MgSO4·11H2O and MgCrO4·11H2O based on time‐of‐flight neutron single‐crystal Laue data

Hexaaquamagnesium(II) sulfate pentahydrate, [Mg(H₂O)₆]SO₄·5H₂O, and hexaaquamagnesium(II) chromate(II) pentahydrate, [Mg(H₂O)₆][CrO₄]·5H₂O, are isomorphous, being composed of hexaaquamagnesium(II) octahedra, [Mg(H₂O)₆]²⁺, and sulfate (chromate) tetrahedral oxyanions, SO₄²⁻ (CrO₄²⁻), linked by hydrogen bonds. There are two symmetry‐inequivalent centrosymmetric octahedra: M1 at (0, 0, 0) donates hydrogen bonds directly to the tetrahedral oxyanion, T1, at (0.405, 0.320, 0.201), whereas the M2 octahedron at (0, 0, ) is linked to the oxyanion via five interstitial water molecules. Substitution of Cr^VI for S^VI leads to a substantial expansion of T1, since the Cr—O bond is approximately 12% longer than the S—O bond. This expansion is propagated through the hydrogen‐bonded framework to produce a 3.3% increase in unit‐cell volume; the greatest part of this chemically induced strain is manifested along the b* direction. The hydrogen bonds in the chromate compound mitigate ∼20% of the expected strain due to the larger oxyanion, becoming shorter (i.e. stronger) and more linear than in the sulfate analogue. The bifurcated hydrogen bond donated by one of the interstitial water molecules is significantly more symmetrical in the chromate analogue.     

A single‐crystal neutron diffraction study of RbTiOAsO4

A rubidium titanyl arsenate single‐crystal has been studied by neutron diffraction (λ = 1.207 Å). The polished sample used was 5 × 3 × 2 mm and was cut from a crystal made by top‐seeded solution growth. The crystal showed severe extinction. It was, however, possible to obtain a structural model with well defined oxy­gen sites and reasonable anisotropic displacement parameters.     

(NH4)2WTe2O8 at 5.09 GPa: a single‐crystal study using synchrotron radiation

The polar crystal structure of diammonium [octaoxidoditellurato(IV)]tungstate, (NH₄)₂WTe₂O₈, was studied at high pressures using single‐crystal X‐ray diffraction in a diamond‐anvil cell at the HASYLAB synchrotron (DESY, Hamburg, Germany). No phase transition was observed up to 7.16 GPa. However, a full structure determination at 5.09 GPa shows that the coordination number of one of the two non‐equivalent Te atoms has decreased from four to three.     

Penkvilksite‐2O: Na2TiSi4O11·2H2O

The crystal structure of synthetic penkvilksite‐2O, disodium titanium tetrasilicate dihydrate, Na₂TiSi₄O₁₁·2H₂O, a microporous titanosilicate, confirms the major features of a previous model that had been obtained by order–disorder (OD) theory from the known structure of penkvilksite‐1M. An important difference from the previous model involves the hydrogen bonding of the water molecule which, on the basis of a Raman spectrum and the finding of only one of the two H atoms, is proposed to be disordered about a fixed O–H direction. The structure of penkvilksite‐2O is based on (100) silicate layers linked by isolated TiO₆ octahedra to form a heteropolyhedral framework. The layer is strongly corrugated, based on interlaced spiral chains, and is crossed by two different channels that have an effective channel width of about 3 Å.     

K2TiSi3O9·H2O

Single crystals of dipotassium titanium trisilicate hydrate were synthesized and the crystal structure was refined using data from single‐crystal X‐ray diffraction. The structure is a three‐dimensional mixed framework and contains channels formed by six‐ and eight‐membered rings. K⁺ ions and water mol­ecules are located in the channels.     

RbCrIII(C2O4)2·2H2O,Cs2Mg(C2O4)2·4H2O and Rb2CuII(C2O4)2·2H2O: three new complex oxalate hydrates

Rubidium chromium(III) dioxalate dihydrate [di­aqua­bis(μ‐oxalato)­chromium(III)­rubidium(I)], [RbCr(C₂O₄)₂(H₂O)₂], (I), and dicaesium magnesium dioxalate tetrahydrate [tetra­aqua­bis(μ‐oxalato)­magnesium(II)­dicaesium(I)], [Cs₂Mg(C₂­O₄)₂(H₂O)₄], (II), have layered structures which are new among double‐metal oxalates. In (I), the Rb and Cr atoms lie on sites with imposed 2/m symmetry and the unique water molecule lies on a mirror plane; in (II), the Mg atom lies on a twofold axis. The two non‐equivalent Cr and Mg atoms both show octahedral coordination, with a mean Cr—O distance of 1.966 Å and a mean Mg—O distance of 2.066 Å. Dirubid­ium copper(II) dioxalate dihydrate [di­aqua­bis(μ‐oxalato)­copper(II)­dirubidium(I)], [Rb₂Cu(C₂O₄)₂(H₂O)₂], (III), is also layered and is isotypic with the previously described K₂‐ and (NH₄)₂Cu^II(C₂O₄)₂·2H₂O compounds. The two non‐equivalent Cu atoms lie on inversion centres and are both (4+2)‐coordinated. Hydro­gen bonds are medium‐strong to weak in the three compounds. The oxalate groups are slightly non‐planar only in the Cs–Mg compound, (II), and are more distinctly non‐planar in the K–Cu compound, (III).     

X‐ray and neutron powder diffraction analyses of Gly·MgSO4·5H2O and Gly·MgSO4·3H2O,and their deuterated counterparts

We have identified a new compound in the glycine–MgSO₄–water ternary system, namely glycine magnesium sulfate trihydrate (or Gly·MgSO₄·3H₂O) {systematic name: catena‐poly[[tetraaquamagnesium(II)]‐μ‐glycine‐κ²O:O′‐[diaquabis(sulfato‐κO)magnesium(II)]‐μ‐glycine‐κ²O:O′]; [Mg(SO₄)(C₂D₅NO₂)(D₂O)₃]_n}, which can be grown from a supersaturated solution at ∼350 K and which may also be formed by heating the previously known glycine magnesium sulfate pentahydrate (or Gly·MgSO₄·5H₂O) {systematic name: hexaaquamagnesium(II) tetraaquadiglycinemagnesium(II) disulfate; [Mg(D₂O)₆][Mg(C₂D₅NO₂)₂(D₂O)₄](SO₄)₂} above ∼330 K in air. X‐ray powder diffraction analysis reveals that the trihydrate phase is monoclinic (space group P2₁/n), with a unit‐cell metric very similar to that of recently identified Gly·CoSO₄·3H₂O [Tepavitcharova et al. (2012). J. Mol. Struct. 1018 , 113–121]. In order to obtain an accurate determination of all structural parameters, including the locations of H atoms, and to better understand the relationship between the pentahydrate and the trihydrate, neutron powder diffraction measurements of both (fully deuterated) phases were carried out at 10 K at the ISIS neutron spallation source, these being complemented with X‐ray powder diffraction measurements and Raman spectroscopy. At 10 K, glycine magnesium sulfate pentahydrate, structurally described by the `double' formula [Gly(d₅)·MgSO₄·5D₂O]₂, is triclinic (space group P, Z = 1), and glycine magnesium sulfate trihydrate, which may be described by the formula Gly(d₅)·MgSO₄·3D₂O, is monoclinic (space group P2₁/n, Z = 4). In the pentahydrate, there are two symmetry‐inequivalent MgO₆ octahedra on sites of symmetry and two SO₄ tetrahedra with site symmetry 1. The octahedra comprise one [tetraaquadiglcyinemagnesium]²⁺ ion (centred on Mg1) and one [hexaaquamagnesium]²⁺ ion (centred on Mg2), and the glycine zwitterion, NH₃⁺CH₂COO⁻, adopts a monodentate coordination to Mg2. In the trihydrate, there are two pairs of symmetry‐inequivalent MgO₆ octahedra on sites of symmetry and two pairs of SO₄ tetrahedra with site symmetry 1; the glycine zwitterion adopts a binuclear–bidentate bridging function between Mg1 and Mg2, whilst the Mg2 octahedra form a corner‐sharing arrangement with the sulfate tetrahedra. These bridged polyhedra thus constitute infinite polymeric chains extending along the b axis of the crystal. A range of O—H…O, N—H…O and C—H…O hydrogen bonds, including some three‐centred interactions, complete the three‐dimensional framework of each crystal.     

(NH4)4Na2[V10O28]·10H2O

Tetra­ammonium disodium decavanadate decahydrate crystallizes in the triclinic system in space group P. The structure contains typical centrosymmetric OV₆ double octahedra and centrosymmetric pairs of edge‐shared NaO₆ double octahedra forming a layered structure. In contrast to other monovalent cationic decavanadates, the NaO₆ double octahedra are integrated in the layer.     

[CoII4MoV12O28(OH)12(H2O)12]·12H2O: facilitating single‐crystal growth by deuteration

The structure of the neutral heterometal oxide cluster dodecaaqua‐di‐μ₃‐hydroxido‐deca‐μ₂‐hydroxido‐octacosaoxidotetracobalt(II)dodecamolybdenum(V) dodecahydrate, [Mo₁₂O₂₈(μ₂‐OH)₁₀(μ₃‐OH)₂{Co(H₂O)₃}₄], is virtually identical to the previously reported Ni^II analogue [Mo₁₂O₂₈(μ₂‐OH)₁₀(μ₃‐OH)₂{Ni^II(H₂O)₃}₄] [Müller, Beugholt, Kögerler, Bögge, Budko & Luban (2000). Inorg. Chem. 39 , 5176–5177], the first molecular magnet to exhibit signs of magnetostriction. The formation kinetics of the neutral cluster species, which is insoluble in water, can be significantly slowed by the use of deuterated reactants in order to grow single crystals of sufficient size for single‐crystal X‐ray diffraction studies using standard diffractometers. One half of the main cluster and six solvent water molecules constitute the asymmetric unit. The main cluster is located on a mirror plane.     

Kristallstrukturbestimmung von NaHC2O4 · H2O

NaHC₂O₄ · H₂O crystallizes in space group P 1 with a₀ = 6,51, b₀ = 6,66, c₀ = 5,70 Å, α₀ = 95,0°, β₀ = 109,8°, γ₀ = 74,9° and Z = 2. The structure was solved by direct methods. The refinement was carried out with 679 reflections to R₁ = 7,7%. The angle between the O? C? O planes is 12,6°.     

Preparation and crystal data for two trimetaphosphate tellurates: Te(OH)6 · 2Na3P3O9 · 6H2O and Te(OH)6 · K3P3O9 · 2H2O

Te(OH)₆ · 2Na₃P₃O₉ · 6H₂O, is hexagonal (P6₃/m) with a = 11,67(1), c = 12,12(1) Å, Z = 2 and D_x = 2,225 g/cm³. Te(OH)₆ · K₃P₃O₉ · 2H₂O, is monoklin (P2₁/c) with a = 19,61(5), b = 7,456(1), c = 14,84(6) Å, = 108,01(4), Z = 4 and D_x = 2,506 g/cm³. Both compounds are the first examples of phosphate tellurates in which the anion phosphate is condensed to the ring anion P₃O₉. As in phosphate tellurates already described the phosphate groups are independent of the TeO₆ octahedra.     

Preparative and Structural Studies of Halodimolybdates (II). II Preparation of (NH4)4Mo2Br8, (NH4)5Mo2Br9 · H2O,Rb5Mo2Cl9 · H2O and Crystal Structure of (NH4)4Mo2Br8

Iron(III) Complexes with Ethylene Diamine Tetraacetic Acid or Nitrilotriacetic Acid and Phenol Quarternary complexes of iron(III) with phenol (HR) and ethylene diamine tetraacetic acid (H₄Y) as well as nitrilotriacetic acid (H₃X) in aqueous solution could be detected. The equilibria have been controlled by spectrophotometric and electrophoretic methods. The measured optical properties and the equilibrium constants are discussed. The following particles are present : (see ?Inhaltsübersicht”?)     

Co0.50VOPO4·2H2O

The crystal structure of cobalt vanadophosphate dihydrate {systematic name: poly[diaqua‐μ‐oxido‐μ‐phosphato‐hemicobalt(II)vanadium(II)]}, Co_0.50VOPO₄·2H₂O, shows a three‐dimensional framework assembled from VO₅ square pyramids, PO₄ tetrahedra and Co[O₂(H₂O)₄] octahedra. The Co^II ions have local 4/m symmetry, with the equatorial water molecules in the mirror plane, while the V and apical O atom of the vanadyl group are located on the fourfold rotation axis and the P atoms reside on sites. The PO₄ tetrahedra connect the VO₅ polyhedra to form a planar P–V–O layer. The [Co(H₂O)₄]²⁺ cations link adjacent P–V–O layers via vanadyl O atoms to generate an unprecedented three‐dimensional open framework. Powder diffraction measurements reveal that the framework collapses on removal of the water molecules.     

Crystal structures of hydrates of simple inorganic salts. II. Water‐rich calcium bromide and iodide hydrates: CaBr2·9H2O,CaI2·8H2O,CaI2·7H2O and CaI2·6.5H2O

Single crystals of calcium bromide enneahydrate, CaBr₂·9H₂O, calcium iodide octahydrate, CaI₂·8H₂O, calcium iodide heptahydrate, CaI₂·7H₂O, and calcium iodide 6.5‐hydrate, CaI₂·6.5H₂O, were grown from their aqueous solutions at and below room temperature according to the solid–liquid phase diagram. The crystal structure of CaI₂·6.5H₂O was redetermined. All four structures are built up from distorted Ca(H₂O)₈ antiprisms. The antiprisms of the iodide hydrate structures are connected either via trigonal‐plane‐sharing or edge‐sharing, forming dimeric units. The antiprisms in calcium bromide enneahydrate are monomeric.     

New coordination modes in potassium edta salts: K2[H2edta]·2H2O,K3[Hedta]·2H2O and K4[edta]·3.92H2O

Three potassium edta (edta is ethylenediaminetetraacetic acid, H₄Y) salts which have different degrees of ionization of the edta anion, namely dipotassium 2‐({2‐[bis(carboxylatomethyl)azaniumyl]ethyl}(carboxylatomethyl)azaniumyl)acetate dihydrate, 2K⁺·C₁₀H₁₄N₂O₈²⁻·2H₂O, (I), tripotassium 2,2′‐({2‐[bis(carboxylatomethyl)amino]ethyl}ammonio)diacetate dihydrate, 3K⁺·C₁₀H₁₃N₂O₈³⁻·2H₂O, (II), and tetrapotassium 2,2′,2′′,2′′′‐(ethane‐1,2‐diyldinitrilo)tetraacetate 3.92‐hydrate, 4K⁺·C₁₀H₁₂N₂O₈⁴⁻·3.92H₂O, (III), were obtained in crystalline form from water solutions after mixing edta with potassium hydroxide in different molar ratios. In (II), a new mode of coordination of the edta anion to the metal is observed. The HY³⁻ anion contains one deprotonated N atom coordinated to K⁺ and the second N atom is involved in intramolecular bifurcated N—H...O and N—H...N hydrogen bonds. The overall conformation of the HY³⁻ anions is very similar to that of the Y⁴⁻ anions in (III), although a slightly different spatial arrangement of the –CH₂COO⁻ groups in relation to (III) is observed, whereas the H₂Y²⁻ anions in (I) adopt a distinctly different geometry. The preferred synclinal conformation of the –NCH₂CH₂N– moiety was found for all edta anions. In all three crystals, the anions and water molecules are arranged in three‐dimensional networks linked via O—H...O and C—H...O [and N—H...O in (I) and (II)] hydrogen bonds. K...O interactions also contribute to the three‐dimensional polymeric architecture of the salts.     

Preparation and crystal structure of copper tetrasodium trimetaphosphate tetrahydrate: CuNa4(P3O9)2 · 4H2O

The preparation of copper-tetrasodium trimetaphosphate tetrahydrate: Na₄Cu(P₃O₉)₂ · 4H₂O is described. This salt is the first example of the occurence of Cu^II in a trimetaphosphate. The triclinic unit cell has the dimensions a = 7.907(5), b = 8.364(5), c = 7.122(5) Å, α = 102.46(5), β = 97.89(5), γ = 84.04(5)°. Crystal structure has been solved by using 2019 independent reflexions with a final R value 0.017. Both copper and sodium atoms are in octahedral coordination. NaO₆ octahedra form ribbons running in (011) planes. These ribbons are interconnected by CuO₆ octahedra as to form a three dimensional network. Hydrogen atoms have been located and refined. The hydrogen bond scheme is described.     

Preparation and crystal structure of Ammonium Cyclooctaphosphate Trihydrate: (NH4)8P8O24 · 3H2O

Ammonium cyclooctaphosphate trihydrate, (NH₄)₈P₈O₂₄ · 3H₂O, is monoclinic, Cc, with Z = 4 and the following unit-cell dimensions: a = 24.268(14), b = 6.700(3), c = 20.586(13) Å, β = 112,06(6)° Chemical preparation and crystal structure are reported. Using 4 668 unique reflections the atomic arrangement was determined with a final R value of 0.037. The organization of ring-anions and ammonium groups is almost centrosymmetrical but the location of the water molecules is not. The ring anion itself has a strong pseudo centrosymmetric conformation.     

(NH4)3[VO2(SO4)2(H2O)2]·1.5H2O

The title compound, tri­ammonium cis‐di­aqua‐cis‐dioxo‐trans‐disulfatovanadate 1.5‐hydrate, was obtained by oxidizing V^IV to V^V in a 2 M sulfuric acid solution of vanadyl­ sulfate and adding ammonium sulfate. Here, the V atom is sandwiched by two sulfate groups by corner‐sharing to form a discrete [VO₂(SO₄)₂(OH₂)₂]^3? anion. The water mol­ecules occupy cis positions in the equatorial plane of the vanadium octahedron.     

复合物HNO···H2O2内N-H···O蓝移氢键的理论研究

A theoretical study on the blue-shifted H-bond N-H…O and red-shifted H-bond O-H…O in the complexHNO…H_2O_2 was conducted by employment of both standard and counterpoise-corrected methods to calculate thegeometric structures and vibrational frequencies at the MP2/6-31G(d),MP2/6-31 G(d,p),MP2/6-311 q G(d,p),B3LYP/6-31G(d),B3LYP/6-31 G(d,p) and B3LYP/6-311 G(d,p) levels.In the H-bond N-H…O,the calcu-lated blue shift of N-H stretching frequency is in the vicinity of 120 cm~(-1) and this is indeed the largest theoreticalestimate of a blue shift in the X-H…Y H-bond ever reported in the literature.From the natural bond orbital analy-sis,the red-shifted H-bond O-H…O can be explained on the basis of the dominant role of the hyperconjugation.For the blue-shifted H-bond N-H…O,the hyperconjugation was inhibited due to the existence of significant elec-tron density redistribution effect,and the large blue shift of the N-H stretching frequency was prominently due tothe rehybridization of sp~n N-H hybrid orbital.