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This programme deals with crystal structure, molecular structure and their determination by X-ray diffraction techniques. After a briel introduction by Prof. Haynes, Dr. Harding uses models to show... how a crystal may be described in terms of its Unit Cell, and how planes through the crystal can be described in terms of Miller Indices. Dr. Ross then describes a typical laboratory X-ray diffraction camera. He shows how three types of photograph are obtained from the same crystalline material by presenting the sample to the X-ray beam as : (i) a single crystal, randomly rotated (ii) a powder (iii) a single crystal rotated about a. principle axis of symmetry. The photographs are then compared by smperimposition on one another. Dr, Ross continues with a laser experiment to show the basis of The Fourier Fringe method for determining molecular structures from X-ray diffraction data. The programme finishes by showing how this method results in an electron density contour map of the molecule.
Metadata describing this Open University video programme
Module code and title: S24-, Introduction to the chemistry of carbon compounds
Item code: S24-; 02; 1972
First transmission date: 29-02-1972
Published: 1972
Rights Statement: Rights owned or controlled by The Open University
Restrictions on use: This material can be used in accordance with The Open University conditions of use. A link to the conditions can be found at the bottom of all OUDA web pages.
Duration: 00:23:45
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Producer: Barrie Whatley
Contributors: Charles Harding; Len Haynes
Publisher: BBC Open University
Keyword(s): Crystal structure; Electron density contour map; Laser experiment; Miller indices; Molecular structure; Unit cell; X-ray diffraction techniques
Footage description: Same as S24-/S25-/02 (1973) Charlie Harding with a model of an NaCl crystal. He points out the components including the unit cell. Harding shows two other molecular models both unit cells of NaCl. He uses these models to explain how Miller indices are determined for crystals. Harding uses a larger model of NaCl to point out the 1-0-0 face. He then takes the model apart to show the 1-1-1 face and explains how this Miller index is determined. Same as S24-/S25-/O2 (1973) sequences 2 and 3.
Master spool number: 6LT/70298
Production number: 00521_2166
Videofinder number: 1851
Available to public: no