Kaliumhydrogensulfat-Dihydrogensulfat,K(HSO4)(H2SO4) – Synthese und Kristallstruktur

Potassium Hydrogensulfate Dihydrogensulfate, K(HSO₄)(H₂SO₄) – Synthesis and Crystal Structure Single crystals with the composition KH₃(SO₄)₂ have been synthesized from the system Potassium sulfate/sulfuric acid. The hitherto crystallographically not investigated compound crystallizes in the monoclinic space group P2₁/c (14) with the unit cell parameters a = 7.654(3), b = 11.473(5) and c = 8.643(3) Å, β = 112.43(3)°, V = 701.6 ų, Z = 4 and D_x = 2.22 g · cm^?3. The structure contains two types of tetrahedra, SO₃(OH) and SO₂(OH)₂. These tetrahedra form tetramers via hydrogen bonds consisting of both, two SO₃(OH) and two SO₂(OH)₂ tetrahedra. The tetramers are linked to each other via hydrogen bonds. Potassium is coordinated by 9 oxygen atoms which belong to both kinds of tetrahedra. These potassium oxygen polyhedra are connected by common faces forming chains running parallel z.     

Syntheses and Structures of Na2Mg3(OH)2(SO4)3·4H2O and K2Mg3(OH)2(SO4)3·2H2O

The crystal structures of Na₂Mg₃(OH)₂(SO₄)₃ · 4H₂O and K₂Mg₃(OH)₂(SO₄)₃ · 2H₂O, were determined from conventional laboratory X‐ray powder diffraction data. Synthesis and crystal growth were made by mixing alkali metal sulfate, magnesium sulfate hydrate, and magnesium oxide with small amounts of water followed by heating at 150 °C. The compounds crystallize in space group Cmc2₁ (No. 36) with lattice parameters of a = 19.7351(3), b = 7.2228(2), c = 10.0285(2) Å for the sodium and a = 17.9427(2), b = 7.5184(1), c = 9.7945(1) Å for the potassium sample. The crystal structure consists of a linked MgO₆–SO₄ layered network, where the space between the layers is filled with either potassium (K⁺) or Na⁺‐2H₂O units. The potassium‐bearing structure is isostructural to K₂Co₃(OH)₂(SO₄)₃ · 2(H₂O). The sodium compound has a similar crystal structure, where the bigger potassium ion is replaced by sodium ions and twice as many water molecules. Geometry optimization of the hydrogen positions were made with an empirical energy code.     

Hydrogensulfate mit fehlgeordneten Wasserstoffatomen – Synthese und Struktur von Li[H(HSO4)2](H2SO4)2 sowie Verfeinerung der Struktur von α-NaHSO4

Hydrogen Sulfates with Disordered Hydrogen Atoms – Synthesis and Structure of Li[H(HSO₄)₂](H₂SO₄)₂ and Refinement of the Structure of α-NaHSO₄ The structure of Li[H(HSO₄)₂](H₂SO₄)₂ has been determined for the first time whereas the structure of α-NaHSO₄ has been refined, so that direct determination of the hydrogen positions was possible. Both compounds crystallize triclinic in the space group P1 with the lattice constants a = 6.708(2), b = 6.995(1), c = 7.114(1) Å, α = 75.53(1), β = 84.09(2) and γ = 87.57(2)° (Z = 4) for α-NaHSO₄ and a = 4.915(1), b = 7.313(1), c = 8.346(2) Å, α = 82.42(3), β = 86.10(3) and γ = 80.93(3)° (Z = 1) for Li[H(HSO₄)₂](H₂SO₄)₂. In both compounds there are disordered hydrogen positions. In the structure of α-NaHSO₄ there are two crystallographically different HSO₄^? tetrahedra and two different coordinated Na atoms. The system of hydrogen bonds can be described by chains in [0–11] direction. The disordering of the H atoms reduces the differences between the S? O and S? OH distances (1.45 and 1.50 Å) while in the ordered HSO₄ unit “regular” bond lengths are observed (1.45 und 1,57 Å). In the structure of Li[H(HSO₄)₂](H₂SO₄)₂ there are two crystallographically different SO₄-tetrahedra. The first one belongs to the [H(HSO₄)₂]^? unit while the second one represents H₂SO₄ molecules. The H atom which is located nearby the symmetry centre and connects two HSO₄ units by a short O…?O distance of 2.44 Å. Li is located on a symmetry centre and is slightly distorted octahedrally coordinated by oxygen atoms of six different SO₄ tetrahedra. The system of hydrogen bonds can be regarded as consisting of double layers parallel to the xy-plane.     

Ein neues Kaliumhydrogensulfat,K(H3O)(HSO4)2 — Synthese und Struktur

A New Potassium Hydrogensulfate, K(H₃O)(HSO₄)₂ — Synthesis and Structure Single crystals of the new compound K(H₃O)(SO₄)₂ are synthesized from the system potassium sulfate/sulfuric acid. The up to day not described compound crystallizes in the monoclinic space group P2₁/c with the unit cell parameters a = 7.203(1) b = 13.585(2) and c = 8.434(1) Å, β = 105.54(1)°, V = 795.1 ų, Z = 4 and D_x = 2.107 g · cm^?3. There are two crystallographically different tetrahedral SO₃(OH) anions. The first kind S1 tetrahedra forms dimers, whereas the second kind S2 forms infinite chains bonded via hydrogen bridges. The S1 dimers are linked to the S2 chains via oxonium ions (hydrogen bonds). Potassium is coordinated by 8 oxygen atoms which belong to four different SO₃(OH) tetrahedra. These potassium oxygen polyhedra are connected by common edges forming chains running parallel z.     

Polymorphism in Bi2(SO4)3

A new polymorph of Bi₂(SO₄)₃ was prepared by reaction of LiBiO₂ with H₂SO₄ and its crystal structure was solved from X-ray powder diffraction. This new polymorph crystallizes in C2/c space group with lattice parameters a = 17.3383(3) Å, b = 6.77803(12) Å, c = 8.30978(13) Å, β = 101.4300(12)°. Bi₂(SO₄)₃ presents a layered structure made of SO₄ sulfate groups and signs of stereochemically active Bi³⁺ lone pairs. The new Bi₂(SO₄)₃ absorbs water to form Bi₂(H₂O)₂(SO₄)₂(OH)₂ through an intermediate Bi₂O(OH)₂SO₄ phase, and the transition is reversible when heated under vacuum.     

Hydroxo Bridged Dinuclear Rare Earth Complexes: Syntheses and Crystal Structures of [Ln2(phen)4(H2O)4(OH)2](NO3)4(phen)2 with Ln = Er,Lu

Reactions of phenanthroline (phen) and Er(NO₃)₃ · 5 H₂O or Lu(NO₃)₃ · H₂O in CH₃OH/H₂O yield [Ln₂(phen)₄(H₂O)₄(OH)₂](NO₃)₄(phen)₂ with Ln = Er ( 1 ), Lu ( 2 ). Both isostructural complex compounds crystallize in the triclinic space group P 1 (no. 2) with the cell dimensions: a = 11.257(2) Å, b = 11.467(2) Å, c = 14.069(2) Å, α = 93.93(2)°, β = 98.18(1)°, γ = 108.14(1)°, V = 1696.0(6) ų, Z = 1 for ( 1 ) and a = 11.251(1) Å, b = 11.476(1) Å, c = 14.019(1) Å, α = 93.83(1)°, β = 98.27(1)°, γ = 108.27(1)°, V = 1689.0(3) ų, Z = 1 for ( 2 ). The crystal structures consist of the hydroxo bridged dinuclear [Ln₂(phen)₄(H₂O)₄(OH)₂]⁴⁺ complex cations, hydrogen bonded NO₃^– anions and π‐π stacking (phen)₂ dimers. The rare earth metal atoms are coordinated by four N atoms of two phen ligands and four O atoms of two H₂O molecules and two μ‐OH groups to complete tetragonal antiprisms. Via two common μ‐OH groups, two neighboring tetragonal antiprisms are condensed to a centrosymmetric dinuclear [Ln₂(phen)₄(H₂O)₄(OH)₂]⁴⁺ complex cation. Based on π‐π stacking interactions and hydrogen bonding, the complex cations and (phen)₂ dimers form 2 D layers parallel to (1 0 1), between which the hydrogen bonded NO₃^– anions are sandwiched. The structures can be simplified into a distorted CsCl structure when {[Ln₂(phen)₄(H₂O)₄(OH)₂](NO₃)₄} and (phen)₂ are viewed as building units.     

Synthese und Kristallstruktur von K2(HSO4)(H2PO4), K4(HSO4)3(H2PO4) und Na(HSO4)(H3PO4)

Synthesis and Crystal Structure of K₂(HSO₄)(H₂PO₄), K₄(HSO₄)₃(H₂PO₄), and Na(HSO₄)(H₃PO₄) Mixed hydrogen sulfate phosphates K₂(HSO₄)(H₂PO₄), K₄(HSO₄)₃(H₂PO₄) and Na(HSO₄)(H₃PO₄) were synthesized and characterized by X‐ray single crystal analysis. In case of K₂(HSO₄)(H₂PO₄) neutron powder diffraction was used additionally. For this compound an unknown supercell was found. According to X‐ray crystal structure analysis, the compounds have the following crystal data: K₂(HSO₄)(H₂PO₄) (T = 298 K), monoclinic, space group P 2₁/c, a = 11.150(4) Å, b = 7.371(2) Å, c = 9.436(3) Å, β = 92.29(3)°, V = 774.9(4) ų, Z = 4, R₁ = 0.039; K₄(HSO₄)₃(H₂PO₄) (T = 298 K), triclinic, space group P 1, a = 7.217(8) Å, b = 7.521(9) Å, c = 7.574(8) Å, α = 71.52(1)°, β = 88.28(1)°, γ = 86.20(1)°, V = 389.1(8)ų, Z = 1, R₁ = 0.031; Na(HSO₄)(H₃PO₄) (T = 298 K), monoclinic, space group P 2₁, a = 5.449(1) Å, b = 6.832(1) Å, c = 8.718(2) Å, β = 95.88(3)°, V = 322.8(1) ų, Z = 2, R₁ = 0,032. The metal atoms are coordinated by 8 or 9 oxygen atoms. The structure of K₂(HSO₄)(H₂PO₄) is characterized by hydrogen bonded chains of mixed H_nS/PO₄^– tetrahedra. In the structure of K₄(HSO₄)₃(H₂PO₄), there are dimers of H_nS/PO₄^– tetrahedra, which are further connected to chains. Additional HSO₄^– tetrahedra are linked to these chains. In the structure of Na(HSO₄)(H₃PO₄) the HSO₄^– tetrahedra and H₃PO₄ molecules form layers by hydrogen bonds.     

Synthese und Struktur von Hydrogensulfaten des Typs M(HSO4)(H2SO4) (M = Rb,Cs und NH4)

Synthesis and Structure of Hydrogen Sulfates of the Type M(HSO₄)(H₂SO₄) (M = Rb, Cs and NH₄) From the binary systems M₂SO₄/H₂SO₄ (M = Rb, Cs, NH₄), three new hydrogen sulfates of the type M(HSO₄)(H₂SO₄) could be synthesized and structural characterized. The rubidium and caesium compounds are isotypic whereas NH₄(HSO₄)(H₂SO₄) is topologically very similar to both. All three compounds crystallize with nearly identical cell parameters [Rb: a = 7.382(1), b = 12.440(2), c = 7.861(2), β = 93.03(3); Cs: a = 7.604(1), b = 12.689(2), c = 8.092(2), β = 92.44(3); NH₄: a = 7.521(3), b = 12.541(5), c = 7.749(3), β = 92.74(3)], in the monoclinic space group P2₁/c, There exist two kinds of SO₄-tetrahedra: HSO₄^? anions (S1) and H₂SO₄-molecules (S2). The HSO₄^? anions form hydrogen bridged zigzag chains. In the case of the Rb and Cs compounds, the H₂SO₄ molecules connect these chains forming double layers. The metal atoms are coordinated by 9 O-atoms with M? O-distances of 2.97 – 3.39 Å (Rb) and 3.13 – 3.51 Å (Cs). In the ammonium compound additional hydrogen bonds are formed originating from the NH₄⁺ cation. This finally leads to the formation of S2? NH₄⁺ chains (parallel to the S1 chains) as well as to a three-dimensional connection of both kinds of chains.     

New Structure Type among Octahydrated Rare‐Earth Sulfates, β‐Ce2(SO4)3·8H2O,and a new Ce2(SO4)3·4H2O Polymorph

Syntheses, crystal structures and thermal behavior of two new hydrated cerium(III) sulfates are reported, Ce₂(SO₄)₃·4H₂O ( I ) and β‐Ce₂(SO₄)₃·8H₂O ( II ), both forming three‐dimensional networks. Compound I crystallizes in the space group P2₁/n. There are two non‐equivalent cerium atoms in the structure of I , one nine‐ and one ten‐fold coordinated to oxygen atoms. The cerium polyhedra are edge sharing, forming helically propagating chains, held together by sulfate groups. The structure is compact, all the sulfate groups are edge‐sharing with cerium polyhedra and one third of the oxygen atoms, belonging to sulfate groups, are in the S–Oμ₃–Ce₂ bonding mode. Compound II constitutes a new structure type among the octahydrated rare‐earth sulfates which belongs to the space group Pn. Each cerium atom is in contact with nine oxygen atoms, these belong to four water molecules, three corner sharing and one edge sharing sulfate groups. The crystal structure is built up by layers of [Ce(H₂O)₄(SO₄)]_nⁿ⁺ held together by doubly edge sharing sulfate groups. The dehydration of II is a three step process, forming Ce₂(SO₄)₃·5H₂O, Ce₂(SO₄)₃·4H₂O and Ce₂(SO₄)₃, respectively. During the oxidative decomposition of the anhydrous form, Ce₂(SO₄)₃, into the final product CeO₂, small amount of CeO(SO₄) as an intermediate species was detected.     

Synthese und Struktur neuer Natriumhydrogensulfate Na(H3O)(HSO4)2; Na2(HSO4)2(H2SO4) und Na(HSO4)(H2SO4)2

Synthesis and Structure of New Sodium Hydrogen Sulfates Na(H₃O)(HSO₄)₂, Na₂(HSO₄)₂(H₂SO₄), and Na(HSO₄)(H₂SO₄)₂ Three acidic sodium sulfates have been synthesized from the system sodium sulfate/sulfuric acid and have been crystallographically characterized. Na(H₃O)(HSO₄)₂ ( A ) crystallizes in the space group P2₁/c with the unit cell parameters a = 6.974(2), b = 13.086(2), c = 8.080(3) Å, α = 105.90(4)°, V = 709.1 Å3, Z = 4. Na₂(HSO₄)₂(H₂SO₄) ( B ) is orthorhombic (space group Pna2₁) with the unit cell parameters a = 9.970(2), b = 6.951(1), c = 13.949(3) Å, V = 966.7 ų and Z = 4. Na(HSO₄)(H₂SO₄)₂ ( C ) crystallizes in the triclinic space group P1 with the unit cell parameters a = 5.084(1), b = 8.746(1), c = 11.765(3) Å, α = 68.86(2)°, β = 88.44(2)°, γ = 88.97(2)°, V = 487.8 Å3 and Z = 2. All three compounds contain SO₄ tetrahedra as HSO₄^? anions and additionally in B and C in form of H₂SO₄ molecules. The ratio H:SO₄ determines the connectivity degree in the hydrogen bond system. In A , there are zigzag chains and dimers additionally connected via oxonium ions. Complex chains consisting of cyclic trimers (two HSO₄^? and one H₂SO₄) are present in B . In structure C , several parallel chains are connected to columns due to the greater content of H₂SO₄. Sodium cations show a distorted octahedral coordination by oxygen in all three structures, the NaO₆ octahedra being “isolated” (connected via SO₄ tetrahedra only) in A . Pairs of octahedra with common edge form Na₂O₁₀ dimeric units in C . Such double octahedra are connected via common corners forming zigzag chains in B .     

Crystal Structures of [Mn2(H2O)4(phen)2(C4H4O4)2] · 2 H2O and [Mn(phen)2(H2O)2][Mn(phen)2(C4H4O4)](C4H4O4) · 7 H2O

Reactions of 1,10‐phenanthroline monohydrate, Na₂C₄H₄O₄ · 6 H₂O and MnSO₄ · H₂O in CH₃OH/H₂O yielded a mixture of [Mn₂(H₂O)₄(phen)₂(C₄H₄O₄)₂] · 2 H₂O ( 1 ) and [Mn(phen)₂(H₂O)₂][Mn(phen)₂(C₄H₄O₄)](C₄H₄O₄) · 7 H₂O ( 2 ). The crystal structure of 1 (P1 (no. 2), a = 8.257(1) Å, b = 8.395(1) Å, c = 12.879(2) Å, α = 95.33(1)°, β = 104.56(1)°, γ = 106.76(1)°, V = 814.1(2) ų, Z = 1) consists of the dinuclear [Mn₂(H₂O)₄(phen)₂(C₄H₄O₄)₂] molecules and hydrogen bonded H₂O molecules. The centrosymmetric dinuclear molecules, in which the Mn atoms are octahedrally coordinated by two N atoms of one phen ligand and four O atoms from two H₂O molecules and two bis‐monodentate succinato ligands, are assembled via π‐π stacking interactions into 2 D supramolecular layers parallel to (101) (d(Mn–O) = 2.123–2.265 Å, d(Mn–N) = 2.307 Å). The crystal structure of 2 (P1 (no. 2), a = 14.289(2) Å, b = 15.182(2) Å, c = 15.913(2) Å, α = 67.108(7)°, β = 87.27(1)°, γ = 68.216(8)°, V = 2934.2(7) ų, Z = 2) is composed of the [Mn(phen)₂(H₂O)₂]²⁺ cations, [Mn(phen)₂(C₄H₄O₄)] complex molecules, (C₄H₄O₄)^2– anions, and H₂O molecules. The (C₄H₄O₄)^2– anions and H₂O molecules form 3 D hydrogen bonded network and the cations and complex molecules in the tunnels along [001] and [011], respectively, are assembled via the π‐π stacking interactions into 1 D supramolecular chains. The Mn atoms are octahedrally coordinated by four N atoms of two bidentate chelating phen ligands and two water O atoms or two carboxyl O atoms (d(Mn–O) = 2.088–2.129 Å, d(Mn–N) = 2.277–2.355 Å). Interestingly, the succinato ligands in the complex molecules assume gauche conformation bidentately to chelate the Mn atoms into seven‐membered rings.     

A Novel Dinuclear Copper(II) Complex Molecule: Synthesis and Crystal Structure of Cu2(phen)2(H2O)2(C5H6O4)2 with phen = 1,10‐phenanthroline

Blue crystals of Cu₂(phen)₂(H₂O)₂(C₅H₆O₄)₂ were obtained from a CH₃OH–H₂O solution containing CuCl₂, 1,10‐phenanthroline (phen), glutaric acid and Na₂CO₃. The crystal structure (monoclinic, P2₁/c (no. 14), a = 10.271(1), b = 10.595(1), c = 15.585(1) Å, β = 107.105(3)°, Z = 2, R = 0.0328, wR² = 0.1027 for 3376 observed reflections (F ≥ 2σ(F ) out of 3728 unique reflections) is built up of dinuclear Cu₂(phen)₂(H₂O)₂(C₅H₆O₄)₂ complex molecules centered at inversion centers. The Cu atoms are square‐pyramidally coordinated by two nitrogen atoms of one bidentate chelating phen ligand and three oxygen atoms from two bridging glutarate anions and one axial water molecule (d(Cu–N) = 2.018(2), 2.024(2) Å; basal d(Cu–O) = 1.949(2), 1.956(2) Å; axial d(Cu–O) = 2.382(2) Å). Through the π‐π stacking interactions extending in a direction, the complex molecules are interlinked into 2 D layers parallel to the ac plane. The resultant 2 D layers are held together by hydrogen bonds between water molecules and uncoordinated carboxyl oxygen atoms.     

Pt2(HSO4)2(SO4)2, the First Binary Sulfate of Platinum

Red single crystals of Pt₂(HSO₄)₂(SO₄)₂ were obtained by the reaction of elemental platinum with conc. sulfuric acid at 350 °C in sealed glass ampoules. The crystal structure (monoclinic, P2₁/c, Z = 2, a = 868.6(2), b = 826.2(1), c = 921.8(2) pm, β=116.32(1)°, R_all = 0.0348) shows dumbbell shaped Pt₂⁶⁺ cations which are coordinated by four SO₄^2— and two HSO₄^— ions. Each of the sulfate ions is attached to another Pt₂⁶⁺ ion yielding layers according to equation/tex2gif-stack-1.gif[Pt₂(SO₄)_4/2(HSO₄)_2/1]. The layers are connected by hydrogen bonds with the OH group of the hydrogensulfate ion as donor and the non‐bonding oxygen atom of the sulfate ion as acceptor.     

Crystal Structures of [Cu2(bpy)2(H2O)(OH)2(SO4)]·4H2O and [Cu(bpy)(H2O)2]SO4 with bpy = 2, 2′‐Bipyridine

Two sulfato Cu^II complexes [Cu₂(bpy)₂(H₂O)(OH)₂(SO₄)]· 4H₂O ( 1 ) and [Cu(bpy)(H₂O)₂]SO₄ ( 2 ) were synthesized and structurally characterized by single crystal X—ray diffraction. Complex 1 consists of the asymmetric dinuclear [Cu₂(bpy)₂(H₂O)(OH)₂(SO₄)] complex molecules and hydrogen bonded H₂O molecules. Within the dinuclear molecules, the Cu atoms are in square pyramidal geometries, where the equatorial sites are occupied by two N atoms of one bpy ligand and two O atoms of different μ₂—OH groups and the apical position by one aqua ligand or one sulfato group. Through intermolecular O—H···O and C—H···O hydrogen bonds and intermolecular π—π stacking interactions, the dinuclear complex molecules are assembled into layers, between which the hydrogen bonded H₂O molecules are located. The Cu atoms in 2 are octahedrally coordinated by two N atoms of one bpy ligand and four O atoms of two H₂O molecules and two sulfato groups with the sulfato O atoms at the trans positions and are bridged by sulfato groups into ¹[Cu(bpy)(H₂O)₂(SO₄)_2/2] chains. Through the interchain π—π stacking interactions and interchain C—H···O hydrogen bonds, the resulting chains are assembled into bi—chains, which are further interlinked into layers by O—H···O hydrogen bonds between adjacent bichains.     

Die Molekül- und Kristallstruktur von [Co3(CN)2 {(OH)4} (NH3)8][Co2(NO2)6 {(OH)2, NO2}] · H2O

The structure of [Co₃(CN)₂ {(OH)₄} (NH₃)₈] [Co₂(NO₂)₆ {(OH)₂, NO₂}] · H₂O has been determined by X-ray methods. The compound crystallizes in the monoclinic space group C_2h⁵–P2₁/n with a = 7.21, b = 12.38, c = 33.13 Å, β = 94°, Z = 4. The crystals contain trinuclear cations in which three Co(III) atoms are bound to two pairs of oxygen atoms. At the central Co atom there are two CN^– ligands in the cis position. The cation is of symmetry C₂. The anion is found to be a binuclear Co(III) complex. The two Co atoms are bound to two OH^– and one NO₂^– groups.     

Reaction with SO3 in Ionic Liquids: The Example of K2(S2O7)­(H2SO4)

The ionic liquid 1‐butyl‐3‐methylimidazolium hydrogensulfate, [bmim]HSO₄, turned out to be resistant even to strong oxidizers like SO₃. Thus, it should be a suitable solvent for the preparation of polysulfates at low temperatures. As a proof of principle we here present the synthesis and crystal structure of K₂(S₂O₇)(H₂SO₄), which has been obtained from the reaction of K₂SO₄ and SO₃ in [bmim]HSO₄. In the crystal structure of K₂(S₂O₇)(H₂SO₄) (orthorhombic, Pbca, Z = 8, a = 810.64(2) pm, b = 1047.90(2) pm, c = 2328.86(6) pm, V = 1978.30(8) ų) two crystallographically unique potassium cations are coordinated by a different number of monodentate and bidentate‐chelating disulfate anions as well as by sulfuric acid molecules. The crystal structure consists of alternating layers of [K₂(S₂O₇)] slabs and H₂SO₄ molecules. Hydrogen bonds between hydrogen atoms of sulfuric acid molecules and oxygen atoms of the neighboring disulfate anions are observed.     

Struktur und thermisches Verhalten von Gadolinium(III)-sulfat-Octahydrat Gd2(SO4)3 · 8 H2O

Structure and Thermal Behaviour of Gadolinium(III)-sulfate-octahydrate Gd₂(SO₄)₃ · 8 H₂O . Gd₂(SO₄)₃ · 8 H₂O crystallizes monoclinic with space group C2/c and the lattice constants a = 13.531(7), b = 6.739(2), c = 18.294(7) Å, β = 102.20(8)°. In the structure Gd is coordinated by 4 oxygen atoms of crystal water and 4 oxygens of sulfate giving rise to a distorted square antiprism. During DTA-TG-experiments the title compound first loses crystal water in a two-step mechanism in the temperature range 130–306°C. The resulting Gd₂(SO₄)₃ is amorphous and recrystallization occurs in the range 380–411°C. The so-obtained low-temperature modification β-Gd₂(SO₄)₃, undergoes a monotropic phase transition at about 750°C to the high-temperature form α-Gd₂(SO₄)₃. The powder pattern of this modification was indexed based on monoclinic symmetry with space group C2/c and lattice constants a = 9.097(3), b = 14.345(5), c = 6.234(2) Å, β = 97.75(8)°. The hightemperature modification of gadolinium-sulfate shows decomposition to Gd₂O₂SO₄ at 900°C and, subsequently, decomposition at 1 200°C yields the formation of C-Gd₂O₃.     

LiLa2F3(SO4)2 und LiEr2F3(SO4)2: Fluoridsulfate der Selten‐Erd‐Elemente mit Lithium

LiLa₂F₃(SO₄)₂ and LiEr₂F₃(SO₄)₂: Fluoride‐Sulfates of the Rare‐Earth Elements with Lithium The reaction of LiF with the anhydrous sulfates M₂(SO₄)₃ (M = La, Er) in sealed gold ampoules yields single crystals of the pseudo quaternary compounds LiLa₂F₃(SO₄)₂ and LiEr₂F₃(SO₄)₂. According to X‐ray single crystal investigations, LiLa₂F₃(SO₄)₂ crystallizes with the monoclinic (I2/a, Z = 4, a = 828.3(2), b = 694.7(1), c = 1420.9(3) pm, β = 95.30(2)°, R_all = 0.0214) and LiEr₂F₃(SO₄)₂ with the orthorhombic crystal system (Pbcn, a = 1479.1(2), b = 633.6(1), c = 813.7(1) pm, R_all = 0.0229). A common feature of both structures is a dimeric unit of metal atoms connected via three fluoride ions. This leads to relatively short metal‐metal distances (La³⁺–La³⁺: 389 pm, Er³⁺–Er³⁺: 355 pm). In LiLa₂F₃(SO₄)₂, Li⁺ is surrounded by four oxygen atoms of four sulfate groups and one fluoride ion in form of a trigonal bipyramid, in LiEr₂F₃(SO₄)₂ two further fluoride ligands are attached.     

Crystal Structure of the Mixed‐Valent Basic Mercury Nitrate HgI2(NO3)2·HgII(OH)(NO3)·HgII(NO3)2·4HgIIO [= Hg8O4(OH)(NO3)5]

Light‐yellow single crystals of the mixed‐valent mercury‐rich basic nitrate Hg₈O₄(OH)(NO₃)₅ were obtained as a by‐product at 85 °C from a melt consisting of stoichiometric amounts of (Hg^I₂)(NO₃)₂·2H₂O and Hg^II(OH)(NO₃). The title compound, represented by the more detailed formula Hg^I₂(NO₃)₂·Hg^II(OH)(NO₃)·Hg^II(NO₃)₂·4Hg^IIO, exhibits a new structure type (monoclinic, C2/c, Z = 4, a = 6.7708(7), b = 11.6692(11), c = 24.492(2) Å, β = 96.851(2)°, 2920 structure factors, 178 parameters, R1[F² > 2σ(F²)] = 0.0316) and is made up of almost linear [O‐Hg^II‐O] and [O‐Hg^I‐Hg^I‐O] building blocks with typical Hg^II‐O distances around 2.06Å and a Hg^I‐O distance of 2.13Å. The Hg₂²⁺ dumbbell exhibits a characteristic Hg‐Hg distance of 2.5079(7) Å. The different types of mercury‐oxygen units form a complex three‐dimensional network exhibiting large cavities which are occupied by the nitrate groups. The NO₃^? anions show only weak interactions between the nitrate oxygen atoms and the mercury atoms which are at distances > 2.6Å from one another. One of the three crystallographically independent nitrate groups is disordered.     

An Azelaato‐bridged Dinuclear Copper(II) Complex, [Cu2(phen)2(C9H14O4)2] · 6 H2O (phen = 1,10‐phenanthroline)

The title compound [Cu₂(phen)₂(C₉H₁₄O₄)₂] · 6 H₂O was prepared by the reaction of CuCl₂ · 2 H₂O, 1,10‐phenanthroline (phen), azelaic acid and Na₂CO₃ in a CH₃OH/H₂O solution. The crystal structure (monoclinic, C2/c (no. 15), a = 22.346(3), b = 11.862(1), c = 17.989(3) Å, β = 91.71(1)°, Z = 4, R = 0.0473, wR² = 0.1344 for 4279 observed reflections) consists of centrosymmetric dinuclear [Cu₂(phen)₂(C₉H₁₄O₄)₂] complexes and hydrogen bonded H₂O molecules. The Cu atom is square‐planar coordinated by the two N atoms of the chelating phen ligand and two O atoms of different bidentate bridging azelaate groups with d(Cu–N) = 2.053, 2.122(2) Å and d(Cu–O) = 1.948(2), 2.031(2) Å. Two azelaate anions bridge two common Cu atoms via the terminal O atoms (d(C–O) = 1.29(2) Å; d(C–C) = 1.550(4)–1.583(4) Å). Phen ligands of adjacent complexes cover each other at distances of about 3.62 Å, indicating π‐π stacking interaction, by which the complexes are linked to 1 D bands.