Michael Schwarz

Cs8[Fe4S10] and Cs7[Fe4S8], two new sulfido ferrates with different tetrameric anions.

The two new cesium sulfido ferrates Cs(8)[Fe(4)S(10)] and Cs(7)[Fe(4)S(8)] were synthesized at a maximum temperature of 1070 K in corundum crucibles from stoichiometric samples containing elemental Fe and S together with cesium disulfide, Cs(2)S(2). Their crystal structures have been determined by means of single-crystal X-ray diffraction. Cs(8)[Fe(III)(4)S(10)] crystallizes in the triclinic Cs(6)[Ga(4)Se(10)]-type structure and is thus isotypic to the corresponding rubidium salt. The structure exhibits tetramers [Fe(4)S(10)](8-) of edge-sharing tetrahedra, which represent segments of the well-known chain compounds A[FeS(2)]. The monoclinic mixed-valent iron(II/III) sulfido ferrate Cs(7)[Fe(4)S(8)], which is isotypic to the cesium tellurido ferrate, likewise contains oligomeric tetramers of four edge-sharing [FeS(4)] tetrahedra, in this case resulting in only slightly distorted tetrahedral [Fe(4)S(8)](7-) anions with a Fe(4)S(4) cubane core resembling the prominent [Fe(4)(μ(3)-S(4))](+) cluster, e.g., in the active site of ferredoxins. These sulfido ferrate anions are surrounded by 26 Cs cations, which are located at the 8 corners, 6 faces, and 12 edges of a cube. A dense stacking of these cubes, which ultimately results in the overall seven cesium countercations per cluster anion, describes the overall crystal structure completely. According to this arrangement of cluster-centered cubes, a relationship of the packing of Cs cations and cluster anions with the simple cubic packing (α-Po-type structure) can be established by applying the crystallographic group-subgroup formalism. FP-LAPW band-structure calculations applying antiferromagnetic spin ordering of the high-spin Fe ions in the two tetramers predict a small band gap of 1 eV associated with a L → M-CT for Cs(8)[Fe(III)(4)S(10)] and a tiny energy gap of 0.1 eV resulting from a d-d transition for the mixed-valent cluster compound Cs(7)[Fe(II/III)(4)S(8)].

Neue Sulfido-Antimonate der schweren Alkalimetalle: Synthese, Kristallstruktur und chemische Bindung von (K=Rb=Cs)3SbS3 und Cs3SbS4 · H2O / New Sulfido Antimonates of the Heavy Alkali Metals: Synthesis, Crystal Structure and Chemical Bonding of (K=Rb=Cs)3SbS3 and Cs3SbS4 · H2O

The new sulfido antimonates(III) (Rb=Cs)3SbS3 were prepared from the alkali metal sulfides Rb2S=Cs2S2 and elemental antimony and sulfur or Sb2S3 at reaction temperatures of about 700 °C. The known isotypic potassium compound was similarily synthesized from the elements. The structures of the light-yellow crystals were refined using single-crystal X-ray data. Both compounds are isotypic to the respective Na salt forming the Na3AsS3 structure type (cubic, space group P213, K/Rb/Cs: a = 947:21(7)=982:28(5)=1025:92(5) pm, Z = 4, R1 = 0:0159=0:0560=0:0582). The Ψ - tetrahedral SbS3-3 anions with Sb-S bond lengths of 242 pm are arranged in a cubic face centered packing, in which the three crystallographically different A+ cations occupy the tetrahedral and octahedral voids, overall exhibiting a distorted octahedral sulfur coordination. The chemical bonding and the characteristics of the stereochemically active lone electron pair have been investigated by means of FP-LAPW band structure calculations. Needle-shaped crystals of the monohydrate of the antimony(V) salt Cs3SbS4 · H2O were obtained from a suspension of Sb2O3, CsOH and elemental sulfur. Cs3SbS4 · H2O crystallizes in a new structure type (monoclinic, space group P21/c, a = 987:17(10), b = 994:83(7), c = 1600:46(14) pm, β = 126:895(8)°, Z = 4, R1 = 0:0234). As expected, the Sb-S distances (233.1 - 234.7 pm) in the nearly ideally tetrahedral anion SbS3-4 are considerably shorter than in the antimonates(III) but match the bond lengths in the anhydrous sulfido antimonate(V) Cs3SbS4. Due to their similar fcc-like anion packing and the stereochemically active lone electron pair of Sb in the antimonates(III), the whole series of compounds A3SbIII,VS3/4 shows a uniform structure relation, which is elucidated using crystallographic group-subgroup relations Graphical Abstract Neue Sulfido-Antimonate der schweren Alkalimetalle: Synthese, Kristallstruktur und chemische Bindung von (K=Rb=Cs)3SbS3 und Cs3SbS4 · H2O / New Sulfido Antimonates of the Heavy Alkali Metals: Synthesis, Crystal Structure and Chemical Bonding of (K=Rb=Cs)3SbS3 and Cs3SbS4 · H2O

Rubidium chalcogenido diferrates(III) containing dimers [Fe2Q6]6− of edge-sharing tetrahedra (Q=O, S, Se)

Abstract The two isotypic rubidium chalcogenido diferrates Rb12[Fe2Q6](Q2)3 (Q=S/Se), which both form needles with green-metallic lustre, were synthesized from Rb2S, elemental iron, rubidium and sulfur (Q=S) or from the pure elements (Q=Se) at maximum temperatures of 500–800°C. Their triclinic crystal structures were determined by means of X-ray single crystal data (space group P1̅, a=863.960(10)/903.2(3), b=942.790(10)/982.1(3), c=1182.70(2)/1227.4(4) pm, α=77.4740(10)/77.262(6), β=71.5250(10)/71.462(6), γ=63.7560(10)/63.462(5)°, Z=1, R1=0.0308/0.0658 for Q=S/Se). The structures contain isolated dinuclear anions [FeIII2Q6]6− composed of two edge-sharing [FeQ4] tetrahedra (dFe−Q =223.4–232.3/236.2–244.8 pm), which are also found in the two polymorphs of the pure alkali diferrates Rb6[Fe2Q6]. The diferrate ions are arranged in layers running in the a/b plane around z=0. Inbetween (around z≈12

Complex cubic metallides AM~6 (A=Ca, Sr; M=Zn, Cd, Hg). Synthesis, crystal chemistry and chemical bonding

z approx {1 over 2}

The new Hg-rich barium indium mercurides BaIn{sub x}Hg{sub 7−x} (x=3.1) and BaIn{sub x}Hg{sub 11−x} (x=0–2.8)

), two crystallographically different disulfide/diselenide ions Q22−

The new barium zinc mercurides Ba{sub 3}ZnHg{sub 10} and BaZn{sub 0.6}Hg{sub 3.4} - Synthesis, crystal and electronic structure

Q_2^{2 - }

Evolution and structure of the Upper Rhine Graben: insights from three-dimensional thermomechanical modelling

(dQ−Q =211.1–213.4/237.9–241.1 pm), which are arranged in slightly puckered 36 nets, are intercalated. The intra-anionic distances and angles, the Rb coordination numbers and the molar volumes of these two ‘double-salts’ are in accordance with their corresponding reference compounds, Rb6[Fe2Q6] and Rb2Q2. In addition, the two polymorphs of Rb6[Fe2Se6], which are both isotypic with the sulfido analogous (Cs6[Ga2Se6]-type, monoclinic, space group P21/c, a=827.84(5), b=1329.51(7), c=1074.10(6) pm, β=127.130(5)°, R1=0.0443 and Ba6[Al2Sb6]-type, orthorhombic, space group Cmce, a=1963.70(3), b=718.98(3), c=1348.40(7) pm, R1=0.0264) were prepared and characterized to complete the series of alkali diferrates(III) with oxido, sulfido and selenido ligands. The electronic band structures of the three Rb salts Rb6[Fe2Q6], which have been calculated within the GGA+U approach applying an AFM spin ordering in the dimers and appropriate Hubbard parameters, allow a comparison of the chemical bonding characteristics (e.g. covalency) and the magnetic properties (magnetic moments) within the series of chalcogenido ligands. An analysis of the spin densities enables a comparative consideration of the mechanisms crucial for the magnetic ordering in chalcogenido ferrates. Ultimately, the electronic structure of the new compound Rb12[Fe2S6](S2)3 nicely compares with those of the S2-free reference compound Rb6[Fe2S6].

Die neuen Alkalimetall‐Sulfidoferrate K9[FeIIIS4](S2)S, (K/Rb)6[FeIII2S6], Rb8[FeIII4S10] und K7[FeII/IIIS2]5

Abstract In a systematic synthetic, crystallographic and bond theoretical study, the stability ranges as well as the distribution of the isoelectronic late d-block elements Zn, Cd and Hg (M) in the polyanions of the YCd6-type phases (Ca/Sr)Cd6 have been investigated. Starting from Ca(Cd/Hg)6, 12−30% of the M atoms can be substituted by Zn, which gradually occupies the center of the empty cubes. In all ternary compounds, smaller/less electronegative Zn/Cd atoms occupy the disordered tetrahedra explaining the lack of the YCd6-type for pure mercurides. Along the section SrCd6-SrHg6, the ordered Eu4Cd25-type is formed (Sr4Cd16.1Hg8.9: cF1392, Fd3̅, a=3191.93(5) pm, R1=0.0404). Besides, two new complex cubic Ca phases appear at increased Zn proportion: Ca2Zn5.1Cd5.8, which exhibits a nearly complete site preference of Zn and Cd, crystallizes in the rare cubic Mg2Zn11-type structure (cP39−δ, Pm3̅, a=918.1(1) pm, R1=0.0349). In the Ca–Hg system, an increased Zn proportion yielded the new compound CaZn1.31Hg3.69 (cF480, F4̅3m, a=2145.43(9) pm, R1=0.0572), with a complex cubic structure closely related to Ba20Hg103. All structures, which are commonly described using nested polyhedra around high-symmetric sites, are alternatively described in accordance with the calculated electron densities and charge distribution: building blocks are face-sharing [M4] tetrahedra (star polyhedra such as TS, IS, OS), each with a cage-critical point in its center, and [M8] cubes (deformed TS), which are either empty, distorted or filled. The M element distribution in the anion is determined by size criteria and the difference in electronegativity, which induces a preferred formation of heteroatomic polar bonds.

Novel barium triel/tetrelides with the Pu3Pd5 structure type

Abstract The title compounds BaInxHg7−x (x=3.1(1)) and BaInxHg11−x (x=0–2.8) were synthesized from stoichiometric ratios of the elements in Ta crucibles. Their crystal structures have been determined using single crystal X-ray data. BaInxHg7−x (x=3.1(1)) crystallizes in a new structure type (orthorhombic, oC16, space group Cmmm: a=512.02(1), b=1227.68(3), c=668.61(2)xa0pm, Z=2, R1=0.0311). In the structure, the atoms of the three crystallographically different mixed In/Hg positions form planar nets of four-, six- and eight-membered rings. These nets are shifted against each other such that the four-membered rings form empty distorted cubes. The cubes are connected via common edges, corners and folded ladders, which are also found in BaIn2/BaHg2 (KHg2 structure type) and BaIn (α-NaHg type). The Ba atoms are centered in the eight-membered rings and exhibit an overall coordination number of 20. The [BaM20] polyhedra and twice as many distorted [M8] cubes tesselate the space. BaIn2.8Hg8.2 (cubic, cP36, space group Pm 3 ¯ m , a=961.83(1)xa0pm, Z=3, R1=0.0243) is the border compound of the phase width BaInxHg11−x of the rare BaHg11 structure type. In the structure, ideal [M8] cubes (at the corners of the unit cell) and BaM20 polyhedra (at the edges of the unit cell) represent the building blocks comparable to the other new In mercuride. In accordance with the increased In/Hg content, additional M-pure regions appear: the center of the unit cell contains a huge [Hg(1)M(2)12M(3,4)32] polyhedron, a Hg-centered cuboctahedron of In/Hg atoms surrounded by a capped cantellated cube of 32 additional M atoms. For both structure types, the bonding situation and the ‘coloring’, i.e. the In/Hg distribution of the polyanionic network, are discussed considering the different sizes of the atoms and the charge distribution (Bader AIM charges), which have been calculated within the framework of FP-LAPW density functional theory.The title compounds BaIn{sub x}Hg{sub 7−x} (x=3.1(1)) and BaIn{sub x}Hg{sub 11−x} (x=0–2.8) were synthesized from stoichiometric ratios of the elements in Ta crucibles. Their crystal structures have been determined using single crystal X-ray data. BaIn{sub x}Hg{sub 7−x} (x=3.1(1)) crystallizes in a new structure type (orthorhombic, oC16, space group Cmmm: a=512.02(1), b=1227.68(3), c=668.61(2) pm, Z=2, R1=0.0311). In the structure, the atoms of the three crystallographically different mixed In/Hg positions form planar nets of four-, six- and eight-membered rings. These nets are shifted against each other such that the four-membered rings form empty distorted cubes. The cubes are connected via common edges, corners and folded ladders, which are also found in BaIn{sub 2}/BaHg{sub 2} (KHg{sub 2} structure type) and BaIn (α-NaHg type). The Ba atoms are centered in the eight-membered rings and exhibit an overall coordination number of 20. The [BaM{sub 20}] polyhedra and twice as many distorted [M{sub 8}] cubes tesselate the space. BaIn{sub 2.8}Hg{sub 8.2} (cubic, cP36, space group Pm3{sup ¯}m, a=961.83(1) pm, Z=3, R1=0.0243) is the border compound of the phase width BaIn{sub x}Hg{sub 11−x} of the rare BaHg{sub 11} structure type. In the structure, ideal [M{sub 8}] cubes (at the corners of the unit cell) and BaM{sub 20}morexa0» polyhedra (at the edges of the unit cell) represent the building blocks comparable to the other new In mercuride. In accordance with the increased In/Hg content, additional M-pure regions appear: the center of the unit cell contains a huge [Hg(1)M(2){sub 12}M(3,4){sub 32}] polyhedron, a Hg-centered cuboctahedron of In/Hg atoms surrounded by a capped cantellated cube of 32 additional M atoms. For both structure types, the bonding situation and the ‘coloring’, i.e. the In/Hg distribution of the polyanionic network, are discussed considering the different sizes of the atoms and the charge distribution (Bader AIM charges), which have been calculated within the framework of FP-LAPW density functional theory. - Graphical abstract: BaIn{sub 2.6}Hg{sub 4.4}: distorted cubes [(In/Hg){sub 8}] (green, like in BaHg{sub 11}), folded ladders (violet, like in BaIn, BaHg{sub 2} and BaIn{sub 2}) and Ba coordination polyhedra [Ba(In/Hg){sub 20}] (blue, like in BaHg{sub 11}). - Highlights: • The Hg-rich In-mercuride BaIn{sub 3.1}Hg{sub 3.9} crystallizes with a singular structure type. • The phase width of the BaHg{sub 11} structure in BaIn{sub x}Hg{sub 11-x} ends at x=2.8. • The relations of both compounds with other alkaline-earth mercurides are outlined. • The Hg/In coloring of the polyanion is discussed considering the structure features. • Bonding aspects are explored using band structure calculations.«xa0less

Synthesis, Crystal and Electronic Structure of the Sulfido Ferrate Oxide, Cs11[Fe5S8]2[O]

The title compounds Ba{sub 3}ZnHg{sub 10} and BaZn{sub 0.6}Hg{sub 3.4} were synthesized from stoichiometric ratios of the elements in Ta crucibles. Their crystal structures, which both represent new structure types, have been determined using single crystal X-ray data. The structure of Ba{sub 3}ZnHg{sub 10} (orthorhombic, oP28, space group Pmmn, a=701.2(3), b=1706.9(8), c=627.3(3)pm, Z=2, R1=0.0657) contains folded 4{sup 4} Hg nets, where the meshes form the bases of flat rectangular pyramids resembling the structure of BaAl{sub 4}. The flat pyramids are connected via Hg-Zn/Hg bonds, leaving large channels at the folds, in which Ba(1) and Hg(2) atoms alternate. Whereas the remaining Hg/Zn atoms form a covalent 3D network of three- to five-bonded atoms with short M-M distances (273-301 pm; CN 9-11), the Hg(2) atoms in the channels adopt a comparatively large coordination number of 12 and increased distances (317-348 pm) to their Zn/Hg neighbours. In the structure of BaZn{sub 0.6}Hg{sub 3.4} (cubic, cI320, space group I4{sup Macron }3d, a=2025.50(7) pm, Z=64, R1=0.0440), with a chemical composition not much different from that of Ba{sub 3}ZnHg{sub 10}, the Zn/Hg atoms of the mixed positions M(1/2) are arranged in an slightly distorted primitive cubic lattice with a 4 Multiplication-Sign 4 Multiplication-Sign 4 subcell relationmorexa0» to the unit cell. The 24 of the originating 64 cubes contain planar cis tetramers Hg(5,6){sub 4} with Hg in a nearly trigonal planar or tetrahedral coordination. In another 24 of the small cubes, two opposing faces are decorated by Hg(3,4){sub 2} dumbbells, two by Ba(2) atoms respectively. The third type of small cubes are centered by Ba(1) atoms only. The complex 3D polyanionic Hg/Zn network thus formed is compared with the Hg partial structure in Rb{sub 3}Hg{sub 20} applying a group-subgroup relation. Despite their different overall structures, the connectivity of the negatively charged Hg atoms, the rather metallic Zn bonding characteristic (as obtained from FP-LAPW band structure calculations) and the coordination number of 16 for all Ba cations relate the two title compounds. - Graphical abstract: Six of the 64 small sub-cubes of three types (A, B, C) forming the unit cell of the Hg-rich mercuride BaZn{sub 0.6}Hg{sub 3.4}. Highlights: Black-Right-Pointing-Pointer Two new Hg-rich Ba mercurides, both synthesized from the elements in pure phase. Black-Right-Pointing-Pointer BaZn{sub 0.6}HgG{sub 3.4} and Ba{sub 3}ZnHg{sub 10} with new complex structure types. Black-Right-Pointing-Pointer Structure relation to other complex cubic intermetallics. Black-Right-Pointing-Pointer Discussion of covalent and metallic bonding aspects, as found by the structure features and band structure calculations.«xa0less