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1.
Mg2(PO2NH)4 · 8 H2O ( 1 ), Mn2(PO2NH)4 · 8 H2O ( 2 ), Co2(PO2NH)4 · 8 H2O ( 3 ) and Zn2(PO2NH)4 · 8 H2O ( 4 ) were obtained as microcrystalline powders by combining aqueous solutions of K4(PO2NH)4 · 4 H2O and MX2 · y H2O (M = Mg, Mn, Co, Zn; X = Cl, NO3). Single crystals were obtained by crystallization in gelatine gels in U‐tubes or test‐tubes. 2 and 4 were characterized by thermogravimetry and 4 was additionally characterized by temperature dependend in situ powder diffractometry. The structures of 1 , 2 , 3 and 4 were found to be isotypic and were solved by single‐crystal X‐ray methods: P 21/c, Z = 2 ( 1 : a = 645.4(2), b = 1050.1(2), c = 1283.3(3) pm, β = 104.66(3)°; 2 : a = 648.7(2), b = 1063.1(2), c = 1310.8(3) pm, β = 103.93(3)°; 3 : a = 643.3(2), b = 1049.0(2), c = 1286.7(3) pm, β = 104.28(3)°; 4 : a = 644.18(5), b = 1049.22(7), c = 1282.43(8) pm, β = 104.122(6)°). The structure is composed of MO6 octahedra and (PO2NH)44— anions. The P4N4 rings of the (PO2NH)44— anions exhibit a slightly distorted chair conformation, which is supported by IR data and has been described by torsion angles, Displacement Asymmetry Parameters and Puckering Parameters. Via M2+ ions and hydrogen bonds, the tetrametaphosphimate anions are connected forming layers perpendicular to [100]. These layers are connected by hydrogen bonds.  相似文献   

2.
Cd2(PO2NH)4 · 8H2O crystallizes in space group P21/c (no. 14), Z = 2, with a = 648.5(2), b = 1070.5(2), c = 1328.7(3) pm and β = 103.11(3) °. The structure, isotypic with M2(PO2NH)4 · 8H2O (M = Mg, Mn, Co, Ni, Zn), is composed of Cd2+ and (PO2NH)44? ions as well as crystal water molecules. The P4N4 rings of the (PO2NH)44? ions exhibit a slightly distorted chair‐2 conformation, which has been described by torsion angles, displacement asymmetry parameters and puckering parameters. The tetrametaphosphimate anions are connected forming layers. These layers are linked solely by hydrogen bonds, forming a three‐dimensional network.  相似文献   

3.
Ni2(PO2NH)4 · 8 H2O is isotypic with M2(PO2NH)4 · 8 H2O (M = Mg, Mn, Co, Zn) and crystallizes in the space group P21/c, Z = 2, with a = 641.25(1), b = 1041.42(1), c = 1278.18(2) pm and β = 104.243(1)°. The structure is composed of Ni2+ and (PO2NH)44? ions as well as crystal water molecules. The P4N4 rings of the (PO2NH)44? ions exhibit a slightly distorted chair–2 conformation, which has been described by torsion angles, displacement asymmetry parameters and puckering parameters. The tetrametaphosphimate anions are connected forming layers. These layers are linked solely by hydrogen bonds, forming a three‐dimensional network.  相似文献   

4.
Synthesis, Crystal Structure, and Properties of Tetrasodium Bis(trimetaphosphimato)cuprate(II) Decahydrate, Na4{Cu[(PO2NH)3]2} · 10 H2O Tetrasodium bis(trimetaphosphimato)cuprate(II) decahydrate, Na4{Cu[(PO2NH)3]2} · 10 H2O, was obtained by the reaction of an aqueous solution of Na3(PO2NH)3 · 4 H2O with Cu(NO3)2 · 3 H2O (molar ratio 2 : 1). The structure of Na4{Cu[(PO2NH)3]2} · 10 H2O ( 1 ) was solved by single‐crystal X‐ray methods (P 1, a = 912.51(6), b = 932.14(6), c = 966.10(6) pm, α = 94.840(5), β = 108.652(6), γ = 118.588(6)°, Z = 1). The P3N3 rings of the trimetaphosphimate ions exhibit a slightly distorted sofa conformation. The conformation of the anions have been analysed using torsion angles, displacement asymmetry parameters, and puckering parameters. The trimetaphosphimate ions act as bidentate ligands of Cu2+. With additionally coordinated water molecules, anionic complexes {Cu[(PO2NH)3]2 · 2 H2O}4– are formed. In the crystal these complexes are interconnected by N–H…O und O–H…O hydrogen bonds and they coordinate the Na+. Thus, a three‐dimensional network is formed.  相似文献   

5.
Synthesis and Crystal Structure of the Transition Metal Trimetaphosphimates Zn3[(PO2NH)3]2 · 14 H2O and Co3[(PO2NH)3]2 · 14 H2O The transition metal trimetaphosphimates Zn3[(PO2NH)3]2 · 14 H2O and Co3[(PO2NH)3]2 · 14 H2O were obtained by the reaction of an aqueous solution of Na3(PO2NH)3 · 4 H2O with the respective metal nitrate or halide (molar ratio 1 : 4). The structure of Zn3[(PO2NH)3]2 · 14 H2O was solved by single crystal X‐ray methods. The structure of isotypic Co3[(PO2NH)3]2 · 14 H2O was refined from X‐ray powder diffraction data using the Rietveld method (Zn3[(PO2NH)3]2 · 14 H2O ( 1 ): P 1, a = 743.7(2), b = 955.9(2), c = 980.1(2) pm, α = 102.70(3), β = 90.46(3), and γ = 100.12(3)°, Z = 1; Co3[(PO2NH)3]2 · 14 H2O ( 2 ): P 1, a = 746.05(1), b = 957.06(2), c = 988.51(2) pm, α = 102.162(1), β = 90.044(1), and γ = 99.258(1)°, Z = 1). In 1 and 2 the P3N3 rings of the trimetaphosphimate ions attain a conformation which can be described as a combination of an ideal boat and an ideal twist conformation. The trimetaphosphimate ions act as bridging ligands. Thus chains of alternating M2+ and (PO2NH)33– ions are formed which are interconnected by additional M2+ ions forming electro‐neutral double chains. In the solid these double chains are connected by hydrogen bonds.  相似文献   

6.
Synthesis, Structure, and Properties of Three Tetrasodium Tetrametaphosphimate Hydrates Single crystals of three tetrasodium tetrametaphosphimate hydrates Na4(PO2NH)4 · x H2O with x = 2 and 3, respectively, have been obtained and characterized by single crystal X-ray diffraction. Dimorphous Na4(PO2NH)4 · 3 H2O is formed at RT. It crystallizes monoclinic ( 1 ) or triclinic ( 2 ) (α-Na4(PO2NH)4 · 3 H2O ( 1 ): P21, a = 1002.7(2), b = 1189.7(2), c=1193.1(2)pm, β=104.93(1)°, Z=4; β-Na4(PO2NH)4 · 3 H2O ( 2 ): P 1¯, a = 843.64(9), b = 848.54(10), c = 994.7(2) pm, α = 83.07(1), β = 76.31(1), γ = 87.46(1)°, Z = 2). Compound 2 is formed in the presence of NaCl during the crystallization from aqueous solution. Tetrasodium tetrametaphosphimate dihydrate ( 3 ) is formed at 60 °C (Na4(PO2NH)4 · 2 H2O ( 3 ): C2/c, a = 2225.6(3), b = 513.0(1), c = 1566.7(2) pm, β = 134.21(1)°, Z = 4). In 1 and 2 the P4N4 ring of the tetrametaphosphimate ions attains a saddle and in 3 a twistboat conformation. The conformations of the anions have been analysed using torsion angles, displacement asymmetry parameters, and puckering parameters. The (PO2NH)44– rings of the compounds 1 , 2 , and 3 are linked by N–H · · &mid  相似文献   

7.
The reactions of Ln(NO3)3 · 6H2O and 4‐acetamidobenzoic acid (Haba) with 4,4′‐bipyridine (4,4′‐bpy) in ethanol solution resulted in three new lanthanide coordination polymers, namely {[Ln(aba)3(H2O)2] · 0.5(4,4′‐bpy) · 2H2O} [Ln = Sm ( 1 ), Gd ( 2 ), and Er ( 3 ), aba = 4‐acetamidobenzoate]. Compounds 1 – 3 are isomorphous and have one‐dimensional chains bridged by four aba anions. 4,4′‐Bipyridine molecules don’t take part in the coordination with LnIII ions and occur in the lattice as guest molecules. Moreover, the adjacent 1D chains in the complex are further linked through numerous N–H ··· O and O–H ··· O hydrogen bonds to form a 3D supramolecular network. In addition, complex 1 in the solid state shows characteristic emission in the visible region at room temperature.  相似文献   

8.
In the title compound, disodium cobalt tetrakis­(dihydrogen­phosphate) tetrahydrate, the CoII ion lies on an inversion centre and is octahedrally surrounded by two water molecules and four H2PO4 groups to give a cobalt complex anion of the form [Co(H2PO4)4(OH2)]2?. The three‐dimensional framework results from hydrogen bonding between the anions. The relationship with the structures of Co(H2PO4)2·2H2O and K2CoP4O12·5H2O is discussed.  相似文献   

9.
The crystal structures of acetonitrile solvates of two related lithium calixarene complexes have been determined by low‐temperature single‐crystal X‐ray diffraction using synchrotron radiation. Bis(μ‐5,11,17,23‐tetra‐tert‐butyl‐26,28‐dihydroxy‐25‐methoxy‐27‐oxidocalix[4]arene)dilithium(I) acetonitrile tetrasolvate, [Li2(C45H57O4)2]·4C2H3N or [p‐tert‐butylcalix[4]arene(OMe)(OH)2(OLi)]2·4MeCN, (I), crystallizes with the complex across a centre of symmetry and with four molecules of unbound acetonitrile of crystallization per complex. Tetraacetonitrilebis(μ‐5,11,17,23‐tetra‐tert‐butyl‐26,28‐dihydroxy‐25,27‐dioxidocalix[4]arene)tetralithium(I) acetonitrile octasolvate, [Li4(C44H54O4)2(C2H3N)4]·8C2H3N or {p‐tert‐butylcalix[4]arene(OH)2(OLi)[OLi(NCMe)2]}2·8MeCN, (II), also crystallizes with the complex lying across a centre of symmetry and contains eight molecules of unbound acetonitrile per complex plus four more directly bound to two of the lithium ions, two on each ion. The cores of both complexes are partially supported by O—H...O hydrogen bonds. The methoxy methyl groups in (I) prevent the binding of any more than two Li+ ions, while the corresponding two O‐atom sites in (II) bind an extra Li+ ion each, making four in total. The calixarene cone adopts an undistorted cone conformation in (I), but an elliptical one in (II).  相似文献   

10.
Three new metal–nitroxide complexes {[Ni(NIT4Py)2(obb)(H2O)2] · 1.5H2O}n ( 1 ), {[Co(NIT4Py)2(obb)(H2O)2] · 2H2O}n ( 2 ), and [Co(IM4Py)2(obb)2(H2O)2][Co(IM4Py)2(H2O)4] · 10H2O ( 3 ) with the V‐shaped 4,4′‐oxybis(benzoate) [NIT4Py = 2‐(4′‐pyridyl)‐4,4,5,5‐tetramethylimidazoline‐1‐oxyl‐3‐oxide, IM4Py = 2‐(4′‐pyridyl)‐4,4,5,5‐tetramethylimidazoline‐1‐oxide, and obb = 4, 4′‐oxybis(benzoate) anion] were synthesized and structurally characterized. Single‐crystal X‐ray analyses indicate that complexes 1 and 2 crystallize in neutral one‐dimensional (1D) zigzag chains, in which the nitroxide–metal–nitroxide units are linked by the V‐shaped 4,4′‐oxybis(benzoate) anions, whereas complex 3 consists of isolated mononuclear [Co(IM4Py)2(obb)2(H2O)2]2– anions and [Co(IM4Py)2(H2O)4]2+ ions. Magnetic measurements show that complexes 1 and 2 both exhibit weak antiferromagnetic interactions between the metal ions and the nitroxides.  相似文献   

11.
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) Å3, 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) Å3, 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.  相似文献   

12.
Investigations on the Crystal Structure of Lithium Dodecahydro‐closo‐dodecaborate from Aqueous Solution: Li2(H2O)7[B12H12] By neutralization of an aqueous solution of the acid (H3O)2[B12H12] with lithium hydroxide (LiOH) and subsequent isothermic evaporation of the resulting solution to dryness, it was possible to obtain the heptahydrate of lithium dodecahydro‐closo‐dodecaborate Li2[B12H12] · 7 H2O (≡ Li2(H2O)7[B12H12]). Its structure has been determined from X‐ray single crystal data at room temperature. The compound crystallizes as colourless, lath‐shaped, deliquescent crystals in the orthorhombic space group Cmcm with the lattice constants a = 1215.18(7), b = 934.31(5), c = 1444.03(9) pm and four formula units in the unit cell. The crystal structure of Li2(H2O)7[B12H12] can not be described as a simple AB2‐structure type. Instead it forms a layer‐like structure analogous to the well‐known barium compound Ba(H2O)6[B12H12]. Characteristic feature is the formation of isolated cation pairs [Li2(H2O)7]2+ in which the water molecules form two [Li(H2O)4]+ tetrahedra with eclipsed conformation, linked to a dimer via a common corner. The bridging oxygen atom (∢(Li‐ O ‐Li) = 112°) thereby formally substitutes Ba2+ in Ba(H2O)6[B12H12] according to (H2 O )Li2(H2O)6[B12H12]. A direct coordinative influence of the [B12H12]2— cluster anions to the Li+ cations is not noticeable, however. The positions of the hydrogen atoms of both the water molecules and the [B12H12]2— units have all been localized. In addition, the formation of B‐Hδ—···δ+H‐O‐hydrogen bonds between the water molecules and the hydrogen atoms from the anionic [B12H12]2— clusters is considered and their range and strength is discussed. The dehydratation of the heptahydrate has been investigated by DTA‐TG measurements and shown to take place in two steps at 56 and 151 °C, respectively. Thermal treatment leads to the anhydrous lithium dodecahydro‐closo‐dodecaborate Li2[B12H12], eventually.  相似文献   

13.
The structures of the LiI and NaI salts of 2‐thiobarbituric acid (2‐sulfanylidene‐1‐3‐diazinane‐4,6‐dione, H2TBA) have been studied. μ‐Aqua‐octaaquabis(μ‐2‐thiobarbiturato‐κ2O:O′)bis(2‐thiobarbiturato‐κO)tetralithium(I) dihydrate, [Li4(C4H3N2O2S)4(H2O)9]·2H2O, (I), crystallizes with four symmetry‐independent four‐coordinated LiI cations and four independent HTBA anions. The structure contains two structurally non‐equivalent LiI cations and two non‐equivalent HTBA anions (bridging and terminal). Eight of the coordinated water ligands are terminal and the ninth acts as a bridge between LiI cations. Discrete [Li4(HTBA)4(H2O)9]·2H2O complexes form two‐dimensional layers. Neighbouring layers are connected via hydrogen‐bonding interactions, resulting in a three‐dimensional network. Poly[μ2‐aqua‐tetraaqua(μ4‐2‐thiobarbiturato‐κ4O:O:S:S)(μ2‐thiobarbiturato‐κ2O:S)disodium(I)], [Na2(C4H3N2O2S)2(H2O)5]n, (II), crystallizes with six‐coordinated NaI cations. The octahedra are pairwise connected through edge‐sharing by a water O atom and an O atom from the μ4‐HTBA ligand, and these pairs are further top‐shared by the S atoms to form continuous chains along the a direction. Two independent HTBA ligands integrate the chains to give a three‐dimensional network.  相似文献   

14.
Pseudo‐Isomerism by Different Jahn‐Teller Ordering: Crystal Structures of the Hemihydrate and the Monohydrate of (pyH)[MnF(H2PO4)(HPO4)] With pyridinium counter cations (pyH+) the MnIII fluoride phosphate anion [MnF(H2PO4)(HPO4)] can be stabilized. It forms a chain structure with Mn3+ ions bridged by a fluoride ion and two bidentate phosphate groups. Under sleightly differing conditions either the hemihydrate (pyH)[MnF(H2PO4)(HPO4)]·0.5H2O ( 1 ) or the monohydrate (pyH)[MnF(H2PO4)(HPO4)]·H2O ( 2 ) is formed. The hemihydrate 1 crystallizes monoclinic in space group P21/n, Z = 8, a = 7.295(1), b = 17.052(2), c = 18.512(3) Å, β = 100.78(1)°, R = 0.033, the monohydrate triclinic in space group P1¯, Z = 2, a = 7.374(1), b = 8.628(1), c = 10.329(1) Å, α = 83.658(8)°, β = 77.833(9)°, γ = 68.544(8)°, R = 0.025. Whereas the topology of the chain anions is identical in both structures, the Jahn‐Teller effect is expressed in different ordering patterns: in 1 antiferrodistortive ordering of [MnF2O4] octahedra is observed, with alternating elongation of an F—Mn—F‐axis or a O—Mn—O‐axis, respectively. This leads to asymmetrical Mn—F—Mn‐bridges. In 2 ferrodistortive ordering is found, with elongation of all octahedra along the F—Mn—F‐axis. Thus, symmetrical bridges are formed with long Mn—F distances. This unusual pseudo‐isomerism is attributed to the differing influence of inter‐chain hydrogen bonds.  相似文献   

15.
Metal Salts of Benzene‐1, 2‐di(sulfonyl)amine. 9. The Barium Complex [[Ba{C6H4(SO2)2N}2(H2O)22]: A Columnar Coordination Polymer with Lamellar Crystal Packing The title complex, obtained by treating ortho‐benzenedi‐sulfonimide with Ba(OH)2 in aqueous solution, has been characterized by low‐temperature X‐ray diffraction (monoclinic, space group C2/c, Z = 4, Ba2+ on a crystallographic twofold axis). The cation attains a tenfold coordination by accepting bonds from two water molecules, four κ1O‐bonding anions and two (O, N)‐chelating anions. The cation‐anion interactions create columnar strands parallel to the z axis, from which protrude twin stacks of benzo rings in the directions ±x, and water molecules and non‐coordinating sulfonyl oxygen atoms in the directions ±y. Adjacent strands related by translation parallel to y are associated via O(W)—H···O=S hydrogen bonds to form lamellar sandwich layers. The contiguous benzo rings of adjacent layers are markedly interlocked.  相似文献   

16.
The novel tetrameric gadolinium(III) compound [Gd4(OH)4(CF3COO)8(H2O)4] · 2.5 H2O was synthesized and structurally characterized by X‐ray crystallography. The Gd3+ ions are bridged by hydroxide ions and carboxylate groups to tetramers with Gd3+‐Gd3+ distances between 384.2(2) and 388.1(2) pm. The compound crystallizes in the monoclinic space group C2/c (Z = 4). The magnetic behaviour of [Gd4(OH)4(CF3COO)8(H2O)4] · 2.5 H2O was investigated in the temperature range of 2 to 300 K. The magnetic data of this compound indicate antiferromagnetic interactions (Jex = ?0.0197 cm?1).  相似文献   

17.
Benzene 1,2,4,5‐tetrasulfonic acid (H4B4S) was prepared in two steps starting from 1,2,4,5‐Tetrachlorobenzene. Slow evaporation of an aqueous reaction mixture of H4B4S and Cu2(OH)2(CO3) led to light green single crystals of [Cu2(B4S)(H2O)8] · 0.5H2O. X‐ray single crystal investigations revealed the compound to be triclinic [P , Z = 1, a = 710.0(1), b = 713.7(1), c = 1077.1(2) pm, α = 98.41(2)°, β = 102.91(2)°, γ = 100.69(2)°]. In the crystal structure the Cu2+ ions are coordinated by four water molecules and two monodentate sulfonate anions yielding a tetragonally distorted [CuO6] octahedron. The anions are connected to further copper ions leading to ladder shaped chains running along the [100] direction. According to DTA/TG investigations the dehydration of the compound is finished at 240 °C and the decomposition of the anhydrous sulfonate starts at 340 °C.  相似文献   

18.
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 C4S42? ions with almost undistorted D4h 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, C4S42? 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.  相似文献   

19.
Structure and 1D‐magnetic properties of (pipzH2)[MnF4(H2PO4)] From hydrofluoric and phosphoric acid solution of Manganese(III), using piperazinium(2+) counter cations (pipzH22+) the chain‐anion [MnF4(H2PO4)]2— can be stabilized providing an interesting model system for studying the magnetic exchange interaction via phosphate bridges. Depending on the HF/H3PO4 excess (pipzH2)[MnF4(H2PO4)] crystallizes in two polymorphs I und II , differing mainly in the orientation of the cations. Form I is monoclinic, space group P21/c, Z = 4, a = 6.749(1), b = 12.039(1), c = 12.501(1) Å, β = 94.420(4)°, R = 0.023, Form II crystallizes in the same space group type P21/c, Z = 4, a = 6.651(1), b = 12.799(1), c = 12.825(1) Å, β = 110.312(5)°, R = 0.037. The Mn3+ ions are octahedrally surrounded by four terminal fluoride ligands and axially by bidentate bridging dihydrogenphosphate groups. The shape of the chain anions is very close in both modifications and characteristic for ferrodistortive Jahn‐Teller ordering.The Mn—O‐bonds along the chain direction are strongly elongated (distances 2.16 to 2.21 Å) whereas all Mn—F bond (1.81—1.88Å) are ruther short. On a large single crystal of form I 1D‐antiferromagnetic properties were found. By fitting an appropriate model based on the temperature dependence of the correlation lengths using an anisotropy constant D/k = —2.9 K a remarkably high exchange energy of J/k = —1.6(1) K along the chains could be determined.  相似文献   

20.
Structures and Thermal Behaviour of Alkali Metal Dihydrogen Phosphate HF Adducts, MH2PO4 · HF (M = K, Rb, Cs), with Hydrogen Bonds of the F–H…O Type Three HF adducts of alkali metal dihydrogen phosphates, MH2PO4 · HF (M = K, Rb, Cs), have been isolated from fluoroacidic solutions of MH2PO4. KH2PO4 · HF crystallizes monoclinic: P21/c, a = 6,459(2), b = 7,572(2), c = 9,457(3) Å, β = 101,35(3)°, V = 453,5(3) Å3, Z = 4. RbH2PO4 · HF and CsH2PO4 · HF are orthorhombic: Pna21, a = 9,055(3), b = 4,635(2), c = 11,908(4) Å, V = 499,8(3) Å3, Z = 4, and Pbca, a = 7,859(3), b = 9,519(4), c = 14,744(5) Å, V = 1102,5(7) Å3, Z = 8, respectively. The crystal structures of MH2PO4 · HF contain M+ cations, H2PO4 anions and neutral HF molecules. The H2PO4 anions are connected to layers by O–H…O hydrogen bonds (2,53–2,63 Å), whereas the HF molecules are attached to the layers via very short hydrogen bonds of the F‐H…O type (2,36–2,38 Å). The thermal decomposition of the adducts proceeds in three steps. The first step corresponds to the release of mainly HF and a smaller quantity of water. In the second and third steps, water evolution caused by condensation of dihydrogen phosphate is the dominating process whereas smaller amounts of HF are also released.  相似文献   

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