Browsing by Author "Ivlev, Sergei I."
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- Binary Lead Fluoride Pb3F8
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2019-12-05) Deubner, H. Lars; Sachs, Malte; Bandemehr, Jascha; Ivlev, Sergei I.; Karttunen, Antti J.; Kachel, Stefan R.; Klein, Benedikt P.; Ruppenthal, Lukas; Schöniger, Maik; Krug, Claudio K.; Herritsch, Jan; Gottfried, J. Michael; Aman, Jamal N.M.; Schmedt auf der Günne, Jörn; Kraus, FlorianThe binary lead fluoride Pb3F8 was synthesized by the reaction of anhydrous HF with Pb3O4 or by the reaction of BrF3 with PbF2. The compound was characterized by single-crystal and powder X-ray diffraction, IR, Raman, and solid-state MAS 19F NMR spectroscopy, as well as thermogravimetric analysis, XP and near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Solid-state quantum-chemical calculations are provided for the vibrational analyses and band assignments. The electronic band structure offers an inside view of the mixed valence compound. - The Crystal Structure of MnF3 Revisited
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2020-07-15) Bandemehr, Jascha; Stoll, Christiane; Heymann, Gunter; Ivlev, Sergei I.; Karttunen, Antti J.; Conrad, Matthias; Huppertz, Hubert; Kraus, FlorianWe correct the crystal structure of MnF 3, of which the space group was reported as monoclinic C2/c (no. 15) with a = 8.9202, b = 5.0472, c = 13.4748 Å, β = 92.64°, V = 606.02 ų, Z = 12, mS48, T not given, likely 298 K. In the structure model proposed here, we use a unit cell of one third of the former volume. The ruby red crystals of MnF 3 were synthesized by a high-pressure/high-temperature method, where MnF 4 was used as a starting material. As determined on a single crystal, MnF 3 crystallizes in the monoclinic space group I2/a (no. 15) with a = 5.4964(11), b = 5.0084(10), c = 7.2411(14) Å, β = 93.00(3)°, V = 199.06(7) Å 3, Z = 4, mS16, T = 183(2) K. The crystal structure of MnF 3 is related by a direct group-subgroup transition to the VF 3 structure-type. We performed quantum chemical calculations on the crystal structure to allow the assignment of bands of the obtained vibrational spectra. - The Crystal Structures of α- and β-F 2 Revisited
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2019-01-01) Ivlev, Sergei I.; Karttunen, Antti J.; Hoelzel, Markus; Conrad, Matthias; Kraus, FlorianThe crystal structures of α-F 2 and β-F 2 have been reinvestigated using neutron powder diffraction. For the low-temperature phase α-F 2 , which is stable below circa 45.6 K, the monoclinic space group C2/c with lattice parameters a=5.4780(12), b=3.2701(7), c=7.2651(17) Å, β=102.088(18)°, V=127.26(5) Å 3 , mS8, Z=4 at 10 K can now be confirmed. The structure model was significantly improved, allowed for the anisotropic refinement of the F atom, and an F−F bond length of 1.404(12) Å was obtained, which is in excellent agreement with spectroscopic data and high-level quantum chemical predictions. The high-temperature phase β-F 2 , stable between circa 45.6 K and the melting point of 53.53 K, crystallizes in the cubic primitive space group Pm (Formula presented.) n with the lattice parameter a=6.5314(15) Å, V=278.62(11) Å 3 , cP16, Z=8, at 48 K. β-F 2 is isotypic to γ-O 2 and δ-N 2 . The centres of gravity of the F 2 molecules are arranged like the atoms in the Cr 3 Si structure type. - Crystal Structures of α- And β-Nitrogen Trifluoride
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2019-05-06) Ivlev, Sergei I.; Conrad, Matthias; Hoelzel, Markus; Karttunen, Antti J.; Kraus, FlorianThe crystal structures of α-NF 3 and β-NF 3 are reported for the first time. As shown by powder neutron diffraction, the lowerature α-NF 3 crystallizes in the orthorhombic space group Pnma (oP16) with lattice parameters a = 6.71457(13) Å, b = 7.30913(14) Å, c = 4.55189(8) Å, V = 223.396(7) Å 3 , and Z = 4 at T = 6 K. The intramolecular atom distances in α-NF 3 are 1.3639(16) and 1.3677(11) Å for N-F, and 2.1216(16) and 2.120(2) Å for F···F. The F-N-F bond angles are 101.92(7)° and 101.63(10)°. All data are in excellent agreement with quantum-chemical predictions and previously reported experimentally obtained gas-phase data. The higherature β-NF 3 is a plastic crystal, space group P4 2 /mnm (tP120), with the lattice parameters a = 15.334(6) Å, c = 7.820(3) Å, V = 1838.6(12) Å 3 , and Z = 30 at T = 60 K. Its crystal structure is closely related to that of the Frank-Kasper sigma phase. - DFT-Guided Crystal Structure Redetermination and Lattice Dynamics of the Intermetallic Actinoid Compound UIr
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2021-11-01) Sachs, Malte; Ivlev, Sergei I.; Etter, Martin; Conrad, Matthias; Karttunen, Antti J.; Kraus, FlorianUIr has been discussed as a rare example of a noncentrosymmetric, ferromagnetic superconductor crystallizing in the acentric PdBi structure type (P21, mP16). Here we present a new structure model for UIr. By means of single-crystal and powder X-ray diffraction we find UIr to crystallize in the centrosymmetric space group P21/c, in line with previous ab initio calculations. The discrepancy with the previous noncentrosymmetric model in space group P21 is explained by the occurrence of twinning. The observed twinning hints toward a high-temperature displacive phase transition of UIr to the CrB structure type (Cmcm, oS8): we discuss the lattice dynamics corresponding to this transition by crystallographic symmetry mode analysis and by density functional theory (DFT). We find that spin-orbit coupling is essential to understand this phase transition. We apply our theoretical considerations for a critical judgment of the structure models of UPt and NpIr that have been reported to crystallize isotypically with UIr. We confirm that UPt is isotypic to UIr (P21/c), whereas we predict NpIr to crystallize in the CrB structure type. Our report on the centrosymmetric crystal structure of UIr has an effect on all those theoretical models that investigated potentially novel superconducting coupling mechanisms of this compound on the basis of the noncentrosymmetric structure model. - Difluorochloronium(III) Fluoridometallates - from Molecular Building Blocks to (Helical) Chains
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2020-12-20) Scheibe, Benjamin; Haiges, Ralf; Ivlev, Sergei I.; Karttunen, Antti J.; Müller, Ulrich; Christe, Karl O.; Kraus, FlorianDifluorochloronium(III) compounds were synthesized from the reaction of metal powders (Ru, Os, Ir, Au), metal fluorides (NbF5, SbF3, BiF5) or a metal chloride (TaCl5) with excess liquid chlorine trifluoride. The compounds ClF2[AuF4], ClF2[MF6] (M = Nb, Ta, Ru, Os, Ir, Sb, Bi) and ClF2[Ta2F11] were obtained in crystalline form and their crystal structures were determined by single-crystal X-ray diffraction. The ClF2+ cations in the investigated compounds are bent, containing two strong, short, mainly covalent Cl-F bonds and two sterically active, free valence electron pairs in a pseudo-tetrahedral arrangement. The coordination around the Cl atom is extended by two highly ionic, long fluorine bridges to neighboring fluoridometallate anions, resulting in a total coordination number of six. The crystal structures vary among the ClF2+ compounds and range from molecular building blocks, such as dimeric (ClF2[AuF4])(2) and (ClF2[Ta2F11])(2), to chains, some of which being helical, as in ClF2[MF6], (M = Nb, Ta, Ru, Os, Ir, Sb, Bi). Quantum-chemical solid-state and gas-phase calculations were carried out to elucidate the bonding within the ClF2+ cations and their interactions with the bridging F atoms. - The Interhalogen Cations [Br2F5]+ and [Br3F8]+
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2018-10-26) Ivlev, Sergei I.; Karttunen, Antti J.; Buchner, Magnus R.; Conrad, Matthias; Kraus, FlorianThe synthesis and characterization of unique polyhalogen cations containing μ-bridging fluorine atoms are reported. The [Br2F5]+ cation features a symmetric [F2Br-μ-F-BrF2] bridge, whereas the [Br3F8]+ contains asymmetric μ-F bridges. These fluoronium ions, obtained as [SbF6]- salts, were investigated using Raman and 19FNMR spectroscopy, as well as single-crystal X-ray diffraction. Quantum chemical calculations were carried out for the gas-phase cations as well as for the solid-state compounds. Population analyses show the μ-F atoms to possess the most negative partial charge within the cations. - Low-Temperature Single-Crystal Structure and Phonon Properties of A-Site Ordered Double Perovskite CaMnTi2O6
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2024-10-04) Albrecht, Elisabeth K.; Graubner, Tim; Ivlev, Sergei I.; Rautama, Eeva-Leena; Karppinen, Maarit; Kraus, Florian; Karttunen, Antti J.We have used high-pressure methods to synthesize CaMnTi2O6 single crystals with edge lengths of up to 70 μm. Compared to previously reported synthetic pathways, we were able to use gold capsules and smaller pressures of 4 GPa. X-ray diffraction analysis of the single crystals at low temperatures between 100 and 230 K confirmed that no phase transitions occur in this temperature range. We found square planar-coordinated Mn ions to shift further out of the plane with lower temperatures which could lead to a higher polarization. The measured Raman spectrum of CaMnTi2O6 has been compared with quantum chemically calculated Raman spectrum to assign the vibrational modes. Calculated single-crystal Raman spectrum has also been also analyzed from the point of view of direction dependency of the Raman intensities. - A Neutron Diffraction and Quantum-Chemical Study of [Mn(ND3)6](N3)2
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2018-06-11) Ivlev, Sergei I.; Müller, Thomas G.; Karttunen, Antti J.; Hoelzel, Markus; Kraus, Florian[Mn(ND3)6](N3)2 was obtained by careful decomposition of [Mn(ND3)6](N3)2·4ND3 at room temperature. It crystallizes in the monoclinic space group I2/m with a = 8.5905(5), b = 6.8506(4), c = 9.7530(6) Å, β = 94.618(6)°, V = 572.10(6) Å3, Z = 2, at T = 3 K. Its crystal structure was elucidated using powder neutron diffraction and confirmed by quantum chemical calculations. The MnII cation is coordinated octrahedron-like by ND3 ligands. The azide anion is linear with 178.7(10)° and shows N-N distances of 1.178(11) and 1.180(12) Å. - PbF[Br2F7], a Fluoridobromate(III) of a p-Block Metal
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2020-01-09) Bandemehr, Jascha; Sachs, Malte; Ivlev, Sergei I.; Karttunen, Antti J.; Kraus, FlorianThe compound PbF[Br2F7] represents the first fluoridobromate(III) of a p-block element. It was synthesized in form of needle-shaped crystals among its colorless powder from the direct reaction of PbF2 with BrF3. Powder X-ray diffraction, IR and Raman spectroscopy show that it was obtained in almost pure form with Pb3F8 and Pb2F6 as by-products. The single crystal structure was determined by X-ray diffraction. PbF[Br2F7] crystallizes in space group P21/c (No. 14) with a = 4.3698(3), b = 13.3767(7), c = 12.0836(8) Å, β = 97.509(5)°, V = 700.27(8) Å3, Z = 4 at T = 100 K. PbF[Br2F7] decomposes above 50 °C due to loss of BrF3 and pure PbF2 remains. Quantum chemical calculations were performed on the crystal structure of the compound to assign the bands of the vibrational spectra and to obtain electron density difference maps that visualize the electron density around the Pb atoms. CHARDI calculations support the assignment of the oxidation states +II, +III, and –I to the Pb, Br, and F atoms, respectively. - Photochemical Synthesis of Tungsten Pentafluoride, WF5
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2021-02-24) Stene, Riane; Scheibe, Benjamin; Ivlev, Sergei I.; Karttunen, Antti J.; Petry, Winfried; Kraus, FlorianA new synthetic route for the synthesis of WF5 utilizing a mercury photosensitized reduction of tungsten hexafluoride with H2 is described. Crystals of WF5 were studied using single-crystal X-ray diffraction, resulting in the first-reported crystal structure of WF5. Powder X-ray diffraction studied at room-temperature showed the compound was phase-pure. The IR spectrum of WF5 was reinvestigated and interpreted with the use of solid-state quantum-chemical calculations using the DFT-PBE0 density functional method. The compound synthesized herein was free of HF and moisture but may have contained minute amounts of WOF4, that were only observed in the IR spectrum. - Surprises in the Solvent-Induced Self-Ionization in the Uranium Tetrahalide UX4(X = Cl, Br, I)/Ethyl Acetate System
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2022-04-12) Deubner, H. Lars; Graubner, Tim; Buchner, Magnus R.; Weigend, Florian; Ivlev, Sergei I.; Karttunen, Antti J.; Kraus, FlorianThe reaction of the uranium(IV) halides UCl4, UBr4, or UI4 with ethyl acetate (EtOAc) leads to the formation of the complexes [UX3(EtOAc)4][UX5(EtOAc)] (X = Cl, Br) or [UI4(EtOAc)3]. Thus, both UCl4 and UBr4 show self-ionization in ethyl acetate to a distorted pentagonal bipyramidal [UX3(EtOAc)4]+ cation and a distorted octahedral [UX5(EtOAc)]- anion. Surprisingly, the chloride and bromide compounds are not isotypic. While [UCl3(EtOAc)4][UCl5(EtOAc)] crystallizes in the orthorhombic crystal system, space group P212121 at 250 K, the bromide compound crystallizes in the monoclinic crystal system, P121/n1 at 100 K. Unexpectedly, UI4 does not show self-ionization but forms [UI4(EtOAc)3] molecules, which crystallize in the monoclinic crystal system, P21/c, at 100 K. The compounds were characterized by single-crystal X-ray diffraction, IR, Raman, and NMR spectroscopy, as well as molecular quantum chemical calculations using solvent models. - A Symmetric F−H−F Hydrogen Bond in Strontium Bifluoride, Sr[HF2]2
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2022-05-25) Stene, Riane E.; Graubner, Tim; Ivlev, Sergei I.; Karttunen, Antti J.; Kraus, FlorianSingle crystal X-ray diffraction shows the hydrogen bond within the [F−H−F]− anion of Sr[HF2]2 to be symmetric with H−F bond lengths of 1.143(5) Å and an intramolecular F⋅⋅⋅F distance of 2.2826(18) Å. The [HF2]− anion adopts crystallographic C2-symmetry, however, it is essentially linear with a F−H−F angle of 174(4)°. Solid-state quantum chemical calculations agree with the experimental findings, showing a slightly bent F−H−F angle of 177.8°. The decomposition of Sr[HF2]2 to SrF2 and HF is endothermic by +64 kJ/mol at room temperature. The bonding in the [F−H−F]− anion is clearly ionic both in the solid state and gas phase. - Syntheses and Characterization of the Mixed-Valent Manganese(II/III) Fluorides Mn2F5and Mn3F8
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2021-09-06) Bandemehr, Jascha; Zimmerhofer, Fabian; Ivlev, Sergei I.; Pietzonka, Clemens; Eklund, Kim; Karttunen, Antti J.; Huppertz, Hubert; Kraus, FlorianWe obtained single crystals of the binary mixed-valent fluorides Mn2F5 and Mn3F8 using a high-pressure/high-temperature approach. Mn2F5 crystallizes isotypic to CaCrF5 in the monoclinic space group C2/c (No. 15), with a = 8.7078(8) Å, b = 6.1473(6) Å, c = 7.7817(7) Å, β = 117.41(1)°, V = 369.80(6) Å3, Z = 4, and mC28 at T = 173 K. Mn3F8 crystallizes in the monoclinic space group P21 (No. 4) with a = 5.5253(2) Å, b = 4.8786(2) Å, c = 9.9124(4) Å, β = 92.608(2)°, V = 266.92(2) Å3, Z = 2, and mP22 at T = 183 K and presents a new structure type. Crystal-chemical reasoning, CHARDI calculations, and quantum-chemical calculations allowed for the assignment of the oxidation states of the Mn atoms. In both bulk compounds, MnF2 was present as an impurity, as evidenced by powder X-ray diffraction and IR and Raman spectroscopy. - Syntheses and Crystal Structures of Sodium Hydrogen Fluorides NaF·nHF (n = 2, 3, 4)
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2017-11-17) Ivlev, Sergei I.; Soltner, Theresa; Karttunen, Antti J.; Mühlbauer, Martin J.; Kornath, Andreas J.; Kraus, FlorianA series of higher sodium hydrogen fluorides were synthesized and structurally characterized. Sodium tetrahydrogen pentafluoride, NaH4F5, crystallizes in space group type I41/a with cell parameters a = 6.0275(4), c = 11.6208(13) Å, V = 422.19(7) Å3, Z = 4 at 100 K. Sodium trihydrogen tetrafluoride, NaH3F4, crystallizes in space group type R3 with cell parameters a = 6.5139(4), c = 13.4040(15) Å, V = 492.55(8) Å3, Z = 6 at 100 K. Sodium dihydrogen trifluoride, NaH2F3, crystallizes in space group type Pnma with cell parameters a = 7.9276(9), b = 3.4514(3), c = 9.6937(10) Å, V = 265.23(5) Å3, Z = 4 at 100 K. The investigations were complemented by IR spectroscopy and theoretical calculations. NaH2F3 was additionally characterized by means of powder neutron diffraction. All observed F–H···F hydrogen bonds are unsymmetric, close to linearity and can be considered as strong hydrogen bonds. - Synthesis and characterization of barium hexafluoridoosmates
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2018-01-01) Ivlev, Sergei I.; Karttunen, Antti J.; Buchner, Magnus R.; Conrad, Matthias; Ostvald, Roman V.; Kraus, FlorianTwo barium hexafluoridoosmates, Ba(OsF6)2 and BaOsF6, were synthesized and were characterized for the first time using X-ray powder and single crystal diffraction, IR spectroscopy, as well as NMR spectroscopy in anhydrous hydrogen fluoride. Ba(OsF6)2 crystallizes in the space group type P21/c with the cell parameters a = 6.4599(4), b = 10.7931(8), c = 14.7476(10) Å, β = 115.195(5)◦, V = 930.42(12) Å3, Z = 4 at 293 K. BaOsF6 crystallizes in the space group type R3 with the cell parameters a = 7.3286(10), c = 7.2658(15) Å, V = 337.95(12) Å3, Z = 3 at 100 K. Additionally, we have obtained the compounds Ba(OsF6)2·3BrF3, Ba(OsF6)2·HF, Ba(OsF6)2·6H2O from the respective solvents, and Ba(OsF6)2. - Synthesis and characterization of the pyridine—bromine trifluoride (1/1) complex, [py∙BrF3]
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2018-11-01) Ivlev, Sergei I.; Buchner, Magnus R.; Karttunen, Antti J.; Kraus, FlorianThe pyridine—bromine trifluoride (1/1) complex was synthesized and characterized. It crystallizes in the monoclinic space group C2/c with a = 6.9044(9), b = 14.769(2), c = 6.9665(9) Å, β = 111.686(9)°, V = 660.12(16) Å3, Z = 4 at 100 K. The crystal structure consists of isolated non-planar molecules linked via C–H⋯F hydrogen bonds. The obtained results were confirmed by quantum chemical calculations, vibrational and NMR spectroscopy. Calculations of an isolated molecule in the gas phase showed that a planar conformation of the molecule with intramolecular C–H⋯F hydrogen bonds is stable. - Synthesis and Characterization of the Tetrafluoridochlorates(III) A[ClF4] (A = K, Rb, Cs)
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2020-04-16) Scheibe, Benjamin; Ivlev, Sergei I.; Karttunen, Antti J.; Kraus, FlorianSingle-crystalline tetrafluoridochlorates(III) A[ClF4] (A = K, Rb, Cs) were synthesized from solvolysis reactions of alkali metal fluorides in liquid chlorine trifluoride. The structures were examined by means of single-crystal X-ray diffraction. K[ClF4] crystallizes in the K[BrF4] structure type, whereas the Rb and Cs compounds crystallize in the Li[AuF4] structure type. The compounds were further characterized by Raman and IR spectroscopy. Solid-state quantum-chemical calculations with hybrid density functional methods reproduced the experimental structures and enabled the interpretation of the experimental Raman and IR spectra. - Uranium Cyanides from Reactions in Liquid Ammonia Solution
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2024-06-03) Graubner, Tim; Rudel, Stefan S.; Ivlev, Sergei I.; Karttunen, Antti J.; Kraus, FlorianReactions of uranium tri- and tetrahalides, UBr3, UI3, UCl4, and UI4, with different cyanides MCN (M=K, Ag) in liquid anhydrous ammonia led to three novel uranium(IV) cyanide compounds. The reaction of UCl4 in the presence of KCN resulted in the compound [U(CN)(NH3)8]Cl3 ⋅ 3NH3, while UBr3 and UI3 were oxidized in the presence of AgCN to form the compounds (Formula presented.) (μ-CN){(H3N)5U(μ-NH2)3U(NH3)5}]Br4 ⋅ 2NH3, and (Formula presented.) (μ-CN){(H3N)5U(μ-NH2)3U(NH3)5}]I4 ⋅ 2NH3. The reaction of UI4 with KCN in aNH3 also yielded the compound (Formula presented.) (μ-CN){(H3N)5U(μ-NH2)3U(NH3)5}]I4 ⋅ 2NH3. The compounds (Formula presented.) (μ-CN){(H3N)5U(μ-NH2)3U(NH3)5}]X4 ⋅ 2NH3 (X=Br, I) crystallize in different space groups, Pmn21 (no. 31) and Imm2 (no. 44), respectively. In both cases, the (Formula presented.) (μ-CN){(H3N)5U(μ-NH2)3U(NH3)5}]4+ cation forms infinite strands. We conducted quantum-chemical calculations and Intrinsic Bond Orbital analyses on the observed [U(CN)(NH3)8]3+ cation and the [(μ-CN)2{(H3N)5U(μ-NH2)3U(NH3)5}]3+ model cation to gain insight into the bonding situation.