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Reaction of the binary Zintl anion (Sn2Sb2)2− with the β-diketiminato complex [LCu(NCMe)] (L=nacnac=[(N(C6H3iPr2-2,6)C(Me))2CH]−) in ethylenediamine or DMF affords the ternary cluster dimer {[CuSn5Sb3]2−}2 (1) as its [K(crypt-222)]+ salt. The chemical formulation of 1 is supported by energy-dispersive X-ray spectroscopy (EDX) and quantum chemical calculations. Each monomeric part of the dimer represents a trimetallic “[CuSn5Sb3]2−” cluster, with an architecture in between a tricapped trigonal prism and a capped square antiprism. As shown by quantum chemical investigations, the presence of Sb atoms and, in particular, of Cu atoms in the cluster skeleton makes the monomeric unit behave like an inhomogeneous superatom, which clearly prefers to dimerize, thereby producing a relatively short, yet virtually non-bonding Cu⋅⋅⋅Cu distance.

Two thallium (I) thorium (IV) fluorides, TlTh3F13 and TlThF5 were obtained by solid state synthesis and their crystal structures determined from single crystal X-ray diffraction data recorded at room temperature with an APEX-II CCD diffractometer. TlTh3F13 is orthorhombic, space group Pmc21, with a=8.1801(2) A, b=7.4479(2) A, c=8.6375(2) A, V=526.24(2) A3, Z=2 and TlThF5 is monoclinic, space group P21/n, with a=8.1128(5) A, b=7.2250(4) A, c=8.8493(6) A, β=116.683(3)°, V=463.46(5) A3, Z=4. The structure of TlTh3F13 comprises layers of corner and edge-sharing ThF9 polyhedra further linked by chains of trans connected tricapped trigonal prisms ThF9 through corners and edges. The three dimensional thorium frameworks delimits channels parallel to [0 0 1] where the 11-coordinated Tl+ ions are arranged into double columns located in mirror planes of the structure. TlTh3F13 is isotypic with RbTh3F13, RbU3F13 and with one of the two polymorphs of CsTh3F13. The structure of TlThF5 may be regarded as a layer structure built up from the regular succession of ∞2[M′F5]− corrugated layers further held by the Tl+ ions along the [1 0 1] direction. The layers are built up from edge and corner-sharing thorium polyhedra where each (ThF9)5− monocapped square antiprism is connected to five others by sharing three edges and two corners. TlThF5 is isostructural with β-NH4UF5 and with one of the polymorphs of CsThF5. A comparison of the different structural types of MM′F5 pentafluorides is presented and a diagram of repartition of their structures is given. From the comparison of the Tl structures with their Rb or Cs homologs, where very similar monovalent cation environments are observed it should be concluded to a stereochemically inactivity of the 6s2 lone pair of Tl(I) in both TlTh3F13 and TlThF5, contrary to what is observed in richer Tl(I) content Tl3ThF7 fluorothorate.

A review of recent structure determination of non-metal anions containing simple ligands, mostly halogenes, is given, where the total number of ligands exceeds 6. It will be shown that these anions exist in the form of regular polyhedra, the pentagonal bipyramid and the square antiprism. A non-bonding electron pair (or two) will influence such geometries in a complex way: the general principle that such pairs are stereochemically active needs to be carefully revised in compounds of large coordination numbers.

The structure of the title compound consists of columns of Ca ions surrounded by four columns of perbromate ions and four columns of water molecules alternating in pairs. The CaO8 complex was found to be dimensionally similar to corresponding complexes in other simple tetrahydrated calcium salts. The eight coordinating O atoms form a polyhedron which departs only slightly from a (distorted) square antiprism. Each of the crystallographically inequivalent perbromate ions was found to conform to rigid-body behavior while the CaO8 complex did not. Although the perbromate ions depart moderately from regular tetrahedral geometry, the mean Br--O bond length agrees well with previously determined values. Hydrogen bonds in this structure involve water-oxygen acceptors as well as perbromate-oxygen acceptors.

The title structure, Pb(HSeO 3 ) 2 , consists of layers of Pb-O polyhedra connected into a two-dimensional network by Se atoms. The layers are parallel to the bc plane and are not interconnected by chemical bonds. Hydrogen bonding between layers is improbable. The coordination polyhedron of Pb consists of eight O atoms in the form of a square antiprism, with all Pb-O distances less than 3.0A. There is no apparent lone-pair effect on the lead ion.

Pr 3 (SiO 4 ) 2 Cl is isostructural with La 3 (SiO 4 ) 2 Cl. The Pr(1)O 7 Cl polyhedron is irregular. The Pr(2)O 8 Cl 2 polyhedron is a distorted square antiprism with the Cl atom capping distorted square faces. The site of Pr(2) can also be described as at the centre of a Pr(2)(SiO 4 ) 4 Cl 2 octahedron. The structure comprises layers of Pr(2)(SiO 4 ) 4 Cl 2 octahedra separated in the a direction by Pr(1) cations occupying the Pr(1)O 7 Cl polyhedral sites. The Cl atom is four-coordinate forming a distorted square.

The first nine-atom deltahedral clusters of lead in the solid state are found in the Zintl-phase K4Pb9. The compound crystallizes in the monoclinic space group P21/m, Z = 4, with a = 9.648(3) A, b = 13.243(5) A, c = 15.909(8) A, and β = 103.24(4)°. The isolated Pb94- clusters are of two different geometries, a monocapped square antiprism and an elongated tricapped trigonal prism.

The title compound, trimercury(II) bis­[selenite(IV)] selen­ate(VI), contains three crystallographically inequivalent HgII cations with coordination numbers of eight (denoted Hg1 and Hg2) and five (denoted Hg3). The corresponding coordination polyhedra around the metal atoms might be described as intermediates between a square antiprism and a triangulated dodecahedron for both Hg1 and Hg2, and a strongly distorted truncated octahedron for Hg3. {_{\infty}^{\kern 4pt 2}}[HgO8/2] layers of edge-sharing [HgO8] polyhedra propagate parallel to the bc plane, and are connected via SeVIO4 tetrahedra and [Hg3O5] polyhedra along the a axis, forming an arrangement with channels propagating parallel to the b axis. The two independent SeIVO3 pyramids bridge the Hg atoms, and the non-bonding orbitals of the SeIV ions protrude into the channels from opposite sides.

The title anion was synthesized by a reaction of nido-Ge94-, made from K4Ge9 dissolved in ethylenediamine and 2,2,2-crypt(4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane), with BiPh3. It was structurally characterized in (K-2,2,2-crypt)2[Ge9(BiPh2)2]·en which was crystallized from the solution. The anion is a monocapped square antiprism of Ge9 with two diphenylbismuth ligands exo-bonded to opposite vertexes of the open face of the cluster. This is the first example where covalently exo-bonded ligands are attached to a deltahedral cluster that can exist without them as well.

The bismuth rich bromidostannate(II) Bi18Sn7Br24 = (Bi95+)2[Sn7Br2410–] was crystallized from a melt of bismuth, tin, and BiBr3. X-ray diffraction on a single crystal revealed a polar, tetragonal structure (space group I4cm, no. 108) with lattice parameters a = 1323.70(5) pm and c = 1816.86(8) pm at 110(5) K. In agreement with Wade’s rules and quantum chemical calculations, the homonuclear nido cluster Bi95+ is a monocapped square antiprism (point group C4v). The anions of the bromidostannate(II) groups mainly comply with the pseudosymmetry of the space group I4/mcm and thereby affect substantial disorder of the SnII cations.

The fluoride-derivatized lanthanoid(III) ortho-oxomolybdates(VI) LnF[MoO4] (Ln=Sm–Tm) crystallize in the monoclinic space group P21/c with four formula units per unit cell (a=516–528 pm, b=1220–1248 pm, c=659–678 pm, β=112.5–113.1°). The structure contains one crystallographically unique Ln3+ cation surrounded by two fluoride and six oxide anions in a square antiprism (CN=8). The square antiprisms [LnF2O6] are interconnected via three edges to form layers ∞ 2 { [ Ln F 2 / 2 e O 4 / 2 e O 2 / 1 t ] 6 - } parallel (010), which are cross-linked along [010] by Mo6+ in tetrahedral oxygen coordination to form the three-dimensional crystal structure. The fluoride anions within this arrangement exhibit a twofold coordination of Ln3+ cations in the shape of a boomerang, which is connected to another F− anion to form planar [F2Ln2]4+ rhombuses. Magnetic measurements for GdF[MoO4], TbF[MoO4], and DyF[MoO4] show Curie–Weiss behavior, despite the peculiar arrangement of the lanthanoid(III) cations in layers comparable with those of gray arsenic. Furthermore, Raman, infrared, and diffuse reflectance spectroscopy data for these compounds were recorded and interpreted.

The geometries of metal clusters and supramolecular architectures that contain nine metal atoms are analyzed within the framework of continuous shape measures (CShM). The most common polyhedra in nine coordinate complexes, the capped square antiprism and the tricapped trigonal prism, are also found among these families of compounds, even if much more scarcely. In addition, a variety of new shapes, not found among coordination polyhedra, can be identified and their proximity to the ideal geometries quantified. These include a linear chain, two types of trigonal columns, the planar regular enneagon, two-dimensional hexagonal and square grids, fragments of a close-packed structure, the triangular cupola, the tridiminished icosahedron or different fragments of the icosahedron. Among the nine-atom boranes and related clusters of the groups 13 and 14 elements, those having between 18 and 20 framework electrons present the structure of the tricapped trigonal prism, the expected closo structure. However, clusters with 21 and 22 framework electrons present a variety of structures with geometries covering nearly all the path that takes one from the capped square antiprism (nido form) to the tricapped trigonal prism (closo form).

The structure of barium chlorite hydrate, Ba(ClO2)2·3.5H2O, has been determined by single-crystal X-ray analysis at 150 K. The structure is monoclinic, space group C2/c, with Z = 8. It contains layers of Ba2+ cations coordinated by ClO2− anions and water mol­ecules. There are also solvate water mol­ecules involved only in hydrogen bonding of the layers. Three solvate water O atoms are on sites of twofold symmetry, while all other atoms are in general positions. The full coordination environment of the Ba2+ cation consists of ten O atoms belonging to six chlorites and three water mol­ecules, forming a bicapped square antiprism.

The bismuth polyhedra in ternary transition metal-centered bismuth cluster halides may form discrete molecules or ions, infinite chains, and/or infinite layers. The chemical bonding in many of these diverse structures is related to that in deltahedral boranes exhibiting three-dimensional aromaticity by replacing the multicenter core bond in the boranes with two-center two-electron (2c-2e) bonds from the central transition metal to the nearest neighbor bismuth vertices. Examples of discrete molecules or ions include octahedral MBi(6)(micro-X)(12)(z)()(-) (X = Br, I; M = Rh, Ir, z = 3; M = Ru, z = 4) with exclusively 2c-2e bonds and pentagonal bipyramidal RhBi(7)Br(8) with a 5c-4e bond in the equatorial pentagonal plane indicative of Möbius aromaticity. The compound Ru(3)Bi(24)Br(20) contains a more complicated discrete bismuth cluster ion Ru(2)Bi(17)(micro-Br)(4)(5+), which can be dissected into a RuBi(5) closo octahedron and a RuBi(8) nido capped square antiprism bridged by a Ru(2)Bi(4)(micro-Br)(4) structural unit. In RuBi(4)X(2) (X = Br, I), the same Ru(2)Bi(4)(micro-Br)(4) structural unit bridges Bi(4) squares similar to those found in the known Zintl ion Bi(4)(2)(-) to give infinite chains of Ru(2)Bi(4) octahedra. The electron counts of the RuBi(5), RuBi(8), and Ru(2)Bi(4) polyhedra in these structures follow the Wade-Mingos rules. A different infinite chain structure is constructed from fused RhBi(7/2)Bi bicapped trigonal prisms in Rh(2)Bi(9)Br(3). This Rh(2)Bi(9)Br(3) structure can alternatively be derived from alternating Rh(2/2)Bi(4) octahedra and Rh(2/)(2)Bi(5) pentagonal bipyramids with electron counts obeying the Wade-Mingos rules. Related chemical bonding principles appear to apply to more complicated layer structures such as Pt(3)Bi(13)I(7) containing Kagomé nets of PtBi(8/2) cubes and Ni(4)Bi(12)X(3) containing linked chains of NiBi(6/3)Bi capped trigonal prisms.

The crystal structure of potassium plutonium(IV) tetrasulphate, K 4 Pu(SO 4 ) 4 ·2H 2 O has been investigated and resolved by Rietveld refinement of X-ray powder diffraction data. The compound crystallises in a monoclinic unit cell with lattice parameters a =1.24175(7) nm, b =1.11583(7) nm, c =1.35530(9) nm, β =111.82(1)°, space group P2 1 /c and Z =4. The structure consists of dimeric [(SO 4 ) 3 Pu(SO 4 ) 2 Pu(SO 4 ) 3 ] 8− anions in which each plutonium has nine oxygen atoms from five sulphate groups coordinated to it at an average Pu–O distance of 0.239(4) nm, forming distorted monocapped square antiprism geometry. Bridging sulphate groups are tridentate while others are bidentate chelating type. The two water molecules are not coordinated to the plutonium atom in the structure.

The title compound, disodium cerium pentanitrate monohydrate, was synthesized from a nitric acid solution of Ce(NO(3))(3).6H(2)O and NaNO(3), and its structure has been determined from single-crystal X-ray diffraction data. The structure is built from isolated chains of irregular icosahedral [Ce(NO(3))(6)](3-) anions. Na atoms and water molecules are located between the chains. The Na coordination polyhedra, in the form of a square antiprism or a monocapped square antiprism, share common vertices and contribute to the formation of a three-dimensional network. Ten nitrate groups act as bridging ligands.

Substitution of a borane vertex by an isolobal transition metal vertex in a deltahedron can change the shape and apparent electron count. More specifically, in many metallaborane deltahedra with 9, 10, and 11 vertices some transition metal units are found to occur at degree 6 vertices. In the case of 9- and 10-vertex deltahedra this requires a change in the shape of the deltahedron from the metal-free closo borane deltahedra having only degree 4 and 5 vertices to alternative so-called isocloso deltahedra having a single degree 6 vertex. The change in electron count from 2 n +2 skeletal electrons for metal-free borane closo deltahedra having the maximum number of degree 4 and 5 vertices to 2 n skeletal electrons for metallaborane isocloso deltahedra with the metal at a single degree 6 vertex can be rationalized by a major change in the skeletal bonding topology from globally delocalized in the closo deltahedra to face-localized in the isocloso deltahedra. In this model the skeletal bonding in closo deltahedra with n vertices can be constructed from n two-center two-electron surface bonds and a single n -center core bond whereas the entire skeletal bonding in isocloso deltahedra can arise from n three-center two-electron bonds in n of the 2 n −4 faces. The isocloso metallaboranes with n vertices can be considered to be metal complexes of an open borane ligand having all triangular faces except for a single hexagonal face, which forms a hexahapto bond to the transition metal vertex similar to the hexahapto arenemetal bonds in arene metal complexes. The 10-vertex deltahedra (C 5 H 5 M) 2 C 2 B 6 H 8 (M=Co, Fe) discovered by Hawthorne and co-workers in the 1970s provide an early example of a structurally characterized closo / isocloso deltahedral pair of the same stoichiometry in which the cobalt derivative has the 2 n +2 skeletal electrons and geometry of the closo 10-vertex deltahedron (the bicapped square antiprism) whereas the iron derivative has only 2 n skeletal electrons and the different geometry of the isocloso 10-vertex deltahedron with one of the iron atoms at the unique degree 6 vertex.

Reaction between Y5O(OiPr)13 and acetylacetone at room temperature under anhydrous conditions, produced in high, reproducible yield a compound characterized—by 1H and 13 C NMR, as well as X-ray diffraction—as Y2(μ2-OAc)2(acac)4(H2O)2. It crystallizes in the orthorhombic Pcnb system, with unit cell dimensions a = 13.385 (3), b = 15.107(4), c = 16.100(4) A and Z = 4. Least-squares refinement converged to a final R = 0.0356. The molecule is a centrosymmetric dimer with chelating tridentate acetato groups in the bridging positions. The yttrium atoms are eight-coordinated, with a distorted square antiprism geometry. Intra- as well as intermolecular hydrogen bonding between the water molecules and the β-diketonato ligands is observed. The formation of this acetatoacetylacetonate derivative as well as its behaviour in solution are discussed.

Reaction between neodymium chips and isopropanol led to the isolation of [Nd(OiPr)3]4·4iPrOH. Its desolvation results in a soluble polynuclear neodymium(III) oxoisopropoxide, whose reactivity has been investigated. Reaction with acetylacetone produced a compound analysing as Nd2(OH)(acac)5, which has been characterized by IR and ESR spectroscopy, as well as by X-ray diffraction. It crystallizes in the monoclinic P 21/n system with unit cell dimensions α = 14.52(5), b = 14.20(4), c = 15.25(5) A, β = 101.4° and Z = 4. Least-squares refinement converged to a final Rw = 0.050. The molecule is a centrosymmetric, tetranuclear neodymium(III) hydroxo acetylacetonate cluster, [Nd4(μ3-OH)2(μ2,μ1-acac)6(acac)4]. Two dinuclear Nd2(OH)(acac)5 units are linked by two triply bridging pyramidal μ-hydroxo ligands and by two bridging-chelating β-diketonate ligands. The metal atoms are eight-coordinated with a distorted square antiprism geometry.

The pentadentate ligand 2,6-diacetylpyridinedisemicarbazone, DAPSC, reacts with Th(NO 3 ) 4 in ethanolwater mixture and a di-μ-hydroxo Th(IV) dimer is formed. The compound [Th 2 (OH) 2 (DAPSC) 2 (NO 3 ) 2 (H 2 O) 2 ](NO 3 ) 4 ·4H 2 O ( I ) is monoclinic, space group P 2 1 / n with a = 10.705(1), b = 19.008(2), c = 11.782(1) A, β = 107.82(2)°, V = 2282(1) A 3 and Z = 2. Detailed X-ray structural analysis showed that each thorium atom in the complex is coordinated to one pentadentate DAPSC ligand, which is subjected to a considerable distortion, one bidentate nitrate group, one water ligand and two bridging hydroxo groups. The coordination number is ten and the best presentation of the polyhedron is that of a distorted bicapped square antiprism. The ThTh separation is 4.0181(6) A and the average ThO(H) bridge is 2.366 A. The structure was refined using 3185 reflections to an R value of 5.0%.