.1107/S0567740882007080
[63] Damian Paliwoda et al. 'U-Turn Compression to a New Isostructural Ferrocene Phase'. In: The Journal of Physical Chemistry Letters 4.23 (2013), pp. 4032- 4037. (cit. on pp. 20, 21).
https://doi.org/10.1021/jz402254b
[64] Benjamin A. Palmer et al. 'An incommensurate thiourea inclusion compound'. In: Chem. Commun. 47 (13 2011), pp. 3760-3762. (cit. on p. 72).
https://doi.org/10.1039/c0cc05477a
[65] Benjamin A. Palmer et al. 'Structural Rationalization of the Phase Transition Behavior in a Solid Organic Inclusion Compound: Bromocyclohexane/- Thiourea'. In: Crystal Growth & Design 12.2 (Feb. 2012), pp. 577-582. (cit. on pp. 28, 29, 71, 72, 132).
https://doi.org/10.1021/cg201656y
[66] Zhigang Pan et al. 'Structural Properties of Low-Temperature Phase Transitions in the Prototypical Thiourea Inclusion Compound: Cyclohexane/- Thiourea'. In: The Journal of Physical Chemistry C 112.3 (2008), pp. 839-847. (cit. on pp. 28-30, 100, 132).
https://doi.org/10.1021/jp076706y
[67] Simon Parsons. 'Introduction to twinning'. In: Acta Crystallographica Section D 59.11 (Nov. 2003), pp. 1995-2003. (cit. on p. 138).
https://doi.org/10.1107/S0907444903017657
[68] Peter L. Pauson. 'Ferrocene-how it all began'. In: Journal of Organometallic Chemistry 637-639 (2001), pp. 3-6. (cit. on p. 19).
https://doi.org/10.1016/S0022-328X(01)01126-3
[69] Fernando Pérez and Brian E. Granger. 'IPython: a System for Interactive Scientific Computing'. In: Computing in Science and Engineering 9.3 (May 2007), pp. 21-29. (cit. on p. 79).
https://doi.org/10.1109/MCSE.2007.53
[70] Václav Petřı Michal Dušek and Lukáš Palatinus. 'Crystallographic Computing System JANA2006: General features'. In: Zeitschrift für Kristallographie - Crystalline Materials 229.5 (2014), pp. 345-352. (cit. on p. 68).
https://doi.org/10.1515/zkri-2014-1737
[71] Thomas Proffen and Reinhard B. Neder. Diffuse Scattering and Defect Structure Simulations: A Cook Book Using the Program DISCUS. International Union of Crystallography Texts on Crystallography. Oxford University Press, Jan. 2009 (cit. on p. 88).
[72] Thomas Proffen and Reinhard B. Neder. 'DISCUS: a program for diffuse scattering and defect-structure simulation'. In: Journal of Applied Crystallography 30.2 (Apr. 1997), pp. 171-175. (cit. on pp. 88, 91).
https://doi.org/10.1107/S002188989600934X
[73] Queen star hands in science PhD. Aug. 2007. url: http://news.bbc.co.uk/1/hi/entertainment/6929290.stm (visited on 03/08/2007) (cit. on p. ix).
[74] Stian Ramsnes. 'Aspects of X-Ray Diffraction Using Mathematica'. MA thesis. University of Stavanger, June 2016 (cit. on pp. 33, 34, 59).
[75] Stian Ramsnes, Helge Bøvik Larsen and Gunnar Thorkildsen. 'Using Mathematica as a platform for crystallographic computing'. In: Journal of Applied Crystallography 52.1 (Feb. 2019), pp. 214-218. (cit. on pp. xiii, 82, 84, 155).
https://doi.org/10.1107/S1600576718018071
[76] Stian Penev Ramsnes, Helge Bøvik Larsen and Gunnar Thorkildsen. 'MaXrd updated with emphasis on model construction and reciprocal-space simu- lations'. In: Journal of Applied Crystallography 53.6 (Dec. 2020), pp. 1620-1624. (cit. on pp. xiii, 155).
https://doi.org/10.1107/S160057672001328X
[77] Stian Penev Ramsnes et al. 'Complementary Synchrotron Diffraction and Simulation Studies on a Ferrocene:Thiourea Inclusion Compound'. To be published. 2022 (cit. on pp. xiv, 155).
[78] Herbst-Irmer Regine. 'Twinning in chemical crystallography - a practical guide'. In: Zeitschrift für Kristallographie - Crystalline Materials 231 (2016), pp. 573-581. (cit. on pp. 140, 142).
https://doi.org/10.1515/zkri-2016-1947
[79] Heiko Ress and Martin Zimmermann. High Resolution X-ray Diffractometry. www.bruker-webinars.com. Mar. 2011 (cit. on p. 43).
[80] Rigaku OD. CrysAlis PRO. Rigaku Oxford Diffraction. Yarnton, England, 2015 (cit. on pp. 34, 60).
[81] Anabel Morte Ródenas. 'Solid-State Studies of Inclusion Compounds and Other Organic Materials'. PhD thesis. Cardiff University, Feb. 2011 (cit. on p. 24).
[82] E. A. Seibold and L. E. Sutton. 'Structure of Ferrocene'. In: The Journal of Chemical Physics 23.10 (1955), p. 1967. (cit. on p. 21).
https://doi.org/10.1063/1.1740629
[83] P. Seiler and J. D. Dunitz. 'A new interpretation of the disordered crystal structure of ferrocene'. In: Acta Crystallographica Section B 35.5 (May 1979), pp. 1068-1074. (cit. on p. 20).
https://doi.org/10.1107/S0567740879005598
[84] P. Seiler and J. D. Dunitz. 'Redetermination of the ruthenocene structure at room temperature and at 101 K: molecular internal motion'. In: Acta Crystal- lographica Section B 36.12 (Dec. 1980), pp. 2946-2950. (cit. on p. 21).
https://doi.org/10.1107/S0567740880010588
[85] P. Seiler and J. D. Dunitz. 'The structure of triclinic ferrocene at 101, 123 and 148 K'. In: Acta Crystallographica Section B 35.9 (Sept. 1979), pp. 2020-2032. (cit. on pp. 20, 21).
https://doi.org/10.1107/S0567740879008384
[86] Madhumati Sevvana et al. 'Non-merohedral twinning: from minerals to proteins'. In: Acta Crystallographica Section D 75.12 (Dec. 2019), pp. 1040-1050. (cit. on pp. 141, 142).
https://doi.org/10.1107/S2059798319010179
[87] George M. Sheldrick. 'A short history of SHELX'. In: Acta Crystallographica Section A 64.1 ( Jan. 2008), pp. 112-122. (cit. on p. 57).
https://doi.org/10.1107/S0108767307043930
[88] George M. Sheldrick. 'Crystal structure refinement with SHELXL'. In: Acta Crystallographica Section C 71.1 ( Jan. 2015), pp. 3-8. (cit. on p. 60).
https://doi.org/10.1107/S2053229614024218
[89] George M. Sheldrick. 'SHELXT - Integrated space-group and crystal-structure determination'. In: Acta Crystallographica Section A 71.1 ( Jan. 2015), pp. 3- 8. (cit. on p. 60).
https://doi.org/10.1107/S2053273314026370
[90] Michio Sorai, Kouji Ogasahara and Hiroshi Suga. 'Heat Capacity and Phase Transitions of Thiourea-Ferrocene Channel Inclusion Compound'. In: Molecular Crystals and Liquid Crystals 73.3-4 (1981), pp. 231-254. (cit. on pp. 25, 27, 33, 36, 38, 42, 43, 53, 54, 112, 131, 132).
https://doi.org/10.1080/00268948108072337
https://doi.org/10.1080/00268948108076261
[91] M. R. Srinivasan et al. 'Studies on the phase transitions in thiourea'. In: Ferroelectrics 21.1 (1978), pp. 539-541. (cit. on p. 23).
https://doi.org/10.1080/00150197808237322
[92] F. Takusagawa and T. F. Koetzle. 'A neutron diffraction study of the crystal structure of ferrocene'. In: Acta Crystallographica Section B 35.5 (May 1979), pp. 1074-1081. (cit. on p. 21).
https://doi.org/10.1107/S0567740879005604
[93] Hanna Tomkowiak and Andrzej Katrusiak. 'High-Pressure Transformations and the Resonance Structure of Thiourea'. In: The Journal of Physical Chemistry C 122.9 (Mar. 2018), pp. 5064-5070. (cit. on p. 23).
https://doi.org/10.1021/acs.jpcc.8b00452
[94] Twin element - Online Dictionary of Crystallography. url: https://dictionary.iucr.org/Twin_element (visited on 20/11/2017) (cit. on p. 139).
[95] Twin operation - Online Dictionary of Crystallography. url: https://dictionary.iucr.org/Twin_operation (visited on 28/10/2020) (cit. on p. 138).
[96] Srivathsa Vaidya. 'Clathrates -An exploration of the chemistry of caged compounds'. In: Resonance 9.7 (2004), pp. 18-31. (cit. on p. 23).
https://doi.org/10.1007/BF02903573
[97] Geoffrey Wilkinson et al. 'The Structure of Iron Bis-Cyclopentadienyl'. In: Journal of the American Chemical Society 74.8 (1952), pp. 2125-2126. (cit. on p. 19).
https://doi.org/10.1021/ja01128a527
[98] B. T. M. Willis. 'Three-dimensional neutron diffraction study of ferrocene'. In: Acta Crystallographica 13.12 (Dec. 1960), p. 1088. doi: 10.1107/S0365110X 60002430 (cit. on p. 21).
[99] Ralph Walter Graystone Wyckoff and Robert B. Corey. 'The Crystal Structure of Thiourea'. In: Zeitschrift für Kristallographie - Crystalline Materials 81 (Oct. 1932), pp. 386-395 (cit. on p. 23).
https://doi.org/10.1524/zkri.1932.81.1.386
[100] Lily Yeo, Kenneth D.M. Harris and Benson M. Kariuki. 'Temperature-Dependent Structural Properties and Crystal Twinning in the Fluorocyclohex- ane/Thiourea Inclusion Compound'. In: Journal of Solid State Chemistry 156.1 ( Jan. 2001), pp. 16-25. (cit. on pp. 28, 29, 39, 132).
https://doi.org/10.1006/jssc.2000.8951
[101] Z. Zikmund. 'Symmetry of domain pairs and domain twins'. In: Czechoslovak Journal of Physics B 34.9 (1984), pp. 932-949. (cit. on p. 140).
https://doi.org/10.1007/BF01589823