Search query: Electronegativity

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abstract: 1. Introduction 2. Theory of Electrons in a Non Crystalline Medium 3. Phonons and Polarons 4. The Fermi Glass and the Anderson Transition 5. Liquid Metals and Semimetals 6. Non Crystalline Semiconductors 7. Tetrahedrally Bonded Semiconductors Amorphous Germanium and Silicon 8. Aresnic and Other Three Fold Co ordinated Materials 9. Chalcogenide and Other Glasses 10. Selenium, Tellurium, and their Alloys
author_names: Nevill Francis Mott

Edward Arthur Davis

Kurt Weiser
title: Electronic Processes In Non Crystalline Materials
year: 1940

abstract: The interatomic distances in crystals of alloys cannot be accounted for by assigning a fixed atomic radius to each kind of atom, and the causes of this variation are discussed with special references to the Brillouin zone characteristics of different structures. According to the theory of Jones, the effect of an overlap across the side of a Brillouin zone is to compress the zone at right angles to the face concerned, and so to expand the crystal lattice in the same direction. This expansion is not a property of an atom which can be transferred to any of its alloys, but is a characteristic of a structure with sufficient electrons to produce an overlap. The lattice spacings of alloys of aluminium and indium with copper, silver, gold, and magnesium are examined, and the apparent sizes of the aluminium and indium atoms are discussed, and are shown to be in agreement with the theory. The previous suggestion, that in metallic aluminium the atoms exist in an incompletely ionized state, is improbable, and is no longer required in order to explain the facts. New experimental data for the lattice spacings of solid solutions of aluminium and indium are presented, and these show that, whilst the curves connecting the a parameter with the composition are smooth and continuous, the corresponding curves for the c parameter show an abrupt change in direction at about 0.75 atomic of indium or aluminium. This is taken to imply that, although in metallic magnesium with two electrons per atom, the overlap of the first Brillouin zone is in the a direction only, the structure is so near to the stage at which the c overlap sets in that the addition of less than one electron per hundred atoms causes the c overlap to take place.
author_names: William Hume-rothery

Geoffrey Vincent Raynor
title: The apparent sizes of atoms in metallic crystals with special reference to aluminium and indium, and the electronic state of magnesium
venue: Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences
year: 1940

abstract: IT has been recognized for many years that under certain conditions a hydrogen atom can form a connecting link between two other atoms. It may be considered as forming a bond between them, known as the hydrogen bond. Although the hydrogen bond is not strong, recent investigations have shown it to be of very wide occurrence. The concept has been extremely useful in explaining the association of polar liquids like water, the association of carboxylic acids, alcohols, amides, etc. the closure of rings within the molecule, and in interpreting many measurements of structure by X ray and electron diffraction methods and of the frequency shifts of the infra red absorption bands of certain known groupings. It was investigations of this type that not only established the existence of this form of bond but also provided information regarding the conditions in which its formation is to be expected, and, in many cases, of the actual energy of the bond. In spite of the enormous amount of experimental data now available, there is still much information which is lacking; the exact mechanism of the bonding power of the hydrogen is not clear, and there are many difficulties with questions of terminology.
author_names: Cecil Edwin Henry Bawn
title: The Hydrogen Bond
venue: Nature
year: 1940

abstract: Since the discovery by Bohr and coworkers in 1904 of the effect of acidity on the oxygen equilibrium of hemoglobin, there have been a large number of investigations directed towards clarification of the physicochemical relationships of acid groups with the hemes in hemoglobin and its derivatives. It is the purpose of this paper to analyze modern quantitative data, including those for ferrihemoglobin (methemoglobin) in order to throw new light on the general problem, to establish the ionization constant of an acid group in ferrihemoglobin previously unrecognized, and to give a structural interpretation of shifts in the pK of groups caused by changing chemical environment.
author_names: Charles D Coryell

Linus Pauling
title: A STRUCTURAL INTERPRETATION OF THE ACIDITY OF GROUPS ASSOCIATED WITH THE HEMES OF HEMOGLOBIN AND HEMOGLOBIN DERIVATIVES
year: 1940

abstract: Simultaneous hemoglobin and creatinine renal clearance studies have been presented which indicate that hemoglobin is eliminated by the kidney at a rate which is 3 per cent of the creatinine clearance, above a plasma hemoglobin concentration of approximately 250 mg. per 100 cc. In dogs whose average glomerular filtration rate is 66 cc. per minute, about 2 cc. of plasma are cleared of hemoglobin per minute. A definite renal threshold exists for hemoglobin at a plasma concentration of about 100 mg. per 100 cc. below which hemoglobinuria does not occur. The uniformity of the process indicates that hemoglobinuria is not the result of a transient glomerular injury induced by the hemoglobin. It is tentatively suggested that the experimental results obtained may be interpreted in terms of the following concept. The glomerulus permits the filtration of hemoglobin in amounts directly dependent upon plasma concentration. However, only 3 per cent of all the pores of the membrane are electrostatically large enough to permit the passage of an undissociated hemoglobin molecule. Of that hemoglobin which passes down the tubule, a relatively constant though small amount is recovered by the tubules by a process not unlike that of phagocytosis found elsewhere in the body. An average value for this "athrocytic" capacity in a medium sized dog is 2 mg. of hemoglobin per minute. This pattern of renal hemoglobin excretion is in agreement with the principles of the modern theory of kidney function.
author_names: J Victor Monke

Charles L Yuile
title: THE RENAL CLEARANCE OF HEMOGLOBIN IN THE DOG
venue: The Journal of experimental medicine
year: 1940

abstract: In an attempt to determine the fraction of ions lost by recombination in an x ray ionization chamber, a theory has been developed for the processes involved in preferential and initial ionic and electronic recombination. The theory considers the change of the energy distribution of the electrons as they diffuse away from the parent atom. From this, together with a knowledge of the electron capture process, the space distribution of negative ions formed may be obtained. The probability of the initial electron recombining preferentially with the parent positive ion is considered as well as the preferential process for the negative ion. Knowing the initial spacing of the ions, it is possible to calculate the recombination occurring during the diffusion process until random distribution is reached. The final volume recombination may then be calculated in the usual manner. The theory may be employed in both electronegative and free electron gases and to ions formed in the presence or absence of an electric field.
author_names: Norris E Bradbury
title: Preferential and Initial Ionic Recombination in Gases
year: 1940

abstract: The reaction chosen for the determination was the decomposition of nitrogen iodide in dilute hydriodic acid according to the equation (with excess hydriodic acid present) 2NH3.NI3 5HI 2NH4I 3HI3. This reaction has the advantage that it is unnecessary to prepare the nitrogen iodide in the dry state, a difficulty met with in the method involving the detonation of the substance in some form of bomb calorimeter, quite apart from the complexity of the reaction products in that case. The reaction with hydriodic acid proceeds rapidly, and appears to be quantitative (Chattaway and Orton 1899) A difficulty was encountered when analyses were made of the final products, as it was found that the amount of ammonia obtained was greater than that corresponding to the composition NH3.NI3. Since the excess varied quite considerably from sample to sample, it was considered to be adsorbed or loosely combined ammonia, such as is frequently met with in compounds containing ammonia. The existence of higher ammines of NI3 lends support to this view. To overcome the difficulty introduced by this excess of which the state of combination and heat content were unknown, and which it was not considered correct to treat as free ammonia, advantage was taken of the fact that the proportion of excess ammonia could be varied quite considerably. The experiments were considered in pairs, the effect of the excess ammonia being eliminated between them.
author_names: F R Meldrum
title: The heat of formation of nitrogen iodide
venue: Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences
year: 1940

abstract: a catalogue of diseases, drugs and doses, or even analyses of results achieved, as an impression of the general trend of antispecific therapy, and an indication of the significance and importance of the far reaching changes which the last twenty, and more especially the last five, years have inaugurated. In the case of gonorrhoea and chancroid, the changes in treatment have been greater and more striking than in the case of syphilis. The treatment of syphilis is still carried on mainly by the intravenous or intramuscular injection of trivalent arsenical compounds such as neoarsphenamine or " 914 " and stabilarsan, and the intramuscular injection of bismuth metal
author_names: R C L Batchelor
title: Modern Therapy in Specific Infections A Honyman Gillespie Lecture delivered on 25th April 1940.
venue: Edinburgh medical journal
year: 1940

author_names: S J Kramer
title: Effect of substituents on the electronegativity of the naphthyl radicals
year: 1940

author_names: Ed F Degering

Karl Schaff

Leslie Gillette
title: A consideration of the concepts of relative electronegativity
year: 1940