Crystal Structure and Thermal Behaviour of K2[CrF5·H2O]

K₂[CrF₅·H₂O] is monoclinic: a = 9.6835(3) Å, b = 7.7359(2) Å, c = 7.9564(3) Å, β = 95.94(1)°, Z = 4, space group C2/c (n^o 15). Its crystal structure was solved from its X‐ray powder pattern recorded on a powder diffractometer, using for the refinement the Rietveld method. It is built up from isolated octahedral [CrF₅·OH₂]^2? anions separated by potassium cations. The dehydration of K₂[CrF₅·H₂O] leads to anhydrous orthorhombic K₂CrF₅: a = 7.334(2) Å, b = 12.804(4) Å, c = 20.151(5) Å, Z = 16, space group Pbcn (n^o 60), isostructural with K₂FeF₅.     

Three Crystal Structures,One Chemical Formula – Barium Dihydrogen‐hypodiphosphate(IV)‐dihydrate,BaH2P2O6·2H2O

Three polymorphs of barium dihydrogen‐hypodiphosphate(IV)‐dihydrate, BaH₂P₂O₆ · 2H₂O ( A , B and C ), were obtained and structurally characterized by single‐crystal X‐ray diffraction. A crystallizes in the monoclinic space group P2₁/n (no. 14) with a = 7.459(1) Å, b = 8.066(1) Å, c = 12.460(2) Å, β = 91.27(1) ° and Z = 4. B crystallizes in the monoclinic space group C2/c (no. 15) with a = 11.049(8) Å, b = 6.486(3) Å, c = 10.956(6) Å, β = 106.89(5) ° and Z = 4. C crystallizes in the orthorhombic space group C222₁ (no. 20) with a = 9.193(3) Å, b = 6.199(2) Å, c = 12.888(4) Å and Z = 4. Discrete [H₂P₂O₆]^2– units, barium cations and water molecules, held together by intermolecular hydrogen bonds of the type O–H ··· O, build up the structures of the three polymorphs. The phase purity of A and C was verified by powder diffraction measurements.     

Fluorenyl Zinc Phosphonate Zn(H2O)PO3–C13H9·H2O: Hybrid Columnar Structure with Strong C–H···π Interactions

A new zinc phosphonate Zn(H₂O)PO₃–C₁₃H₉ · H₂O with a columnar structure was synthesized in hydrothermal conditions. This compound crystallizes in space group P2₁/c [a = 15.832(4) Å, b = 5.1915(10) Å, c = 17.519(4) Å and β = 114.479(6)°]. Its inorganic framework consists of isolated chains of corner‐sharing ZnO₃(H₂O) and PO₃C tetrahedra. These chains are linked to fluorene cycles, forming hybrid columns, interconnected through C–H ··· π bonds. The photoluminescence properties of this hybrid material show that its emission bands are red shifted with respect to those of the mother phosphonic acid. This effect is explained on the basis of the structural constraints imposed by the inorganic Zn‐phosphonate chains.     

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.     

Syntheses and Crystal Structures of Three Polymeric Silver(I) Terephthalate Complexes with Organic N‐Donor Ligands: [Ag(pren)]2(tp)·2H2O, [Ag(en)][Ag(μ2‐tp)]·H2O,and [Ag2(μ4‐tp)(apy)2]

Three polymeric silver(I) complexes with terephthalate anions as counterions or ligands, [Ag(pren)]₂(tp)·2H₂O ( 1 ), [Ag(en)][Ag(μ₂‐tp)]·H₂O ( 2 ), and [Ag₂(μ₄‐tp)(apy)₂] ( 3 ) (where pren = 1, 2‐propylenediamine, tp =terephthalate dianion, en = ethylenediamine, and apy = 2‐aminopyridine) were synthesized and characterized by X‐ray single crystal analysis and infrared spectroscopy. 1 crystallizes in the monoclinic space group P2₁1/c with a = 11.3221(5), b = 7.1522(3), c = 14.8128(5)Å, V = 1015.77(7)ų, β = 122.132(2), and Z = 2. 2 crystallizes in the orthorhombic space group Pnma with a = 9.6144(6), b = 11.3465(7), c = 11.4810(7)Å, V = 1252.5(1)ų, and Z = 4. 3 crystallizes in the monoclinic space group P2₁/n with a = 8.2003(5), b = 5.8869(4), c = 18.3769(11)Å, β = 92.593(1), V = 886.2(1)ų, and Z = 4. Terephthalate dianions are not coordinated to the metal atoms in 1 , but act as a μ₂‐bridging ligand in 2 and as a μ₄‐bridging ligand in 3 .     

Earth Alkaline Tetrathiosquarates: Syntheses and Crystal Structures of MgC4S4 · 6 H2O and CaC4S4 · 4 H2O

Concentrated aqueous solutions of magnesium chloride and calcium nitrate, respectively, allow on addition of the potassium salt of tetrathiosquarate, K₂C₄S₄ · H₂O, the isolation of the earth alkaline salts MgC₄S₄ · 6 H₂O ( 1 ) and CaC₄S₄ · 4 H₂O ( 2 ) as orange and red crystals. The crystal structure determinations ( 1 : monoclinic, C2/c, a = 17.2280(7), b = 5.9185(2), c = 13.1480(4) Å, β = 104.730(3)°, Z = 4; 2 : monoclinic, P2₁/m, a = 7.8515(3), b = 12.7705(5), c = 10.6010(4) Å, β = 93.228(2)°, Z = 4) show the presence of C₄S₄^2? ions with almost undistorted D_4h symmetry having average C–C and C–S bond lengths of 1.451Å and 1.659Å for 1 and 1.451Å and 1.655Å for 2 . The structure of 1 contains discrete, octahedral [Mg(H₂O)₆]²⁺ complexes. Several O–H····O and O–H····S bridges with H····O and H····S distances of less than 2.50Å connect cations and anions. The structure of 2 is built of concatenated, edge‐sharing Ca(H₂O)₆S₂ polyhedra. The Ca²⁺ ions have the coordination number eight, C₄S₄^2? act as a chelating ligands towards Ca²⁺ with Ca–S distances of 3.14Å. The infrared and Raman spectra show bands typical for the molecular building units of the two compounds.     

{[Zn2(Bim)3(OH)(H2O)]·(DMF)(H2O)3}∞: A Two Dimensional Coordination Polymer with Layer Silicate‐like Structure

A layer silicate‐like zinc(II) benzimidazolate polymer {[Zn₂(Bim)₃(OH)(H₂O)]·(DMF)(H₂O)₃}_∞ ( 1 ) was synthesized at room temperature and characterized with X‐ray single‐crystallography: Monoclinic, space group C2/m (No.12), a = 10.423(3) Å, b = 17.416(6) Å, c = 16.583(5) Å, β = 92.698(4), V = 3006.8(17) ų.     

Hybrid Inorganic‐Organic Frameworks: Synthesis and Crystal Structures of RbFe(SO4)(C2O4)0.5·H2O and CsM(SO4)(C2O4)0.5·H2O (M = Mn,Fe)

Three new alkali metal transition metal sulfate‐oxalates, RbFe(SO₄)(C₂O₄)_0.5 · H₂O and CsM(SO₄)(C₂O₄)_0.5 · H₂O (M = Mn, Fe) were prepared through hydrothermal reactions and characterized by single‐crystal X‐ray diffraction, solid state UV/Vis/NIR diffuse reflectance spectroscopy, infrared spectra, thermogravimetric analysis, and powder X‐ray diffraction. The title compounds all crystallize in the monoclinic space group P2₁/c (no. 14) with lattice parameters: a = 7.9193(5), b = 9.4907(6), c = 8.8090(6) Å, β = 95.180(2)°, Z = 4 for RbFe(SO₄)(C₂O₄)_0.5 · H₂O; a = 8.0654(11), b = 9.6103(13), c = 9.2189(13) Å, β = 94.564(4)°, Z = 4 for CsMn(SO₄)(C₂O₄)_0.5 · H₂O; and a = 7.9377(3), b = 9.5757(4), c = 9.1474(4) Å, β = 96.1040(10)°, Z = 4 for CsFe(SO₄)(C₂O₄)_0.5 · H₂O. All compounds exhibit three‐dimensional frameworks composed of [MO₆] octahedra, [SO₄]^2– tetrahedra, and [C₂O₄]^2– anions. The alkali cations are located in one‐dimensional tunnels.     

Syntheses and Structures of Two Selenite Chloride Hydrates: Co(HSeO3)Cl · 3 H2O and Cu(HSeO3)Cl · 2 H2O

The first selenite chloride hydrates, Co(HSeO₃)Cl · 3 H₂O and Cu(HSeO₃)Cl · 2 H₂O, have been prepared from solution and characterised by single‐crystal X‐ray diffraction. The cobalt phase adopts an unusual “one‐dimensional” structure built up from vertex‐sharing pyramidal [HSeO₃]^2–, and octahedral [CoO₂(H₂O)₄]^2– and [CoO₂(H₂O)₂Cl₂]^4– units. Inter‐chain bonding is by way of hydrogen bonds or van der Waals' interactions. The atomic arrangement of the copper phase involves [HSeO₃]^2– pyramids and Jahn‐Teller distorted [CuCl₂(H₂O)₄] and [CuO₄Cl₂]^8– octahedra, sharing vertices by way of Cu–O–Se and Cu–Cl–Cu bonds. Crystal data: Co(HSeO₃)Cl · 3 H₂O, M_r = 276.40, triclinic, space group P 1 (No. 2), a = 7.1657(5) Å, b = 7.3714(5) Å, c = 7.7064(5) Å, α = 64.934(1)°, β = 68.894(1)°, γ = 71.795(1)°, V = 337.78(7) ų, Z = 2, R(F) = 0.036, wR(F) = 0.049. Cu(HSeO₃)Cl · 2 H₂O, M_r = 263.00, orthorhombic, space group Pnma (No. 62), a = 9.1488(3) Å, b = 17.8351(7) Å, c = 7.2293(3) Å, V = 1179.6(2) ų, Z = 8, R(F) = 0.021, wR(F) = 0.024.     

Earth Alkaline Tetrathiosquarates. II. – Syntheses and Crystal Structures of SrC4S4·4 H2O and Ba4K2(C4S4)5·16 H2O

Concentrated aqueous solutions of strontium chloride and barium chloride, respectively, allow on addition of the potassium salt of tetrathiosquarate, K₂C₄S₄·H₂O, the isolation of the earth alkaline salts SrC₄S₄·4 H₂O ( 1 ) and Ba₄K₂(C₄S₄)₅·16 H₂O ( 2 ), both as dark red crystals. The crystal structure determinations ( 1 : orthorhombic, Pnma, a = 8.149(1), b = 12.907(2), c = 10.790(2) Å, Z = 4; 2 : orthorhombic, Pbca, a = 15.875(3), b = 21.325(5), c = 16.119(1) Å, Z = 4) show the presence of C₄S₄²⁻ ions with only slightly distorted D_4h symmetry having average C–C and C–S bond lengths of 1.41Å and 1.681Å for 1 and 1.450Å and 1.657Å for 2 . The structure of 1 contains concatenated edge‐sharing Sr(H₂O)₆S₂ polyhedra. The Sr²⁺ ions are in eight‐fold coordination with Sr–O distances of 2.50–2.72Å and Sr–S distances of 3.21Å, (C₄S₄)²⁻ acts as a chelating ligand towards Sr²⁺. The structure is closely related to the previously reported Ca²⁺ containing analogue, which is of lower symmetry belonging to the monoclinic crystal system. A supergroup‐subgroup relation between the space groups of both structures is present. The structure of 2 is made up of Ba²⁺ and K⁺ ions in eight and nine‐fold coordination by H₂O molecules and (C₄S₄)²⁻ ions which act as chelating ligands towards one cation and bridging between two cations. The coordination polyhedra of the cations are connected by common edges and corners in two dimensions to layers which are connected by tetrathiosquarate ions to a three‐dimensional network. The infrared and Raman spectra show bands typical for the molecular building units of the two compounds.     

Synthesis,Structural Characterization and Thermal Stability of [Mn(3‐bpd)2(NCS)2(H2O)2]·2H2O (1) and {[Mn(bpe)(NCS)2(H2O)2]·(3‐bpd)·(bpe)·H2O}n (2) from One‐Pot Crystallization

Two supramolecular architectures, [Mn(3‐bpd)₂(NCS)₂(H₂O)₂]·2H₂O ( 1 ) and {[Mn(bpe)(NCS)₂(H₂O)₂]·(3‐bpd)·(bpe)·H₂O}_n ( 2 ) [bpe = 1,2‐bis(4‐pyridyl)ethylene and 3‐bpd = 1,4‐bis(3‐pyridyl)‐2,3‐diaza‐1,3‐butadiene] have been synthesized and characterized by spectroscopic, elemental and single crystal X‐ray diffraction analyses. Compound 1 crystallizes in the monoclinic system, space group P2₁/c, with chemical formula C₂₆H₂₈Mn N₁₀O₄S₂, a = 9.1360(6), b = 9.7490(6), c = 17.776(1) Å, β = 93.212(1)°, and Z = 2 while compound 2 crystallizes in the orthorhombic system, space group P2₁2₁2₁, with chemical formula C₃₈H₃₆Mn₁N₁₀O₃S₂, a = 14.1902(6), b = 15.4569(7), c = 18.2838(8) Å, α = β = γ = 90°, and Z = 4. Structural determination reveals that the coordination geometry at Mn(II) in compound 1 or 2 is a distorted octahedral which consists of two nitrogen donors of two NCS^?ligands, two oxygen donors of two water molecules, and two nitrogen donors of two 3‐bpd ligands for 1 and two dpe ligands for 2 , respectively. The two 3‐bpd ligands in 1 adopt a monodentate binding mode and the dpe in 2 adopts a bismonodentate bridging mode to connect the Mn(II) ions forming a 1D chain‐like coordination polymer. Both the π‐π stacking interactions between the coordinated and the free pyridyl‐based ligands and intermolecular hydrogen bonds among the coordinated and the crystallized water molecules and the free pyridyl‐based ligands play an important role in construction of these 3D supramolecular architectures.     

Influence of the Organic Species and Oxoanion in the Synthesis of two Uranyl Sulfate Hydrates, (H3O)2[(UO2)2(SO4)3­(H2O)]·7H2O and (H3O)2[(UO2)2(SO4)3(H2O)]·4H2O,and a Uranyl Selenate‐Selenite [C5H6N][(UO2)(SeO4)(HSeO3)]

Two uranyl sulfate hydrates, (H₃O)₂[(UO₂)₂(SO₄)₃(H₂O)] · 7H₂O (NDUS) and (H₃O)₂[(UO₂)₂(SO₄)₃(H₂O)] · 4H₂O (NDUS1), and one uranyl selenate‐selenite [C₅H₆N][(UO₂)(SeO₄)(HSeO₃)] (NDUSe), were obtained and their crystal structures solved. NDUS and NDUSe result from reactions in highly acidic media in the presence of L ‐cystine at 373 K. NDUS crystallized in a closed vial at 278 K after 5 days and NDUSe in an open beaker at 278 K after 2 weeks. NDUS1 was synthesized from aqueous solution at room temperature over the course of a month. NDUS, NDUS1, and NDUSe crystallize in the monoclinic space group P2₁/n, a = 15.0249(4) Å,b = 9.9320(2) Å, c = 15.6518(4) Å, β = 112.778(1)°, V = 2153.52(9) ų,Z = 4, the tetragonal space group P4₃2₁2, a = 10.6111(2) Å,c = 31.644(1) Å, V = 3563.0(2) ų, Z = 8, and in the monoclinic space group P2₁/n, a = 8.993(3) Å, b = 13.399(5) Å, c = 10.640(4) Å,β = 108.230(4)°, V = 1217.7(8) ų, Z = 4, respectively.The structural units of NDUS and NDUS1 are two‐dimensional uranyl sulfate sheets with a U/S ratio of 2/3. The structural unit of NDUSe is a two‐dimensional uranyl selenate‐selenite sheets with a U/Se ratio of 1/2. In‐situ reaction of the L ‐cystine ligands gives two distinct products for the different acids used here. Where sulfuric acid is used, only H₃O⁺ cations are located in the interlayer space, where they balance the charge of the sheets, whereas where selenic acid is used, interlayer C₅H₆N⁺ cations result from the cyclization of the carboxyl groups of L ‐cystine, balancing the charge of the sheets.     

Crystal Structures of [Mn2(H2O)4(bpy)2(C8H12O4)2] · 2 H2O and [Mn(H2O)2(bpy)(C8H12O4)2/2] · H2O with bpy = 2,2′‐bipyridine

Reaction of MnSO₄ · H₂O, 2,2′‐bipyridine (bpy), suberic acid and Na₂CO₃ in CH₃OH/H₂O yielded a mixture of [Mn₂(H₂O)₄(bpy)₂(C₈H₁₂O₄)₂] · 2 H₂O ( 1 ) and [Mn(H₂O)₂‐ (bpy)(C₈H₁₂O₄)_2/2] · H₂O ( 2 ). In both complexes, the Mn atoms are octahedrally coordinated by two N atoms of one bpy ligand and four O atoms of two trans positioned H₂O molecules and two suberato ligands (d(Mn–O) = 2.107–2.328 Å; d(Mn–N) = 2.250–2.330 Å). The bis‐monodentate suberato ligands bridge Mn atoms to form dinuclear [Mn₂(H₂O)₄(bpy)₂(C₈H₁₂O₄)₂] complex molecules in 1 and 1D [Mn(H₂O)₂(bpy)(C₈H₁₂O₄)_2/2] chains in 2 . Via the intermolecular hydrogen bondings and π‐π stacking interactions, the dinuclear molecules in 1 are assembled into 2D networks parallel to (100), between which the crystal H₂O molecules are sandwiched. The polymeric chains in 2 are linked together by interchain hydrogen bonding and π‐π stacking interactions into 3D networks with the crystal H₂O molecules located in tunnels along [010]. Crystal data for 1 : P2₁/c (no. 14), a = 10.092(1) Å, b = 11.916(2) Å, c = 17.296(2) Å, β = 93.41(1)° and Z = 2. Crystal data for 2 : P2₁/c (no. 14), a = 11.176(2) Å, b = 9.688(1) Å, c = 37.842(6) Å, β = 90.06(1)° and Z = 8.     

New Borate‐citrate: Synthesis,Structure, and Properties of Sr[B(C6H5O7)2](H2O)4·3H2O

Single crystals of Sr[B(C₆H₅O₇)₂](H₂O)₄ · 3H₂O, a new borate‐citrate material, were grown with sizes up to 8 × 6 × 2 mm by slow evaporation of water at room temperature. The structure of Sr[B(C₆H₅O₇)₂](H₂O)₄ · 3H₂O was determined by single‐crystal X‐ray diffraction. It crystallizes in the monoclinic space group P2₁/c, with a = 11.363(3) Å, b = 18.829(4) Å, c = 11.976(3) Å, β = 110.736(3)°, and Z = 4. The SrO₈ dodecahedra, BO₄ tetrahedra and citrate groups are linked together to form chains. The compound was characterized by IR and UV/Vis/NIR transmittance spectroscopy as well as thermal analysis.     

Synthesis,Crystal Structures,and Magnetic Properties of Three New Iron Complexes Derived from 3,5‐Bis(pyridin‐2‐yl)‐1,2,4‐triazole

Two new iron(III) complexes and one iron(II) complex have been synthesized from the solvothermal reactions of FeCl₃·6H₂O with 3,5‐bis(pyridin‐2‐yl)‐1,2,4‐triazole (Hbpt) in methanol or acetonitrile. KSCN acted as the reducing agent in the synthesis of iron(II) complex of 3 . [FeCl₃(Hbpt)(H₂O)]·H₂O ( 1 ) crystallizes in the triclinic space group with a = 7.475(1), b = 9.468(2), c = 12.309(2) Å, α = 73.880(2), β = 74.746(2), γ = 81.849(2)°, V = 805.2(2) ų, Z = 2. [Fe₂(bpt)₂Cl₄] ( 2 ): orthorhombic space group Pnnm with a = 9.895(2), b = 10.632(2), c = 13.195(2) Å, V = 1388.1(4) ų, Z = 2. [Fe₂(bpt)₂(MeOH)₂Cl₂] ( 3 ): orthorhombic space group Pbca with a = 14.4204(16), b = 9.8737(11), c = 19.792(2) Å, V = 2818.1(5) ų, Z = 4. 1 features the first structurally characterized metal complex of the neutral Hbpt ligand in which the Hbpt ligand adopts an unprecedented zwitterionic form. 2 shows a neutral dinuclear iron(III) complex and the [Fe₂(bpt)₂]⁴⁺ unit is ideally planar. The two iron(III) ions separated by a distance of 4.408(2) Å are doubly triazolate‐bridged. Each dimeric unit is connected with six other dimeric ones via the bifurcated C‐H···Cl hydrogen bonds, these connections extend the dimeric moieties into a three‐dimensional molecular architecture. 3 is a neutral centrosymmetric dinuclear Fe^II complex, in which intermolecular moderate O‐H···N hydrogen bonding interactions between the methanol molecules and 4‐position nitrogen atoms of the triazolato groups extend the dinuclear species into a two‐dimensional supramolecular architecture of (4,4) topology. Magnetic studies indicate there exists an antiferromagnetic spin coupling in Fe^III₂ and Fe^II₂ units via the double triazolate bridges in 2 and 3 .     

Molecular and Low‐dimensional Coordination Compounds of Copper(II) and 3, 5‐Dimethylpyrazole — Synthesis,Crystal Structure,and Properties

Three 3, 5‐dimethylpyrazole (pz*) copper(II) complexes, [Cu(pz*)₄(H₂O)](ClO₄)₂ ( 1 ), [Cu(pz*)₂(NCS)₂]·H₂O ( 2 ), and [Cu(pz*)₂(OOCCH=CHCOO)(H₂O)]·1.5H₂O ( 3 ), have been synthesized and characterized with single crystal X‐ray structure analysis. 1 crystallizes in the tetragonal space group, 14/m, with a = 14.027 (3) Å, c = 16.301 (5) Å, and Z = 4. 2 crystallizes in the monoclinic space group, P2₁/c, with a = 8.008 (3) Å, b = 27.139 (9) Å, c = 8.934 (3) Å, β = 106.345 (6)°, and Z = 4. 3 crystallizes in the triclinic space group, P1¯, with a = 7.291 (9) Å, b = 10.891 (13) Å, c = 11.822 (14) Å, α = 80.90 (2)°, β = 79.73(2)°, γ = 70.60(2)°, and Z = 2. In 1 , one water molecule and four pz* ligands are coordinated to Cu^II. Two [Cu(pz*)₄(H₂O)]²⁺ units are connected to ClO₄^— via hydrogen bonds. One lattice water molecule is found in the unit cell of 2 , which forms an one‐dimensional chain via intermolecular hydrogen bonds with the N‐H atom of pz*. In 3 , the oxygen atom of the coordinated water molecule is connected with two C=O groups of two neighbouring maleic acid molecules to form a linear parallelogram structure. Another C=O group of maleic acid forms a hydrogen bond with the N‐H atom of pz* to create a two‐dimensional structure. The spectroscopic and bond properties are also discussed.     

Synthesis,Crystal Structure,and Magnetic Properties of {[Cu(phen)]2(C4H2O4)2} · 4.5H2O with C4H4O4 = Maleic Acid

Reaction of CuCl₂ · 2H₂O, phenanthroline, maleic acid and NaOH in CH₃OH/H₂O (1:1 v/v) at pH = 7.0 yielded blue {[Cu(phen)]₂(C₄H₂O₄)₂} · 4.5H₂O, which crystallizes in the monoclinic space group C2/c (no. 15) with cell dimensions: a = 18.127(2)Å, b = 12.482(2)Å, c = 14.602(2)Å, β = 103.43(1)°, U = 3213.5(8)ų, Z = 4. The crystal structure consists of the centrosymmetric dinuclear {[Cu(phen)]₂(C₄H₂O₄)₂} complex molecules and hydrogen bonded H₂O molecules. The Cu atoms are each square‐pyramidally coordinated by two N atoms of one phen ligand and three carboxyl O atoms of two maleato ligands with one carboxyl O atom at the apical position (d(Cu‐N) = 2.008, 2.012Å, equatorial d(Cu‐O) = 1.933, 1.969Å, axial d(Cu‐O) = 2.306Å). Two square‐pyramids are condensed via two apical carboxyl O atoms with a relatively larger Cu···Cu separation of 3.346(1)Å. The dinuclear complex molecules are assembled via the intermolecular π—π stacking interactions into 1D ribbons. Crossover of the resulting ribbons via interribbon π—π stacking interactions forms a 3D network with the tunnels occupied by H₂O molecules. The title complex behaves paramagnetically between 5—300 K, following the Curie‐Weiss law _χm(T—θ) = 0.435 cm³ · mol^—1 · K with θ = 1.59 K.     

Preparation,Structure, and Second‐order Nonlinear Optical Properties of a Borate‐Carboxylic Acid Compound: NH4B[d‐(+)‐C4H4O5]2·H2O

The organic‐inorganic hybrid nonlinear optical (NLO) material NH₄B(d‐ (+)‐C₄H₄O₅)₂ · H₂O (NBC) was synthesized in a borate‐carboxylic acid system. Its structure was determined by single crystal X‐ray diffraction. It crystallizes in the orthorhombic system, space group Pna2₁ (No. 33), with cell parameters a = 11.484(6) Å, b = 5.354(3) Å, c = 21.079(12) Å, V = 1296.0(12), Z = 4. It exhibits a three‐dimensional pseudo tunnel structure consisting of fundamental building block [B(d‐ (+)‐C₄H₄O₅)₂]^– anions. The small cavities are occupied by the H₂O molecules and NH₄⁺ cations, which stabilize the whole structure by O–H ··· O and N–H ··· O hydrogen bonds. The powder X‐ray diffraction (PXRD) of the crystal was also recorded. Elemental analyses, FT‐IR and FT‐Raman spectra analyses, thermal analysis, and diffuse‐reflectance spectra for the compound are also presented, as are band structures and density of states calculation. Nonlinear optical measurements indicate that the material has second harmonic generation (SHG) properties and is phase‐matchable.     

Kristallstruktur von Natrium‐Dihydrogencyamelurat‐Tetrahydrat Na[H2(C6N7)O3] · 4 H2O

Crystal Structure of Sodium Dihydrogencyamelurate Tetrahydrate Na[H₂(C₆N₇)O₃] · 4 H₂O Sodium dihydrogencyamelurate‐tetrahydrate Na[H₂(C₆N₇)O₃]·4 H₂O was obtained by neutralisation of an aqueous solution, previously prepared by hydrolysis of the polymer melon with sodium hydroxide. The crystal structure was solved by single‐crystal X‐ray diffraction ( a = 6.6345(13), b = 8.7107(17), c = 11.632(2) Å, α = 68.96(3), β = 87.57(3), γ = 68.24(3)°, V = 579.5(2) ų, Z = 2, R1 = 0.0535, 2095 observed reflections, 230 parameters). Both hydrogen atoms of the dihydrogencyamelurate anion are directly bound to nitrogen atoms of the cyameluric nucleus, thus proving the preference of the keto‐tautomere in salts of cyameluric acid in the solid‐state. The compound forms a layer‐like structure with an extensive hydrogen bonding network.     

Structural Studies of New Sulfito Mercurates(II) with General Formula xM[XHgSO3]middot;yHgX2·zMX·nH2O (M = NH4, K; X = Cl,Br)

Several solid phases with the general formula xM[XHgSO₃]·yHgX₂·zMX·nH₂O were obtained from aqueous solutions during phase formation studies in the systems M₂SO₃/HgX₂ (M = NH₄, K; X = Cl, Br). All phases were structurally characterized on the basis of single crystal X‐ray diffraction data and adopt new structure types. Compounds with x, y, z = 1 and n = 0 are isostructural (structure type I ) and crystallise with two formula units in space group P2₁/m and lattice parameters of a ≈ 9.7, b ≈ 6.2, c ≈ 10.4Å, β ≈ 111°. Compounds with x, y = 1 and z, n = 0 (structure type II ) crystallize in space group Cmc2₁ with four formula units and lattice parameters of a ≈ 5.9, b ≈ 22.0, c ≈ 6.9Å. The structures with x = 2, y, z = 1 and n = 0 are likewise isostructural (stucture type III ) and consist of four formula units in space group Pnma with lattice parameters of a ≈ 22.2, b ≈ 6.1, c ≈ 12.4Å. K[HgSO₃Cl]·KCl·H₂O is the only representative where x = 1, y = 0, z = 1 and n = 1 (structure type IV ). It is triclinic (space group ) with four formula units and lattice parameters of a = 6.1571(8), b = 7.1342(9), c = 10.6491(14) Å, α = 76.889(2), β = 88.364(2), γ = 69.758(2)°. Characteristic for all structures types is the segregation of the M⁺ cations and the anions and/or HgX₂ molecules into layers. The [XHgSO₃]⁻ anions are present in all structures and have m symmetry, except for K[HgSO₃Cl]·KCl·H₂O with 1 symmetry (but very close to m symmetry). The different [XHgSO₃] units exhibit very similar Hg‐S distances (average 2.372Å) and are more or less bent with ∠(X‐Hg‐S) angles ranging from 159.7 to 173.7°. The molecular HgX₂ entities present in structure types I ‐ III deviate only slightly from linearity with ∠(X‐Hg‐X) angles ranging from 174 to 179°. The structures are stabilised by interaction of the K⁺ or NH₄⁺ cations that are located between the anionic layers or in the vacancies of the framework, by K‐O contacts or, in case of ammonium compounds, by medium to weak hydrogen bonding interactions of the type N‐H···O.