Prediction of KSP from Rf Values: Thin Layer Chromatography of 47 Metal Ions on Stannic Arsenate in Aqueous Hydrochloric Acid Systems

Abstract

The adsorption behaviour of 47 metal ions has been studied in aqueous HCl systems using stannic ersenate layers. The effect of solvent pH on R_f alongwith the complexation effect of HCl has been investigated. On the basis of R_f values the K_SP of some metel arsenates have been predicted. HCl has been utilized to resolve some binary and ternary mixtures such as Be²⁺ - Mg²⁺, Zr⁴⁺ - La³⁺, Th⁴⁺ - Ce⁴⁺, Th⁴⁺ - UO²⁺ ₂, Cr³⁺ - Mo⁶⁺ or W⁶⁺, Sb³⁺ - Bi³⁺ - Cd²⁺ and Ag⁺ - Cu²⁺ - Cd²⁺.     

Chelation Ion Chromatography on DMSO Impregnated Silica Gel-G Layers: Specific Separation of Cd2+, W6+, and Zr4+ from Transitional Metal Ions

Abstract

Chelation ion chromatography of metal ions on DMSO impregnated silica gel-G layers in ether; DMSO: 1M HNO₃ (1:1); n-butanol: acetone: HNO₃ (6:6:1) and di-isopropyl ether: DMSO: THF systems having varying compositions, was performed. The zero R_f for a number of cations is explained in terms of precipitation and strong adsorption. It was possible to separate Cd²⁺, W⁶⁺, Zr⁴⁺, Zn²⁺ and VO²⁺ from numerous metal ions. A number of analytically important binary and ternary separations were also achieved and were found useful in synthetic alloy analysis.     

Chromatographic study of anionic complexes

Summary In this paper the variation of diffusion, through filter paper strips by the ascending method, of citrate complexes of Cu²⁺, Ni²⁺, Co²⁺ and Fe³⁺ has been studied using 50%, 55% and 60% ethanol as solvents. The R_f value is found to be less with higher concentrations of ethanol used. It has been noted that with 50% ethanol the R_f value increases with the addition of citrate and finally tends to become constant with high concentrations of citrate ions. In 55% ethanol the R_f value becomes constant at a later stage. In 60% ethanol it is noted that the R_f value does not change with small additions of citrate, but on increasing its concentration the R_f value begins to diminish.Part II see Z. analyt. Chem. 165, 81 (1959).     

Chromatographic behaviour of metal ions on tin(IV) and titanium(IV) antimonate papers

Summary The chromatographic behaviour of 49 metal ions has been studied on papers impregnated with Sn(IV) and Ti(IV) antimonates in aqueous HNO₃ and mixed solvent systems containing dimethyl sulphoxide. Numerous separations have been achieved and the Alberti equation, for Sn(IV) and Ti(IV) antimonate papers, in the modified form: –nloga K⁺=R_M + constant (a K⁺=activity of K⁺), has been verified. The effect of the concentration of impregnating reagents on these papers has been determined and compared with other papers. The effect of pH on R_f, R_i, log R_f and R_M values of metal ions has also been examined in aqueous systems.     

Fractional precipitation synthesis and photoluminescence of La2Ti2O7:xEu3+ phosphors

Eu³⁺ ions activated La₂Ti₂O₇ (La₂Ti₂O₇:xEu³⁺) phosphors have been successfully synthesized by a fractional precipitation method from commercially available La₂O₃, Eu₂O₃, HNO₃, Ti(SO₄)₂·9H₂O and NH₃·H₂O as the starting materials. Detailed characterizations of the synthetic products were obtained by fourier transform infrared spectroscopy (FT-IR), X-ray diffractometry (XRD), differential thermal analysis, thermogravimetry and derivative thermogravimetry (DTA-TG-DTG), transmission electron microscopy (TEM), and photoluminescence (PL) spectroscopy. The results show that the precursor is composed of amorphous particles with quasi-spherical in shape and about 50 nm in size. Moreover, the precursor could be converted into pure La₂Ti₂O₇ phase by calcining at 1000 °C for 2 h in air. The as-synthesized La₂Ti₂O₇ particles are approximate polyhedron in shape and about 100–200 nm in size. PL spectroscopy of La₂Ti₂O₇:xEu³⁺ phosphors reveals that the strongest emission peak is located at 616 nm under 275 nm ultraviolet (UV) light excitation, which corresponds to the ⁵D₀→⁷F₂ transition of Eu³⁺ ions. The quenching concentration of Eu³⁺ ions is 10.0 mol%, and its corresponding fluorescence lifetime was 1.82 ms according to the linear fitting result. Decay study reveals that the ⁵D₀→⁷F₂ transition of Eu³⁺ ions has a single exponential decay behavior.     

Oxidative nonstoichiometry in perovskites,an experimental survey; the defect structure of an oxidized lanthanum manganite by powder neutron diffraction

Oxide perovskites showing oxidative nonstoichiometry (ABO_3+x) have been investigated. The structure of LaMn³⁺_0.76Mn⁴⁺_0.24O_3.12 has been investigated by powder neutron diffraction and a composition (La_0.94±0.02□_0.06±0.02)(Mn³⁺_0.745Mn⁴⁺_0.235□_0.02)O₃ with partial elimination of La₂O₃ and vacancies on both the A and B metal sites determined. A much smaller degree of nonstoichiometry has been found for LaVO_3+x(x ? 0.05), and LaCrO₃, and EuTiO₃ did not show nonstoichiometry under the conditions used. A single phase region from Ba_0.8La_0.2Ti⁴⁺_0.8Ti³⁺_0.2O_3.0 to Ba_0.8La_0.2Ti⁴⁺O_3.1 has been confirmed for lanthanum-doped BaTiO₃, but the solubility of La³⁺ in SrTiO₃ is very small; consideration of the ionic radii indicates that the dopant ion of higher oxidation state must be significantly smaller than the normal ion to stabilize a wide nonstoichiometric region with B site vacancies. The extensive nonstoichiometry shown by LaMnO_3+x, in contrast to the other lanthanum-transition-metal perovskites LaBO₃, may result from the much larger reduction in ionic radius from Mn³⁺ to Mn⁴⁺ than is found for other transition-metal ions.     

Thin layer chromatography of 57 metal ions on an inorganic ion-exchanger in mixed solvent systems

Summary Thin layers of stannic arsenate have been used to study the chromatographic behaviour of 57 metal ions in different mixed solvents. Au³⁺, Hg²⁺, UO ₂ ²⁺ , Be²⁺ and Al³⁺ and others can be easily separated from numerous metal ions. Fast quaternary, ternary and binary separations have been also achieved. Important separations are discussed. The effect of pH, duration of heating of ionexchanger plates and layer thickness on the R_f values has been studied and discussed. It is shown that Lederer's equation is also obeyed by thin layers of stannic arsenate, if instead of concentration of Na⁺ ion its activity is taken into consideration.     

Selective Amperometric Determination of Thorium by Ethyl Cyanoglyoxalate Phenyl-2-Carboxylic Acid Hydrazone

Abstract

The reagent ethyl cyanoglyoxalate phenyl-2-carboxyllc acid hydrazone has been developed for the selective amperometric determination of thorium. Commonly associated ions like UO²⁺ ₂, Pe³⁺, La³⁺, Ce⁴⁺, and Zr⁴⁺ do not interfere even when present in ten fold molar excess. 23μg to 4.6mg thorium can be determined within an error of ±1.5 percent.     

Paper Chromatographic Separations of Metal Ions on Collidinium Tungstoarsenate Papers

Abstract

A systematic study of the chromatography of metal ions on collidinium tungstoarsenate papers has been performed using seven different mixed solvent systems. R_f values of 30 metal ions have been determined by ascending technique and are discussed. The study demonstrates that specific extraction of both Sn(ii) and Sn(iv) is possible in 0.1 mol dm^?3 HNO₃ in 80% (v/v) 1-propanol and their mutual separation can be carried out in solvent system 1 mol dm^?3 HCl in 33% (v/v) 1-propanol. In addition some binary and ternary separation of metal ions have also been achieved on these papers. For a comparison R_f values on plain papers have also been determined in all the solvent systems.     

Lipophilicity of Metallic Complexes of 4-Methoxyphenyl - 4' - Chlorobenzoylhydrazine as Estimated from Principal Component Analysis of thin Layer Chromatographic Retention Data

ABSTRACT

The relative lipophilicity of ten metallic complexes of 4-methoxyphenyl-4'-chlorobenzoylhydrazine with Cu²⁺, Co²⁺, Mn²⁺, Ni²⁺, Pd²⁺, Fe³⁺, Cr³⁺, La³⁺, Ce⁴⁺ and UO₂ ²⁺ with potentially anti-inflammatory properties have been determined by reversed-phase thin-layer chromatography using C₁₈ plates and water-methanol mixtures as eluents. The R_F values of each compound increased linearly with increasing concentration of methanol in the eluent. Principal component analysis allowed a more rational and objective estimation and comparison of lipophilicity determined by RPTLC. Scatterplots of the scores onto a plane described by the first two components showed clustering of the complexes according to the nature of the central cation, obtaining in this way a "congeneric lipophilicity chart". Generally, the presence of cation increases the lipophilicity expressed as scores along the first principal component, practically in the same way. This means that the lipophilic behavior of metallic complexes depends firstly of the structure of ligand. However, the most lipophilic effect was observed in the case of Cu²⁺, Pd²⁺, La³⁺ and Cr³⁺.     

Chromatographic study of anionic complexes

Summary The diffusion of tartrate complexes of Cu²⁺, Co²⁺, Ni²⁺ and Cd²⁺ through filter paper strips has been examined using 50% and 60% ethanol as solvents. The R_f values are higher when 50% ethanol is used. When 50% ethanol is used, it is noted in the case of Cu²⁺, Co²⁺ and Ni²⁺ that the R_f values decrease with the addition of tartrate in the beginning. Then the value increases and finally becomes constant. In case of Cd²⁺ the R_f value decreases by the addition of tartrate. In 60% ethanol the R_f value does not change by small additions of tartrate but decreases with higher concentration of the complexing agent. In case of Cd²⁺ the R_f value becomes zero by increasing the concentration of tartrate.Part I: See Z. analyt. Chem. 159, 332 (1957/58).     

Potentiometric and thermodynamic studies of 3-methyl-1-phenyl-{p-[N-(pyrimidin-2-yl)-sulfamoyl]phenylazo}-2-pyrazolin-5-one and its metal complexes

The dissociation constants of 3-methyl-1-phenyl-{p-[N-(pyrimidin-2-yl)sulfamoyl]phenylazo}-2-pyrazolin-5-one and metal-ligand stability constants of its complexes with some transition metal ions have been determined potentiometrically in 0.1 M-KCl and ethanol—water mixture (30 vol. %). The order of the stability constants of the formed complexes increases in the sequence Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, La³⁺, Hf³⁺, UO ₂ ²⁺ , Zr⁴⁺. The effect of temperature was studied and the corresponding thermodynamic parameters (ΔG, ΔH, and ΔS) were derived and discussed. The dissociation process is nonspontaneous, endothermic, and entropically unfavourable. The formation of the metal complexes was found to be spontaneous, exothermic, and entropically favourable. Abstracted from his M.Sc. Thesis.     

Effect of p-tert-butylcalix[4]arene fitted with phosphinoyl pendant arms as synergistic agent in the solvent extraction of trivalent lanthanoids with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione and structural study of solid complexes by IR,NMR and X-ray

The synergistic solvent extraction of five selected lanthanoid ions (La³⁺, Nd³⁺, Eu³⁺, Ho³⁺ and Lu³⁺) with 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione (HL) and 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetrakis-(dimethylphosphinoylmethoxy)calix[4]arene, (S) in CHCl₃ has been studied. It was found that in presence of this phosphorus-containing calix[4]arene the lanthanoid ions have been extracted as [LnL₃S₂]. The values of the equilibrium constants and the separation factor have been calculated. The influence of the synergistic agent on the extraction process has been discussed.     

Wasserfreie Selenite des Lanthans: Synthese und Kristallstruktur von La2(SeO3)3 und LaFSeO3

Anhydrous Selenites of Lanthanum: Syntheses and Crystal Structures of La₂(SeO₃)₃ and LaFSeO₃ Colorless single crystals of La₂(SeO₃)₃ were obtained via the decomposition of La₂(SeO₄)₃ in the presence of NaCl in sealed gold ampoules. The compound crystallizes in the orthorhombic system (Pnma, Z = 4, a = 846.7(1), b = 1428.6(1), c = 710.3(2) pm, R_all = 0.0223) and contains La³⁺ in tenfold coordination of oxygen atoms which belong to seven SeO₃^2– groups. Hence, three of the latter act as bidentate ligands. The reaction of LiF with La₂(SeO₄)₃ in sealed gold ampoules yielded colorless single crystals of LaFSeO₃ (monoclinic, P2₁/c, Z = 12, a = 1819.8(3), b = 715.75(8), c = 846.4(1) pm, β = 96.89(2)°, R_all = 0.0352). The crystal structure contains three crystallographically different La³⁺ ions. La1 is surrounded by six oxygen atoms from five SeO₃^2– groups and four fluoride ions, La2 is coordinated by two bidentate SeO₃^2– ions and seven fluoride ligands. La3 is surrounded by oxygen atoms only with the coordination number and polyhedron being almost the same as found for La³⁺ in La₂(SeO₃)₃. Furthermore, the crystal structures of both compounds are strongly influenced by the lone pairs of the SeO₃^2– groups.     

Selective ion-exchangers containing phosphorus in their functional groups

A series of selective ion-exchangers was synthetized, containing phosphinic or phosphonic acid functional groups. The selective sorption of Sc³⁺, Fe³⁺, Ga³⁺, In³⁺, Al³⁺, La³⁺, Pb²⁺, Co²⁺ and Ca²⁺ ions in 0.1–4.0M HNO₃ medium was investigated using a batch experiment technique. The selectivity of these exchangers generally decreased in the order: Sc>Fe>In>Ga>Al>La>Pb>Cu>Co>Ca. The observed large differences in selectivity resulted in effective separation procedures of scandium from lanthanides, and gallium (or indium) from bivalent elements. The selective separation of these ions from their different mixtures is also possible.     

Cation ordering in Ca2La8(SiO4)6O2

The distribution of La³⁺ and Ca²⁺ over the cation sites in Ca₂La₈(SiO₄)₆O₂ was determined by single-crystal X-ray diffraction. Ca₂La₈(SiO₄)₆O₂ has the apatite structure, and all available evidence indicates that the space group is $\text{P6}{}_3\text{m}$, thus precluding a completely ordered structure. The 6h lattice sites are occupied by La³⁺. In contrast, the 4f sites are occupied equally by La³⁺ and Ca²⁺ ions. Consideration of the properties of the La³⁺ and Ca²⁺ ions suggests that this distribution is thermodynamically favored for this composition. A simple Ising model suggests ordered columns. These would not be precluded by space group $\text{P6}{}_3\text{m}$, if the correlation between adjacent columns were random.     

Weitere magnetische Untersuchungen an Ti3−xMxO5-Phasen (M = Al3+, Fe2+, Mn2+, Mg2+) mit einem Beitrag über CrTi2O5

Additional Magnetic Examinations of Ti_3?xM_xO₅-Phases (M = Al³⁺, Fe²⁺, Mn²⁺, Mg²⁺) with a Contribution about CrTi₂O₅ Ti_3?xM_xO₅ was prepared with M = Al³⁺, Fe²⁺, Mn²⁺, and Mg²⁺. Die magnetic properties of this phases were examinated by the Faraday method in respect to the temperature. The well known magnetic effect of Ti₃O₅ near 450 K is shifted to lower degrees if Ti is replaced by Al, Fe, Mn, or Mg. Compared to Ti_3?xV_xO₅ and Ti_3?xCr_xO₅ the stability of the low temperature-form of Ti₃O₅ is much more reduced in Ti_3?xM_xO₅ (M = Al, Fe, Mn, Mg). The crystal structure investigation of CrTi₂O₅ explained the anomalous behaviour of the Cr³⁺ and V³⁺ doped Ti₃O₅.     

Chromatographic separation of inorganic ions on thin layers of lanthanum silicate ion-exchanger

Summary Thin layers of lanthanum silicate have been used to study the chromatographic behaviour of 28 metal ions in aqueous and mixed systems. As³⁺, Mo⁶⁺, Sb³⁺, Ti⁴⁺ and others can be easily separated from a number of inorganic ions. Fast ternary and binary separations have also been achieved and various separations are discussed. It is shown that Alberti's relation is also obeyed by thin layers of lanthanum silicate. Presented at the 21^st ISC held in Stuttgart, Germany, 15^th–20^th September, 1996     

Li2O-Ln2O3-SiO2:Eu3+,Bi3+体系的结构

采用ｓｏｌ－ｇｅｌ法合成了系列发光体Ｌｉ２Ｏ－Ｌｎ２Ｏ３－ＳｉＯ２：Ｅｕ＾３＾＋，Ｂｉ＾３＾＋，并确定了发光体的物相结构。当Ｌｎ＾３＾＋＝Ｙ＾３＾＋和Ｌｎ＾３＾＋＝Ｌａ＾３＾＋时，紫外光激发下Ｅｕ＾３＾＋的发射分别以红光和橙光为主，只存在一种Ｅｕ＾３＾＋发光中心；Ｌｎ＾３＾＋＝Ｇｄ＾３＾＋时，至少存在两种Ｅｕ＾３＾＋发光中心和两种Ｂｉ＾３＾＋发光中心（共掺杂Ｅｕ＾３＾＋，Ｂｉ＾３＾＋的吸收和发射所     

Ein Beitrag über Oxide vom Typ AMO4 (A = Ti3+, Cr3+; M = Nb5+, Ta5+)

A Contribution on Ternary Oxides of the AMO₄-Type (A = Ti³⁺, Cr³⁺; M = Nb⁵⁺, Ta⁵⁺ ) CrNbO₄, CrTaO₄, TiNbO₄, and TiTaO₄ were prepared by CO₂-laser technique. X-ray single crystal investigations show a random distribution of the metal ions in Rutil type structure, space group D–P4₂/mnm. Calculations of the free energy of reaction between Ti₂O₃ and Nb₂O₅ show higher stability of TiO₂ beside NbO₂. In TiNbO₄ both metals exhibit the oxidation state +4.