Showing papers in "Journal of Inorganic and Nuclear Chemistry in 1968"

Thermodynamics of formation of simple spinels

Abstract: The enthalpies of formation from the oxides of thirty-two 2–3 and 2–4 spinels have been determined by solution calorimetry in molten oxide solvents at 970°K. Spinels studied were the aluminates, ferrites, gallates, and manganites of Mg, Co, Ni, Cu, Zn, and Cd, ZnAlFeO4, Mg2TiO4, Co2TiO4, Zn2TiO4, CoZnTiO4, ZnNiTiO4, Co2GeO4, and Ni2GeO4. When possible the enthalpy data have been combined with free energy data from the literature to calculate entropies of formation. Regularities in the thermodynamics of spinel formation have been discussed in terms of a “characteristic spinel-forming reaction”.

Metal complexes as ligands—IV [1,2,3]: Bi- and Tri- nuclear complexes derived from metal complexes of tetradentate salicylaldimines

Abstract: The detailed synthesis is reported for a series of bi- and tri- nuclear complexes formed by using the donor properties of the two cis-oxygen atoms in metal (M) complexes of tetradentate Shiff bases (TSB) derived from salicylaldehyde or o-hydroxyacetophenone. The “complex ligands” [MTSB, M  Cu(II), NiU(II) or Zn(II)] readily react with metal halides M′X 2 [M′  Cu(II) or Zn(II)] or metal perchlorates M′(ClO 4 ) n [M′  Cu(II), Ni(II), Fe(II), Al(III), Mg(II), Ca(II), Sr(II), Ba(II), Na(I), or Ag(I) to form the complexes of the general types [MTSB) M′X 2 ] and M′(MTSB) 2 (ClO 4 ) n , many of which are hydrated. The low magnetic moments of a number of the compounds are due to an antiferromaagnetic interactions between the metals. While a number of complexes of type [(MTSB)M′X n ] have previously been reported to be non-ionic, the complexes M′(MTSB) 2 (ClO 4 ) n are found to have the expected electrical conductivities in nitrobenzene solution. A systematic trend in the magnetic moments and spectral absorptions of the complexes CuTSB is due to an increased steric distortion from a planar towards a pseudo-tetrahedral environment about the copper atom as the length of the carbon chain(R) joining the adjacent nitgrogen atoms in TSB(-O…N-R-N.…O-) increases. The spectra indicate that the chlorine bonded copper atom in [(CuTSB)(CuCl 2 complexes becomes increasingly distorted from a planar towards a tetrahedral configuration as the copper inside the CuTSB distorts the same way, up to a point where the approach of the two pseudo-tetrahedral copper atoms would be too close. As expected, this distortion appears to be slightly greater when bromine atoms are substituted for chlorine atoms in such compounds. In a given [CuTSB)CuCl 2 or M′(CuTSB) 2 (ClO 4 ) n ·xH 2 O complex, the copper atom inside the CuTSB appears to be considerably closer to planar stereochemistry than it is the free CuTSB. It is concluded that the stereochemistries of the metals in the mono-, bi-, and tri-nuclear complexes are due to, and to a large extent predictable from, the steric requirements of the ligands and metals. Some i.r. spectra of MTSB and the bi- and tri-nuclear derivatives are reported, and earlier assignments of absorptions in the complexes MTSB are re-examined.

Crystal nucleation in Fe(III) solutions and hydroxide gels

Abstract: Fe(III) hydroxide gels were produced from a series of 0·5 molal Fe(III) nitrate solutions hydrolyzed for varying times and at pH values up to 1·5. The types and sizes of crystals produced by aging the gels at 60°C in the presence of excess NaOH were examined qualitatively by electron microscopy, selected area diffraction and X-ray diffractometry. Acicular goethite crystals were nucleated in the gel by extremely small goethite crystals which had formed during slow hydrolysis in the parent iron solution. Goethite crystals occurred as cruciform twins showing an apparent (021) twin plane when epitaxial growth commenced on nuclei which were extremely small crystals of hematite formed during very rapid hydrolysis at precipitation. According to conditions of pH the hematite nuclei grew to hematite, to hematite with epitaxial growths of goethite, or to twinned goethite crystals apparently free of hematite.

New crystalline phases of zirconium phosphate possessing ion-exchange properties

Abstract: The preparation of two new crystalline zirconium phosphates, Zr(HPO4)2 and Zr(HPO4)2 · 2H2O, is reported. The compounds are characterized and formulated on the basis of their X-ray diffraction powder patterns, chemical analysis, thermal dehydration behaviour, and ion-exchange properties. Model structures for the new compounds are proposed on the basis of the previously known structure of Zr(HPO4)2·H20.

Rare-earth trishexafluoroacetylacetonates and related compounds☆

Abstract: Rare-earth trishexafluoroacetylacetonates, Ln(hfac)3·nH2O, have been prepared and characterized by chemical analyses, infra-red spectra, and X-ray powder diffraction patterns. Two series of hydrates exist: Ln(hfac)3·3H2O (Ln = LaNd) and Ln(hfac)3·2H2O (Ln = LaLu). No evidence for a lower hydrate was found. A mixed ligand chelate, Ln(hfac)2CF3CO2·2H2O, is a byproduct of the tris chelate preparations. Several series of salts were also prepared, including NH4Ln (hfac)4·nH2O (n = 0 and 1 for Ln = LaNd; n = 0 for Ln = SmLu), pyHLn(hfac)4·nH2O (n = 0 and 1 for Ln = LnNd; n = 0 for Ln = SmLu), and (pyH)2Ln(hfac)5 (Ln = LaNd). Ln(hfac)3·3H2O. NH4Ln(hfac)4·H2O, and pyHLn(hfac)4·H2O are reversibly converted with great ease to Ln(hfac)3·2H2O, NH4Ln(hfac)4, and pyHLn(hfac)4, respectively. Most of the chelates studied are probably eight-co-ordinate, including Ln(hfac)3·3H2O, NH4Ln(hfac)4·H2O, and pyHLn(hfac)4·H2O, but (pyH)2Ln(hfac)5 may be ten-co-ordinate.

Preferential extraction of lanthanides over trivalent actinides by monoacidic organophosphates from carboxylic acids and from mixtures of carboxylic and aminopolyacetic acids

Abstract: In the extraction of lanthanides and trivalent actinides by monoacidic organophosphates from mineral acid solutions the distribution coefficients of the two groups of elements overlap, with americium behaving most like cerium or praseodymium. Substitution of carboxylic acids, especially hydroxy acids, for the mineral acids shifts the americium distribution coefficients downward slightly relative to the lanthanides. This effect becomes more pronounced with increasing pH. The presence of strongly-complexing aminopolyacetic acids causes a much larger shift, which increases with the number (at least up to five) of acetic acid groups in the complexing agent. Extraction by di(2-ethylhexyl) phosphoric acid (HDEHP) from lactic acid solutions containing the sodium salt of diethylenetriaminepentaacetic acid (DTPA) provides an effective system for completely separating the two groups of elements. Monoesters of phosphonic acids give similar preferential extraction of the lanthanides. Under conditions optimum for group separation, neodymium is the least extractable of the lanthanides and californium is the most extractable of the transplutonium elements. At a constant pH, extractions of americium, californium, and the middle lanthanides are inversely proportional to the DTPA concentrations from 10−4 to 10−1 M, while extractions of the other lanthanides vary so as to reverse the order of extractability of the lower lanthanides. With a constant DTPA concentration, the difference between the extractability of americium and the middle lanthanides increases slowly with pH, while lanthanum and cerium gradually reverse their positions relative to the middle lanthanides. The extracted species contains a metal carboxylate complex.

The infra-red spectra and structure of the rare-earth benzoates

Abstract: The i.r. absorption spectra for benzoic acid and the benzoates of Na, Pr, Nd, Er, and Tm have been measured over the frequency range 3400−200 cm−1. Frequencies for the rare-earth benzoates are reported for the first time. Previously published data and observations made in this research are used to suggest several band assignments. The CC and CH bands of the phenyl nucleus are not greatly changed in the lanthanon salts. The various bands associated with the carboxylate group motions are considerably altered in the salt. The modifications of several of the bands are interpreted to indicate the benzoate ion is serving as a bidendate ligand, and the lanthanon ion is 6-co-ordinated in lanthanon benzoates. Such an interpretation accounts for some of the properties of these benzoates such as: solubility, ease of dehydration, and conductance. Benzoic acid, sodium benzoate, the light lanthanon benzoates, and the heavy lanthanon benzoates can be distinguished from each other in terms of their i.r. spectra. The bands useful for such distinctions are reported.

Phase relationships in the americium--oxygen system.

Abstract: Phase relations in the americium-oxygen system between 1·50 < O/Am < 2·00 were studied using Guinier and Debye diffraction methods on quenched and annealed samples. The cubic Am2O3 phase was found to be capable of dissolving excess oxygen and exists, at room temperature, over a wide range of stoichiometry. The upper boundary of this phase occurs at about AmO1·67, Between this composition and AmO2·00 at least one other intermediate phase is thought to exist. Evidence was found for what is believed to be a new Am2O3 phase which is probably monoclinic (B-type rare earth sesquioxide structure). The likelihood for the existence of this phase, as well as the cubic and hexagonal Am2O3 phases, is discussed in terms of a lanthanide/actinide oxide analogy based on considerations of ionic radii. A homologous series of substoichiometric ordered intermediate phases was not observed. The lack of such phases in this system is thought to be influenced by self-induced radiation damage caused by the alpha decay of americium-241.

Multiple and single bond energies in inorganic molecules

Abstract: The new method of calculating bond energies recently reported has now been extended to include multiple bonds. For carbon-carbon double and triple bonds the energy is 1·50 and 1·75 times the single bond energy when corrected for the multiple bond length. These multiplicity factors are used to calculate the single bond energies for nitrogen and oxygen that would correspond to the experimental bond lengths and dissociation energies of N 2 and O 2 . Three different single bond energy contributions each for nitrogen and oxygen are thus determined, and estimates are made for similar values for fluorine, phosphorus, sulfur, chlorine, bromine and iodine. The possible significance of such values is discussed in terms of bond energy calculations for 141 gaseous molecules, based on a consideration of the effect of lone pair electrons in bond weakening. Calculated bond energies for CO, CO 2 , NO, NO 2 , and other compounds are in excellent agreement with the experimental values.

Structure and ion-exchange characteristics of polyantimonic acid

Abstract: The chemical analysis of a hydrated antimony oxide has shown that its composition may be represented by the empirical formula Sb2O5·4H2O. By X-ray analysis a cubical unit cell of 10·3 A and a face-centered symmetry could be determined, leading to the formula {[ H 3 Sb 3 O 5 (OH) 8 ] 3 [ H 5 Sb 5 O 6 (OH) 18 ]} . The ion-exchange capacity amounts to 5·05 m-equiv./g and the compound is very selective for Ag+, Pb2+, Tl+ and Sr2+. The ion-exchange mechanism is very similar to that for zeolites, although the origin of the induced charges is here ascribed to polymerization and condensation of antimony oxide. At very low loading polyantimonic acid has a pronounced selectivity for Sr2+ in an acid medium.

Ion exchange properties of tin(IV) materials — I Hydrous tin(IV) oxide and its cation exchange properties

Abstract: The preparation of hydrous tin(IV) oxide in a suitable form for use as an ion exchanger is described. The evidence of X-ray, Mossbauer and differential thermal analysis data suggests that the exchange material is simply “wet” tin(IV) oxide and that the oxide is simply a host for adsorbed water, which itself must act as the exchanger. The cation exchange properties of the hydrous oxide both as a precipitate and a dried gel have been investigated and compared. High distribution coefficients and apparent capacities have been obtained, a selectivity series Cu(II) > Zn(II) > Co(II) ≥ Fe(II) > Ni(II) > Mn(II) is established, and the dried material shows good stability towards strong solutions of HNO3 and H2SO4.

Synthesis and structure of phases in the In2O3Ga2O3 system

Abstract: Compositions Ga2−xInxO3(x = 0·0–1·0) having the β-Ga2O3 structure have been prepared in powder form and as single crystals by several techniques and characterized by X-ray and resistivity measurements. The composition InGaO3 was found to transform at high pressures to a new phase, InGaO3 II. InGaO3 II has a simple hexagonal oxide structure which is the first structure reported containing Ga+3 in five-fold co-ordination. The cell parameters are: a = 3·310 ± 0·002 A , c = 12·039 ± 0·002 A , Z = 2, ϱ c = 6·756 g/cm 3 , space group P63/mmc. Interatomic distances obtained from least-squares refinement results are In-O(1)[×2], 3·010 A; InO(2)[×6], 2·174 A; GaO(1)[×3], 1·911 A; GaO(2)[×2], 1·973 A. InGaO3 II is isotypic with hexagonal YA1O3, and its structure is related to that of YMnO3 which contains five-co-ordinated Mn+3.

Compound formation and Mn2+-activated luminescence in the binary systems R2O- and ROGa2O3

Abstract: The binary systems arising from combinations of Ga2O3 with the common oxides of Li, Na, K, Mg, Ca, Sr, Ba, Zn, Cd, and Pb have been investigated by solid state methods. Twenty compounds were isolated and their Mn2+-activated luminescence examined. The Li2O, Na2O, and K2O systems each contain two compounds (X2O·Ga2O3 and X2O·5Ga2O3); the MgO, ZnO, and CdO one (XO· Ga2O3); the SrO and BaO, three (4XO·Ga2O3, 3XO·Ga2O3, and XO·Ga2O3); and the PbO two (2PbO·Ga2O3 and PbO·Ga2O3). The three calcium gallate compounds previously reported (3CaO· Ga2O3, CaO·Ga2O3, and CaO·2Ga2O3), were confirmed. Four compounds were found to give significant Mn2+-activated luminescence; MgO·Ga2O3, ZnO·Ga2O3, K2O·5Ga2O3, and CaO·2Ga2O3 with characteristic peak emissions at 512, 513·5, 507 and 587 mn respectively. The crystal chemistry of AB2O4 compounds is discussed in view of the probable crystal structures of the compounds of this study and previous literature.

Crystalline insoluble salts of polybasic metals - III: Preparation and ion exchange properties of cerium(IV) phosphate of various crystallinities

Abstract: The effects of temperature, digestion time, PO 4 Ce ratio in solution and order of mixing the reactants on the composition and degree of crystallinity of cerium phosphate are reported. Four different cerium phosphate materials have been obtained; (1) amorphous CeP with PO 4 Ce ⋍ 1·7 , (2) microcrystalline CeP with PO 4 Ce = 1·15 , (3) microcrystalline CeP with PO 4 Ce = 1·55 , and (4) fibrous crystalline CeP with PO 4 Ce ∼ 2 . Preparative procedures and some ion exchange properties of these materials are reported and discussed. Fibrous CeP has been employed for the preparation of inorganic ion exchange papers or membranes containing no binder.

pH-meter corrections for titrations in mixtures of water and dioxan

Abstract: New measurements are reported for the values of the correction term log UH (valid for μ = 0·1 M(NaCl) and 25° and 30°C) which must be added to pH-meter readings taken in solutions of aqueous dioxan of mole fraction n2=0−0·387 (0–75 per cent v/v) in order to give the true concentration of hydrogen ion. Earlier data have been corrected in the light of later measurements of mean ionic activity coefficients, γ±, for hydrochloric acid in aqueous-dioxan mixtures and values of log ( 1 gg ± ) have been computed and tabulated by equal values of the argument n2.

Infra-red and PMR spectra of some organotin(IV) N,N-dimethyldithiocarbamates

Abstract: Several types of tin(IV) N,N-dimethyldithiocarbamato complexes, Cl2Sn(SSCN Me2)2, Me2Sn(SSCN Me2)2, MeXSn(SSCN Me2)2 (X=Cl, Br, I), and Me2SnX(SSCN Me2) (X=Cl, Br, I) have been prepared. Infra-red and PMR spectra of these complexes have been measured. The results suggest the chelation of dithiocarbamato group. An octahedral trans-configuration have been proposed for Me2Sn(SSCN Me2)2. Configuration of penta-co-ordinated Me2SnX(SSCN Me2) have also been discussed.

Diffuse reflectance and far-infra-red (450-190 cm−1) spectra of some tetragonally distorted copper(II) halide complexes with n-heterocyclic ligands

Abstract: The diffuse-reflectance and far-infra-red (450-190 cm −1 ) spectra are reported for complexes of the type Cu X 2 L 2 (where X = Cl or Br, L = 2-chloro-, 2-bromo-, 2-methyl-, 4-chloro-, or 3-bromopyridine), Cu X 2 (1,2,4-triazole) and CuCl 2 (phenazine). The spectra are discussed in terms of a varying tetragonal distortion and tentative assignments of the bands are given.

Thermodynamics and thermochemistry of cation exchange in zeolite Y

Abstract: A thermodynamic and thermochemical study has been made of the exchanges Na+ → Li+, Na+ → K+, Na+ → Rb+, Na+ → Cs+, Na+ → Cg+, Na+ → TV, 2Na+ → Ca2, 2Na2+, 2Na+ → Sr2+ and 2Na+ → Ba+ in the near-faujasite Linde Sieve Y. Of these ions only Li+, K+ and Ag+ were found to replace all Na+ at 25°C; the remainder replaced approximately 70 per cent of the Na+. An attempt has been made to correlate this limit with known cation positions of the Na+ ions. From the exchange equilibria thermodynamic affinity sequences have been obtained for the ions that give complete or partial exchange with Na+. For the former group Ag+ > K+ > Na+ > Li+; and for the latter Tl+ > Cs+ > Rb+ > Ba2+ > Na+ > Sr2+ > Ca2+. The thermodynamic equilibrium constants were calculated from exchange capacities corresponding to the maximum observed extents of exchange. From exchange heats obtained by direct calorimetry standard heats of partial and complete exchange have been evaluated. Exchanges of Na+ by Li+, Ca2+ and Sr2+ were endothermic, the remainder exothermic. Exchange of Na+ by K+ in methanolic solutions showed that the solvent had little effect upon this equilibrium but greatly influenced the rate of exchange. Standard entropy changes for the replacement of Na+ have been evaluated where possible. These were negative for uni-univalent exchanges except for Na+ → Ag+ and Na+ → Tl+. Positive entropy changes were observed for exchanges of Na+ by divalent ions. The thermodynamic functions for the formation of the mixed exchangers showed that the end members formed non-ideal solid solutions with each other. This behaviour was also reflected in the activity coefficients of the exchange ions in the mixed exchangers.

Metal complexes as ligands — V[1]: Binuclear copper complexes derived from bidentate Schiff base complexes

Abstract: The syntheses and properties are reported for the binuclear copper(II) complexes obtained when cupric chloride is reacted with bis(NR-salicylaldimino)copper(II) complexes, where R is a normal, secondary or tertiary alkyl, or a phenyl group. The binuclear complexes exhibit the pair-wise antiferromagnetism that typifies so many dimeric copper(II) complexes, but the singlet-triplet separation is unusually high (of the order of 300 cm −1 , or higher), and the magnetic properties do not differ greatly from compound to compound. This is in stark contrast to the known behaviour of copper halide adducts of tetradentate salicylaldimine copper(II) complexes, which have smaller singlet-triplet separations but exhibit much larger variations from compound to compound. These properties are explained in terms of a trans structure. for the binuclear compounds derived from the bidentate salicylaldimines, as opposed to the cis structure for the analogous tetradentate salicylaldimine derivatives. The trans structure allows the two copper atoms to adopt a configuration near to planar, with only a small amount of steric distortion towards tetrahedral, as the R-group on the salicylaldimine nitrogen becomes more bulky. The ligand field absorption spectra are also in keeping with the trans structure: the differences from compound to compound are consistent with a quite small trend from planar towards tetrahedral configuration as the R-group becomes more bulky; and the environment seems alike about each copper atom: band positions indicate that the copper in the binuclear complexes is closer to a planar configuration than in the parent bis(NR-salicylaldimino)copper(II) complexes.

Influence of atmosphere on the thermal decomposition of some transition metal oxalates

Abstract: The thermal decomposition of manganese, cobalt and nickel oxalate dihydrates have been studied by TGA and DTA in air and nitrogen atmospheres. In nitrogen the decomposition of the oxalate first yields the metal oxide MO, which in the case of cobalt and nickel is reduced to the metal by the nascent carbon monoxide. Correlations between nitrogen decomposition temperatures and cation electronegativities have been obtainnd. In air decomposition is initiated at a lower temperature than in nitrogen by the oxidation of the cation from the divalent to the trivalent state and a correlation between ease of oxidation and temperature reduction has been found.

A kinetic study of isotopic exchange reactions between lanthanide ions and lanthanide polyaminopolycarboxylic acid complex ions—I isotopic exchange reactions of Ce(III) with Ce(HEDTA), Ce(EDTA)−, Ce(DCTA)− and Ce(DTPA)2−

Abstract: The rates and mechanisms of the isotopic exchange reactions of Ce(III) ions with Ce(HEDTA); Ce(EDTA) − ; Ce(DCTA) − and Ce(DTPA) 2− complex ions have been investigated. The rate equations and the experimentally determined rate constants at 20°C, μ = 0·1 and acetate buffer concentration of 10 −2 M are as follows: • Rate = k 1 [H + ][Ce(HEDTA)]; where k 1 = 23·1 × 10 4 l.mole −1 min −1 • Rate = k 2 [H + ][Ce(EDTA) − ]; where k 2 = 9·4 × 10 4 l.mole −1 min −1 • Rate = k 3 [H + ][Ce(DCTA) − ] + k 4 [Ce(DCTA) − ] + k 5 [C(III)][Ce(DCTA) − ] where k 3 = 3·9 × 10 3 l.mole −1 min −1 ; k 4 = 4·2 × 10 −3 min −1 and k 5 = 5·6l.mole −1 min −1 • Rate = k 6 [Ce(DTPA) 2− ][H + ] 2 + k 7 [Ce(III)][Ce(DTPA) 2− ] where k 6 = 3·0 × 10 8 l. −2 mole −2 min −1 and k 7 = 1·6 l.mole −1 min −1 The mechanisms of the exchange reactions of the multidentate chelates are discussed in terms of the lability of the carboxylic acid groups. The exchange reactions are catalysed by acetate ions and the effects of increased acetate concentration on the various terms of the rate equations have been examined. Activation energies have been determined.

On the nature of the blue solutions of sulfur

Abstract: Deep blue solutions are formed by dissolving alkali tetrasulfides in aprotic, polar, organic solvents. Their spectra show three bands in the visible and the near UV - region at 16·2 × 103, 23·0 × 103, and 36·2 × 103 cm−1. The band at 16·2 × 103 cm−1. shows a weak, but well defined, vibrational fine structure at room temperature. The spacing between the subpeaks of 430 cm−1 is assigned to vibrations of the S2− ion formed by the homolytic dissociation of the S42− ion. The position of the S42− ⇄ 2S2− equilibrium has been studied in water-dimethylformamide mixtures as a function of the solvent composition and in pure DMF as a function of the ratio S:S2−. EPR investigations suggest the presence of two further sulfur radicals. It is proposed that the color of ultra-marine is also due to S2− ions.

The distribution of alkali metal, ammonium, and tetraethylammonium dipicrylaminates between water and nitrobenzene phases

Abstract: The extraction of univalent metal dipicrylaminates into nitrobenzene was investigated colorimetrically at pH = 10 keeping the ionic strength of the aqueous phase constant by means of the corresponding nitrates. The extraction of caesium and rubidium traces in the presence of weighable amounts of lithium and sodium dipicrylaminates and nitrates was studied radiometrically. Data are given on the coextraction of water with the alkali dipicrylaminates into nitrobenzene. The distribution is shown to be controlled by the following equilibria Me a + + DPA a − ⇌ Me org + + DPA org − and Me a + + DPA a − ⇌ MeDPA org . The equilibrium constants involved were evaluated and are discussed.

Crystalline insoluble acid salts of polyvalent metals and polybasic acids — VI

Abstract: The preparation of amorphous and crystalline titanium arsenate is described. Amorphous titanium arsenate is a very hydrolyzable material; its AsO4/Ti ratio was strongly dependent on the extent of washing. The crystalline material also hydrolyses, although to a lesser extent, at pH > 5. An apparent ion exchange capacity of 2·6 meq/g was found for Na+ at pH = 5. Some ion exchange properties of crystalline titanium arsenate are compared with those of crystalline titanium phosphate and zirconium arsenate. The formula Ti(HAsO4)2·H2O is ascribed to the crystalline product dried over P4O10.

Lanthanide complexes—VII: Complexes of yttrium and lanthanide chlorides and thiocyanates with triphenylarsine oxide and triphenylphosphine oxide

Abstract: Yttrium and the lanthanide chlorides and thiocyanates form complexes of the types MCl3(OPPh3)3, MCl3(OPPh3)4, M(NCS)3(OPPh3)3, M(NCS)3(OPPh3)4 and M(NCS)3(OAsPh3)3. Infra-red spectra in the region 4000-200 cm−1 are reported. Dissociative equilibria in solution have been investigated and possible structures are discussed.

Hydrazine complexes of nickel(II) chloride

Abstract: The reactions of nickel(II) chloride with hydrazine, methylhydrazine and 1,1-dimethyl-hydrazine have been investigated. As well as the hydrazine bridged complex Ni(N2H4)2Cl2, nickel(II) chloride forms Ni(N2H4)3Cl2 in which the nickel atom is surrounded by six nitrogen atoms as nearest neighbours. Methylhydrazine forms Ni(MeNHNH2)2Cl2 and Ni(MeNHNH2)6Cl2 while 1,1-dimethyl-hydrazine (DMH) forms NiCl2·4DMH, NiCl2·2DMH and NiCl2·DMH. The spectra and magnetic moments of all the complexes are consistent with octahedral (or tetragonal) stereochemistry.

Chemistry of lanthanons—XVII: Bis-salicylaldehyde ethylenediamine and bis-salicylaldehyde o-phenylenediamine complexes of rare-earths

Abstract: A new series of rare-earth metal chelates derived from N-coordinating ligands like bis-salicylaldehyde ethylenediamine (H 2 Salen) and bis-salicylaldehyde o-phenylenediamine (H 2 Salphen) have been prepared with La, Ce, Pr, Nd, Sm, Gd, Dy, Er, Yb and Y. These compounds are of the general formula Ln 2 (Salen) 3 and Ln 2 (Salphen) 3 (where Ln stands for the above lanthanides except Ce). The cerium complex prepared with H 2 Salen has the composition Ce(Salen) 2 . Many compounds of the former series are solvated and contain ethanol or water molecules. These compounds have been characterised by their thermal analyses and i.r. spectra.

Synergism in the solvent extraction of alkali metal ions by thenoyl trifluoracetone

Abstract: Large synergistic effects for polyvalent metals have been previously reported for the system H2O/Mn+/HTTA/S/diluent where HTTA is thenoyltrifluoracetone and S is a neutral donor solvent. Similar effects for the monovalent alkali metals are reported here. The formula for the extracted species has been found to be M(TTA)S2 (M = Li, Na, K or Cs), where S may be a phosphine oxide, a phosphate, an alcohol, a ketone or an amide. Nitromethane (NM) on the other hand forms Li(TTA)(NM)2 and M(TTA) (NM)3 (M = Na, K or Cs). Equilibrium constants for these synergistic reactions are reported and are shown to vary with the alkali metal over a wide range.