SrCl2 · 1/2 H2O und SrCl2 · H2O Röntgenographische,thermoanalytische, Raman- und IR-spektroskopische Untersuchungen

SrCI₂ · 1/2 H₂O and SrCl₂ · H₂O. X-ray, Thermalanalytical, Raman, and I. R. Data The formation of the new compound SrCI₂ · 1/2 H₂O was detected with help of high-temperature X-ray and high-temperature Raman measurements. Strontium chloride hemihydrate was prepared by dehydration of the higher hydrates in a water-vapour atmosphere of 1 bar at 165 °C. The Course of dehydration of SrCI₂ · 6 H₂O, and SrCI₂ · 2 H₂O is discussed. X-ray, i.r.-and Raman data of SrCI₂ · 1/2 H₂O and SrCl₂ · H₂O are reported. SrCI₂ · H₂O crystallizes ortho-rhombic in the BaCI₂ · H₂O type (space group Pnma) with a = 1088.1(1), b = 416.2(1), and c = 886.4(1) pm. The water modes of the hydrates as well as the force constants and bond energies of the hydrogen bridges are discussed.     

Humidity controlled calorimetric investigation of the hydration of MgSO4 hydrates

The isothermal heat of hydration of MgSO₄ hydrates was studied by humidity controlled calorimetry. Two hydrates, starkeyite (MgSO₄·4H₂O) and a mixture of MgSO₄ hydrates with summary 1.3 mol H₂O were investigated. The solid-gas reactions were initiated at 30°C and 85% relative humidity. The heat of hydration was determined in a circulation cell in the calorimeter C80 (Setaram). The crystal phases formed after the hydration process were analyzed by thermogravimetry (TG) and X-ray powder diffraction (XRD). Starkeyite reacted with the water vapour to the thermodynamic stable epsomite and the MgSO₄ hydrate mixture with 1.3 mol water to hexahydrite. The hydration heats of starkeyite and the mixture were determined to be −169±3 and −257±5 kJmol⁻¹, respectively.     

Hydratstufen und Kristallstrukturen von Bariumchlorid

Hydrates and crystal Structure of Barium Chloride The dehydrating process of BaCl₂ · 2H₂O and the phase transformations of BaCl₂ were observed by using a modified high temperature X-ray camera. The following compounds appeared with increasing temperature: BaCl₂ · 2H₂O → BaCl₂ · 1H₂O → BaCl₂(cubT) [BaCl₂(hex)]→ α-BaCl₂(ortho) → β-BaCl₂(cubH). The phase BaCl₂(cubT) is supposed to be the metastable low temperature form of β-BaCl₂(cubH). Structural relationships were demonstrated by comparing the different phases of the BaCl₂? H₂O system.     

Thermal behavior of some compounds of methanesulfonic acid with transition metals

The following compounds of methanesulfonic acid, CH₃SO₃H, have been prepared: Cu(CH₃SO₃)₂ · 4 H₂O; Zn(CH₃SO₃)₂ · 4 H₂O; Mn(CH₃SO₃)₂ · 2 H₂O; Cd(CH₃SO₃)₂ · 2 H₂O and Ag(CH₃SO₃). Their thermal behavior has been studied using TG and DTA, together with X-ray analysis of the solid products formed during the heating. The water of hydration is evolved in one step (Mn, Cd) or in two step (Cu, Zn). The intermediate hydrates and the anhydrous salts are crystallized. The anhydrous Zn, Ag and Cd compounds melt, the anhydrous Cd salt undergoing a polymorphic transition before melting. They then begin to decompose in the temperature range 325–440°C. Under an inert atmosphere, the decomposition yields well-crystallized residues of various composition: Cu + Cu₂S; Ag + Ag₂S (the sulfides being in very minute amounts); MnS; CdS; ZnO + ZnS.     

Das System Strontiumazid–Wasser

The System Strontiumazide–Water The system strontiumazide–water has been investigated by means of solubility determinations, X-ray methods and vapor pressure measurements, and the phase diagramm has been determined. Besides anhydrous Sr(N₃)₂ there exist three hydrates, Sr(N₃)₂ · 2 H₂O, Sr(N₃)₂ · 4 H₂O, and Sr(N₃)₂ · 6 H₂O, for which thermodynamic data have been given. Characteristic for this system is the great stability of metastable phases.     

Studies on ion association. Calorimetric study of the formation of monoazido complexes of Ni(II), Zn(II) and Cd(II)

From rehydration experiments the hydrates Ba(OH)₂ · 8 H₂O, Ba(OH)₂ · 3 H₂O β-Ba(OH)₂, · 1 H₂O, and γ-Ba(OH)₂ · 1 H₂O have been found in the system Ba(OH)₂-H₂O. Thermoanalytical measurements (DTA, TG, DTG, high temperature X-ray diffraction, high temperature Raman scattering) on these hydrates are reported. Thermal decomposition of Ba(OH)₂ · 8 H₂O and Ba(OH)₂ · 3 H₂O always results in the formation of β-Ba(OH)₂ · 1 H₂O, the stable form of the monohydrates at ambient temperature. Dehydration of β- and γ-Ba(OH)₂ · 1 H₂O, both of which form anhydrous β-Ba(OH)₂ as the first product of decomposition, starts at 105 and 115°C, respectively. Single crystals of Ba(OH)₂ · 3 H₂O and γ-Ba(OH)₂ · 1 H₂O were prepared from Ba(OH)₂ · 8 H₂O meltings and from ethanolic solutions of Ba(OH)₂ , respectively. The crystal data are: Ba(OH)₂ · 3 H₂O (orthorhombic, Pnma): a = 764.0(2), b = 1140,3(5), c = 596.5(1) pm, Z = 4; γ-Ba(OH)₂ · 1 H₂O (monoclinic, P2₁/m or P2₁): a = 704.9(2), b = 418.4(1), c = 633.3(1) pm, β = 111.45(2)°, Z = 2.     

Thermal studies on yttrium,neodymium and holmium oxalates

The thermal decomposition patterns of Y₂(C₂O₄)₃ · 9 H₂O, Nd₂(C₂O₄)₃ · 10 H₂O and Ho₂(C₂O₄)₃ · 5.5 H₂O have been studied using TG and DTG. The hydrated neodymium oxalate loses all the water of hydration in one step to give the anhydrous oxalate while Y₂(C₂O₄)₃ · 9 H₂O and Ho₂(C₂O₄)₃ · 5.5 H₂O involve four or more dehydration steps to yield the anhydrous oxalates. Further heating of the anhydrous oxalates results in the loss of CO₂ and CO to give the stable metal oxides.     

Zur Kenntnis der Sulfite und Sulfithydrate des Eisens und Nickels Röntgenographische,thermoanalytische, IR- und Raman-spektroskopische Untersuchungen

In den Systemen FeSO₃? H₂O und NiSO₃? H₂O konnten folgende Hydrate erhalten werden: α-FeSO₃ · 3H₂O, γ-FeSO₃ · 3H₂O, FeSO₃ · 2,5 H₂O, FeSO₃ · 2 H₂O, NiSO₃ · 6 H₂O, NiSO₃ · 3 H₂O, NiSO₃ · 2,5 H₂O und NiSO₃ · 2 H₂O. Die Gitterdaten der folgenden Hydrate wurden anhand von Einkristallmessungen bestimmt: γ-FeSO₃ · 3 H₂O: a = 965,9(1), b = 557,1(1), c = 944,7(1) pm, Z = 4, FeSO₃ · 2 H₂O (P2₁/n): a = 645,6(1), b = 863,1(1), c = 761,2(1) pm, β = 99,84(1)°, Z = 4, NiSO₃ · 3 H₂O: a = 945,0(1), b = 547,2(1), c = 932,5(1) pm, Z = 4, NiSO₃ · 2,5 H₂O (P4₁2₁2): a = b = 935,3(1), c = 1016,6(1) pm, Z = 8, NiSO₃ · 2 H₂O (P2₁/n): a = 631,4(1), b = 851,0(1), c = 744,7(1) pm, β = 98,91(1)°, Z = 4. Die IR- und Raman-Spektren sowie das Ergebnis thermoanalytischer Messungen (DTA, DTG, Röntgenheizaufnahmen) werden mitgeteilt. Die bei Sulfiten und Sulfithydraten zweiwertiger Metalle bisher beobachteten Strukturtypen werden diskutiert. Sulfites and Sulfite Hydrates of Iron and Nickel. X-ray, Thermoanalytical, I.R., and Raman Data In the systems FeSO₃? H₂O and NiSO₃? H₂O the following hydrates have been found: α-FeSO₃ · 3H₂O, γ-FeSO₃ · 3H₂O, FeSO₃ · 2,5 H₂O, FeSO₃ · 2 H₂O, NiSO₃ · 6 H₂O, NiSO₃ · 3 H₂O, NiSO₃ · 2,5 H₂O and NiSO₃ · 2 H₂O. The following crystal data have been determined by single crystal measurements: γ-FeSO₃ · 3 H₂O: a = 965,9(1), b = 557,1(1), c = 944,7(1) pm, Z = 4, FeSO₃ · 2 H₂O (P2₁/n): a = 645,6(1), b = 863,1(1), c = 761,2(1) pm, β = 99,84(1)°, Z = 4, NiSO₃ · 3 H₂O: a = 945,0(1), b = 547,2(1), c = 932,5(1) pm, Z = 4, NiSO₃ · 2,5 H₂O (P4₁2₁2): a = b = 935,3(1), c = 1016,6(1) pm, Z = 8, NiSO₃ · 2 H₂O (P2₁/n): a = 631,4(1), b = 851,0(1), c = 744,7(1) pm, β = 98,91(1)°, Z = 4. IR, Raman, and thermoanalytical (DTA, DTG, high temperature X-ray) data are presented. The structure types found for sulfites and sulfite hydrates of bivalent metals are discussed.     

Higher hydrates of lithium chloride,lithium bromide and lithium iodide

For lithium halides, LiX (X = Cl, Br and I), hydrates with a water content of 1, 2, 3 and 5 moles of water per formula unit are known as phases in aqueous solid–liquid equilibria. The crystal structures of the monohydrates of LiCl and LiBr are known, but no crystal structures have been reported so far for the higher hydrates, apart from LiI·3H₂O. In this study, the crystal structures of the di‐ and trihydrates of lithium chloride, lithium bromide and lithium iodide, and the pentahydrates of lithium chloride and lithium bromide have been determined. In each hydrate, the lithium cation is coordinated octahedrally. The dihydrates crystallize in the NaCl·2H₂O or NaI·2H₂O type structure. Surprisingly, in the tri‐ and pentahydrates of LiCl and LiBr, one water molecule per Li⁺ ion remains uncoordinated. For LiI·3H₂O, the LiClO₄·3H₂O structure type was confirmed and the H‐atom positions have been fixed. The hydrogen‐bond networks in the various structures are discussed in detail. Contrary to the monohydrates, the structures of the higher hydrates show no disorder.     

DSC study of the kinetics of the thermal dehydration of BaCl2 · 2H2O and BaCl2 · H2O

The kinetics of the thermal dehydration of various kinds of BaCl₂ · 2H₂O and of BaCl₂ · H₂O are investigated using a differential scanning calorimeter. The loss of H₂O proceeds in two steps: BaCl₂ · 2H₂O→BaCl₂ · H₂O→BaCl₂ and is therefore revealed by two endothermic peaks. In the experiments at varying temperature both steps follow a contracting-circle law, after an initial acceleratory stage according to a (n=2) power law. In the experiments at constant temperature, after an initial acceleratory stage according to a (n=2) power law, both steps (except BaCl₂ · 2H₂O single-crystals which follow a contracting-circle law) follow an Avrami-Erofeev law (withn=2) in the form used by Galwey and Jacobs. The activation energies for the various steps are compared and the different kinetic behaviour is discussed.     

Introduction to bioenergetics: Thermodynamics for the biologist — a learning program for students of the biological and medical sciences | by N. Christensen and Richard A. Cellarius,W.B. Saunders Company,Philadelphia, 1972, pp. xii + 223, price £2.35

The infrared and Raman spectra of the light blue modification of anhydrous copper(II) formate, Cu(HCOO)₂, and copper(II) formate-d₂, Cu(DCOO)₂, are reported, as well as the Raman spectra of copper(II) formate tetrahydrate Cu(HCOO)₂ · 4H₂O and copper(II) formate tetrahydrate-d₈ Cu(HCOO)₂ · 4D₂O over a wide range of temperatures. In the latter two compounds, the fundamental formate modes, active in the Raman spectra, showed splittings when the phase transition temperature was traversed. These low-temperature Raman spectra were interpreted in terms of a P2₁ space group and prove that the phase transition not only involves an ordering in the orientation of the water molecules, but also displacements of the heavy atoms. Only a limited number of weak translational modes of the water molecules could be identified in the Raman spectra of the copper(II) formate tetrahydrate, and it is not possible therefore to determine exactly how ordering affects the Raman-active lattice modes of these molecules.     

Y(NCS)3·4(1/2)H2O和Y(NCS)3·2(1/2)H2O的制备、性质及标准生成焓的测定

本文首次制备了异硫氰酸钇低水合物Y(NCS)₃·4 1/2H₂O和Y(NCS)₃·2 1/2H₂O,采用量热法测定了它们在298.15K时的标准生成焓,进而计算了它们的晶格能以及相应的标准脱水焓。     

Zur Kenntnis der Hydrate M(HSeO3)2 · 4H2O (M = Mg,Co, Ni,Zn). Röntgenstrukturanalytische,schwingungsspektroskopische und thermoanalytische Untersuchungen

On the Hydrates M(HSeO₃)₂ · 4H₂O (M = Mg, Co, Ni, Zn) – Crystal Structures, IR, Raman, and Thermoanalytical Investigations From aqueous solutions of M(HSeO₃)₂ single crystals of Mg(HSeO₃)₂ · 4H₂O and of the hitherto unknown compounds Co(HSeO₃)₂ · 4H₂O, Ni(HSeO₃)₂ · 4H₂O and Zn(HSeO₃)₂ · 4H₂O could be obtained. The crystal structures, X-ray powder, IR, Raman and thermoanalytical (DTA, TG, Raman heating) data are presented and discussed. The crystal data of the isotypic compounds are: monoclinic, space group C2/c, Z = 4, Mg: a = 1 464.6(2), b = 755.3(1), c = 1 099.9(1) pm, β = 126.59(1)°, V = 0.9769(1) nm³, Co: a = 1 462.5(2), b = 756.5(2), c = 1 102.2(2) pm, β = 126.53(1)°, V = 0.9798(2) nm³, Ni: a = 1 452.2(2), b = 751.0(1), c = 1 091.5(1) pm, β = 126.28(1)°, V = 0.9595(1) nm³, Zn: a = 1 468.3(2), b = 755.8(1), c = 1 103.1(1) pm, β = 126.79(1)°, V = 0.9804(2) nm³. The crystal structures consist of hexagonal packed [M(HSeO₃)₂ · 2H₂O]_n chains of [MO₄(H₂O)₂] octahedra linked by Se atoms. They contain trigonal pyramidal SeO₂OH^?ions with “free” hydroxyl groups and also “free” molecules of water of crystallization. The hydroxyl groups build strong H-bonds (O? H …? O distances: 265–268 pm). The IR spectra show AB doublett bands in the OH stretching mode region of the hydroxyl groups. The water molecules of crystallization are linked to planar (H₂O)₄ tetramers by H-bonds with unusually short O? H …? O bond distances of 271–273 pm. DTA and TG measurements indicate that thermal decomposition results in the direct formation of the respective diselenite MSe₂O₅. Raman heating measurements show under quasi static conditions the intermediate formation of the anhydrous hydrogen selenites.     

Production of doubly charged clusters (H2O)n · Ba2+ and (H2O)n · Ca2+ under low temperature fast atom bombardment conditions

Production of doubly charged ions of alkaline earth metals Ba²⁺ and Ca²⁺ and their doubly charged clusters with water molecules (H₂O)_n · Ba²⁺, (H₂O)_n · Ca²⁺ (n = 1, 2, 3) by means of low temperature fast atom bombardment technique is observed in the case of crystalline hydrates of BaCl₂ and CaCl₂ salts, formed during freezing of water-salt solutions. Reasons for a possibility of production of the doubly charged species in the case of the two indicated salts and their absence in the case of chlorides of some other divalent metals (Mg, Mn, Co, Cu, Zn) are discussed. As to singly charged secondary ions Me⁺, MeCl⁺, MeOH⁺, [(H₂O)_n · MeCl]⁺, [(H₂O)_n · MeOH]⁺ (where Me is metal), high efficiency of their production from crystalline hydrates was observed and possible explanation of the phenomenon is suggested.     

The characteristics of the nanosized η-TiO2 polymorph

The nanosized η-TiO₂ polymorph was prepared by the hydrolysis of titanyl sulfate (TiO)SO₄ · xH₂SO₄ · yH₂O. η-TiO₂ was studied by X-ray diffraction, X-ray photoelectron spectroscopy, IR spectroscopy, and Raman spectroscopy. Characteristic X-ray data and distinguishing Raman spectrum features were found for η-TiO₂,. The surface of η-TiO₂ samples contained adsorbed OH⁻ particles and water molecules or water molecules of crystal hydrates. The free specific surface area of samples with crystallite sizes of L = 50 (4) and 60 (5) ? was S = 10.17 (9) and 15.6 (1) m²/g. The characteristics of samples with η-TiO₂ were favorable for their use as photocatalysts and adsorbents.     

Rb3LnCl6 · 2 H2O (Ln = La?Nd): Darstellung,Kristallstruktur und thermisches Verhalten

Rb₃LnCl₆ · 2 H₂O (Ln = La? Nd): Preparation, Crystal Structure, and Thermal Behaviour The compounds Rb₃LnCl₆ · 2 H₂O (Ln = La? Nd) were prepared from acetic acid as powders. The preparation from aqueous solutions does not yield the pure products because RbCl precipitates as first compound. The structure of Rb₃LaCl₆ · 2 H₂O was determined by X-ray analysis of a single crystal obtained from aqueous solution. The compounds with Ln = La? Nd are isotypic. They crystallize hexagonally in the space group P6₃/m (Rb₃LaCl₆ · 2 H₂O: a = 1 220.4(2) pm, c = 1 688.6(3) (pm) with Z = 6. Anionic trimeric units [Ln₃Cl₁₂(H₂O)₆]^3? are stacked along the c-axis over the corners of the unit cell. In the stacking frequency the units are rotated by 60° with respect to each other around the c-axis. The coordination number (C. N.) of Ln³⁺ is 8, which is satisfied by four bridging and two terminal chloride ions and two water molecules. The coordination spheres of the three rubidium ions in the different atomic positions are composed differently, their C.N. are 9, 8(+1) and 6(+6). The thermal dehydration of the compounds occurs in one step. The hydrates decompose at ca. 100°C to form the anhydrous compounds Rb₂LnCl₅ und RbCl since the anhydrous chlorides Rb₃LnCl₆ are thermodynamically stable above ca. 400°C only.     

Über die thermischen Eigenschaften von Heteropolysäuren des Typs H3+n[PVnMo12−nO40] · x H2O (n = 0, 1, 2, 3) II. Raman- und IR-spektroskopische Untersuchungen

On the Thermal Behaviour of Heteropoly Acids of the Type H_3+n[PV_nMo_12?nO₄₀] · x H₂O (n = 0, 1, 2, 3). II. Raman and Infrared Spectroscopic Investigations The investigation of de- and rehydratization of the heteropoly acids H_3+n[PV_nMo_12?nO₄₀] · x H₂O (n = 0, 1, 2, 3) shows typical changes in the region of valence and bridging vibrations in the Raman and infrared spectra, in particular during the existence of ?anhydrous”? forms. The time dependence of rehydratization is also demonstrated well with a special Raman sample technique.     

The confirmation of the formation of clathrate-like hydrates of poly(tetrabutylammonium ethenesulfonate) and of poly(tetraisopentylammonium ethenesulfonate)

A thermal method using differential scanning calorimeter has been applied to aqueous solutions of a series of poly(tetraalkylammonium ethenesulfonates) (R₄NPES). It was found that only the salts withR=n-C₄H₉ andR=i-C₅H₁₁ could form stable hydrates having large hydration numbers. The melting point and hydration numbers of these two hydrates were 12.0°C and 30±1 for the (n-C₄H₉)₄NPES hydrate and 16.0°C and 53±2 for the (i-C₅H₁₁)₄NPES hydrate, respectively. It was concluded that these hydrates were clathrate-like essentially similar to such hydrates as (n-C₄H₉)₄NF·30H₂O and (i-C₅H₁₁)₄NF·40H₂O.     

Synthesis and characterization of some metal(II) and sodium ions with cyclopentane-1,2,3,4-tetracarboxylate anion

New divalent metal cyclopentane-1,2,3,4-tetracarboxylate (CPTC) hydrates of empirical formula M₂C₅H₆(COO)₄ · nH₂O, where M = Ni, Co, Cu, or Zn and n = 3?6, and sodium CPTC Na₃C₅H₆COOH(COO)₃ · 7H₂O have been prepared and characterized by elemental analysis, magnetic measurements, thermal, and infrared spectral studies. For the sodium salt, a single crystal (Na₃C₅H₆COOH(COO)₃ · 8H₂O) was also obtained. IR spectra of the metal(II) complexes indicate the coordination of metal ions through all carboxylates. For the sodium compound, a band at 1681 cm^?1 indicates that some carboxylic groups have not been deprotonated. The presence of protonated carboxylic group was also confirmed by an X-ray single crystal analysis. On heating in air atmosphere, all complexes lose water molecules and next anhydrous compounds decompose to corresponding metal oxides and sodium carbonate.     

Crystal structures of hydrates of simple inorganic salts. III. Water‐rich aluminium halide hydrates: AlCl3·15H2O,AlBr3·15H2O,AlI3·15H2O,AlI3·17H2O and AlBr3·9H2O

Water‐rich aluminium halide hydrate structures are not known in the literature. The highest known water content per Al atom is nine for the perchlorate and fluoride. The nonahydrate of aluminium bromide, stable pentadecahydrates of aluminium chloride, bromide and iodide, and a metastable heptadecahydrate of the iodide have now been crystallized from low‐temperature solutions. The structures of these hydrates were determined and are discussed in terms of the development of cation hydration spheres. The pentadecahydrate of the chloride and bromide are isostructural. In AlI₃·15H₂O, half of the Al³⁺ cations are surrounded by two complete hydration spheres, with six H₂O in the primary and 12 in the secondary. For the heptadecahydrate of aluminium iodide, this hydration was found for every Al³⁺.