A Laboratory Apparatus for Single Crystal Preparation by Czochralski Method

The rapid development of the application of semiconductors has stimulated extensive investigations of single crystal growth from a melt. Czochralski method has proved to be the most suitable for that purpose, and therefore it has been mostly studied and developed1•2 • In the present communication a simple laboratory apparatus for »crystal pulling« is described. The apparatus can be used not only for growing single crystal of germanium but also of other materials with relative low melting point and convenient crystallization properties

A Press for Electric Resistivity Measurements of Powders

In research work on semiconductors, the electric resistivity measurements are very important. In most cases it is impossible to obtain a compact sample and the measurements have to be done on the powdered material. For this purpose the resistivity is measured on a sample which is obtained by pressing the powder to a definite pressure between two electrodes

A Press for Electric Resistivity Measurements of Powders

In research work on semiconductors, the electric resistivity measurements are very important. In most cases it is impossible to obtain a compact sample and the measurements have to be done on the powdered material. For this purpose the resistivity is measured on a sample which is obtained by pressing the powder to a definite pressure between two electrodes

Crystal and Molecular Structure of Bis(2,2\u27 -bipyridyl)mercury(II) Nitrate Dihydrate

The crystal structure of bis(2,2\u27-bipyridyl)mercury(II) nitrate dihydrate has been determined from diffractometer X-ray intensity data by means of Patterson and Fourier methods and refined by the full-matrix least-squares technique based on 3589 independent reflexions to the index R of 0.069. Crystals are monoclinic holohedral, space group P2i/c with four formula units in the unit cell of dimensions a = 10.091(2), b = 7.378(3), c = 32.990(6) A, (J = 105.49(3)0, Dobs =\u27 1.87 g cm-3, D eal e = 1.888 g cm-3• The nitrogen atoms of the bipyridyl ligands, which are both in their chelate function, form a flattened tetrahedron around the mercury atom at a mean Hg-N distance of 2.29 A. Three nitrate oxygen atoms at a mean Hg . . . 0 distance of 2.72 A, complete the coordination of mercury to a distorted capped octahedron, whereas the water molecules are out of the mercury coordination sphere

The Determination of Molybdenum, Uranium and Silicon in Molybdenum and Uranium Silicides

In the course of an investigation of refractory silicides of molybdenum and uranium1, as well as multiphase systems containing molybdenum, uranium and ,silicon2 , the problem of analytical determination of these elements in such systems has appeared. Methods hitherto recommended for the analytical determination of molybdenum, uranium and silicon in various materials3- 6 have been examined. However, none of these methods could be directly applied for the analysis of the samples of this kind