Atomvolumen, Atomabstände und chemische Bindung in festen metallischen Elementen Atomic Volume, Atomic Distances and Chemical Bonding in Solid Metallic Elements
نویسندگان
چکیده
vom Atomabstand R abhängt [2], ergibt sich, dass nicht nur die kubisch innenzentrierte Struktur und die dichtesten Kugelpackungen, sondern noch wei tere Strukturen die gleiche maximale Packungs dichte aufweisen, d.h. dichte Strukturen sind. Die Masszahl für die Packungsdichte der Atome in ei ner Struktur ist das Verhältnis q = VD/VA. Dabei ist VA das experimentell ermittelte Atomvolumen und VD das reduzierte Atomvolumen, d.h. das Atomvo lumen, das sich unter Annahme gleicher Wertigkeit für das Element in dichter Struktur berechnet, q < 1 ist charakteristisch für die jeweilige Struktur und unabhängig von der jeweiligen Atomart und deren Elektronenkonfiguration. Damit wird das Atomvo lumen in guter Näherung in die strukturspezifische Packungsdichte und in das elementspezifische, re duzierte Atomvolumen aufgeteilt [1].
منابع مشابه
Atomvolumen, Packungsdichte und chemische Bindung in festem Iod unter Druck Atomic Volume, Packing Density and Chemical Bonding in Solid Iodine under Pressure
The volume changes of solid iodine under pressure are discussed with respect to the packing density of the atoms and to valence. The packing density of solid iodine which is 0.805 under ambient pressure increases to 0.976 in monoatomic iodine-II, 0.993 in iodine-III, and 1 in fcc iodine-IV. Simultaneously, the valence increases from 1 in the free molecule to 1.78 in the crystal structure under ...
متن کاملValence, coordination number, and PAV cells in metallic rare earth compounds
— Polyhedral atomic volumes, Voronoi volumes, generalized coordination numbers, and Pauling's metallic valences are given for 24 intermetallic rare earth compounds. The results clearly indicate that as much as 33 % rare earth isovalent volume contraction can occur upon compound formation while the atomic volumes of aluminum and the transition elements are nearly constant. Earlier discussions of...
متن کاملEffect of Cu Content on TiN-Cu Nanocomposite Film Properties: Structural and Hardness Studies
Titanium nitride-Copper (TiN-Cu) nanocomposite films were deposited onto stainless steel substrate using hollow cathode discharge ion plating technique. The influence of Cu content in the range of 2-7 at.% on the microstructure, morphology and mechanical properties of deposited films were investigated. Structural properties of the films were studied by X-ray diffraction pattern. Topography of t...
متن کاملاثر نسبت حجمی مذاب- جامد و سرعت دوران بر فصل مشترک جفت فلزی منیزیم- آلومینیم در ریختهگری گریز از مرکز
In this study, centrifugal casting process was used for producing Al/Mg bimetal. Molten Mg was poured at 700 oC, with 1.5 and 3 melt-to-solid volume ratio (Vm/Vs) into the 450 oC preheated solid Al rotating at 800, 1200, 1600 and 2000 rpm. Castings were kept inside the centrifuged casting machine and cooled down to 150 oC. Investigating the effect of melt-to-solid volume ratio showed that incre...
متن کاملAtomic Absorption Spectrometric Determination of Lead after Extraction and Preconcentration with 5-Br-PADAP
Lead is quantitatively retained on 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP)-ammonium tetraphenylborate with microcrystalline naphthalene or by a column method in the pH range 4.0-6.0 from a large volume of aqueous solutions of various samples with preconcentration factor of 60. After filtration, the solid mass consisting of the lead complex and naphthalene was dissolved wi...
متن کامل