Synthesis,Crystal Structure and Magnetic Properties of Rb2Mn3O4

Rb₂Mn₃O₄, which is the first rubidium oxomanganates(II), has been synthesized via the azide/nitrate route from a stoichiometric mixture of the precursors RbN₃, RbNO₃, and MnO, as well as from Rb₂O and MnO, through an all solid state reaction. Its crystal structure (C2/c, Z = 4, a = 1546.9(2) pm, b = 666.22(7) pm, c = 588.06(6) pm) consists of a 3D arrangement of edge‐ and corner‐sharing MnO₄ tetrahedra with rubidium filling the space between. Magnetic susceptibility measurements indicate a magnetic phase transition at 126 K. The magnetic response as a function of temperature is complex, indicating strong, partly frustrated magnetic exchange interactions.     

Synthesis,Crystal Structure and Properties of RbMnO2

RbMnO₂ was prepared via the azide/nitrate route. Stoichiometric mixtures of the precursers (Mn₂O₃, RbN₃ and RbNO₃) were heated in a special regime up to 600 °C and annealed at this temperature for 30 h in specially designed silver crucibles. Single crystals have been grown by annealing a 1:1 mixture of Rb₂O and MnO_x at 585 °C for 1200 h. According to the crystal structure determination Mn³⁺ is in a square‐pyramidal coordination by oxygen. These [MnO₅] units form double chains extending along the crystallographic c‐axis. RbMnO₂ shows Curie‐Weiss behaviour down to ～ 100 K. A fit of the susceptibility data yields an average value of the magnetic moment (per manganese atom) of μ_eff = 5.33 μ_B, and θ_p = –820 K. At 50 K and low field strength onset of ferromagnetic order due to spin canting has been observed.     

Ein neuartiges Polyoxocobaltat(II)‐Anion in Rb2Co2O3

A New Polyoxocobaltate(II) Anion in Rb₂Co₂O₃ Rb₂Co₂O₃ was prepared via the azide/nitrate route. Mixtures of the precursors Co₃O₄, RbN₃ and RbNO₃ in the molar ratios 6:17:1 were heated in a special regime up to 450 °C and annealed at this temperature for 50 h in silver crucibles. Single crystals have been grown by subsequent annealing of prepared powder at 450 °C for 500 h in silver crucibles, which were sealed in glass ampoules under dried Ar. According to the X‐ray analysis of the crystal structure (Pnma, Z = 8, 11.729(2), 6.058 (1), 8.004(1) Å) cobalt is trigonal planar coordinated by oxygen atoms. The CoO₃‐units share through all corners and build up an infinite two‐dimensional Co₂O₃‐network.     

Synthesis and Crystal Structure of Rb3AgO2

Rb₃AgO₂ was prepared via the azide/nitrate route. Stoichiometric mixtures of the precursors (Ag₂O, RbN₃ and RbNO₃) were heated in a special regime up to 450 °C and annealed at this temperature for 50 h in silver crucibles. Single crystals have been grown by subsequent annealing of the as prepared powder at 450 °C for 500 h in silver crucibles, which were sealed in glass ampoules under dried Ar. According to the X‐ray analysis of the crystal structure (P2₁2₁2₁, Z = 16, a = 12.800(1), b = 12.848(1), c = 14.329(1)Å, 6566 independent reflections, R(all) = 0.0795, R_w(all) = 0.0218), Rb₃AgO₂ is isostructural with K₃AgO₂. The structure can be derived from the fluorite structure type. Silver is linearly coordinated by oxygen atoms, while Rb has pseudo‐tetrahedral coordination. The crystal under investigation was composed of four twin individuals.     

Synthesis,Crystal Structure and Properties of Na2MnO2

Na₂MnO₂ was prepared via the azide/nitrate route. Stoichiometric mixtures of the precursors (Mn₂O₃, NaN₃ and NaNO₃) were heated in an appropriate regime up to 390 °C and annealed at this temperature for 20 h, in specially designed silver containers. As the most prominent feature, the crystal structure of Na₂MnO₂ (C2/c, Z = 12, a = 12.5026(9), b = 12.1006(9), c = 6.0939(4) Å, β = 117.94(0)°, 1556 independent reflections, R₁ = 3.83 % (all data)) forms a three dimensional framework polyanion of corner sharing MnO₄‐tetrahedra. The connectivity pattern of the tetrahedral building units corresponds to the moganite structure, a rare SiO₂ modification. According to measurements of the magnetic susceptibility in the temperature range from 2 to 750 K, Na₂MnO₂ shows antiferromagnetic ordering below 250 K. Evaluation of the high temperature data employing the Curie‐Weiss law revealed a magnetic moment of μ_eff = 5.93 μ_B, confirming the presence of divalent manganese.     

Rb3CoO2, a Novel Oxocobaltate(I) Synthesized via the Azide/Nitrate Route

Rb₃CoO₂ was prepared via the azide/nitrate route. Stoichiometric mixtures of the precursors (Co₃O₄, RbN₃ and RbNO₃) were heated in a special regime up to 500 °C and annealed at this temperature for 100 h in silver crucibles. The crystal structure of the obtained red product was solved and refined by powder methods (Pnma, Z = 4, 12.3489(2), 7.6648(1), 6.2251(1) Å). Rb₃CoO₂ is isostructural with K₃CoO₂ and contains Co¹⁺, which is coordinated by two oxygen atoms forming a slightly distorted dumb‐bell. Rb₃CoO₂ decomposes at 580 °C to Rb₂O, Co and CoO.     

Synthesis, structure and magnetic properties of Na6Co2O6

Na₆Co₂O₆ was synthesized via the azide/nitrate route by reaction between NaN₃, NaNO₃ and Co₃O₄. Stoichiometric mixtures of the starting materials were heated in a special regime up to 500°C and annealed at this temperature for 50 h in silver crucibles. Single crystals have been grown by subsequent annealing of the reaction product at 500°C for 500 h in silver crucibles, which were sealed in glass ampoules under dried Ar. According to the X-ray analysis of the crystal structure (, Z=1, a=5.7345(3), b=5.8903(3), c=6.3503(3) Å, α=64.538(2), β=89.279(2), γ=85.233(2)°, 1006 independent reflections, R₁=8.34% (all data)), cobalt is tetrahedrally coordinated by oxygen. Each two CoO₄ tetrahedra are linked through a common edge forming Co₂O₆^6- anions. Cobalt ions within the dimers, being in a high spin state (S=2), are ferromagnetically coupled (J=17 cm^-1). An intercluster spin exchange (zJ′=−4.8 cm^-1) plays a significant role below 150 K and leads to an antiferromagnetically ordered state below 30 K. Heat capacity exhibits a λ-type anomaly at this temperature and yields a value of 19.5 J/mol K for the transition entropy, which is in good agreement with the theoretical value calculated for the ordering of the ferromagnetic-coupled dimers. In order to construct a model for the spin interactions in Na₆Co₂O₆, the magnetic properties of Na₅CoO₄ have been measured. This compound features isolated CoO₄ tetrahedra and shows a Curie-Weiss behavior (μ=5.14 μ_B, Θ=−20 K) down to 15 K. An antiferromagmetic ordering is observed in this compound below 10 K.     

Synthesis and Crystal Structure of CsCu3O2, Containing a New Type of Oxocuprate(I) Polyanion

CsCu₃O₂ was prepared via the azide route. Stoichiometric mixtures of the precursors (CsN₃, Cu₂O and CuO) were heated in a special regime up to 450 °C and annealed at this temperature for 50 h in silver crucibles. Single crystals have been grown by subsequent annealing of as prepared powders at 450 °C for 2000 h in silver crucibles, which were sealed in glass ampoules under dried Ar. According to the X‐ray analysis of the crystal structure (P3¯m1, Z = 1, a = 5.250(1), c = 5.442(1)Å, γ = 120°) copper is linearly coordinated by oxygen atoms. The CuO₂‐dumb‐bells are connected to an infinite two‐dimensional Cu₃O₂‐network. CsCu₃O₂ is isostructural with CsCu₃S₂, CsAu₃S₂, CsAu₃Se₂ and RbAu₃Se₂.     

Synthesis, structure and properties of new chain cuprates, Na3Cu2O4 and Na8Cu5O10

Na₃Cu₂O₄ and Na₈Cu₅O₁₀ were prepared via the azide/nitrate route from stoichiometric mixtures of the precursors CuO, NaN₃ and NaNO₃. Single crystals have been grown by subsequent annealing of the as prepared powders at 500 °C for 2000 h in silver crucibles, which were sealed in glass ampoules under dried Ar. According to the X-ray analysis of the crystal structures (Na₃Cu₂O₄: P2₁/n, Z=4, a=5.7046(2), b=11.0591(4), c=8.0261(3) Å, β=108.389(1)°, 2516 independent reflections, R₁(all)=0.0813, wR₂ (all)=0.1223; Na₈Cu₅O₁₀: Cm, Z=2, a=8.228(1), b=13.929(2), , β=111.718(2)°, 2949 independent reflections, R₁(all)=0.0349, wR₂ (all)=0.0850), the main feature of both crystal structures are CuO₂ chains built up from planar, edge-sharing CuO₄ squares. From the analysis of the Cu-O bond lengths, the valence states of either +2 or +3 can be unambiguously assigned to each copper atom. In Na₃Cu₂O₄ these ions alternate in the chains, in Na₈Cu₅O₁₀ the periodically repeated part consists of five atoms according to Cu^II-Cu^II-Cu^III-Cu^II-Cu^III. The magnetic susceptibilities show the dominance of antiferromagnetic interactions. At high temperatures the compounds exhibit Curie-Weiss behaviour (Na₃Cu₂O₄: , , Na₈Cu₅O₁₀: , , magnetic moments per divalent copper ion). Antiferromagmetic ordering is observed to occur in these compounds below 13 K (Na₃Cu₂O₄) and 24 K (Na₈Cu₅O₁₀).     

Synthesis and Crystal Structure of Na7Cu3O8, Containing a New Type of Oxocuprate(III) Oligoanion

Na₇Cu₃O₈ was prepared through oxidation of a Na₃CuO₂/NaCuO mixture (2:1) in dried oxygen at 450 °C. Single crystals have been grown by annealing of Na₇Cu₃O₈, in the presence of Na₂O₂, at 450 °C for 2000 h in silver crucibles, which were sealed in glass ampoules under dried Ar. According to the X-ray analysis of the crystal structure ( , Z = 1, a = 5.5891(2), b = 6.0945(2), c = 7.8890(3) Å, α = 110.059(2), β = 108.669(2), γ = 90.237(2)°) a new Cu₃O₈^7- oxocuprate anion, consisting of three edge sharing CuO₄ squares, is the prominent structural feature. These anions are aligned parallel to the space diagonal of the unit cell and can be regarded as infinite chains from which every fourth copper atom has been removed. This new representative of an oxocuprate(III) anion gives support to the expectation that the gap between dimeric and infinite edge sharing units of square planar cuprate anions can be closed, in principle.     

Neue Oxocadmate der Alkalimetalle: K6[CdO4],Rb6[CdO4], Rb2CdO2 und Rb2Cd2O3

The crystal structure of K₆[CdO₄] and Rb₂CdO₂ has been determined from single crystal X-ray diffraction data and refined toR=0.058 (K₆[CdO₄]) andR=0.088 (Rb₂CdO₂). K₆[CdO₄] crystallizes hexagonal, space group P6₃mc with lattice constantsa=867.42 (6),c=665.5 (1) pm,c/a=0.767 andZ=2. It is isotypic with Na₆[ZnO₄]. Rb₂CdO₂ is orthorhombic, space group Pbcn witha=1045.0 (2),b=629.1 (1),c=618.3 (1) pm,Z=4, and crystallizes with the K₂CdO₂ structure type. The crystal structures can be deduced from the motif of a closest packed arrangement of O^2– with hexagonal (K₆[CdO₄]) or cubic (Rb₂CdO₂) stacking. The tetrahedra occupied by Cd²⁺ are isolated (K₆[CdO₄]) or edge-shared (formation of infinite SiS₂-like chains [CdO_4/2]) (Rb₂CdO₂). The powder diffraction pattern of Rb₆[CdO₄] [a=906.6 (1),c=694.3 (1) pm] and Rb₂Cd₂O₃ [a=642.6 (2),b=679.0 (1),c=667.9 (2) pm, =115.2 (1)] confirm isotypie with K₆[CdO₄] and K₂Cd₂O₃ respectively.

Herrn Prof. Dr.Gutman zum 65. Geburtstag gewidmet.     

The Family of A6M2O6 Oxometalates: Synthesis and Crystal Structure Determination of Cs6Mn2O6, Magnetic Exchange within Dimeric Poly‐oxoanions,and Classification of Crystal Structures

The new compound Cs₆Mn₂O₆ was synthesized via the azide/nitrate route. According to single‐crystal X‐ray analysis (P1 ; a = 695.74(7), b = 733.24(7), c = 735.12(7) pm, α = 78.559(4), β = 62.685(3), γ = 88.788(4)°; 2705 independent data, R₁ = 0.041), the anionic part of the compound consists of dimeric Mn₂O₆ units, formed by edge sharing of two MnO₄ polyhedra of a shape intermediate between tetrahedral and square planar. The crystal structure is singular, however, can be related to several oxides of the same general formula by group‐subgroup symmetry descent. The magnetic properties of Cs₆Mn₂O₆ have been simulated by an antiferromagnetic dimer model of spin S = 2 entities, considering a small temperature dependence of the spin exchange parameters.     

Darstellung und Kristallstruktur von Rb4Br2O und Rb6Br4O

Syntheses and Crystal Structures of Rb₄Br₂O and Rb₆Br₄O In the quasi‐binary system RbBr/Rb₂O, the addition compounds Rb₄Br₂O and Rb₆Br₄O are obtained by solid state reaction of the boundary components RbBr and Rb₂O. Crystals of red‐orange Rb₄Br₂O as well as of orange Rb₆Br₄O decompose immediately when exposed to air. Rb₄Br₂O (Pearson code tI14, I4/mmm, a = 544.4(6) pm, c = 1725(2) pm, Z = 2, 175 symmetry independent reflections with I_o > 2σ(I), R₁= 0.0618) crystallizes in the anti K₂NiF₄ structure type; Rb₆Br₄O (Pearson code hR22, R3c, a = 1307.8(3) pm, c = 1646.6(5) pm, Z = 6, 630 symmetry independent reflections with I_o > 2σ(I), R₁ = 0.0759) in the anti K₄CdCl₆ structure type. Both structures contain characteristic ORb₆‐octahedra and can be understood as expanded perovskites, following the general systematics of alkaline metal oxide halides.     

Crystal Structure and Raman Spectroscopic Study of K5[CuO2][CO3]

Air and moisture sensitive K₅[CuO₂][CO₃] was prepared via the azide/nitrate route from stoichiometric mixtures of the precursors CuO, KN₃, KNO₃ and K₂CO₃. According to the single‐crystal X‐ray analysis of the crystal structure [P4/nbm, Z = 2, a = 7.4067(5), c = 8.8764(8) Å, R₁ = 0.053, 433 independent reflections] K₅[CuO₂][CO₃] represents an ordered superstructure of Na₅[NiO₂][CO₃]. The structure contains isolated [CuO₂]^3– dumbbells and CO₃^2– anions, with the latter not connected to the transition element. Raman spectroscopic measurements confirm the presence of CO₃^2– in the structure.     

Synthesis,Crystal Structure,and Physical Properties of the New Chain Alkalioxocuprate K3Cu2O4

Single crystals of K₃Cu₂O₄ were prepared by the azide/nitrate route from respective stoichiometric mixtures of KN₃, KNO₃ and CuO, at 923 K, whereas powder samples were synthesised by solid state reaction of K₂O, KCuO₂ and CuO, sealed in gold ampoules and treated at 723 K. According to the single crystal structure analysis (Cmcm, Z = 4, a = 6.1234(1), b = 8.9826(2), c = 10.8620(2) Å, R₁ = 0.044, R₂ = 0.107), the main structural feature are undulating CuO₂ chains built up from planar, edge sharing CuO₄ square units. From an analysis of the Cu–O bond lengths, the valence state of either +2 or +3 can be unambiguously assigned to each copper atom. The magnetic susceptibilities show the dominance of antiferromagnetic (AFM) interactions. At high temperatures, the magnetic behaviour can be fitted with the Curie–Weiss law (μ_eff = 1.84μ_B, Θ = –105 K). The experimental data can be very well described by a uniform Heisenberg chain with a nearest‐neighbour spin intrachain interaction (J_nn) of ~ 101 K.     

Zur Kristallstruktur von Rb2C2 und Cs2C2

On the Crystal Structure of Rb₂C₂ and Cs₂C₂ By reaction of rubidium or caesium solved in liquid ammonia with acetylene AC₂H with A = Rb, Cs was obtained, which was subsequently converted into the binary acetylide A₂C₂ in vacuum at temperatures of 520 K (Rb₂C₂) and 470 K (Cs₂C₂) using a surplus of the respective alkali metal. The crystal structures of the very air sensitive compounds were solved and refined by a combination of both neutron and X‐ray powder diffraction data. Rb₂C₂ as well as Cs₂C₂ coexist in two modifications. The hexagonal modification (P 6 2m, Z = 3) crystallises in the known Na₂O₂ structure type with two crystallographic independent sites for the C₂^2– dumbbells. For the orthorhombic modification (Pnma, Z = 4) a new structure type was found, which is related to the PbCl₂ structure type with ordered C₂^2– dumbbells occupying the Pb sites. Temperature dependent investigations between 4 K and the decomposition temperature by the means of neutron and X‐ray powder diffraction resulted in a very complex dynamic disorder of the C₂ dumbbells, which is still not completely understood. The frequencies of the C–C stretching vibration determined by the help of Raman spectroscopy fit nicely to the results obtained for other alkali metal acetylides and alkali metal hydrogen acetylides. These results seem to indicate that the electronegativity of the alkali metal has a strong influence on the frequency of the C–C stretching vibration.     

Alkalimolybdotellurate: Darstellung und Kristallstruktur von Rb6[TeMo6O24] · 10H2O und Rb6[TeMo6O24] · Te(OH)6 · 6H2O

Alkaline Molybdotellurates: Preparation and Crystal Structures of Rb₆[TeMo₆O₂₄] · 10H₂O and Rb₆[TeMo₆O₂₄] · Te(OH)₆ · 6H₂O Single crystals of Rb₆[TeMo₆O₂₄] · 10 H₂O and Rb₆[TeMo₆O₂₄] · Te(OH)₆ · 6 H₂O, respectively, were grown from aqueous solution. Rb₆[TeMo₆O₂₄] · 10 H₂O possesses the space group P1 . The lattice dimensions are a = 963.40(13), b = 972.56(12), c = 1 056.18(13) pm, α = 97.556(10), β = 113.445(9), γ = 102.075(10)°; Z = 1, 2 860 reflections, 215 parameters refined, R_g = 0.0257. The centrosymmetrical [TeMo₆O₂₄]^6? anions are stacked parallel to [010]. Rb(2) is coordinated with one exception by water molecules only. Folded chains consisting of [TeMo₆O₂₄]^6? anions and Rb(2) coordination polyhedra which are linked to pairs represent the prominent structural feature. Rb₆[TeMo₆O₂₄] · Te(OH)₆ · 6 H₂O crystallizes monoclinically in the space group C2/c with a = 1 886.4(3), b = 1 000.9(1), c = 2 126.5(3) pm, and β = 115.90(1)°; Z = 4, 3 206 reflections, 240 parameters refined, R_g = 0.0333. It is isostructural in high extent with (NH₄)₆[TeMo₆O₂₄] · Te(OH)₆ · 7 H₂O. Hydrogen bonds between Te(OH)₆ molecules and [TeMo₆O₂₄]^6? anions establish infinite strands. The [TeMo₆O₂₄]^6? anions gather around Te(OH)₆ providing channel-like voids extending parallel to [001].     

Synthesis,Structure, and Magnetic Properties of a Mn4 Cluster derived from Benzimidazole‐Alcohol Ligands

The synthesis, crystal structure, and magnetic properties of a [Mn^III₃Mn^II(μ₃‐O)(mbp)₃(OAc)₃] · 4H₂O ( 1 ) [H₂mbp = 2‐(1H‐benzimidazol‐2‐yl)‐2‐ methylpropane‐1,3‐diol] cluster are reported herein. Mn ions in compound 1 have a tetrahedron topology. Solid‐state direct current and alternating current magnetic susceptibility measurements on compound 1 reveal a ground state with S_T = 7/2 as well as the probable single‐molecule magnetic behavior.     

Synthesis and Crystal Structure of the Fluoride‐Rich Rubidium Scandium Fluoride Oxosilicate Rb3Sc2F5Si4O10

The new quinary fluoride‐rich rubidium scandium oxosilicate Rb₃Sc₂F₅Si₄O₁₀ was obtained from mixtures of RbF, ScF₃, Sc₂O₃ and SiO₂ in sealed platinum ampoules after seventeen days at 700 °C. The colourless compound crystallises orthorhombically in space group Pnma with a = 962.13(5), b = 825.28(4), c = 1838.76(9) pm and Z = 4. For the oxosilicate partial structure, [SiO₄]^4– tetrahedra are connected in (001) by vertex‐sharing to form corrugated unbranched vierer single layers ${2}\atop{{\infty}}$ {[Si₄O₁₀]^4–} (d(Si–O) = 158–165 pm, ∠(O–Si–O) = 103–114°, ∠(Si–O–Si) = 125–145°) containing six‐membered rings. Similar oxosilicate layers with 6³‐net topology are well‐known for the mineral group of micas or in sanbornite Ba₂Si₄O₁₀. Regarding other systems, identical tetrahedral layers can be found in the synthetic borophosphate Mg(H₂O)₂[B₂P₂O₈(OH)₂] · H₂O. The Sc³⁺ cations are coordinated octahedrally by four F^– and two O^2– anions. These cis‐[ScF₄O₂]^5– octahedra (d(Sc–F) = 200–208 pm, d(Sc–O) = 202–205 pm) share one equatorial and two apical F^– anions with others to build up slightly corrugated ${1}\atop{{\infty}}$ {[Sc₂F${t}\atop{2/1}$ F${v}\atop{6/2}$ O${t}\atop{4/1}$ ]^7–} double chains along [010]. These are linked with the oxosilicate layers via two oxygen vertices to construct a three‐dimensional framework with cavities apt to host the three crystallographically independent Rb⁺ cations with coordination numbers of eleven, twelve and thirteen.     

新型电荷转移复合物(BEDT-TTF)4·H2O·Fe(C2O3)3·C6H5NO2的合成、结构与物理性质

导电性的电荷转移复合物（盐）由于其特殊的物理性质和潜在的应用前景，近年来得到广泛研究［１，２］．导电电荷转移复合物主要包括基于Ｍ（ｄｍｉｔ）２（ｄｍｉｔ＝１，３－二硫－２－硫酮－４，５－二硫醇盐）阴离子自由基［３～５］和ＢＥＤＴ－ＴＴＦ（乙二硫撑四硫...