Coagulation of Silver Iodide in the Presence of Tensides

In connection with silver iodide systems containing various tensides we can show an »irregular« behaviour of the negative silver iodide sol in the presence ofsodium n-dodecyl sulphate, SDS.1 The AgI-NaI-SDS system is formed in statu nascendi, i. e. by pouring the silver nitrate solution into the solution of sodium iodide + SDS (of specially pure grade BDH reagent)

X-Ray Diffraction Analysis of Differently Prepared AgI. IV

The cubic/hexagonal ratio of Ag! formed by dilution of a solution of silver iodide in Na! and AgN03 solutions respectively, and the cubic/hexagonal ratio of Ag! formed in statu nascendi in mixed solvents has been investigated. The complex solution of Ag! + Na! (1, 2, 3, 4, and 8 M Na!) was diluted with water to 0.01 M Na!. The formed mixtures of cubic and hexagonal Ag! contained less cubic Ag! in systems of lower initial concentrations of Na! as compared with those of higher initial concentrations of Na!. By an increase in the amount of Ag! at constant Na! concentration the amount of cubic Ag! decreased: by aging this amount increased. By dilution of a complex solution of Ag! + AgN03 a larger amount of cubic Ag! was formed when the initial concentration of AgN03 was lower (1 M as compared to 8 M AgNOa). In Ag! sols prepared in water-methanol and water-ethanol mixtures, the amount of cubic and/or hexagonal modifications of Ag! changes, by an increase in the percentage of alcohol, in another way than it does in water-dioxane and water-acetone systems. By comparing the changes of the dielectric constant of the medium, the surface tension and the solubility of Ag! it can be concluded that complexly dissolved Ag! is probably the factor which most influences the formation of a a or ~ structure of Ag!

X-Ray Diffraction Analysis of Differently Prepared AgI. IV

The cubic/hexagonal ratio of Ag! formed by dilution of a solution of silver iodide in Na! and AgN03 solutions respectively, and the cubic/hexagonal ratio of Ag! formed in statu nascendi in mixed solvents has been investigated. The complex solution of Ag! + Na! (1, 2, 3, 4, and 8 M Na!) was diluted with water to 0.01 M Na!. The formed mixtures of cubic and hexagonal Ag! contained less cubic Ag! in systems of lower initial concentrations of Na! as compared with those of higher initial concentrations of Na!. By an increase in the amount of Ag! at constant Na! concentration the amount of cubic Ag! decreased: by aging this amount increased. By dilution of a complex solution of Ag! + AgN03 a larger amount of cubic Ag! was formed when the initial concentration of AgN03 was lower (1 M as compared to 8 M AgNOa). In Ag! sols prepared in water-methanol and water-ethanol mixtures, the amount of cubic and/or hexagonal modifications of Ag! changes, by an increase in the percentage of alcohol, in another way than it does in water-dioxane and water-acetone systems. By comparing the changes of the dielectric constant of the medium, the surface tension and the solubility of Ag! it can be concluded that complexly dissolved Ag! is probably the factor which most influences the formation of a a or ~ structure of Ag!

Radiometric Determination of Agl-TlI-(1311), Agl-HgI2-(1311), and HgI2-TlI-(1311) Systems

The principle and procedure for radioanalytical determination of intermolecular interactions in a polycomponent system of »Solid- liquid: type is described. As models AgI-TlI-(131!), AgI-Hglr( 131!), and HgI2-TlI-(131I) systems were used. The AgI-TlI-(1311) system was analysed in detail and radioanalytical results obtained were compared using X-ray analysis, conductivity and micro differential thermal analysis. Of the other two systems the results obtained were compared only with the remlts of X-ray analysis. As all the results obtained agree with literature data, it is concluded that the described radioanalytical method is applicable for adequate analysis of intermolecular interactions in mixed systems

X-ray Investigations in the System U-N-Te

The crystal structures of the ternary compounds in the system U-N-Te were investigated. The compounds were prepared in a powder form by reacting UN + X Te (0.4 ~ X ~ 2.0). Powdered uranium mononitride, UN, and elementary tellurium were mixed in the desired proportions and subsequently heated at 900-1000 °c in evacuated and sealed quartz tubes. The powder diagrams were taken with a Philips diffractometer (CuK, radiation)

On Negative Silver Iodide Sols in Sodium n-Laurylate Solutions

This paper describes a ·physico-chemical •study of the interaction between the anionic surfactant sodium n-laurylate NaL and the negative stable silver iodide prepared »in statu nascendi«, with emphasis on the colloid properties of the system in aqueous media. Negative stable silver iodide sols of 0.001 M contained NaL solutions from 0.0000001 M to 0.01 M with 0.001 M Na! at 20 °c. Turbidity measurements show the formation of two pronounced Tyndall maxima; eleatmn microscopy and X-ray diffraction analysis data show the dependence of crystallite sizes and sol dens·tties on the concentration of NaL. For the systems examined under ageing the results obtained indicate, as a reasonable possibility, that different effects of NaL on negative silver iodide sol in statu nascendi for systems with NaL below and above the critical micellar concentration can be proposed

The Preparation of Sodium Perchlorate Labelled with Chlorine-36

In order to investigate the effect of perchlornte ion on the thyroid glancP it was 111ecessary to rprepare 36 ~ 1 labelled sodium rperchlornte. The solution of 36Cl in the form of 4.5 ml. 2.1 N hydrochloric acid, with specific activity ca. 120 μc/g Cl obtained from Amernham (Code CIS. 1) was avadlable as the source of radiochlorine. With regard to the experimental results of Izgaryshev et al. 2 radioactive perchlorate was prepared by anodic oxydatio111 of Ca36 Cl 2

The Preparation of Sodium Perchlorate Labelled with Chlorine-36

In order to investigate the effect of perchlornte ion on the thyroid glancP it was 111ecessary to rprepare 36 ~ 1 labelled sodium rperchlornte. The solution of 36Cl in the form of 4.5 ml. 2.1 N hydrochloric acid, with specific activity ca. 120 μc/g Cl obtained from Amernham (Code CIS. 1) was avadlable as the source of radiochlorine. With regard to the experimental results of Izgaryshev et al. 2 radioactive perchlorate was prepared by anodic oxydatio111 of Ca36 Cl 2

Investigation of Subsystems of Colloidal Agl by Radioactive Tracer Technique

Stable silver iodide sols were prepared in statu nascendi, i.e. by direct mixing of precipitation components. The sols contained 0.0001, 0.001 or 0.01 M Nal (pl = 4, 3 or 2) and 0.0001, 0.001 or 0.01 M/l Agl at 293 K. The following subsystem fractions were separated from the stable silver iodide suspensions by radioactive tracer technique with superspeed Sorvall SS-1 centrifuge and Beckman Model L Preparative ultracentrifuge: embrional, metaphasic, and roughly dispersed silver iodide. Formation and transformation of each subsystem was examined under various conditions (pl, age of sols, addition of coagulation electrolyte Mg-nitrate). The results described reveal a number of simultaneous processes in stable silver iodide suspensions: the embrya disappear and are transformed into the metaphase and solid phase; the methoric mass also disappears turning into the solid phase, i. e. the silver iodide particles grow. The method employed is described in detail and the results obtained show the dependence of the silver iodide subsystem structure on its age and conditions at which it is formed

On Silver Iodide in Surfactant Solutions

The roile of n-dodecylammonium nitrate, DDAN03, at the interface (AgI)solid/(electrolyte)solution was 1nvestigated. Silver iodide was prepared (i) by isoelectric precipitation, (ii) by equiva1eint precipitation in statu nascendi, and (iii) in an excess of potassium iodide in the presence of DDAN03• The employed surfactant affects the crys,tallographic and colloid properties of Ag! in various ways. The infliuence of surfactant was examined in the course of precipitation and peptization of silver iodide. Based on the results obtained, a mechanism of the interaction o.f silver iodide sols with surfactants was suggested. The proposed model indicates the role of surfactant 1n the equilibriation process at the interface »orystal/ /electrolyte solution« in the processes of the solid phase formation and peptization