Ternary molybdenum(III) chlorides

The phase diagrams of ACl/MoCl₃ (A=Na, K, Rb, Cs) were elucidated by DTA measurements in sealed quartz ampoules in the range of 0–40 mol% MoCl₃. The samples were prepared from alkali metal chlorides and the compounds A₃MoCl₆ or A₃Mo₂Cl₉. The 31 compounds withA=Na, Rb, Cs were obtained by sintering mixtures of 3ACl+MoCl₃; the enneachlorides A₃Mo₂Cl₉ withA=K, Rb, Cs were precipitated from solutions of MoCl₃·3H₂O and ACl in formic acid. Congruently melting compounds A₃MoCl₆ exist in all four systems, incongruently melting enneachlorides A₃Mo₂Cl₉ in systems withA=K, Rb, Cs. Still unknown structures were determined by analog-indexing powder patterns according to known structure families. Especially Cs₃MoCl₆ is isotypic with the recently found Cs₃CrCl₆ structure. Additionally, the unit cell parameters were determined for the compounds A₃MoCl₅·H₂O (A=K, Rb, Cs) analogous to Cs₂TiCl₅·H₂O, whose structure was determined by single crystal measurements.Dedicated to Prof. Menachem Steinberg on the occasion of his 65th birthday     

Ternäre Chloride in den Systemen ACl/DyCl3 (A = Cs,Rb, K)

Ternary Chlorides in the Systems ACl/DyCl₃ (A = Cs, Rb, K) The phase diagrams of the pseudobinary systems ACl/DyCl₃ (A = Cs, Rb, K) were investigated by DTA. With all alkali metals compounds A₃DyCl₆ (elpasolite family) and Ady₂Cl₇ are formed. Compounds A₂DyCl₅ exist only with Cs (Cs₂DyCl₅-type) and K (K₂PrCl₅-type). By solution calorimetry the formation enthalpies of the ternary chlorides from (nACl + DyCl₃) were measured and ‘synproportionation enthalpies’ for the formation from the compounds, adjacent in the phase diagrams, calculated. K₃DyCl₆ is the only compound, which is formed with a loss in lattice enthalpy. E.m.f. measurements in dependence on the temperature have revealed that, as for the other compounds A₃DyCl₆, a remarkable gain in entropy exists, which stabilizes K₃DyCl₆ at T ≧ 312 K. This entropy gain correlates with the existence of isolated DyCl₆^3? octahedra.     

Ternäre Chloride in den Systemen ACl/GdCl3 (A = Na?Cs)

Ternary Chlorides in the Systems ACl/GdCl₃ (A = Na? Cs) The phase diagrams of the pseudobinary systems ACl/GdCl₃ (A = Na? Cs) were investigated by DTA. Their powder diffractograms were indexed in analogy to known structure families. By solution calorimetry and measurements of e.m.f. = f(T) in galvanic cells for solid electrolytes the enthalpies ΔH⁰ and free enthalpies ΔG⁰ for the formation of the ternary chlorides from the compounds adjacent in the systems were determined. The systems with A = K, Rb, Cs are analogous to those with Sm³⁺ and Eu³⁺. There exist compounds A₃GdCl₆, A₂GdCl₅ and AGd₂Cl₇. Cs₂GdCl₅ is crystallysing in the Cs₂DyCl₅ type; the Rb- and K-compounds and also Na₂GdCl₅ have the K₂PrCl₅?structure. In the system NaCl/GdCl₃ additionally the compounds NaGdCl₄ and Na₃GdCl₆ were found. L? Na₃GdCl₆ is metastable compared with (NaCl + Na₂GdCl₅); above 265°C stable H? Na₃GdCl₆ is existing (cryolite-structure).     

Ternäre Chloride in den Systemen ACl/EuCl3(A = Na?Cs)

Double Chlorides in the Systems ACl/EuCl₃ (A = Na? Cs) The phase diagrams of the pseudobinary systems ACl/EuCl₃ (A = Na? Cs) were investigated by DTA. T? and H? A₃EuCl₆ with A = Cs, Rb and T? and H? NaEuCl₄ were found in addition to other compounds already described in literature. Their powder diffractograms were indexed in analogy to known structure families. By solution calorimetry and measurements of e.m.f. = f(T) in galvanic cells for solid electrolytes the enthalpies ΔH and free enthalpies ΔG for the formation of the ternary chlorides from the compounds adjacent in the systems were determined. With KCl and NaCl only the compounds A₂EuCl₅ and NaEuCl₄ are stable at ambient temperature. Compared to the system with LnCl₃ (Ln = La? Nd) investigated previously, a tendency to structures with lower coordination numbers exists as was already detected in the systems ACl/SmCl₃.     

Thermochemical and structural investigations on alkali metal chlorides-iron(III)-chloride systems

The pseudobinary systems ACl?FeCl₃ (A=Na, K, Rb, Cs) were reinvestigated by means of differential thermal analysis and X-ray powder diffraction. The existence of the compounds AFeCl₄ (A=Na?Cs) and Cs₃Fe₂Cl₉ could be confirmed; Cs₃Fe₂Cl₉ is a stable compound which decomposes to CsCl and CsFeCl₄ above 270°C. Additionally, two Rb-compounds—Rb₃FeCl₆ and Rb₃Fe₂Cl₉—were found, which decompose, when heated, in the solid state. Rb₃Fe₂Cl₉ is isotypic with the analogous Cs-compound; Rb₃FeCl₆ has the Cs₃BiCl₆ structure. Cs₃FeCl₆ is isotypic with Cs₃CrCl₆, a recently found orthorhombic variant of the elpasolite type.     

Ternäre Halogenide vom Typ A3MX6. I A3YCl6 (A = K,NH4, Rb,Cs): Synthese,Strukturen, Thermisches Verhalten. Über einige analoge Chloride der Lanthanide

Ternary Halides of the A₃MX₆ Type I. A₃YCI₆ (A = K, NH₄, Rb, Cs): Synthesis, Structures, Thermal Behaviour. Some Analogous Chlorides of the Lanthanides Reaction of the trichlorides MCl₃ (M = Y, Tb? Lu) with alkali chlorides AC1 (A = K, Rb, Cs) in evacuated silica ampoules at 850?900°C yields A₃MCl₆-type chlorides. (NH₄)₃YCl₆ is obtained via the ammonium-chloride route. The crystal structure of Rb₃YCl₆ (monoclinic, C2/c (no. 15), Z = 8, a = 2583(1)pm, b = 788.9(4)pm, c = 1283.9(7)pm, p = 99.63(4)°, R = 0.062, R_w = 0.050) is that of Cs₃BiCl₆. The Rb₃YCl₆/Cs₃BiCl₆ structure and the closely related structures of K₃MoCl₆ and In₂CI₃ are derived from the elpasolite-type of structure (K₂NaAlF₆) making use of the model of closest-packed layer structures. Cell parameters for the chlorides Rb₃MCl₆ (M = Y, Tb? Lu) and Cs₃YCl₆ and Cs₃ErCl₆ as well, which are all isostructural with Rb₃YCl₆, are given. The “system” (K, NH₄, Rb, Cs)YCl₆ has been investigated by DTA and high-temperature X-ray powder diffractometry.     

Ternary chlorides of the trivalent late lanthanides

A comprehensive review on phase diagrams, crystal structures and thermodynamic properties of ternary chlorides formed in the systems ACl/LnCl₃ (A=Na, K, Rb, Cs) is presented. It continues an earlier review with the same contents on the lanthanides from La to Gd [1]. In both papers the author's own studies, published since 1985, together with original papers from other scientists are treated. With the three larger cations compounds of the composition A₃LnCl₆, A₂LnCl₅, ALn₂Cl₇ and beginning with holmium Cs₃Ln₂Cl₉ are formed. With sodium the compounds Na₃Ln₅Cl₁₈ (Ln=La to Sm) and NaLnCl₄ (Ln=Eu to Lu) also exist. The stability of a ternary chloride in a system ACl/LnCl₃ is given by the 'free enthalpy of synreaction', the formation of a compound from its neighbour compounds in its system. This must be negative. A surprising result is that the highest – melting compounds in the systems, A₃LnCl₆, are formed from ACl and A₂LnCl₅ with a loss of lattice energy, U. They exist as high-temperature compounds due to a sufficiently high gain in entropy at temperatures where the entropy term TΔS compensates the endothermic ΔH.     

Metall-Koordinationsverbindungen aus Essigsäure. I Chlorometallate(III) des Eisens,Chroms und Vanadiums

Metal Coordination Compounds Prepared in Acetic Acid. I. Chlorometalates(III) of Iron, Chromium, and Vanadium Ternary chloride-hydrates A₂MCl₅ · H₂O (A = Cs, Rb, (K)) can be precipitated with HCl from solutions of MCl₃ · 6 H₂O, (M = Fe, Cr, V) and alkali metal acetates in acetic acid. Under special conditions also compounds of the composition Cs₃MCl₆ · H₂O can be obtained. After dehydration of the solutions with acetyl chloride, anhydrous compounds are formed: Cs₃Fe₂Cl₉; A₃CrCl₆ and A₃Cr₂Cl₉ with A = Cs, Rb; Cs₃VCl₆ and Cs₃V₂Cl₉. V^III is partially oxidized to V^IV by an excess of acetyl chloride. Compounds A₂VCl₆ with A = Cs, Rb can be obtained more conveniently by the reaction of VOCl₂ · H₂O in acetic acid with acetyl chloride. The lattice parameters of some compounds were determined from powder patterns in analogy to known structure families.     

Alkalimetall‐Oxoantimonate: Synthesen,Kristallstrukturen und Schwingungsspektren von ASbO2 (A = K,Rb), A4Sb2O5 (A = K,Rb, Cs) und Cs3SbO4

Alkaline Metal Oxoantimonates: Synthesis, Crystal Structures, and Vibrational Spectroscopy of ASbO₂ (A = K, Rb), A₄Sb₂O₅ (A = K, Rb, Cs), and Cs₃SbO₄ The compounds ASbO₂ (A = K/Rb; monoclinic, C2/c, a = 785.4(3)/799.6(1) pm, b = 822.1(4)/886.32(7) pm, c = 558.7(3)/559.32(5) pm, β = 124.9(1)/123.37(6)°, Z = 4) are isotypic with CsSbO₂ and the corresponding bismutates. The structures of the antimonates A₄Sb₂O₅ (A = K/Rb: orthorhombic, Cmcm, a = 394.9(1)/407.34(7) pm, b = 1807.4(1)/1893.5(1) pm, c = 636.34(9)/655.60(8) pm, Z = 2) and Cs₄Sb₂O₅ (monoclinic, Cm, a = 1059.81(7) pm, b = 692.68(8) pm, c = 811.5(1) pm, β = 98.7(1)°, Z = 2) both contain the anion [O₂SbOSbO₂]^4–. Cs₃SbO₄ (orthorhombic, Pnma, a = 1296.1(1) pm, b = 919.24(8) pm, c = 679.95(6) pm, Z = 4) crystallizes with the K₃NO₄ structure type.     

Ternäre Alkalimetall‐Übergangsmetall‐Acetylide der Zusammensetzung A2MC2 mit A = Rb,Cs und M = Pd,Pt

Ternary Alkali Metal Transition Metal Acetylides A₂MC₂ with A = Rb, Cs, and M = Pd, Pt By the reaction of Rb₂C₂ and Cs₂C₂ with palladium or platinum powder in sealed glass ampoules at 653 K ternary acetylides A₂MC₂ (A = Rb, Cs; M = Pd, Pt) were obtained. Their crystal structures were solved and refined by means of X‐ray powder investigations (Na₂PdC₂ structure type, P 3 m1, Z = 1). The crystal structures are characterised by [M(C₂)_2/2^2–] chains separated by the alkali metals. Raman spectroscopic investigations revealed wave numbers of the C–C stretching vibrations between 1833 and 1842 cm^–1, which are in good agreement with the results of the analogous sodium and potassium compounds.     

Phase Equilibrium System of CsCl-YCl3-（9.5%）HCL-H2O at T=298.15 K and Its Compounds

Introduction In a series of papers the authors reported the spec-troscopy results on upconversion luminescence of the double salts between the alkali metal (Rb,Cs) halide and rare earth metal trihalide (REX3).1-4 Consequently, ex-tensive syntheses of new double salts and studies on optical properties of such species have received much more attention.5-12 Although a number of these double salts have been synthesized, the formation in alkali metal halide/rare earth metal halide double salts s…     

Zur Stabilität von Doppelchloriden in den Systemen ACI/PrCl3(A  Na?Cs)

Stability of Double Chlorides in the Systems ACl/PrCl₃(A = Na? Cs) The pseudobinary systems ACl/PrCl₃(A = Na? Cs) were reinvestigated by means of DTA. The following chlorides were found. (Primary detected compounds are underlined.): K₃PrCl₆; K₂PrCl₅; Rb₂PrCl₅, Cs₃PrCl₆, , CsPr₂Cl₇. Measurements of the solution enthalpies and of the free (Gibbs) enthalpies of formation from ACl and PrCl₃ together with the free enthalpies of synproportionation from the adjacent compounds in the phase diagrams with a galvanic cell for solid electrolytes revealed, that only the chlorides A₂PrCl₅ are stable at ambient temperature. All other compounds are high temperature forms. The crystal structures of the compounds were determined by X-ray analysis on powders; the compounds are isotypic with the analogous double chlorides of La and Ce. Magnetic susceptibilities in the range from 80—300 K were measured with a Gouy-balance.     

Kristallstrukturbestimmungen an Cs2NaCr(CN)6 und weiteren Verbindungen A2BM(CN)6 (A = Rb,Cs; B = Na,K, Rb,NH4; M = Cr,Mn, Fe,Co): Oktaederkippung und Toleranzfaktor von Cyanokryolithen

Crystal Structure Determinations of Cs₂NaCr(CN)₆ and further Compounds A₂BM(CN)₆ (A = Rb, Cs; B = Na, K, Rb, NH₄; M = Cr, Mn, Fe, Co): Tilting of Octahedra and Tolerance Factor of Cyano Cryolites The crystal structures of Cs₂NaCr(CN)₆ (space group P2₁/n, Z = 2; a = 763.2(1), b = 789.8(1), c = 1102.4(1) pm, β = 90.09(1)°) and of 9 isostructural cyano cryolites A₂BM(CN)₆ of the elements M = Cr, Mn, Fe, Co were determined by X‐rays at single crystals. The results, including data from the literature, were studied with respect to the interdependence of radii resp. bond lengths and cyano bridge angles M–CN–B resp. tilting of [M(CN)₆] and [BN₆] octahedra: The average tilt angles κ of the latter are within the range 13° ≤ κ ≤ 23° and increase linearly if the modified tolerance factor t (of range 0,87 ≥ t ≥ 0,78) decreases.     

Ternary Chlorides of the Trivalent Early Lanthanides. Phase diagrams,crystal structures and thermodynamic properties

A comprehensive review on phase diagrams, crystal structures and thermodynamics of ternary chlorides formed in systems ACl/LnCl₃ (A=Cs, Rb, K, Na; Ln=La−Gd) is presented. The review summarizes the author’s own studies, published since 1985, and original papers of other scientists. With the larger alkali metal ions compounds such as A₃LnCl₆, A₂LnCl₅ and ALn₂Cl₇were obtained. With sodium additional compounds NaLnCl₄ and Na₃Ln₅Cl₁₈ were obtained. The crystal structures are discussed with the concept of ionic radii, which determine the coordination numbers of Ln³⁺ and A⁺ cations against Cl⁻ anions. The formation enthalpies of the compounds from ACl and LnCl₃ were determined by solution calorimetry. Gibbs’ free energies and entropies for these reactions were obtained by e.m.f. measurements vs. temperature. The stability of a ternary chloride in a systemACl−LnCl₃ is given by the ‘free enthalpy of synproportionation’, that is, the formation of a compound from its neighbour compounds in the system. This ΔG ⁰ _syn must be negative. A surprising result is, that the highest-melting compounds in the systems, A₃LnCl₆, are formed from ACl+A₂LnCl₅ by a loss in lattice energy. They exist as high-temperature compounds due to sufficiently high gain in entropy at temperatures whereTΔS>ΔH. This revised version was published online in August 2006 with corrections to the Cover Date.     

Rubidium‐ und Caesium‐Verbindungen mit dem Isopolyanion [Ta6O19]8– – Synthesen,Kristallstrukturen, thermische und schwingungsspektroskopische Untersuchungen der Oxotantalate A8[Ta6O19] · n H2O (A = Rb,Cs; n = 0, 4, 14)

Rubidium und Caesium Compounds with the Isopolyanion [Ta₆O₁₉]^8– – Synthesis, Crystal Structures, Thermogravimetric and Vibrational Spectrocopic Analysis of the Oxotantalates A₈[Ta₆O₁₉] · n H₂O (A = Rb, Cs; n = 0, 4, 14) The compounds A₈[Ta₆O₁₉] · n H₂O (A = Rb, Cs; n = 0, 4, 14) contain the isopoly anion [Ta₆O₁₉]^8–, which consists of six [TaO₆] octahedra connected via corners to form a large octahedron. They transform into each other by reversible hydratation/dehydratation processes, as shown from thermoanalytic measurements (TG/DSC), and show also structural similarities. Cs₈[Ta₆O₁₉] (tetragonal, I4/m, a = 985.9(1) pm, c = 1403.3(1) pm, Z = 2), the isotypic phases A₈[Ta₆O₁₉] · 14 H₂O (A = Rb/Cs; monoclinic, P2₁/n, a = 1031.30(6)/1055.4(1) pm, b = 1590.72(9)/1614.9(6) pm, c = 1150.43(6)/1171.4(1) pm, β = 100.060(1)/99.97(2)°, Z = 2) and Rb₈[Ta₆O₁₉] · 4 H₂O (monoclinic, C2/c, a = 1216.9(4) pm, b = 1459.2(5) pm, c = 1414.7(4) pm, β = 90.734(6)°, Z = 4) have been characterised on the basis of single crystal x‐ray data. Furthermore the RAMAN spectra allow a detailled comparison of the hexatantalate ions in the four compounds.     

Dampfdruckmessungen an Alkalichlorid-Gadoliniumchlorid-Schmelzen

Vapour Pressure Measurements of Alkali Chloride – Gadolinium Chloride Melts The total vapour pressures and the chemical composition of the vapours have been determined over molten mixtures of NaCl, KCl and CsCl with GdCl₃. These data were used to calculate the partial pressures of ACl, A₂Cl₂, GdCl₃ and AgdCl₄ (A = Na, K or Cs).     

Alkalimetallnitrido‐tecto‐metallate(VI) mit Netzwerken von Sechsringen spitzenverknüpfter Tetraeder [(MNN3/2)6] mit M = Mo,W der unerwarteten Zusammensetzung A9+x[M6N15] mit A = Rb,Cs und 0 < x < 1

Alkali Metal Nitrido Tecto Metallates(VI) with Networks of Six‐membered Rings of Corner‐sharing Tetrahedra [(MNN_3/2)₆] with M = Mo, W of the Unexpected Composition A_9+x[M₆N₁₅] with A = Rb, Cs and 0 < x < 1 Reactions of metal powders of Mo and W respectively with amides and azides of Rb and Cs lead to the compounds Rb_9+x[W₆N₁₅] and Cs_9+x[M₆N₁₅] with M = Mo, W and 0 < x < 1. The reactions are carried out at 650 °C in autoclaves for salt melts and are finished within 5 d. Crystals of the compounds are embedded in a matrix of the corresponding alkali metal. These metals result from the thermal decomposition of the amides and azides used in high molar ratios. The metals are washed out by liquid ammonia. Besides microcrystalline material of the above mentioned compounds single crystals suitable in size for x‐ray structure determinations were isolated. The compounds crystallize in the space group R3c (No. 167) with Z = 6 and the following lattice constants: Rb_9+x[W₆N₁₅]: a = 12.743(7) Å, c = 27.794(8) Å, c/a = 2.181 Cs_9+x[Mo₆N₁₅]: a = 13.104(5) Å, c = 28.430(9) Å, c/a = 2.170 Cs_9+x[W₆N₁₅]: a = 13.136(5) Å, c = 28.472(6) Å, c/a = 2.167 The metal centres of tetrahedra [MNN_3/2] are condensated to cyclohexane analogue six‐membered rings in chair‐form via nitrogen atoms and axial ones connect them to a three‐dimensional network. Nine – as to the formula unit – of the alkali metal atoms are located in vacancies of the anionic partial structure. The residual atoms with 0 < x < 1 centre the six‐membered rings and are coordinated planar hexagonal by N neighbours.     

Structural Study of Alkaline 1-Phenyl-1H-1, 2, 3, 4-tetrazole-5-thiolate Salts: An Example of Periodicity in Alkaline Cations

The alkaline 1-phenyl-1H-1, 2, 3, 4-tetrazole-5-thiolate salts, M[C₆H₅N₄CS] (M = Li ( 1 ), Na ( 2 ), K ( 3 ), Rb ( 4 ) and Cs ( 5 )) were obtained and characterized by means of mass spectrometry (FAB⁺) and NMR (¹H; ¹³C) spectroscopy. The structures of Na ( 2 ), K ( 3 ), Rb ( 4 ) and Cs ( 5 ) compounds were determined by X-ray diffraction methods. The ligand shows a rich variety of coordination patterns with the alkaline cations. The formation of a four-membered ring MSCN in the compounds with heavier alkali cations (K, Rb and Cs) is shown. In all the cations the coordination number around it increases with the ionic radius. Compounds with Cs⁺ and Rb⁺ exhibited the formation of Cs-C and Rb-C interactions with the phenyl group.     

Über Hexafluoroindate(III): A2TllnF6 (A=Rb,Cs), (RbTI)BlnF6 (B= Na,Ag, K) und A2AglnF6 (A=Rb,TI,Cs)

On Hexafluoroindates(II1): A₂TlInF₆ (A = Rb, Cs), (RbTI)BInF₆ (B = Na, Ag, K), and A₂AgInF₆ (A = Rb, TI, Cs) By heating the binary components in a closed system are new prepared the compounds Rb₂AgInF₆, Rb₂CsInF₆, (RbTl)NaInF₆ (RbTI)AgInF₆, (RbTI)KInF₆, Tl₂AgInF₆, Cs₂AgInF₆ and Cs₂TlInF₆, all cubic, colourless Elpasolithes, as well as Rb₂TlInF₆, according to powder photographs tetragonal. The Madelung Part of Lattice Energy, MAPLE, is calculated and discussed.     

Untersuchungen zur Reaktivität in den Systemen A/Cu/M/O (A = Na–Cs und M = Co,Ni, Cu,Ag); Synthese und Kristallstrukturen von K3Cu5O4 und Cs3Cu5O4

Reactivity in the Systems A/Cu/M/O (A = Na–Cs and M = Co, Ni, Cu, Ag); Synthesis and Crystal Structures of K₃Cu₅O₄ und Cs₃Cu₅O₄ The systems A/Cu/M/O with A = Na–Cs and M = Co, Ni, Cu, Ag have been investigated with preparative, thermoanalytical and in situ X‐ray techniques to study the reactivity. For the redox reaction Co/CuO in the presence of Na₂O the intermediate, NaCuO, has been characterized. K₃Cu₅O₄ was obtained by annealing intimate mixtures of K₂O and CuO (molar ratio 1 : 1) in Ag containers at 500 °C. Cs₃Cu₅O₄ could be synthezised by reaction of KCuO₂ with Cs₂O (molar ratio 1 : 1) in Cu containers at 500 °C. Both compounds crystallize in the space group P2₁/c with Z = 4 isotypic to Rb₃Cu₅O₄ [IPDS data, Mo–Kα; K₃Cu₅O₄: a = 946.0(1), b = 735.61(6), c = 1401.3(2) pm, β = 107.21(1)°; 2249 F²(hkl), R₁ = 7.09%, wR₂ = 11.42%; Cs₃Cu₅O₄: a = 1027.7(1), b = 761.42(7), c = 1473.4(2) pm, β = 106.46(1)°, 1712 F²(hkl), R₁ = 6.04%, wR₂ = 14.22%]. Force constants obtained from FIR experiments for the deformation mode δ(O–Cu–O), the Madelung Part of the Lattice Energie, MAPLE, Effective Coordination Numbers, ECoN, calculated via Mean Effective Ionenradii, MEFIR, are given.