The present Supplement Volume Beryllium A 3 continues and completes the description of the physical properties of the element, begun in Supplement Volume A 2, 1991, and also treats the electrochemical behavior of the metal. The unique combination of the Be properties, which was pointed out in Supplement Volume A 2, is also demonstrated in the following chapters of this Volume A 3: 13. Electrical Properties 14. Electronic Properties 15. Optical Properties. Emission and Impact Phenomena 16. Electrochemical Behavior Starting with the electrical properties, Be isarather good electrical conductor in centrast to what might be expected. Superconductivity was studied, especially on films. Quantum effects, which are more pronounced in Be than in most other metals, are the reason for numerous in vestigations of the magnetoresistance and the magnetic-breakdown effect. The basis for many of the characteristic properties is the unique nature of bonding in Be as a consequence of its peculiar electronic structure and the special shape of its Fermi surface which also gave rise to further numerous studies. Detailed cluster calculations were per formed to better understand the bonding in the metal. Regarding the optical properties, the high reflectivity of Be, particularly in the infrared region, makes it attractive for the fabrication of precision optical surfaces (mirrors); it is also useful for solar-collector surfaces in spacecraft applications. Emission and electron-and ion impact phenomena as well as neutron optics are also discussed.

The present voLume describes the chemicaL behavior of eLementaL tungsten toward the non- metaLlic eLements nitrogen to arsenic (i.e., N, F, CL, Sr, I, S, Se, Te, Po, S, C, Si, P, and As). The description of the chemicaL behavior starts with information on the phase diagrams wh ich aLLow an overview of the existing stabLe compounds. The major part of the information in this voLume is about the kinds of products, the experimentaL conditions, as weLL as the kinetics and thermodynamics of their formation. Short descriptions of buLk diffusion in binary systems compLement the kinetic data on the mostLy diffusion-controLLed reactions. Pure surface phenomena on tungsten are not considered. A Large chapter is devoted to the comprehensiveLy studied chemicaL processes and trans- port processes in tungsten-haLogen Lamps. Product formation in the tungsten-carbon and tungsten-silicon systems is aLso of speciaL interest in view of possibLe appLications. The present voLume concLudes the series of voLumes devoted to the chemicaL behavior of eLementaL tungsten. Interactions and reactions with nobLe gases, hydrogen, and oxygen are covered in "Wolfram" Erg.-Sd. S 1. Interactions and reactions with metaLlic eLements are described in "Tungsten" SuppL. VoL. A 6a (eLements antimony to barium) and in "Tungsten" SuppL. VoL. A 6 b (eLements zinc to actinides).