Synthesis and crystal structure of a new lithium cyclohexaphosphate hydrate: Li6P6O18·10H2O

The synthesis and crystal structure of a novel hydrate of lithium cyclohexaphosphate are reported. Li₆P₆O₁₈·10H₂O crystallizes in the space group C2/c with a = 15.113(5), b = 12.006(2), c = 15.892(2) Å, = 122.85(2)°, and Z = 4. The structure consists of P₆O₁₈ ring layers stacked along the c direction in between which are located the lithiumions and water molecules. Two LiO₄ tetrahedra share common edges with LiO₅ pseudosquare pyramids to form two independant Li₃O₉ units. About 50% of the water molecules have fractional occupancy rates and form fragments of molecules. A linear relationship is established between the relative cell volume V/Z and the hydration degree, n, for all the known hydrates: Li₆P₆O₁₈·nH₂O.     

Crystal structure of Zn4Na(OH)6SO4Cl·6H2O

The structure of Zn₄Na(OH)₆SO₄Cl·6H₂O, a secondary mineral from Hettstedt, Germany, was determined by single-crystal X-ray diffraction. The crystals are hexagonal,a=8.413(8),c=13.095(24) Å, space group $P\bar 3$ , Z=2. The structure was refined to R=0.0554 and R_w=0.0903 for 970 reflections with I≥3σ(I). The structure can be described as zinc hydroxide layers perpendicular toc, from which sulfates and chlorides extend. The layers are held together by a system of hydrogen bonds involving hexaaquo Na⁺ ions which occupy the interlayer space.     

Crystal and molecular structure of [Cu2(3,5-dihydroxybenzoate)4 (acetonitrile)2] ⋅ 8H2O

The crystal and molecular structure of the title compound, [Cu₂(3,5-dihydroxybenzoate)₄ (acetonitrile)₂] 8H₂O 1, is reported. Crystal data for 1: tetragonal, space group I 4/m, a = 11.720(2) Å, c = 15.304(3) Å, V = 2102.4(6), and D _c = 1.53 g/cm³, for Z = 2. The metal and organic components crystallize to form a Cu paddle-wheel complex, of idealized D_4h symmetry, that assembles in the solid-state, along with eight equivalents of water, to form a 3D hydrogen-bonded network held together by O–H O hydrogens bonds. The metal complexes pack to form a 2D layered structure.     

Crystal structure of a new mineral lahnsteinite Zn4(SO4)(OH)6 · 3H2O

A sample of a new mineral from the oxidation zone of the hydrothermal Pb, Zn, Ag Friedrichssegen deposit (Rhineland-Palatinate, Germany) was studied by single-crystal X-ray diffraction. The parameters of the triclinic (pseudoorthorhombic) unit cell are found to be a = 8.312(1) ?, b = 14.545(1) ?, c = 18.504(2) ?, ?? = 89.71 (1)°, ?? = 90.05(1)°, ?? = 90.13(1)°, and V = 2237.3(3) ?³. The structure is solved by direct methods into the sp. gr. P1 and refined to an R factor of 10.7% using 3788 reflections with |F| > 3??(F) in the isotropic-anisotropic approximation. The crystallochemical formula of lahnsteinite (Z = 8) is [(Zn_2.6Fe_0.3Cu_0.1)^VI(OH)₃][Zn^IV(OH)₃(H₂O)][SO₄] · 2H₂O, where the compositions of the layer composed of Zn octahedra and isolated Zn and S tetrahedra are given in square brackets. The mineral under study is chemically and structurally similar to namuwite and is a natural analog of synthetic zinc hydroxide sulfate trihydrate.     

Crystal structure of quinoline-2-carboxylic acid ⋅ quinolinium-2-carboxylate

Quinoline-2-carboxylic acid (quinaldic acid), C₁₀H₇NO₂, crystallizes in the monoclinic space group P2₁/c, a =9.724(1) Å, b = 5.937(1) Å, c = 27.545(2) Å, = 90.15(1)°, z = 4, and occurs in the crystal in two tautomeric forms: the neutral molecule and the zwitterion, with molecular ratio 1:1. The compound can be named quinoline-2-carboxylic acid quinolinium-2-carboxylate. The crystal structure is built up of tautomeric pairs consisting of C₉H₆NCOOH and C₉H₆NH⁺COO^– moieties, held up together by hydrogen bonds.     

Crystal structure of aqua[S-prolinato-N-monoacetato)copper(II) dihydrate [Cu(Proma)H2O] ⋅ 2H2O

The crystal structure of [Cu(C₇H₉NO₄)H₂O] ? 2H₂O is determined by X-ray diffraction (λMo, R = 0.0316 for 857 reflections). The crystals are tetragonal, a = 8.219(1) Å, c = 17.449(3) Å, Z = 4, ρ_calcd = 1.627 g cm^?3, and space group P4₃. The coordination polyhedron of the Cu atom is a tetragonal pyramid with the O atom of the acetate arm of the prolinatomonoacetate ion (Proma) in the apical position [Cu-O 2.312(6) Å]. The O atom of the water molecule and the N and O atoms of the prolinate group of the Proma ligand lie in the basal plane. The Cu-N bond length is 2.044(6) Å, and the Cu-O bond lengths are 1.932(7) and 1.927(6) Å. The O atom of the acetate arm of the neighboring Proma ion completes the basal plane [Cu-O 1.951(6) Å], thus linking the copper complexes into infinite chains.     

Crystal structure of aminoguanidinium hexahydro-closo-hexaborate dihydrate, (CN4H7)2B6H6 · 2H2O

The (HAgu)₂B₆H₆ · 2H₂O compound was synthesized and its crystal structure was determined [R = 0.0385 for 2018 reflections with I > 2σ(I)]. The structure consists of HAgu ⁺ cations, centrosymmetric B₆H ₆ ^2? anions, and water molecules. The anions have an almost regular octahedral structure. The bond lengths and angles lie within the following narrow ranges: B-B, 1.715–1.726(2) Å; B-H, 1.08–1.14(2) Å; B-B-B, 59.72°–60.29(9)° and 89.63°–90.20(11)°; and B-B-H, 133.2°–137.0(9)°. The HAgu ⁺ cations and water molecules are involved in the O-H?O, N-H?O, and N-N?N hydrogen bonds and participate in numerous (N, O)-H?H-B specific interactions with the B₆H ₆ ^2? anions, which results in splitting and high-frequency shift of the band of B-H stretching vibrations in the IR spectrum.     

Crystal and molecular structure of complex compound [Fe3O(CH3COO)6(H2O)3]2[ZnCl4] ⋅ 2H2O

The X-ray crystal structure of trinuclear iron acetate [Fe₃O(CH₃COO)₆(H₂O)₃]₂ [ZnCl₄] ? 2H₂O was determined. The crystal has a ionic structure. It is monoclinic, a = 25.363(7), b = 14.533(4), c = 15.692(4) Å, β = 103.11(2)°, space group _C2/c, and R = 0.0685. The structure of the cationic complex [Fe₃O(CH₃COO)₆(H₂O)₃]⁺ is typical of trinuclear iron(III) compounds containing a μ₃-O bridge: the iron atoms are situated at the vertices of an almost equilateral triangle with the O atom at the center. Each Fe atom is coordinated by four O atoms of bridging carboxy groups, the μ₃-bridging O atom, and the water molecule in the trans position to the latter O atom. Mössbauer spectroscopy evidence indicates the high-spin state (_S = 5/2) of the iron(III) ions.     

Growth of Er2(SO4)3 ⋅ 8H2O crystals and study of their structure and properties

New crystals of the composition Er₂(SO₄)₃ ? 8H₂O have been synthesized by the method similar to that used for synthesis of (CH₃)₂NH₂Al(SO₄)₂ ? 6H₂O. The synthesized crystals were studied by the X-ray diffraction method. The crystals are monoclinic C2/c) and contain no (CH₃)₂NH₂ ions. It is established that, contrary to DMAAS crystals, Er₂(SO₄)₃ ? 8H₂O crystals undergo no phase transitions and possess neither ferroelectric nor ferroelastic properties.     

Stereochemical activity of a lone electron pair in antimony(III) and bismuth(III) chelates: Crystal structures of Ca[Sb(Edta)]2 ⋅ 8H2O and Ba{[Bi(Edta)] 2H2O ⋅ H2O

The crystal structures of Ca[Sb(Edta)]₂ ? 8H₂O (I) and Ba{ [Bi(Edta)]₂H₂O} ? H₂O (II) are determined by X-ray diffraction. Crystals I are monoclinic, a = 7.132 Å, b = 21.906 Å, c = 10.896 Å, β = 91.13°, Z = 2, and space group P2₁/n. Crystals II are triclinic, a = 8.995 Å, b = 12.750 Å, c = 13.577 Å, α = 77.42°, β = 73.90°, γ = 86.53°, Z = 2, and space group $P\bar 1$ . In structure I, the coordination number of the antimony atom is 6 + LEP (lone electron pair), and the polyhedron is a ψ-pentagonal bipyramid with the lone electron pair at an equatorial position. In structure II, two crystallographically independent complexes Bi(Edta)^? and the coordination water molecule form tetranuclear associates. The environments of two independent bismuth atoms (the coordination number is eight) are similar, and their polyhedra can be described as distorted dodecahedra. The effect of the lone electron pair on the structures of polyhedra of antimony and bismuth is discussed.     

Crystal structure of a highly hydrated tristrontium phosphate,Sr9(PO4)6·16H2O

The crystal structure of a highly hydrated tristrontium phosphate, nonastrontium hexakis(phosphate) hexadecahydrate, Sr₉(PO₄)₆·16H₂O, has been determined by single crystal X-ray diffraction. The crystals are monoclinic,a=15.203(2),b=6.488(1),c=18.984(7) Å, =98.42(2)^o, space groupP2/c (No. 13),Z=2,V=1852.3 ų,d _c =2.951 Mg·m^–3. The structure was refined by full-matrix least-squares techniques toR=0.038,R _w =0.051, for 2329 reflections with I3(I). The structure can be described in terms of a layer-type arrangement parallel to (100). One layer consists of a compact assembly of columns of Sr and PO₄ ions in a pseudohexagonal arrangement resembling an apatitic structure. A second layer containing all the water molecules and one PO₄ ion that occupies the interstitial space may be referred to as the hydrated layer. The structure has an overall similarity to that of octacalcium phosphate and can be considered as a model for amorphous calcium phosphate.Certain commercial materials and equipment are identified in this paper to specify the experimental procedure. In no instance does such identification imply recommendation or endorsement by the National Institute of Standards and Technology or the ADA Health Foundation or that the material or equipment identified is necessarily the best available for the purpose.     

Crystal structure of [Co(Ox)(NH3)4][Bi(Edta)] ⋅ 3H2O

The crystal structure of [Co(Ox)(NH₃)₄][Bi(Edta)] ? 3H₂O is determined. The crystals are monoclinic, a = 9.291 Å, b = 22.275 Å, c = 11.402 Å, β = 105.79°, V = 2270.7 ų, Z = 4, and space group P2₁/c. The [Bi(Edta)]^? anionic complexes are linked into polymeric chains through two Bi-O bonds with the neighboring complexes.     

Purported “melamine cyanuric acid trihydrochloride” C3H6N6⋅C3H3N3O3⋅3HCl is actually “diprotonated-melamine cyanuric acid dichloride dihydrate” (C3H8N6)2+⋅C3H3N3O3⋅2Cl−⋅2H2O

On the basis of the published results, melamine cyanuric acid trihydrochloride (MCA3HCl) is shown to be better described as diprotonated melamine cyanuric acid dichloride dihydrate (C₃H₈N₆)²⁺C₃H₃N₃O₃2Cl^–2H₂O. Details are given of the revised hydrogen bonding scheme, which requires further elaboration.     

Crystal structure of dibarium (Ethylenediaminetetraacetato)cuprate(II) diperchlorate hexahydrate, Ba2[Cu(Edta)](ClO4)2 ⋅ 6H2O

Compound Ba₂[Cu(Edta)](ClO₄)₂ ? 6H₂O is synthesized and its crystal structure is determined [R = 0.0500 for 4439 reflections with I > 2σ(I)]. The structure consists of the [Cu(Edta)]^2? anionic complexes, hydrated barium cations, Cl ₄ ^? anions, and molecules of crystallization water, which are interlinked into a framework. The hexadentate Edta ^4? ligand coordinates the Cu atom forming the polyhedron in a shape of a tetragonal bipyramid, which is asymmetrically stretched along the OR-Cu-OR, axis (Cu-O, 2.262 and 2.532 Å). The mean lengths of the equatorial Cu-N and Cu-O bonds are 2.011 and 1.952 Å, respectively. The anionic complex is bound to six Ba atoms. Two independent Ba atoms have different environments; their coordination numbers are nine and ten. The Ba-O distances lie in the range 2.669–3.136 Å. Layers of Ba atoms parallel to the x0z plane are distinguished in the structure.     

Crystal and molecular structure of 7-hydroxyflavone monohydrate, C14H10O3·H2O

The X-ray crystal structure of 7-hydroxyflavone monohydrate, C₁₄H₁₀O₃ · H₂O, is determined. The compound crystallizes in the monoclinic space group, P2₁/n with a = 3.801(3), b = 19.665(4), c = 16. 039(6), = 93.69(3)°, and = 0.68 mm^–1 for Z = 4. The phenyl ring of the flavone moiety is rotated 18.6(1)° out of the penzopyran plane, which is a typical value for flavones. In the crystal lattice, there are wide channels which are lined mainly by C–H groups. The water molecules enclosed in these channels are severely disordered.     

K8Gd3Si12O32Cl · 2H2O,a new member of the family of porous silicates with K and RE elements

Crystals of K₈Gd₃Si₁₂O₃₂Cl · 2H₂O (space group $P\bar 1$ ), a new member of the family of porous silicates containing rare earths, are obtained under hydrothermal conditions. The structure retains the main features of the family in which original one-story layers of Si-tetrahedra formed by 6-membered rings of two types and large-in-diameter 8-membered and 12-membered rings are bound by Gd-octahedra to form a framework. Large pores in the interlayer space of the mixed framework are filled with K⁺ ions. The penetration of Cl^? ions from a concentrated mineralizing solution into the centers of the eight-membered rings of the layer corroborates the ion-exchanging properties of the crystals of this structural type. The filling of rings and pores of different types in different members of the family by K⁺ and Cl^? ions, hydroxyl groups, and water molecules is analyzed.     

Crystal structure of N-benzylmethylammonium dihydrogen-monophosphate monohydrate, [C6H5CH2NH2CH3]H2PO4·H2O

The salt N-benzylmethylammonium dihydrogenmonophosphate monohydrate is monoclinic with the following unit cell dimensions: a = 6.356(1)Å, b = 8.385(7)Å, c = 11.472(5)Å, = 104.32(1)°, space group P2₁ with Z = 2. The structure consists of infinite parallel two-dimensional [110] planes built of mutually connected ions and water molecules by strong O–H···O and N–H···O hydrogen bonding. There are no contacts other than normal van der Waals interactions between the layers.     

Crystal and molecular structures of potassium cobalt hydrogen phthalate K2[Co(H2O)6](C8H5O4)4 ⋅ 4H2O and mechanism of Co2+ impurity trapping in KAP crystals

The single-crystal X-ray diffraction analysis of K₂[Co(H₂O)₆](C₈H₅O₄)₄ ? 4H₂O has been carried out. The K₂[Co(H₂O)₆](C₈H₅O₄)₄ ? 4H₂O single crystals are obtained in attempting to grow the KAP crystals with the maximum possible content of Co²⁺ impurity cations. The crystals are isostructural to the earlier-studied similar crystals with Ni(II). The structure is formed by double layers of biphthalate anions and the Co²⁺ and K⁺ cations in between. The Co²⁺ cations are coordinated only by water molecules, whereas the coordination of the K⁺ cations involves both the biphthalate anions and water molecules. A detailed crystal chemical analysis, together with the data on the growth kinetics of KAP crystals in the presence of Co²⁺ and the mass-spectrometric data obtained earlier for the KAP crystals, leads to the conclusion that the Co²⁺ impurity cations should be located in the form of the [Co(H₂O)₆]²⁺ cationic complexes in the interblock layers of the KAP crystals.     

Crystal structure of radical cation salt (BEDT-TTF)4(GaCl4)2 · C6H5CH3

A new radical cation salt based on bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) with the tetrahedral anion GaCl ₄ ^? , namely, (BEDT-TTF)₄(GaCl₄)₂ · C₆H₅CH₃, has been synthesized. The crystal structure of this salt is determined by X-ray diffraction analysis [a = 31.757(2) Å, b = 6.8063(3) Å, c = 34.879(2) Å, β = 90.453(4)°, V = 7538.8(7) ų, space group I2/c, and Z = 4]. In the structure, the radical cation layers alternate with the anion layers along the c-axis. The anion layers consist of the GaCl ₄ ^? tetrahedra and solvent molecules. The packing of BEDT-TTF molecules in the radical cation layer differs from that in the structure of the known salt (BEDT-TTF)₂GaCl₄, even though both compounds exhibit semiconductor properties.