Coloring variants of the Re3B type

The Re3B type, space group Cmcm, has boron-centered trigonal prisms as central building units and is one of the basic structure types with numerous binary and ternary representatives. The coloring of different atoms on the two crystallographically independent rhenium sites leads to a manifold of compounds with different bonding peculiarities that are rather isopointal than isotypic with the prototype. Typical compounds are the S-phase precipitate MgCuAl2, the silicide ScPt2Si or the iodide Th0.5Pb0.5I3 (PuBr3 type). Differences in size or composition might force symmetry reductions. This is discussed for YZn3 (space group Pnma) and the different coloring variants ScRhSi2 and TaNi2P which show different twists of the trigonal prisms. Striking singular representatives with lower symmetry structures are BaThBr6 (Pmma) and NbCo2B (P21/c) which allow different ordering/distortion patterns for the prisms. All these crystal chemical details are discussed on the basis of group subgroup schemes (Bärnighausen trees).

Interconversion between Pd3L2 trigonal prism and Pd6L8 cube via anion exchange: binding affinity of monoatomic vs. polyatomic anions

Systematic interconversion between trigonal prisms [Pd3X6L2] (X- = Cl-, Br-, and I-) and cubic cages [Pd6L8]12+(X-)12 (X- = BF4- with CF3SO3-) via anion exchange was established. Self-assembly of K2PdX4 (X-...

Crystal structure of La24Ru11

The compound La24Ru11 (tetracosalanthanum undecaruthenium) crystallizes in a Ce24Co11-type structure. The non-centrosymmetric crystal structure (space group P63 mc) contains RuLa6 trigonal prisms, La6 octahedra and LaRu4 tetrahedra and is closely related to that of Ce23Ni7Mg4. This communication highlights the crystal-chemical similarities and points out the differences between the two structures. All of the tested crystals were inversion twins.

CRYSTAL STRUCTURE OF THE YNi0.83Ga1.17 AND YNiIn0.15Ga0.85 COMPOUNDS

Crystal structure of the YNi0.83Ga1.17 (KHg2, Imma, a = 0.43006(4), b = 0.69108(6), c = 0.73371(6) nm, R1 = 0.0315, wR2 = 0.0635) and YNiIn0.15Ga0.85 (HoNiGa, Pnma, a = 0.69313(5), b = 0.43225(7), c = 0.74315(9) nm, R1 = 0.0777, wR2 = 0.0658) compounds were determined from the single crystal X-ray diffraction data. Stacking of trigonal prisms in the structures were analyzed and briefly discussed.

Syntheses and structures of piperazin-1-ium ABr2 (A = Cs or Rb): hybrid solids containing `curtain wall' layers of face- and edge-sharing ABr6 trigonal prisms

The isostructural title compounds, poly[piperazin-1-ium [di-μ-bromido-caesium]], {(C4H11N2)[CsBr2]} n , and poly[piperazin-1-ium [di-μ-bromido-rubidium]], {(C4H11N2)[RbBr2]} n , contain singly-protonated piperazin-1-ium cations and unusual ABr6 (A = Cs or Rb) trigonal prisms. The prisms are linked into a distinctive `curtain wall' arrangement propagating in the (010) plane by face and edge sharing. In each case, a network of N—H...N, N—H...Br and N—H...(Br,Br) hydrogen bonds consolidates the structure.

Synthesis and crystal structure of calcium hydrogen phosphite, CaHPO3

The hydrothermal synthesis and crystal structure of the simple inorganic compound CaHPO3, which crystallizes in the chiral space group P43212, are reported. The structure is built up from distorted CaO7 capped trigonal prisms and HPO3 pseudo pyramids, which share corners and edges to generate a three-dimensional network.

New data on fiedlerite-1A from ancient slags of Lavrion, Greece: crystal structure and H-bonding

The crystal structure (R = 0.0750) of fiedlerite-1A Pb3Cl4F(OH) H2O from ancient slags of Lavrion (Greece) was studied on a single crystal. The mineral is triclinic, a = 8.5741(7), b = 8.0480(5), с = 7.2695(4) Å, (a = 90.087(5), (b = 102.126(6), (g = 103.424(6)) V = 476.37(6) Å3, Z = 2. Pb2+ cations centre bicapped trigonal prisms Pb(1)F(H2O)Cl6, Pb(2)(OH)2FCl5 and Pb(3)(OH)F2Cl5. Additional Pb′site with 10% occupancy was revealed in the structure. There are two basic structure fragments alternating along the a axis: (100) layers formed by Pb(2)- and Pb(3)-centred polyhedra and elongated along the b axis zig-zag chains formed by Pb(1)-centred polyhedra sharing common edges. IR spectrum of fiedlerite-1A is given.

Synthesis and crystal structures of the new ternary borides Fe3Al2B2 and Ru9Al3B8 and the confirmation of Ru4Al3B2 and Ru9Al5B8−x (x≈2)

Single crystals of the new ternary borides Fe3Al2B2 and Ru9Al3B8 were obtained from the elements at 1900°C. Both compounds represent new structure types which combine well-known features of binary and ternary borides of transition metals in combination with aluminum. The crystal structure of Fe3Al2B2 (P2/m, Z=2, a=5.724, b=2.857, c=8.723 Å, β=98.57°) contains tetramers of face-sharing trigonal prisms BFe6 with a B4 unit in trans-configuration. The tetrameric units are separated by Al-atoms which occupy all remaining rectangular sites of the trigonal prisms. The structure can be derived from Fe2AlB2 by insertion of additional FeAl fragments in a bcc arrangement. The crystal structure of Ru9Al3B8 (P6̅2m, Z=1, a=9.078, c=2.913 Å) combines zig-zag chains of boron atoms made of face-sharing trigonal prisms BFe6 and isolated BFe6 units. Three of these chains are connected by common corners to rods running in direction [001]. The rods are linked to a three-dimensional framework by isolated prisms via common edges. Again, Al occupies the capping positions of the trigonal prisms. Ru9Al3B8 is the second representative for the combination of boron zig-zag chains and isolated B atoms. The existence of Ru4Al3B2 (P4/mmm, Z=2, a=8.515, c=2.924 Å) and Ru9Al5B8−x (P4/m, Z=1, a=8.741, c=2.923 Å) were confirmed and the crystal structures refined. High quality data reveal a stoichiometric composition for Ru4Al3B2, while in Ru9Al5B8−x there is a significant underoccupation (i.e. x≈2) of the central boron site within the B4 units. The crystal structures of all four compounds represent examples for the combination of CsCl and AlB2 fragments as they were frequently found for ternary borides of transition metals.

Lead flux crystal growth of Ce2Ru12P7

Well-shaped needles of the metal-rich phosphide Ce2Ru12P7 were grown in a lead flux, while a polycrystalline sample became available through a ceramic route followed by arc-melting. Ce2Ru12P7 crystallizes with the hexagonal Zr2Fe12P7 type: P6̅, a = 940.7(2), c = 389.8(1) pm, wR2 = 0.0342, 1001 F2 values and 45 variables. Striking structural motifs in the Ce2Ru12P7 structure are tri-capped trigonal prisms that are centered by the phosphorus atoms: P1@Ru7Ce2, P2@Ru7Ce2 and P3@Ru9. Adjacent prisms are condensed via common edges to propeller-like building units.