@misc{EfimovaPinnauMischkeetal., author = {Efimova, Anastasia and Pinnau, Sebastian and Mischke, Matthias and Breitkopf, Cornelia and Ruck, Michael and Schmidt, Peer}, title = {Development of salt hydrate eutectics as latent heat storage for air conditioning and cooling}, series = {Thermochimica Acta}, volume = {45}, journal = {Thermochimica Acta}, number = {575}, issn = {0040-6031}, doi = {10.1016/j.tca.2013.11.011}, pages = {276 -- 278}, abstract = {Sustainable air conditioning systems require heat reservoirs that operate between 4 and 20 ◦C. A systematic search for binary and ternary eutectics of inorganic salts and salt hydrates with melting temperatures in this temperature regime and with high enthalpies of fusion has been performed by means of differential scanning calorimetry (DSC). Promising results were obtained for the pseudo-ternary system Zn(NO3)2·6H2O, Mn(NO3)2·4H2O, and KNO3 with the melting temperature range 18-21 ◦C and the enthalpy of fusion of about 110 kJ kg-1. Suitable nucleating and thickening agents have been found and tested to prevent the mixture from supercooling and phase separation.}, language = {en} } @misc{GrohBreternitzAhmedetal., author = {Groh, Matthias F. and Breternitz, Joachim and Ahmed, Ejaz and Isaeva, Anna and Efimova, Anastasia and Schmidt, Peer and Ruck, Michael}, title = {Ionothermal Synthesis, Structure, and Bonding of the Catena-Heteropolycation 1∞[Sb2Se2]+}, series = {Zeitschrift f{\"u}r anorganische und allgemeine Chemie}, volume = {641}, journal = {Zeitschrift f{\"u}r anorganische und allgemeine Chemie}, number = {2}, issn = {1521-3749}, doi = {10.1002/zaac.201400543}, pages = {388 -- 393}, abstract = {The reaction of antimony and selenium in the Lewis-acidic ionic liquid 1-butyl-3-methyl-imidazolium tetrachloridoaluminate, [BMIm]Cl·4.7AlCl3, yielded dark-red crystals of [Sb2Se2]AlCl4. The formation starts above 160 °C; at about 190 °C, irreversible decomposition takes place. The compound crystallizes in the triclinic space group Pequation image with a = 919.39(2) pm, b = 1137.92(3) pm, c = 1152.30(3) pm, α = 68.047(1)°, β = 78.115(1)°, γ = 72.530(1)°, and Z = 4. The structure is similar to that of [Sb2Te2]AlCl4 but has only half the number of crystallographically independent atoms. Polycationic chains 1∞[Sb2Se2]+ form a pseudo-hexagonal arrangement along [01-1], which is interlaced by tetrahedral AlCl4- groups. The catena-heteropolycation 1∞[Sb2Se2]+ is a sequence of three different four-membered [Sb2Se2] rings. The chemical bonding scheme, established from the topological analysis of the real-space bonding indicator ELI-D, includes significantly polar covalent bonding in four-member rings within the polycation. The rings are connected into an infinite chain by homonuclear non-polar Sb-Sb bonds and highly polar Sb-Se bonds. Half of the selenium atoms are three-bonded.}, language = {en} } @misc{ZeugnerKaiserSchmidtetal., author = {Zeugner, Alexander and Kaiser, Martin and Schmidt, Peer and Menshchikova, Tatiana V. and Rusinov, Igor P. and Markelov, Anton V. and Van den Broek, Wouter and Chulkov, Evgueni V. and Doert, Thomas and Ruck, Michael and Isaeva, Anna}, title = {Modular Design with 2D Topological-Insulator Building Blocks: Optimized Synthesis and Crystal Growth and Crystal and Electronic Structures of BiₓTeI (x = 2, 3)}, series = {Chemistry of Materials}, volume = {29}, journal = {Chemistry of Materials}, number = {3}, issn = {0897-4756}, doi = {10.1021/acs.chemmater.6b05038}, pages = {1321 -- 1337}, abstract = {Structural engineering of topological bulk materials is systematically explored with regard to the incorporation of the buckled bismuth layer [Bi₂], which is a 2D topological insulator per se, into the layered BiTeI host structure. The previously known bismuth telluride iodides, BiTeI and Bi₂TeI, offer physical properties relevant for spintronics. Herewith a new cousin, Bi₃TeI (sp.gr. R3m, a = 440.12(2) pm, c = 3223.1(2) pm), joins the ranks and expands this structural family. Bi₃TeI = [Bi₂][BiTeI] represents a stack with strictly alternating building blocks. Conditions for reproducible synthesis and crystal-growth of Bi₂TeI and Bi₃TeI are ascertained, thus yielding platelet-like crystals on the millimeter size scale and enabling direct measurements. The crystal structures of Bi₂TeI and Bi₃TeI are examined by X-ray diffraction and electron microscopy. DFT calculations predict metallic properties of Bi₃TeI and an unconventional surface state residing on various surface terminations. This state emerges as a result of complex hybridization of atomic states due to their strong intermixing. Our study does not support the existence of new stacking variants BiₓTeI with x > 3; instead, it indicates a possible homogeneity range of Bi₃TeI. The series BiTeI-Bi₂TeI-Bi₃TeI illustrates the influence of structural modifications on topological properties.}, language = {en} } @misc{KniesKaiserLeAnhetal., author = {Knies, Maximilian and Kaiser, Martin and L{\^e} Anh, Mai and Efimova, Anastasia and Doert, Thomas and Ruck, Michael}, title = {Low-Temperature Ordering in the Cluster Compound (Bi₈)Tl[AlCl₄]₃}, series = {Inorganics}, volume = {7}, journal = {Inorganics}, number = {4}, doi = {10.3390/inorganics7040045}, pages = {1 -- 9}, abstract = {The reaction of Bi, BiCl₃, and TlCl in the ionic liquid [BMIm]Cl·4AlCl₃ (BMIm = 1-n-butyl-3-methylimidazolium) at 180 °C yielded air-sensitive black crystals of (Bi₈)Tl[AlCl₄]₃. X-ray diffraction on single crystals at room temperature revealed a structure containing [Tl(AlCl₄)₃]∞12- strands separated by isolated Bi₈²⁺ square antiprisms. The thallium(I) ion is coordinated by twelve Cl⁻ ions of six [AlCl₄]⁻ groups, resulting in a chain of face-sharing [TlCl₁₂]¹¹⁻ icosahedra. The Bi₈²⁺ polycation is disordered, simulating a threefold axis through its center and overall hexagonal symmetry (space group P6₃/m). Slowly cooling the crystals to 170 K resulted in increased order in the Bi₈ cluster orientations. An ordered structure model in a supercell with a' = 2a, b' = 2b, c' = 3c and the space group P6₅ was refined. The structure resembles a hexagonal perovskite, with complex groups in place of simple ions.}, language = {en} } @misc{PabstChangFinzeletal., author = {Pabst, Falk and Chang, Jen-Hui and Finzel, Kati and Kohout, Miroslav and Schmidt, Peer and Ruck, Michael}, title = {The Subbromide Bi5Br4 - On the Existence of a Hidden Phase}, series = {Zeitschrift f{\"u}r Anorganische und Allgemeine Chemie}, volume = {646}, journal = {Zeitschrift f{\"u}r Anorganische und Allgemeine Chemie}, number = {3}, doi = {10.1002/zaac.201800149}, pages = {149 -- 155}, abstract = {Black and irregularly shaped crystals of the bismuth-rich bromide Bi5Br4 were obtained as a by-product of the reaction of CsBr, Bi, and BiBr3. X-ray diffraction on a single-crystal revealed its orthorhombic structure with the space group Pmmn (no. 59) and lattice parameters a = 1800.0(2) pm, b = 1476.1(1) pm, and c = 924.5(2) pm at 296 K. The structure is composed of Bi82+ and Bi95+ polycations and bromidobismuthate(III) anions according to the structured formula Bi5Br4 = Bi20Br16 = Bi82+Bi95+[BiBr5]2-[Bi2Br11]5-. Bi5Br4 is the bismuth-richest among the bismuth subhalides containing isolated polycations. Extensive differential scanning calorimetry studies indicate that Bi5Br4 decomposes at 262 °C, i.e. one degree below the bismuth-rich eutectic at 263 °C. All attempts towards a rational synthesis yielded predominantly the neighboring phases BiBr and Bi6Br7.}, language = {en} }