摘要:

AbstractThe tetragonal sublimates obtained by prolonged tempering of preparations of compositions about ZrX0.75(X = S, Se, Te) in evacuated quartz tubes1, 2, are found to be ternary compounds ZrSiX. These novel compounds can be prepared conveniently by reaction of “SiX” with zirconium metal at elevated temperatures. The analogous germanium compounds are prepared in a similar way. The crystal structures of the ZrSiX and ZrGeX phases are related to the PbFCl structure type. Unit‐cell dimensions, atomic parameters (see Table I) and interatomic distances (see Table II) have been determined; they are discussed in some d

ISSN:0165-0513    

DOI:10.1002/recl.19640830802

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractThe measurement of surface tensions of liquids is in general a time‐consuming procedure requiring relatively large amounts,i.e.severals mls of liquid. The method to be introduced here is very rapid, using only about two drops of liquid, thereby combining some of the specific advantages of the respective standard methods.The principle is very simple. The pressure required to expel the liquid, of which the surface tension is to be determined, from a narrow pore in athinglass plate is read on a manometer. According to Laplace's equation this pressure is proportional to the surface tension of the liquidP = γ (1/R1+ 1/R2) (1)where P is the pressure in dynes/cm2, γ the surface tension (dynes/cm) and R1and R2the two principal radii of curvature of the liquid surface in the pore (cm.Most organic liquids have contact angles with clean glass which are zero or very nearly so, and if the pore is cylindrical, R1and R2will both be equal to r, the radius of the pore, so that equation (1) reduces toP = 2 γ/r (2)Now if the glass plate is sufficiently thin, so that the hydrostatic head in the pore can be neglected, and if r is known, γ can be determined using equation (2) with the same degree of accuracy as P can be mea

ISSN:0165-0513    

DOI:10.1002/recl.19640830803

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

ISSN:0165-0513    

DOI:10.1002/recl.19640830804

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractAn apparatus for electron‐diffraction by gases has been constructed. It incorporates a peripherally driven rotating sector; the specimen‐film distance is variable through vertical movement of the camera‐sector assembly.Calculation techniques are discussed and a least‐squares calculation with constraints is described, based on comparison of experimental and theoretical intensi

ISSN:0165-0513    

DOI:10.1002/recl.19640830805

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractThe vapour pressure of solid and liquid SeO3was measured in the temperature range between 80°C and 120°C. Measurements are easily affected by the presence of residual SO3. The triple point is situated at 120.9°C and 5.5 mm Hg. The plot of log p against 1/T shows that the heat of vaporisation depends greatly on temperature. Sublimation pressure data can be explained in terms of a tetramer‐monomer dissociation in the gaseous phase. Calculated sublimation and dissociation enthalpies are 9.0 and 119 kcal/mole (Se

ISSN:0165-0513    

DOI:10.1002/recl.19640830806

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractThe enthalpy of solution of CsF in water at 25.00°C has been carefully measured with an adiabatic calorimeter. The value at infinite dilution is: ΔH°sol= −36.08 ± 0.17 kj

ISSN:0165-0513    

DOI:10.1002/recl.19640830807

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractThe apparent acidity constants of substituted β‐phenylthio‐, β‐phenylsulfinyl‐and β‐phenylsulfonyl‐acrylic acids (cisandtrans) with substituentsp‐OCH3,p‐CH3, H,p‐Cl,m‐NO2andp‐NO2have been determined in 50% (by vol.) aqueous ethanol. The acidity constants in the six series obey theHammettequation with satisfactory to excellent fit. The values of the reaction constants δ indicate that substituent effects are better transmitted by S than by SO and SO2, and they do not differ substantially forcisandtransseries.The β‐arylthioacrylic acids are more acidic intrans‐ than incis‐configuration, while the opposite holds for the β‐arylsulfinyl‐ and β‐arylsulfonyl‐acrylic acids. These differences are discussed in terms of steric inhibition of resonance and electrostatic effects through space.Comparison between the acidity constants oftrans‐β‐substituted acrylic acids with those ofpara‐substituted benzoic acids reveals that a carbon‐carbon double bond is 1.9 times as effective as the ph

ISSN:0165-0513    

DOI:10.1002/recl.19640830808

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractThe apparent acidity constants ofcis‐ andtrans‐3‐endo‐arylsulfonylbicyclo‐[2,2,1]hept‐5‐ene‐2‐carboxylic acids, with aryl =p‐CH3OC6H4‐‐,p‐CH3C6H4‐, C6H5‐,p‐ClC6H4‐,m‐NO2C6H4‐andp‐NO2C6H4‐, have been measured in 50% (by vol.) aqueous ethanol at 25°. The acidities ofcis‐compounds are much lower than those oftrans‐isomers, which is most likely due to an intramolecular field effect between the sulfonyl‐oxygens and the carboxylic anion in thecis‐compounds. The data in both series follow the Hammett equation with excellent fit and the values for the reaction constant δ are 0.351 (trans‐series) and 0.418 (cis‐series. This indicates that the magnitude of the field effect is v

ISSN:0165-0513    

DOI:10.1002/recl.19640830809

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractThe apparent acidity constants of a series ofortho‐, α‐ and/or β‐substituted cinnamic acids (cis‐ andtrans‐), with substituents CH3, Br and Cl, have been measured in 50% (by vol.) aqueous ethanol at 25°.The data on α‐ and/or β‐substitution by Br and Cl are discussed on the basis of electronic substituent effects. Similar substitution by CH3invokes the enhanced secondary steric effect of this group and a large departure from additivity of substituent effects is observed in α,β‐dimethyl‐trans‐cinnamic acid.The acidity constants of β‐substitutedcis‐cinnamic acids follow theHammettequation with satisfactory fit.Ortho‐substitution by Cl incis‐cinnamic acid probably implies a direct field effect betwe

ISSN:0165-0513    

DOI:10.1002/recl.19640830810

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY

摘要:

AbstractA few oligomeric and polymericp‐phenylenegermanes have been prepared by Wurtz‐type condensation reactions fromp‐chlorophenyl‐ and chlorogermanes. The oligomeric and polymeric products obtained have been characterized by infrared spectroscopy, elementary analysis and molecular weight determinations.Infrared spectra in the rocksalt region of phenyl andp‐phenylene derivatives of silicon, germanium, tin and lead are discussed. The spectra of thep‐phenylene compounds show some characteristic absorption bands shifting to lower frequencies as the weight of the metal atoms in the molecul

ISSN:0165-0513    

DOI:10.1002/recl.19640830811

出版商:WILEY‐VCH Verlag    

年代:1964

数据来源: WILEY