Activity coefficients and pitzer parameters in the systems Na+/Cs+/Cl-/TcO 4 - or ClO 4 - /H2O at 25°C

Isopiestic vapor pressure experiments are performed at 25°C with aqueous NaTcO₄, mixed NaTcO₄-NaCl, and NaCl reference solutions. The solubility of CsTcO₄ is determined in 0–7.4m CsCl and in 0–5.6m NaCl solutions. The osmotic coefficients of the binary and ternary solutions are used to evaluate the binary Pitzer parameters Β⁰, Β^l, and C^Φ for NaTcO₄ and the mixing parameters θ_{TcO 4} ^- /cl^- and ψ_Na ⁺/TcO ₄ ^- /cl^-. The binary Pitzer parameters for the sparingly soluble CsTcO₄ and CsC1O₄ are calculated together with ψ_Cs ⁺/mo ₄ ^- /cl^- from their solubilities in CsCl solution. The solubilities of CsTcO₄ in NaCl and CsClO₄ in NaClO₄ solution are also included in the parametrization of the reciprocal salt systems Na⁺/Cs⁺/Cl^-/MO ₄ ^- . The parameters Β⁰ and Β^l of pertechnetate and perchlorate salts correlate well with the ionic radii.     

Zur Kenntnis von Na4[CrO4]

On Na₄(CrO₄) Dark-green single crystals of Na₄[CrO₄] were obtained for the first time. (Na₂O/Cr₂O₃; Na:Cr = 4:1 not exactly closed Ni-tube; 1000°C; 30 d). It is isostructural to Na₄(CoO₄); space group P1 , a = 859.7 pm, b = 569.8 pm, c = 640 pm, α = 124°C, β = 98.4°, γ = 98.9°, Z = 2. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these via Mean Effective Ionic Radii, MEFIR, are calculated.     

Über quaternäre Oxoplumbate(IV). Zur Kenntnis von Rb3NaPbO4

On Quaternary Oxoplumbates(IV). On Rb₃NaPbO₄ For the first time, Rb₃NaPbO₄ has been prepared by annealing mixtures of Na₂PbO₃ and RbO_0.84 with Rb:Na:Pb = 4:2:1 [nonhermetic Ag-cylinders, sealed under vacuum in Duran-glass ampoule, 480°C, 180 d (single crystals)]. The colourless crystals are of squatted shape. The structure determination [2943 symmetry independent hkl, four-circle-diffractometer PW 1100 (Fa. Philips), ω-2Θ-scan, AgKα, R = 8.64%, R_W = 6.59%, absorption not considered] confirms the space group P2₁/c with a = 1101.79(26), b = 662.66(11), c = 1115.01(30) pm, β 112.027(21)°. The structure is characterized by isolated [PbO₄]-tetrahedra and [Na₂O₆]-tetrahedra-doubletts, C.N. 5 and 7 for Rb⁺. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these via Mean Effective Ionic Radii, MEFIR, are calculated.     

Zur Kenntnis der K4[Ag4O4]-Verwandtschaft

On the K₄[Ag₄O₄] Relation Single crystals of mainly new oxides A₄[M₄O₄] with M = Cu, A = Li? Rb and M = Ag, A = Na, Rb, Cs have been prepared by “reaction at the metallic substrate” (i.e. the wall) and the crystal structures were refined. For lattice constants and atomic parameters see text. The [M₄O₄]^4? ring is planar only for the M₄-part, the positions of the O^2? particles deviate in a non systematic way from this plane. Only Li₄[Cu₄O₄] contains an almost planar ring. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, are calculated.     

Neues über Oxoferrate(III). I. Zur Kenntnis von Li5FeO4 [1] Mit einer Notiz über Mischkristalle Na5Fe1−xGaxO4

News on Oxoferrates(III). I. On Li₅FeO₄ (with a Remark on Na₅Fe_1?xGa_xO₄ Solid Solutions) For the first time transparent dark yellow single crystals of Li₅FeO₄, corresponding to Li₅□₂FeO₄ an ordered variant of the Na₂O-type of structure, are prepared [by mixtures of Li₂O and α-NaFeO₂ with Li:Na:Fe = 6:1:1, sealed Ag-cylinders, 700°C, 16 d]. Li₅FeO₄ is isostructural with Li₅GaO₄: a = 921.8(1), b = 921.3(1), c = 915.9(1) pm, Z = 8 [space group: Pbca, 4-circlediffractometer data, 2525 I₀ (hkl), R = 9.58% and R_w = 5.85%, d_pyk = 2.60 and d_x = 2.64 gcm^?3, parameters see text]. The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, these via Mean Effective Ionic Radii, MEFIR, are calculated and discussed. The magnetic properties are measured in the temperature range of 3.9–251.3 K.     

Neue Borate der Alkalimetalle: KLi2[BO3]

New Borates of the Alkali Metals: KLi₂[BO₃] The hitherto unknown KLi₂[BO₃] is prepared in the shape of orthorhombic, colour-less-transparent, and columnar single crystals [a = 797.1(4) pm, b = 643.2(3) pm, c = 645.7(3) pm, Z = 4, d_x = 2.25 g/cm³, d_pyk = 2.20g/cm³]. The crystal structure was solved by four-cycle-diffractometer [PW 1100, MoKα, R = 5.78%, R_W = 3.83%, 452 I₀(hkl)]. Kli₂[BO₃] is sensitiv against atmospheric moisture which causes hydrolysis. Effective Coordination Numbers, ECoN, these via Mean Effective Ionic Radii, MEFIR, are calculated and discussed.     

Über gemischtvalente Oxoplumbate. Zur Kenntnis von Rb2Pb4O7 = Rb2PbPbO7

On Mixed-valent Oxoplumbates. On Rb₂Pb₄O₇ = Rb₂Pb Pb O₇ For the first time, Rb₂Pb₄O₇ has been prepared by annealing mixtures of Rb₂O₃ and PbO with Rb:Pb = 1:2 [Ag-cylinders, sealed under vacuum in Duran-glass ampoule, 450°C, 30 d (single crystals)]. The rubin red single crystals are of longish [001] shape. The structure determination [5162 symmetry independent hkl, four-circle-diffractometer CAD 4 (Fa. Enraf-Nonius), ω-2Θ—scan, AgKα, ψ-scan absorption correction, R = 7.54%, R_W = 7.71%] confirms the space group P1 with a = 1036.00(10), b = 733.72(8), c = 663.54(10) pm, α = 90.049(12)°, β = 99.236(12)°, γ = 101.641(12)°, Z = 2, d_rö = 7,58 g · cm^?3, d_pyk = 7,55 g · cm^?3. The structure is characterized by a layer-lattice. The coordination number is three for Pb²⁺, six for Pb⁴⁺. The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these via Mean Effective Ionic Radii, MEFIR, are calculated.     

Über Oxotitanate der Alkalimetalle. Zur Kenntnis von Na4Ti5O12

On Oxotitanates of the Alkaline Metals: On Na₄Ti₅O₁₂ Colourless single crystals of the new titanate Na₄Ti₅O₁₂ (starting from mixtures Na₂O/TiO₂, 1000°C, 6 d, Au-crucible, open system) crystallize in the monoclinic system, space group C2/m, a = 26.544(9), b = 2.952(1), c = 6.322(3) Å, β = 95.79(3)°, Z = 2, d_rö = 3.45 and d_pyk = 3.38 g · cm^?3 (four-cycle-diffractometer data, PW 1100, 2?-scan, MoKα). R = 5.09% and R_w = 4.87% for 1178 independent I₀(hkl) with 3° ≤ 2? ≤ 34°. Corrugated layers of Ti₅O₁₂, held together by Na⁺, are stacked along [001]. Details about partially occupied positions of Na⁺, Effective Coordination Numbers (ECoN), the Madelung part of lattice energy (MAPLE), and the structural differences to Na₂Ti₃O₇ are discussed.     

Unerwartete Strukturverwandtschaft: Das neue Orthotitanat Rb3Na[TiO4]

On Unexpected Structural Relations: The New Orthotitanate Rb₃Na[TiO₄] [1] The new oxide Rb₃Na[TiO₄], platelike colourless crystals, was obtained by heating a well grounded mixture of the binary oxides in Ni-tubes. Therewith the oxides RbO_0.52, NaO_1.03, Ti₂O₃ (Rb:Na:Ti = 2.8:2.5:1.0) were heated for 26 d at 1000°C. Rb₃Na[TiO₄] (monoclinic, P2₁/c) is “isostructural” with Rb₃Na[PbO₄] [2] (lattice constants: a = 1076.3(3) pm, b = 638.8(4) pm, c = 1088.9(7) pm, β = 112.83(12)°; four-circle diffractometer data, Z = 4). The structure was determinated by using four-circle diffractometer data (Siemens AED2, 6683 I₀(hkl), MoKα , R = 6.2%, R_w = 3.8%, additional data see text). The Madelung Part of Lattice Energy (MAPLE), Effective Coordination Numbers (ECoN), Mean Fictive Ionic Radii (MEFIR) and the Charge Distribution in Solids are calculated and discussed.     

Über „Lithovanadate”︁: Zur Kenntnis von Rb2[LiVO4] und Cs2[LiVO4]

On ?Lithovanadates”?: Rb₂[LiVO₄] and Cs₂[LiVO₄] By heating of well ground mixtures of the binary oxides [A₂O, Li₂O, V₂O₅, A : Li: V = 2.2 : 1.1 : 1.0 (A = Rb, Cs); Ni-tube, 750° 25 d] we obtained Rb₂[LiVO₄] and Cs₂[LiVO₄] colourless, orthorhombic single crystals. We found a new type of ?Lithovanadate”?-structure: space group Cmc2₁; a = 587.9(1), b = 1170.1(1), c = 793.3(1) pm, Z = 4 (A = Rb) bzw. a = 610.5(1), b = 1222.6(3), c = 815.5(2) pm, Z = 4 (A = Cs). The structure was determined by four-circle diffractometer data [MoKα -radiation; 997 from 1157 I₀(hkl), R = 7.75%, R_w = 5.54% (A = Rb); 686 from 686 I₀(hkl), R = 6.97%, R_w = 4.20% (A = Cs)] parameters see text. The Madelung part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, have been calculated.     

Zum Aufbau von PbF4 mit Strukturverfeinerung an SnF4

On the Constitution of PbF₄ with Structure Refinement of SnF₄ Colourless single crystals of SnF₄ have been prepared heating powder samples of SnF₄ in Pt-tubes (500°C, 20 d). Single crystals of PbF₄ could be synthesized by pressure fluorination of «PbF_4-x» and sublimation in autoclaves. The fluorides crystallize isostructural in space group I4/mmm with SnF₄: a = 404.42(4) pm; c = 792.41(9) pm; Z = 2 and PbF₄: a = 425.36(8) pm; c = 806.4(1) pm; Z = 2 (Guinier-de Wolff data, Cu-Kα₁). The parameters Z_F2 of both fluorides were refined from four-circle diffractometer data (Siemens AED 2) with SnF₄: R1 = 1.5%; 1623 I₀(hkl) and PbF₄: R1 = 1.0%; 777 I₀(hkl) (SHELXL-93). The structures correspond to the supposition by Hoppe and Dähne from 1962. The Madelung Part of Lattice and Molecule Energy, MAPLE and MAPME, Mean Fictive Ionic Radii, MEFIR, and Effective Coordination Numbers, ECoN, are calculated.     

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.     

Ein neues Orthovanadat(V): Cs2Na[VO4]

A New Orthovanadate (V): Cs₂Na[VO₄] Colourless single-crystals of Cs₂Na[VO₄] resulted by heating intimate mixtures of CsO_0.52, NaO_0.52 and V₂O₅ (Cs: Na: V = 2.2:1.1:1.0) in tightly closed Ni-tubes. The crystal structure was determined (four-circle diffractometer data), 1341 I_o(hkl), R = 6.23%, R_w = 4.23%, parameters see text. The new orthovanadate(V) crystallizes monoclinic (space group P2₁/m) with a = 839.9(1), b = 624.7(1), c = 614.8(1) pm, β = 92.66(1)° (Guinier-Simon powder data), Z = 2. The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, these calculated via Mean Fictive Ionic Radii, MEFIR, are discussed.     

Synthese,Kristallstrukturen und Absorptionsspektren der neuen „Cupriosilicate”︁: K6[CuSi2O8] und Rb4[CuSi2O7]

Synthesis, Crystal Structures, and Absorption Spectra of the New “Cupriosilicates”: K₆[CuSi₂O₈] and Rb₄[CuSi₂O₇] K₆[CuSi₂O₈] and Rb₄[CuSi₂O₇] were obtained by annealing intimate mixtures of K₂O and Rb₂O, respectively, CuO and SiO₂ in sealed Ag cylinders at 500°C as transparent greenish-blue single crystals. The structure solution (IPDS-data Mo Kα; K₆[CuSi₂O₈]: 1292 F²(hkl), R1 = 0.059; wR2 = 0.103 and Rb₄[CuSi₂O₇]: 763 F²(hkl), R1 = 0.049; wR2 = 0.114) confirms the space group P1 for both compounds. K₆[CuSi₂O₈]: a = 619.4(2); b = 665.5(2); c = 753.0(2) pm; α = 83.66(3); β = 87.71(3); γ = 70.19(3)°; Z = 1. Rb₄[CuSi₂O₇]: a = 631.9(9); b = 707.5(10); c = 715.2(6) pm; α = 114.2(1); β = 100.7(1); γ = 107.9(1)°; Z = 1. The Madelung Part of the Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these calculated via Mean Effective Ionic Radii, MEFIR, are given. The absorption spectra of K₆[CuSi₂O₈] and Rb₄[CuSi₂O₇] are discussed in terms of the Angular Overlap Model, AOM.     

Ein Oxomanganat(V) neuen Typs: K11{Li[OMnO3]4}

An Oxomanganate(V) of New Type: K₁₁{Li[OMnO₃]}₄ By heating of well ground mixtures of the oxides [K₂O₂, LiMnO₄, K:Mn = 2.2:1, Ag-tube, 580°C, 30 d] blue-green tetragonal single crystals of K₁₁{Li[OMnO₃]₄} have been prepared for the first time: space group I4 2m; a = 787,18(7) pm, c = 1750.9(3) pm. The structure was determined by four-circle-diffractometer data [MoKα , 1236 from 1303 I_o(h kl), R = 3.9%, R_w = 3.1%], parameters see text. The Madelung Part of Lattice Energy, MAPLE, and the Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, have been calculated.     

Das erste Oxothallat(III) vom Formeltyp AA4′[MO4]: CsK4[TlO4]

The First Oxothallate(III) with the Formula Type AA₄′[MO₄]: CsK₄[TlO₄] For the first time CsK₄[TlO₄] was obtained by heating intimate mixtures of K₂O, CdO and CsTl (molar ratio 3.1:1.0:1.0) in closed Ag-cylinders (25 days, 450°C) in form of yellow, transparent single crystals. The structure determination by four circle diffractometer data (MoKα, 1922 out of 2 094 I_o(hkl), R = 2.98, R_w = 2.49) confirms the space group Pbca with lattice constants a = 1 192.1 pm; b = 685.7 pm; c = 2 143.5 pm; Z = 8. The structure is isotypic with Na₅[GaO₄]. The Madelung Part of Lattice Energy, MAPLE, the Mean Fictive Ionic Radii, MEFIR, Effective Coordination Numbers, ECoN, and Charge Distribution, CHARDI, are calculated.     

Das erste „Lithovanadat”︁: K2{LiVO4}.

The First ?Lithovanadate”?: K₂{LiVO₄} By heating of well ground mixtures of the binary oxides [K₂O, Li₂O, V₂O₅, K:Li: V = 2.2:1.1:1.0; Ni-tube, 900°C, 46 d] colourless monoclinic single crystals of K₂[LiVO₄] have been prepared for the first time: space group C2/m; a = 835.7(1) pm, b = 774.5(1) pm, c = 753,3(1) pm, β = 90.23(1)°. The structure was determined by four-circle diffractometer data [MoKα, 1018 form 1262 I₀ (hkl), R = 8.65%, R_w = 5.67%], parameters see text. The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, have been calculated.     

Ein neues Cobaltat mit Inselstruktur: Li6[CoO4]

A New Cobaltate with Isolated Anion Structure: Li₆[CoO₄] For the first time transparent, blue single crystals of Li₆[CoO₄] have been prepared (Li₂O/Na₂O/?CoO”? (Li:Na:Co = 1.3:1.3:1), Co-tube, 580°C, 22 d). Corresponding to Li₆□CoO; it is an ordered variant of the Li₂O-type of structure: P4₂/nmc; a = 653.6(1) pm, c = 465.4(1) pm; Z = 2; d_x = 2.75 g cm^?3, d_pyk = 2.71 g cm^?3 (4-circle-diffractometer-data (PW 1100), AgKα; 230 from 936 I₀(hkl); R = 9.58%, R_W = 5.25%). Parameters see text. The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, are calculated and discussed. The magnetic properties are measured in the temperature range of 14–297 K.     

Zur kenntnis ‚Kationen-reicher’︁ Tantalate und Niobate Über Na5TaO5 und Na5NbO5

On Tantalates and Niobates ‘rich in Cations’. On Na₅TaO₅ and Na₅NbO₅ Colourless, transparent single crystals of Na₅TaO₅ [annealed mixtures of Na₂O, Li₂O, and Ta₂O₅, Na : Li : Ta = 6.6 : 1.1 : 1, Ni-cylinder, 1000°C, 75 d] as well as Na₅NbO₅ [annealed mixtures of Na₂O, Li₂O, and Nb₂O₅, Na : Li : Nb = 6.6 : 1.1 : 1, Ni-cylinder, 1000°C, 75 d] have been prepared. Single crystal data show that both isotypic oxides represent a deformed variant of the NaCl-type of structure [Na₅TaO₅: 1154 from 1250 I₀ (hkl), four-cycle diffractometer Philips PW 1100, ω2-θ scan, Ag? Kα , R = 4.88%, space group c2/c with a = 629.3(1) pm, b = 1025.4(2) pm, c = 1004.6(2) pm, b? 106.80(2)°, z = 4 and Na₅NbO₅: 998 from 1247 I₀(hkl), four-cycle diffractometer Philips PW 1100, ω-2θ scan, Ag? Kα , R = 8.58% and R_w = 7.67%, space group C2/2 with a = 629.1(1) pm, b = 1024.4(2) pm, c = 1004.2(2) pm, b? = 106.80(2)°, Z = 4]. The Madelung Part of Lattice Energy, MAPLE, and Effective Coordination Numbers, ECoN, the latter derived from Mean Effective Fictive Ionic Radii, MEFIR, as well as Charge Distribution, CHARDI, are calculated.     

Cs4[IrO4], ein neues Iridat mit planarem Anion [IrO4]4−

Cs₄[IrO₄], a New Iridate with Planar Anion [IrO₄]^4? For the first time we obtained black single crystals of Cs₄[IrO₄] by heating intimate mixtures of CsO_0.52 and IrO₂ (molar ratio Cs : Ir = 4.30 : 1.00; “Ag-bomb”, 740°C/86 d). Cs₄[IrO₄] crystallizes monocline, C 2/m, with a = 1031.66(8) pm, b = 671.61(4) pm, c = 660.44(6) pm, b? = 108.118(7)° and Z = 2 in the K₄[IrO₄]-type. The structure has been determined by four-circle-diffractometer data (PW 1100 from Phillips, Ag? Kα , graphite) with 841 I₀(hkl) with I ≥ 3s?(F) (from 947 I₀(hkl) out of 3529 measured reflexes). The Madelung Part of Lattice Energy, MAPLE, Effective Coordination Numbers, ECoN, these via Mean Fictive Ionic Radii, MEFIR, are calculated and discussed.