Synthesis and Crystal Structure of the First Thallium Hydrous Nesosilicate Tl4SiO4·0.5H2O

Orange prismatic crystals of the first thallium hydrous nesosilicate Tl₄SiO₄·0.5H₂O have been obtained by evaporation from aqueous solution. There are three symmetrically independent Tl⁺ cations and five symmetrically independent oxygen atoms in the structure of Tl₄SiO₄·0.5H₂O. The O(4) and O(5) atoms belong to water molecules. Coordination polyhedra of the Tl⁺ cations are strongly distorted because of the stereoactive behavior of lone electron pairs. The structure of Tl₄SiO₄·0.5H₂O contains sheets of SiO₄ tetrahedra and Tl coordination polyhedra. The sheets have the composition [Tl₃SiO₄]^– and are parallel to [100]. Within the sheets, SiO₄ tetrahedra link to thallium polyhedra though common corners. The sheets are linked by dimers of face‐sharing Tl(3)O₅ polyhedra, thus providing interconnection of the sheets into a framework. The framework has large elliptical channels occupied by water molecules (OW2) and electron pairs of Tl⁺ cations.The comparison with some other M⁺ (M = K, Ag, Tl) silicates is given.     

Beiträge zur Kristallchemie und zum thermischen Verhalten von wasserfreien Phosphaten. XXXIII [1] In2P2O7, ein Indium(I)‐diphosphato‐indat(III) und In4(P2O7)3 — Darstellung,Kristallisation und Kristallstrukturen

Contributions on Crystal Chemistry and Thermal Behaviour of Anhydrous Phosphates. XXXIII [1] In₂P₂O₇ an Indium(I)‐diphosphatoindate(III), and In₄(P₂O₇)₃ — Synthesis, Crystallization, and Crystal Structure Solid state reactions via the gas phase lead to the new mixed‐valence indium(I, III)‐diphosphate In₂P₂O₇. Colourless single crystals of In₂P₂O₇ have been grown by isothermal heating of stoichiometric amounts of InPO₄ and InP (800 °C; 7d) using iodine as mineralizer. The structure of In₂P₂O₇ [P2₁/c, a = 7.550(1) Å, b = 10.412(1) Å, c = 8.461(2) Å, b = 105.82(1)°, 2813 independent reflections, 101 parameter, R1 = 0.031, wR2 = 0.078] is the first example for an In⁺ cation in pure oxygen coordination. Observed distances d(In^I‐O) are exceptionally long (d_min(In^I‐O) = 2.82 Å) and support assumption of mainly s‐character for the lone‐pair at the In⁺ ion. Single crystals of In₄(P₂O₇)₃ were grown by chemical vapour transport experiments in a temperature gradient (1000 → 900 °C) using P/I mixtures as transport agent. In contrast to the isostructural diphosphates M₄(P₂O₇)₃ (M = V, Cr, Fe) monoclinic instead of orthorhombic symmetry has been found for In₄(P₂O₇)₃ [P2₁/a, a = 13.248(3) Å, b = 9.758(1) Å, c = 13.442(2) Å, b = 108.94(1)°, 7221 independent reflexes, 281 parameter, R1 = 0.027, wR2 = 0.067].     

Crystalline and Glassy Phases in the Ternary System Tl/Bi/Cl: Synthesis and Crystal Structures of the Thallium(I) Chloridobismutates(III) Tl3BiCl6 and TlBi2Cl7

Slow cooling of melts composed of TlCl and BiCl₃ allows for the isolation of the compounds Tl₃BiCl₆ ( 1 ) and TlBi₂Cl₇ ( 2 ). Compound 1 is formed by sublimation at 480 °C from the black melt of 3 TlCl + 1 BiCl₃ as colourless crystals. The crystal structure determination (tetragonal, P4₂/m) consists of nearly regular octahedral [BiCl₆]^3– anions and two independent Tl⁺ cations, which have coordination number 8 in form of a slightly distorted cube and 10 in form of an Edshamar polyhedron, respectively. The structure is not isotypic with the recently reported naturally occurring form of Tl₃BiCl₆, the mineral steropesite. Compound 2 is obtained from a dark red melt of composition TlCl + 2 BiCl₃. On rapid cooling, this melt solidifies to a metastable dark red glass which at ambient temperature crystallises to a light amber crystalline powder within some weeks. The structure of 2 was determined by powder diffraction (triclinic, P\bar{1} ). A distinct lone pair effect is present causing an irregular coordination on the two independent bismuth atoms. Taking Bi–Cl bonds up to 3.5 Å into account, both bismuth atoms gain coordination number seven. ²⁰³Tl and ²⁰⁵Tl solid state NMR and XANES spectra on the Bi and Tl‐L_III edges of both glassy and crystalline TlBi₂Cl₇ show that a close structural similarity exists between both forms. In contrast, the Raman spectra show distinct differences in the bands of the Bi–Cl vibrations region.     

Syntheses and Crystal Structures of Two New Open‐Framework Tin(II) Phosphates: Sn5O2(PO4)2 and Sn4O(PO4)2

Two new three‐dimensional neutral open‐framework tin(II) phosphates, Sn₅O₂(PO₄)₂ and Sn₄O(PO₄)₂, were synthesized under hydrothermal conditions with different ratio of tin(II) oxalate, phosphoric acid and 4,4′‐diaminodiphenylmethane. Their crystal structures have been solved by single‐crystal X‐ray diffraction methods. Sn₅O₂(PO₄)₂ crystallizes in the space group and contains six‐membered ring and twelve‐membered ring channels running parallel to the b axis. Sn₄O(PO₄)₂ crystallizes in the space group P2₁/n and contains intersecting eight‐membered ring channels. These two compounds have rare trigonal‐planar Sn₃O.     

Preparation,Crystal Structure,Vibrational Spectra,and Thermal Behavior of Tl2H2P2O6 and Tl4P2O6

The new thallium(I) salts, Tl₂H₂P₂O₆ ( 1 ) and Tl₄P₂O₆ ( 2 ), were prepared and structurally characterized by single‐crystal X‐ray diffraction. Compound 1 crystallizes in the monoclinic space group P2₁/c and compound 2 in the orthorhombic space group Pbca. Both structures feature channels occupied by the lone electron pairs of Tl⁺ cations. Furthermore, those are built up by discrete [H₂P₂O₆]^2– for compound 1 and [P₂O₆]^4– units for 2 in staggered conformation for the P₂O₆ skeleton and the thallium cations. In Tl₂H₂P₂O₆ ( 1 ) the hydrogen atoms of the [H₂P₂O₆]^2– ion are in a “trans‐trans” conformation. The O ··· H–O hydrogen bonds between the [H₂P₂O₆]^2– groups consolidate the structure 1 into a three‐dimensional network. FT‐IR/FIR and FT‐Raman spectra of the crystalline title compounds were recorded and a complete assignment for the P₂O₆^4– modes is proposed. The phase purity of 1 was verified by powder diffraction measurements.     

Preparation,Single Crystal Structure Analysis,and Thermal Behaviour of the Acidic Mercury(I) Phosphate (Hg2)2(H2PO4)(PO4)

Yellowish single crystals of acidic mercury(I) phosphate (Hg₂)₂(H₂PO₄)(PO₄) were obtained at 200 °C under hydrothermal conditions in 32% HF from a starting complex of microcrystalline (Hg₂)₂P₂O₇. Refinement of single crystal data converged at a conventional residual R[F² > 2σ(F²)] = 3.8% (C2/c, Z = 8, a = 9.597(2) Å, b = 12.673(2) Å, c = 7.976(1) Å, β = 110.91(1)°, V = 906.2(2) ų, 1426 independent reflections > 2σ out of 4147 reflections, 66 variables). The crystal structure consists of Hg₂²⁺‐dumbbells and discrete phosphate groups H₂PO₄^– and PO₄^3–. The Hg₂²⁺ pairs are built of two crystallographically independent Hg atoms with a distance d(Hg1–Hg2) = 2.5240(6) Å. The oxygen coordination sphere around the mercury atoms is asymmetric with three O atoms for Hg1 and four O atoms for Hg2. The oxygen atoms belong to the different PO₄ tetrahedra, which in case of H₂PO₄‐groups are connected by hydrogen bonding. Upon heating over 230 °C, (Hg₂)₂(H₂PO₄)(PO₄) condenses to (Hg₂)₂P₂O₇, which in turn disproportionates at higher temperatures into Hg₂P₂O₇ and elemental mercury.     

TlCu5O(VO4)3 mit KCu5O(VO4)3‐Struktur – ein Thallium‐kupfer(II)‐oxidvanadat als Oxidationsprodukt einer Tl/Cu/V‐Legierung

TlCu₅O(VO₄)₃ with KCu₅O(VO₄)₃ Structure – a Thallium Copper(II) Oxide Vanadate as an Oxidation Product of a Tl/Cu/V Alloy Brown‐black crystals of the new oxide vanadate TlCu₅O(VO₄)₃ (triclinic, P1, a = 610.4(1) pm, b = 828.9(1) pm, c = 1075.3(1) pm, α = 97.70(1)°, β = 92.25(1)°, γ = 90.28(1)°, Z = 2) were obtained as a byproduct during the reaction of a Tl/Cu/V alloy with oxygen. The compound is isotypic with KCu₅O(VO₄)₃. All the crystals investigated were twins by non‐merohedry with [100] as the twin axis. The structure contains ladder shaped [Cu₁₀O₂₆]‐ribbons composed of edge‐ and corner‐sharing [CuO₅]‐polyhedra (tetragonal pyramids and trigonal bipyramids) and linked by vanadate groups. The thallium ions fill channels running along the a axis. No stereochemical activity of the thallium(I)‐lone pair is observed.     

Crystal structure and ionic conductivity of AgCr2(PO4)(P2O7)

Single crystals of a new phosphate AgCr₂(PO₄)(P₂O₇) have been prepared by the flux method and its structural and the infrared spectrum have been investigated. This compound crystallizes in the monoclinic system with the space group C2/c and the parameters are, a = 11.493 (3) Å, b = 8.486 (3) Å, c = 8.791 (2) Å, β = 114.56 (2)°, V = 779.8 (3) ųand Z = 4. Its structure consists of CrO₆ octahedra sharing corners with P₂O₇ units to form undulating chains extending infinitely along the [110] direction. These chains are connected by the phosphate tetrahedra giving rise to a 3D framework with six-sided tunnels parallel to the [101] direction, where the Ag⁺ ions are located. The infrared spectrum of this compound was interpreted on the basis of P₂O₇^4? and PO₄^3? vibrations. The appearance of ν_sP–O–P in the spectrum suggests a bent P–O–P bridge for the P₂O₇^4? ions in the compound, which is in agreement with the X-ray data. The electrical measurements allow us to obtain the activation energy of (1.36 eV) and the conductivity measurements suggest that the charge carriers through the structure are the silver captions.     

Das Kupfer(II)-oxidphosphat Cu4O(PO4)2 in einer neuen,orthorhombischen Modifikation durch Oxidation einer Tl/Cu/P-Legierung

The Copper(II) Oxide Phosphate Cu₄O(PO₄)₂ in a New, Orthorhombic Modification by Oxidation of a Tl/Cu/P Alloy Single crystals of Cu₄O(PO₄)₂ in a new, orthorhombic modification were prepared by reaction of a Tl/Cu/P alloy with oxygen. The compound crystallizes in the space group Pnma with Z = 4 and lattice constants a = 808.8(5) pm, b = 627.0(7) pm, c = 1338.3(1) pm. It is isotypic with the orthorhombic form of Cu₄O(AsO₄)₂. The copper atoms are five-coordinated by oxygen. The distorted square-pyramidal and trigonal-bipyramidal polyhedra are connected by edges and vertices to form [Cu₈O₁₈] ribbons running along [010] and forming slabs perpendicular to the c-axis interconnected by phosphate groups.     

Tl2CuAsO4 – ein Zwischenprodukt bei der Oxidation von Tl/Cu/As-Legierungen im Sauerstoffstrom

Tl₂CuAsO₄ – an Intermediate Phase in the Oxidation of Tl/Cu/As Alloys with Oxygen Waxy, honey-jellow single crystals of the new compound Tl₂CuAsO₄ (monoclinic, P2₁/c, a = 860.1(1) pm, b = 533.94(7) pm, c = 1200.1(2) pm, β = 98.10(1)°, Z = 4) were prepared as an intermediate product of the oxidation process in the reaction of Tl/Cu/As-alloys with oxygen. Their structure was determined from IPDS data (w2R = 0.071 for 1271 F² values and 74 parameters). The structure contains an isolated [Cu₂As₂O₈]^4– group consisting of two AsO₄-tetrahedra connected by two Cu⁺ ions with an approximately linear O–Cu–O coordination. The [Cu₂As₂O₈]^4– groups are linked to a threedimensional framework by thallium(I) ions which show an hemispheric coordination sphere of oxygen ions indicating the stereochemical activity of the Tl⁺ lone pair.     

Mixed‐Valence Thallium(I,III) Bromides The Crystal Structure of α—Tl2Br3

Thallium sesquibromide Tl₂Br₃ is dimorphic. Scarlet coloured crystals of α‐Tl₂Br₃ were obtained by reactions of aqueous solutions of TlBr₃ and Tl₂SO₄ in agarose gel. In case of rapid crystallisation of hydrous TlBr₃/TlBr solutions and from TlBr/TlBr₂ melts ß‐Tl₂Br₃ is formed as scarlet coloured, extremely thin lamellae. The crystal structures of both forms are very similar and can be described as mixed‐valence thallium(I)‐hexabromothallates(III) Tl₃[TlBr₆]. In the monoclinic unit cell of α‐Tl₃[TlBr₆] (a = 26.763(7) Å; b = 15.311(6) Å; c = 27.375(6) Å; β = 108.63(2)°, Z = 32, space gr. C2/c) the 32 Tl^III‐cations are found in strongly distorted octahedral TlBr₆ groups. The 96 Tl^I cations are surrounded either by four or six TlBr₆ groups with contacts to 8 or 9 Br neighbors. Crystals of β‐Tl₃[TlBr₆] by contrast show almost hexagonal metrics (a = 13.124(4) Å, b = 13.130(4) Å, c = 25.550(7) Å, γ = 119.91(9)°, Z = 12, P2₁/m). Refinements of the parameters revealed structural disorder of TlBr₆ units, possibly resulting from multiple twinning. Both structures are composed of Tl₂[TlBr₆]^— and Tl₄[TlBr₆]⁺ multilayers, which alternate parallel (001). The structural relationships of the complicated structures of α‐ and β‐Tl₃[TlBr₆] to the three polymorphous forms of Tl₂Cl₃ as well as to the structures of monoclinic hexachlorothallates M₃TlCl₆ (M = K, Rb) and the cubic elpasolites are discussed.     

Contributions on Thermal Behaviour and Crystal Chemistry of Anhydrous Phosphates. XXXIV [1] Oxygen Equilibrium Pressures in Ternary Systems M / P / O (M = Co,Ni) and Heats of Formation of Anhydrous Cobalt(II) and Nickel(II) Phosphates

Oxygen equilibrium pressures have been measured in the temperature range 800 °C to 1000 °C by coulometric/potentiometric techniques for several equilibrium regions in the ternary systems M / P / O (M = Co, Ni). In both systems oxygen coexistence pressures of three‐phase equilibrium solids phosphide/phosphate are about 3 to 5 orders of magnitude smaller than p(O₂) above the corresponding M_s / MO_s system. Heats of formation Δ_fH°₂₉₈ and standard entropies S°₂₉₈ for the phosphates have been obtained from 2^nd and 3^rd law evaluation of the temperature dependence of the oxygen coexistence pressures. Thermodynamic data from literature for the phosphides of cobalt and nickel and estimated heat capacities for the anhydrous phosphates Co₃(PO₄)₂, Co₂P₂O₇, Ni₃(PO₄)₂, Ni₂P₂O₇ and Ni₂P₄O₁₂ were used for these calculations. Thus obtained enthalpies and entropies are compared to results from thermodynamic modelling of observed solid phase equilibria in the ternary systems M / P / O (M = Co, Ni).     

Struktur‐ und magnetochemische Untersuchungen an den ternären Phosphaten Ba2MII(PO4)2 (MII = Mn,Co) und Strukturverfeinerung von BaNi2(PO4)2

Structural and Magnetochemical Studies at the Ternary Phosphates Ba₂M^II(PO₄)₂ (M^II = Mn, Co) and Refinement of the Crystal Structure of BaNi₂(PO₄)₂ Single crystals of the following phosphates were grown by the floating zone technique using a mirror furnace and their crystal structures refined (0,02 < R₁ < 0,04 and 0,04 < wR₂ < 0,10, resp.): Ba₂Mn(PO₄)₂ (a = 531.1(1), b = 896.8(1), c = 1625.6(3) pm, β = 90.26(1)°), Ba₂Co(PO₄)₂ (a = 529.8(1), b = 884.4(1), c = 1614.4(3) pm, β = 90.68(2)°) and BaNi₂(PO₄)₂ (a = 480.0(1), c = 2327.3(5) pm, Z = 3, space group R3). Both compounds Ba₂M^II(PO₄)₂ crystallize with Z = 4 in space group P2₁/n of the monoclinic Ba₂Ni(PO₄)₂ type; BaNi₂(PO₄)₂ has the hexagonal‐rhombohedral structure of the BaNi₂(AsO₄)₂ type. Magnetic measurements of powders of Ba₂Mn(PO₄)₂ and Ba₂Co(PO₄)₂ yielded room temperature moments of μ_eff = 5,73 and 4,93 μ_B, resp., but only the manganese compound obeys the Curie‐Weiss law down to low temperatures. Weak antiferromagnetic interactions at both compounds only near T_M ≈ 5 K lead to a reciprocal susceptibility minimum.     

Crystal Structure of Rubidium Tetraiodothallate(III) Dihydrate,RbTlI4·2H2O

The crystal structure of RbTlI₄·2H₂O (cubic, , Nr. 226, Z = 24, a = 1993.5(2) pm, 327 unique reflections with I_o > 2σ(I_o), R₁ = 0.0305, wR₂ = 0.0702, GooF = 1.1199, T = 298(2) K) is characterized by an ReO₃ analogous arrangement of rubidium centered [TlI₄] tetrahedra. The cuboctahedral cavities of this structure are filled with crystal water molecules and additional disordered rubidium cations.     

Präparation,Kristallstruktur und thermisches Verhalten der Quecksilber(I)phosphate α-(Hg2)3(PO4)2, β-(Hg2)3(PO4)2 und (Hg2)2P2O7

Contributions on Crystal Structures and Thermal Behaviour of Anhydrous Phosphates. XXIII. Preparation, Crystal Structure, and Thermal Behaviour of the Mercury(I) Phosphates α-(Hg₂)₃(PO₄)₂, β-(Hg₂)₃(PO₄)₂, and (Hg₂)₂P₂O₇ Light-yellow single crystals of (Hg₂)₂P₂O₇ have been obtained via chemical vapour transport in a temperature gradient (500 °C → 450 °C, 23 d) using Hg₂Cl₂ as transport agent. Characteristic feature of the crystal structure (P2/n, Z = 2, a = 9,186(1), b = 4,902(1), c = 9,484(1) Å, β = 98,82(2)°, 1228 independent of 5004 reflections, R(F) = 0,066 for 61 variables, 7 atoms in the asymmetric unit) are Hg₂²⁺-units with d(Hg1–Hg1) = 2,508 Å and d(Hg2–Hg2) = 2,519 Å. The dumbbells Hg₂²⁺ are coordinated by oxygen, thus forming polyhedra [(Hg1₂)O₄] and [(Hg2₂)O₆]. These polyhedra share some oxygen atoms. In addition they are linked by the diphosphate anion P₂O₇^4– (ecliptic conformation; ∠(P,O,P) = 129°) to built up the 3-dimensional structure. Under hydrothermal conditions (T = 400 °C) orange single crystals of the mercury(I) orthophosphates α-(Hg₂)₃(PO₄)₂ and β-(Hg₂)₃(PO₄)₂ have been obtained from (Hg₂)₂P₂O₇ and H₃PO₄ (c = 1%). The crystal structures of both modifications have been refined from X-ray single crystal data [α-form (β-form): P2₁/c (P2₁/n), Z = 2 (2), a = 8,576(3) (7,869(3)), b = 4,956(1) (8,059(3)), c = 15,436(3) (9,217(4)) Å, β = 128,16(3) (108,76(4))°, 1218 (1602) independent reflections of 4339 (6358) reflections, R(F) = 0,039 (0,048) for 74 (74) variables, 8 (8) atoms in the asymmetric unit]. In the structure of α-(Hg₂)₃(PO₄)₂ three crystallographically independent mercury atoms, located in two independent dumbbells, are coordinated by three oxygen atoms each. Thus, [(Hg₂)O₆] dimers with a strongly distorted tetrahedral coordination of all mercury atoms are formed. Such dimers are present besides [(Hg₂)O₅]-polyhedra in the less dense crystal structure of β-(Hg₂)₃(PO₄)₂ (d(Hg–Hg) = 2,518 Å). The mercury(I) phosphates are thermally labile and disproportionate between 200 °C (β-(Hg₂)₃(PO₄)₂) and 480 °C (α-(Hg₂)₃(PO₄)₂) to elemental mercury and the corresponding mercury(II) phosphate.     

Syntheses and Characterization of Mixed‐Anions Lead(II) Complexes, [Pb(phen)2(CH3COO)]X (X=NCS—, NO3— and ClO4—), Crystal Structure of [Pb(phen)2(CH3COO)](ClO4)

The 1:2 adduct lead(II) complexes with 1, 10‐phenanthroline (phen) containing three different anions, [Pb(phen)₂(CH₃COO)X] (X=NCS^—, NO₃^— and ClO₄^—), have been synthesized and characterized by CHN elemental analysis, IR‐, ¹H‐ and ¹³C NMR spectroscopy. The structure of [Pb(phen)₂(CH₃COO)(ClO₄)] was determined by single crystal X‐ray analysis. The Pb atom of the monomeric complex is coordinated by four nitrogen atoms of two 1, 10‐phenanthroline ligands and two oxygen atoms of the acetate ligand to form an irregular octahedron. The arrangement of the 1, 10‐phenanthroline and acetate ligands, exhibits a coordination gap around the Pb^II ion, possibly occupied by a stereochemical electron active lone pair on lead(II), which results in a hemidirected lead compound. The π‐π stacking interaction between the parallel aromatic rings may help to increase the coordination ‘gap’ around the Pb^II ion.     

A Novel Trinuclear Nickel(II) Phenanthroline Suberato Complex: {Ni[Ni(phen)(H2O)4]2L4/2}L · 4H2O (H2L = suberic acid)

The Reaction of freshly precipitated NiCO₃ with phenanthroline and suberic acid in CH₃OH/H₂O at room temperature gave the title complex consisting of polymeric {Ni[Ni(phen)(H₂O)₄]₂L_4/2}²⁺ cationic chains, suberate anions and hydrogen bonded H₂O molecules. The cationic chains are generated from bis‐monodentate suberato ligands bridging the trinuclear {Ni[Ni(phen)(H₂O)₄]₂}⁶⁺ groups, in which the central Ni atom is, via two μ‐H₂O molecules, coordinated to two monodentate cationic [Ni(phen)(H₂O)₄]²⁺ complex ligands at trans positions. The NiO₆ octahedral coordination about the central Ni atom is elongated tetragonally distorted with d(Ni—O) = 2.033—2.166Å and the NiN₂O₄ octahedra about the side Ni atoms are significantly distorted with d(Ni—N) = 2.089, 2.099Å, d(Ni—O) = 2.046—2.117Å. The polymeric cationic chains are assembled via π—π stacking interactions into open 2D layers, between which the suberate anions and crystal H₂O molecules are sandwiched. Crystal data: triclinic, P1¯ (no. 2), a = 11.397(2)Å, b = 11.975(2)Å, c = 12.500(2)Å, α = 107.75(1)°, β = 104.50(1)°, γ = 109.68(1)°, Z = 1, R = 0.0521, wR² = 0.1249 for 3892 out of 6198 reflections with F_o² > 2σ(F_o²).