Articles

Beobachtungen bei der Kupferchloridkristallisation: vom «Eiweiß-Vorbild» zum «Kupferchlorid-Nachbild»

François Schweizer, Jens-Otto Andersen, Jens Laursen
Elemente der Naturwissenschaft 92, 2010, P. 62-93 | DOI: 10.18756/edn.92.62
Article | Language: German | €6.00
Export Article Citation as

Abstract:

The starting point for the research presented here is Pfeiffer’s postulate that copper chloride crystallisation of a blood sample generates a ‘protein pattern’ which is supposed to contain the essential elements of the crystallisation picture that appears later. In the same way, when crystallising plant extracts, Engqvist interpreted a fine water-insoluble residue observed on the surface of the glass, after washing off the crystals, as the ‘protein pattern’, showing a representation of the crystallisation picture. In the present study preliminary experiments to demonstrate protein-containing compounds with simple staining techniques (Fuchsin S) did not produce the expected results at first. However, surprisingly, they did show the presence of three different crystal types in the copper chloride crystallisation pictures, when applying plant extracts and gelatin as additives: (a) primary crystals in the form of needles that are readily water-soluble and stained by Fuchsin S; (b) secondary crystals present with a 50–80% coverage of the area of the glass plate with primary needles; these are insoluble in water and are not stained by Fuchsin S; they are present as largely opaque, very small and thin-layered crystal patterns which appear along the edges of the primary crystal needles at their contact zone with the glass surface; (c) tertiary crystals, so-called fine structures, mostly in a non-linear form, which appear in the last phase of the crystallisation; they are not soluble in water and are not stained by Fuchsin S. In order to examine the chemical and crystallographic nature of the three crystal types, experiments were carried out using scanning electron microscopy, X-ray diffraction analysis and X-ray fluorescence analysis. These showed that the primary crystals were completely identical to the original substance copper (II) chloride dihydrate (CuCl2∙2H2O). As opposed to these the secondary and tertiary crystals comprised water insoluble basic copper chloride compounds, for the most part identifiable as atacamite (2CuCl2∙5Cu(OH)2∙2H2O) with smaller amounts of anthonite (Cu(OH,Cl)∙2H2O). It is not yet possible to give the exact reasons for these changes. Thus in our experiments we were not able to find any evidence of a ‘protein pattern’ (Vorbild), based on crystallisation of copper chloride with plant extracts or gelatin as additives. On the other hand, during crystallisation a ‘negative picture’ of the actual crystallisation picture arises through the separation of water insoluble secondary and tertiary crystals. We call this the ‘copper chloride after-image’ (Nachbild).

References
  • Barth, J.-G. (1997): Image de cristallisation du chlorure cuivrique et structure chimique de l’additif. Elemente d. N. 66, S. 16–42.
  • Beckmann, H. (1959): Über Keimbildung, Einkristallwachstum und Auffächerungs­ wachstum von CuCl2∙2H2O in rein-wässerigen und Eiweiß-haltigen Lösungen. Diss. Univ. Bonn.
  • Buckley, H. E. (1951): Crystal Growth, New York.
  • Busscher, N. et al. (2006): Das Verfahren der Biokristallisation und das Konzept der Selbstorganisation. Elemente d. N. 85, S. 93–102.
  • Busscher, N. et al. (2010): Evaporation influences on the crystallization of an aqueous dihydrate cupric chloride solution with additives. Journal of Colloid and Interface Science. In Press. Accepted Manuscript.
  • Engqvist, M. (1975): Physische und lebensbildende Kräfte in der Pflanze. Frankfurt am Main.
  • Gallinet, J. P., Gauthier-Manuel, B. (1992): Wetting of a Glass Surface by Protein Adsorption Induces the Crystallization of an Aqueous Cupric Chloride Solution. Journal of Colloid and Interface Science 148, S. 155–159.
  • Kleber, W., Steinike-Hartung, U. (1959): Ein Beitrag zur Kristallisation von Kupfer- (II)-chlorid-Dihydrat aus Lösungen. Zeitschrift für Kristallographie 111, S. 213–239.
  • Mann, S. (2001): Biomineralization. Principles and concepts in bioorganic material chemistry. Oxford.
  • Morris, D. L., Morris, C. T. (1941): The modification of cupric chloride crystallisation patterns by traces of proteins. Journal of Biological Chemistry 141, S. 515–521.
  • Neuhaus, A. (1957): Die kristallographischen Grundlagen der «Diagnostischen Kristallisation». In: Selawry, A., Selawry, O. (Hg.): Die Kupferchloridkristallisation in Naturwissenschaft und Medizin, Stuttgart.
  • Nickel, E. (1967/68): Die Reproduzierbarkeit der sogenannten «empfindlichen Kupferchloridkristallisation». Bull. Soc. Frib. Sc. Nat. 57, Fasc. II, S. 65–179.
  • Pfeiffer, E. in Bessenich, F. (1960): Zur Methode der Empfindlichen Kristallisation, Naturw. Sektion am Goetheanum, Dornach.
  • Pourbaix, M. (1977): Electrochemical corrosion and reduction. In: B. F. Brown et al. (Hg.): Corrosion and Metals Artifacts: A Dialogue Between Conservators, Archaeologists and Corrosion Scientists, NBS Special Publication 479.1, S. 1–16, U.S. Department of Commerce. National Bureau of Standards, Washington, D.C.
  • Romé de l’Isle, J.-B. (1783): Cristallographie ou description des formes propres à tous les corps du règne minéral, 2. Aufl., 1, S. 379.
  • Shibata, T. et al. (1994): Effect of human blood addition on dendritic growth on cupric chloride crystals in aqueous solutions. Journal of Crystal Growth 141, S. 147–155.