- RbBa2(N3)5: A new ternary azide
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Rubidium dibarium pentaazide, RbBa2(N3)5, was prepared from an aqueous solution of the binary azides at room temperature. It crystallizes in the monoclinic system (space group P2/n). Two central atoms of azide groups occupy the 2c (1) and 2b (1) positions, another azide group lies completely on a twofold axis (2f), while Rb atoms are situated in 2e (2) positions. The crystal structure of RbBa2(N 3)5 can be regarded as a distorted AlB7-type arrangement of the metal atoms, with the azide groups occupying the voids between the cations. This results in coordination numbers of 8 (Rb) and 10 (Ba). The N-N distances are in the range 1.169 (8)-1.190 (5) A, typical for the azide group.
- Vajenine, Grigori V.
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- A new polyoxocobaltate(II) anion in Rb2Co2O3
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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) A) cobalt is trigonal planar coordinated by oxygen atoms. The CoO3-units share through all corners and build up an infinite two-dimensional ∞2Co2O3-network.
- Sofin, Mikhail,Peters, Eva Maria,Jansen, Martin
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- Synthesis and Structural Characterization of the layered Selenogallate RbGaSe2
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The chalcogenogallate RbGaSe2 was synthesized by thermal decomposition of rubidium azide in the presence of gallium selenide and selenium. RbGaSe2 crystallizes in the monoclinic space group C2/c (no. 15) with the lattice parameters a = 10.954(1) ?, b = 10.949(1) ?, c = 16.064(1) ?, β = 99.841(4)°, V = 1898.2(2) ?3, and Z = 16 (single-crystal data, 20 °C) in the TlGaSe2 structure type. Its crystal structure features anionic layers 2∞[Ga4Se84–] with a van der Waals distance of 3.30(1) ?. Thermal analysis revealed a melting point of about 930 °C. Using UV/Vis diffuse reflectance spectroscopy, a wide bandgap of 3.16 eV was determined for the colorless semiconductor. The bonding situation in the compound was further compared with the isotypic cesium phases based on the results from Raman spectroscopy and DFT calculations. The slight shifts of the Raman bands suggest a slightly higher covalency of the rubidium compound.
- Friedrich, Daniel,Schlosser, Marc,Pfitzner, Arno
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- Alkali metal nitrido tecto metallates(VI) with networks of six-membered rings of corner-sharing tetrahedra [(MNN3/2)6] with M = Mo, W of the unexpected composition A9+x[M6N15] with A = Rb, Cs and 0 < x < 1
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Reactions of metal powders of Mo and W respectively with amides and azides of Rb and Cs lead to the compounds Rb9+x[W6N15] and Cs9+x[M6N15] with M = Mo, W and 0 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: Rb9+x[W6N15]: a = 12.743(7) A, c = 27.794(8) A, c/a = 2.181 Cs9+x[Mo6N15]: a = 13.104(5) A, c = 28.430(9) A, c/a = 2.170 Cs9+x[W6N15]: a = 13.136(5) A, c = 28.472(6) A, c/a = 2.167 The metal centres of tetrahedra [MNN3/2] 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.
- Stegen,Jacobs
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- Synthesis and crystal structure of Rb3AgO2
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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) A, 6566 independent reflections, R(all) = 0.0795, Rw(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.
- Sofin,Friese,Nuss,Peters,Jansen
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- K5Mn3O6and Rb8Mn5O10, new charge ordered quasi one-dimensional oxomanganates (II, III)
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K5Mn3O6 and Rb8Mn5O10 have been synthesized via the azide/nitrate route from stoichiometric mixtures of MnO and KNO3/ KN3, or RbNO3/RbN3, respectively. The two new members of manganese (II/III) mixed-valent oxides have been studied by single-crystal X-ray diffraction, magnetic susceptibility measurements and density functional theory calculations (DFT). Both crystal structures [K5Mn3O6: Pna21, Z = 4, a = 1632.43(7), b = 970.07(4), c = 616.48(3) pm, R1 = 0.051; Rb8Mn5O10: P21/c, Z = 8, a = 1223(2), b = 2717(3), c = 1220(2) pm, β = 118.25(2)° , R1 = 0.086] display quasi one-dimensional [MnO2]n-- chains, composed of edge sharing MnO4 tetrahedra. Complete charge ordering of Mn2+ and Mn3+ is observed along the chain direction with repetition units [-Mn3+-Mn2+-Mn,2+-] resulting for K5Mn3O6, and [-Mn3+-Mn2+-Mn2+-Mn3+-Mn2+-] for Rb8Mn5O10. Magnetic susceptibility data as well as DFT calculations indicate strong anti-ferromagnetic intra-chain coupling to be present already at ambient temperature, and above. Rb8Mn5O10 features threedimensional spin ordering below TN = 10.9 K, mediated by ferromagnetic coupling between the chains, while such a 3D coupling appears to be frustrated in K5Mn3O6.
- Nuss, Jürgen,Dasari, Prasad L. V. K.,Jansen, Martin
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p. 316 - 321
(2015/03/04)
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- The chain manganates K29Mn17O34, Rb 11Mn8O16, and Cs4Mn 3O6: a new family of mixed-valent one-dimensional transition metallates
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Air and moisture sensitive K29Mn17O34, Rb11Mn8O16 and Cs4Mn 3O6 were prepared via the azide/nitrate route from stoichiometric mixtures of the precursors Mn2O3, AN 3 and ANO3 (A = K, Rb, Cs) in special containers provided with silver inlays. Their compositions can be generalized as A xMnO2 with x varying between 1.703 and 1.333. According to the X-ray analysis of the crystal structures [K29Mn 17O34: lma2, Z = 4, a = 93.149(3), b = 10.0063(3), c = 6.0621(2) A, 6585 independent reflections, R1 = 0.053, wR(all) = 0.143; Rb11Mn8O16: F222, Z = 16, a = 12.2096(4), b = 20.1595(7), c = 43.712(2) A, 11534 independent reflections, R1 = 0.042, wR(all) = 0.131; Cs4Mn3O6: C222, Z = 8, a = 12.790(3), b = 21.123(4), c =8.179(2) A, 2212 independent reflections, R1 = 0.051, wR(fall) = 0.122], the main feature of all three crystal structures are 1∞MnO2n- chains built up from partially distorted edge-sharing MnO4 tetrahedra. The alkali metal ions fill the space between the anionic entities forming honeycomb like arrangements. In all cases manganese is in a mixedvalent state but no full charge ordering is noticeable. The variations of the charges along the MnO 2n- chains seem to be best described in terms of charge density waves. The magnetic susceptibilities show the dominance of strong antiferromagnetic interactions for the rubidium and the cesium compounds, whereas ferro- or ferrimagnetic interactions prevail in the potassium compound.
- Pfeiffer, Steffen,Nuss, Juergen,Jansen, Martin
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- The AFeO2 (A=K, Rb and Cs) family: A comparative study of structures and structural phase transitions
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Structures and phase transitions for the isostructural series of compounds KFeO2, RbFeO2 and CsFeO2 have been systematically studied by synchrotron X-ray high resolution powder diffraction experiments and in case of CsFeO2 also by single crystal diffractometry. At room temperature, all of the three compounds crystallize in the orthorhombic (Pbca) KGaO2 type of structure consisting of a three dimensional network of corner-sharing [FeO4/2]- tetrahedra, which at elevated temperatures shows a reversible phase transformation to a cubic structure (space group Fd over(3, -) m). For KFeO2, RbFeO2 and CsFeO2 this phase transformation takes place at 1003 K, 737 K and 350 K respectively, as confirmed by differential scanning calorimetry and X-ray diffraction. Upon heating through the transitions the major structural changes are driven by the onset or enhancement of librational motion of the FeO4 tetrahedra. Due to this phenomenon the Fe-O-Fe bonds appear to step-wise getting straight, seemingly approaching 180° within the time and space averaged structure.
- Ali, Naveed Zafar,Nuss, Juergen,Sheptyakov, Denis,Jansen, Martin
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p. 752 - 759
(2010/06/13)
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- Synthesis, crystal structures, and vibrational spectra of novel azidopalladates of the alkali metals Cs2[Pd(N3) 4] and Rb2[Pd(N3)4]·2/3H 2O
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The transparent dark orange compounds Cs2[Pd(N3) 4] and Rb2[Pd(N3)4]·2/3H 2O are synthesized by reaction, of the respective binary alkali metal azides with K2PdCl4 in aqueous solutions. According to single-crystal X-ray diffraction investigations, the novel ternary azidopalladates(II) crystallize in the monoclinic space group P21/c (no. 14) with a = 705.7(2) pm, b = 717.3(2) pm, c = 1125.2(5) pm, β= 104.58(2)°, mP30 for Cs2[Pd(N3)4] and a = 1041.4(1) pm, b = 1292.9(2) pm, c = 1198.7(1) pm, β= 91.93(1)°, mP102 for Rb2[Pd(N3)4].2/3H2O, respectively. Predominant structural features of both compounds are discrete [PdII(N3)4]2- anions with palladium in a planar coordination by nitrogen, but differing in point group symmetries. The vibrational spectra of the compounds are analyzed based on the idealized, point group C4h, of the spectroscopically relevant unit, [Pd(N 3]2- taking into account the site symmetry splitting due to the symmetry reduction in the solid phase.
- Afyon, Semih,Hoehn, Peter,Somer, Mehmet
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p. 1301 - 1306
(2011/01/05)
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- RbGa3S5 und CsGa3S5 - Zwei neue strukturtypen
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The title compounds RbGa3S5 and CsGa 3S5 were synthesized by a solid state reaction starting from GaS, S and MN3 (M = Rb, Cs) as alkaline metal source. They crystallize in the space group P21/su
- Schlosser, Marc,Frettloeh, Vanessa,Deiseroth, Hans-Joerg
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- Azidoaurates of the alkali metals
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Synthesis, crystal structure as well as IR- and Raman-spectroscopic properties of the new ternary azidoaurates(III) A[Au(N3)4] (A = K, Rb, Cs) are reported. The translucent orange-red compounds were prepared by reaction of the respective binary azides with HAuCl4 in aqueous solutions at room temperature. The crystal structures determined by single crystal X-ray diffraction methods are monoclinic (C2/c (No. 15), K/Rb/Cs[Au(N3)4]: a = 1049.30(9) pm / 1033.93(10) pm / 1011.9(8) pm, b = 1047.52(8) pm / 1064.20(11) pm / 1093.8(8) pm, c = 776.97(7) pm / 809.79(8) pm / 858.4(6) pm, β = 91.220(5)° / 90.322(5)° / 92.72(5)°) and provide the first examples for azidoaurates with mono-atomic cations. The unusual reduction of the lattice parameter a with increasing cation size in the isotypic series is discussed in detail. IR-and Raman-spectroscopic measurements show strongly covalent gold-nitrogen contacts, a bonding situation which is further supported by quantum chemical calculations and ELF-analyses.
- Afyon, Semih,Hoehn, Peter,Armbruester, Marc,Baranov, Alexey,Wagner, Frank R.,Somer, Mehmet,Kniep, Ruediger
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p. 1671 - 1680
(2008/10/09)
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- Azides and Cyanamides - Similar and Yet Different
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The crystal structures of LiN3*;H2O (P6 3/mcm (No. 193), Z = 6; 924.01(13); 560.06(7) pm); NH 4N3 (Pmna (No. 53), Z = 4; a = 889.78(18), b = 380,67(8), c = 867.35(17) pm); Ca(N3)2 (Fddd (No. 70), Z = 8; a = 595.4(2), b = 1103.6(5), c = 1133.1(6) pm), Sr(N3)2 (Fddd(No. 70), Z = 8; a = 612.02(9), 6 = 1154.60(18), c = 1182.62(15) pm); Ba(N3)2 (P21/m (No. 11), Z = 2; a = 544.8(1), b = 439.9(1), c = 961.3(2) pm, β = 99.64(3)°) and TIN3 (I4/mcm (No. 140), Z = 2; 618.96(9); 732.71(15) pm) have been either determined for the first time or redetermined by X-ray diffraction on single crystals. The afore mentioned compounds, AN3 (A = Na, K, Rb, Cs), M(N 3)2 · 2.5 H2O (M = Mg, Zn) and the cyanamides Li2CN2, CdCN2 and CuCN2 were investigated by Raman and IR spectroscopy (KBr technique). Structural features and spectroscopic data of azides and cyanamides from this work and from literature are listed and compared.
- Reckeweg, Olaf,Simon, Arndt
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p. 1097 - 1104
(2007/10/03)
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- Rb3CoO2, a Novel Oxocobaltate(I) Synthesized Via the Azide/Nitrate Route
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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)?). Rb3CoO2 is isostructural with K3CoO2 and contains Co(1+), which is coordinated by two oxygen atoms forming a slightly distorted dumb-bell. Rb3CoO2 decomposes at 580°C to Rb2O, Co and CoO.
- Sofin, Mikhail,Jansen, Martin
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- Rb3P6N11 and Cs3P6N11 - New highly condensed nitridophosphates by high-pressure high-temperature synthesis
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The nitridophosphates Rb3P6N11 and Cs3P6N11 were synthesized by the reaction of the respective alkali azides with P3N5 at 35 kbar and 1300°C using a multianvil assembly. The products were obtained as colorless crystalline powders. According to powder diffractometry it was obvious that Rb3P6N11 and Cs3P6N11 are isotypic to K3P6N11. The crystal structures were refined from powder diffraction data by the Rietveld method using the atomic coordinates of K3P6N11 as starting values (Rb3P6N11, P4132, Z=4, a=1049.74(1) pm; Cs3P6N11, a=1065.15(1) pm).
- Landskron, Kai,Schnick, Wolfgang
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p. 390 - 393
(2008/10/08)
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- Thermal behavior of alkali metal azides in NaY-FAU zeolite
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The thermal behavior of pure alkali metal azides and their mechanical mixtures with NaY-FAU zeolite was investigated by means of thermogravimetry and IR spectroscopy. LiN3, KN3, RbN3 and CsN3 were prepared from
- Beres,Hannus,Kiricsi
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p. 1301 - 1311
(2008/10/08)
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