Nuclear and magnetic structures and magnetic properties of synthetic brochantite, Cu4(OH)6SO4

Cu4(OH)6SO4 (1) and Cu4(OD)6SO4 (2) were obtained by hydrothermal syntheses from copper sulfate and sodium hydroxide in H2O and D2O, respectively. They crystallize in the monoclinic system, space group P2(1)/a (14), a = 13.1206(5), b = 9.8551(3), c = 6.0295(2) Angstroms, beta = 103.432(3) degrees, V = 758.3(1) Angstroms(3), Z = 4 and a = 13.1187(5), b = 9.8552(3), c = 6.0293(2) Angstroms, beta = 103.410(3) degrees, V = 758.3(1) Angstroms(3), Z = 4, respectively. They are iso-structural to the mineral brochantite and consist of double chains of edge-sharing copper octahedra that are connected to one another by corners to form corrugated planes along bc; these planes are in-turn bridged by the unprecedented mu7-sulfate tetrahedra to give a 3D-structure. All the hydrogen atoms were precisely located from refinement of the neutron powder diffraction data of the deuterated sample. Magnetic susceptibility data reveal a low-dimensional behavior at high temperature and the presence of both ferromagnetic and antiferromagnetic super-exchanges resulting in a 3D long-range antiferromagnetic ordering at 7.5 K accompanied by a small canting of the moments. The transition is confirmed by a lambda-peak in the specific heat. The magnetic structure at 1.4 K shows the moments are oriented perpendicular to the corrugated planes with alternation along +/-a for neighboring chains within the double chains. The enhanced incoherent scattering at low-angle suggests the existence of short-range ferromagnetic clusters.     

Synthesis, nuclear, and magnetic structures and magnetic properties of [Mn3(OH)2(SO4)2(H2O)2

[Mn(3)(OH)(2)(SO(4))(2)(H(2)O)(2)] and its deuterated analogue were synthesized by a hydrothermal technique and characterized by differential thermal analysis, thermogravimetric analysis, and IR spectroscopy. Its nuclear structure, determined by single-crystal X-ray analysis and Rietveld analysis of neutron powder-diffraction data, consists of a 3D network of chains of edge-sharing Mn(1)O(6), running along the c axis, connected by the apices of Mn(2)O(6) and SO(4) units. It is isostructural to the nickel analogue. Determination of the magnetic structure and measurements of magnetization and heat capacity indicate the coexistence of both magnetic long-range ordering (LRO) and short-range ordering (SRO) below a Néel temperature of 26 K, while the SRO is retained at higher temperatures. The moments of the two independent Mn atoms lie in the bc plane, and that of Mn(1) rotates continuously by 54 degrees towards the c axis on decreasing the temperature from 25 to 1.4 K. While the SRO may be associated with frustration of the moments within a Mn(3) trimer, the LRO is achieved by antiparallel alignment of the four symmetry-related trimers within the magnetic unit cell. A spin-flop field, measured by dc and ac magnetization on a SQUID, is observed at 15 kOe.     

Co(II)5(OH)6(SO4)2(H2O)4: the first ferromagnet based on a layered cobalt-hydroxide pillared by inorganic...OSO3-Co(H2O)4-O3SO..

The synthetic mineral Co(II)5(OH)6(SO4)2(H2O)4 (1), obtained by hydrothermal reaction of CoSO4.7H2O and NaOH at 165 degrees C and consisting of brucite-like Co4(OH)6O2 layers pillared by OSO3-Co(H2O)4-O3SO, is a ferromagnet (T(Curie)= 12 K, Hc= 580 Oe).     

The synthesis and characterization of neptunium hydroxysulfate,Np(OH)2SO4

Neptunium (IV) hydroxysulfate, Np(OH)₂SO₄, was synthesized using hydrothermal techniques. The X-ray powder diffraction pattern indicates that the compound is isomorphous with the Th(IV) and U(IV) analogs. Cell constants for the three compounds clearly show the effects of the actinide contraction. Visible and near-ir spectra are consistent with the presence of Np(IV) and are compared to spectra of Np(IV) in acidic solution. The ir spectrum contains bands which are assigned to the hydroxy and sulfate groups.     

Structure and magnetic properties of layered high-spin Co(II)(l-threonine)2(H2O)2

We report the structure and the magnetic properties of a cobalt(II) compound with the amino acid l-threonine, Co(C(4)H(8)NO(3))(2)(H(2)O)(2). It crystallizes in the orthorhombic chiral space group C222(1), with a = 5.843(5) A, b = 10.120(10) A, c = 22.36(3) A, and Z = 4. The Co(II) ion is in a deformed octahedral environment on a 2-fold symmetry axis parallel to the crystallographic axis b. It is bonded to two threonine molecules in a bidentate fashion, via one oxygen from the carboxylate end and the alpha-amino nitrogen. A water molecule occupies the third independent site. The Co(II) ions are arranged in layers with intralayer and interlayer distances of 5.84 and 11.18 A, respectively. Magnetic measurements data reflect the molecular character of a compound with weak exchange interactions. EPR measurements in polycrystalline and single-crystal samples indicate a distorted axial symmetry around the Co(II) ion, as expected from the structural results. Eigenvalues and eigenvectors of the g tensor are determined. The measured principal g values (5.81, 4.56, and 2.23) reflect a high-spin Co(II) ion, as suggested by the type of ligands and the molecular symmetry. From the incomplete collapse of the hyperfine structure we estimate 0.25 < |J| < 1.2 cm(-1) between neighboring Co(II) ions within a layer, transmitted through H-bonds. A higher limit |J'| < 0.07 cm(-1) is estimated for the exchange interactions between Co(II) ions in neighboring layers. From a global fit of a spin Hamiltonian with spin (3)/(2) to magnetization and EPR data we obtain a zero field splitting delta approximately 231 cm(-1) between the two lowest doublet states. The results are discussed in terms of the molecular and electronic structure of the compound.     

Hydrothermal synthesis in the system Ni(OH)(2)-NiSO(4): nuclear and magnetic structures and magnetic properties of Ni(3)(OH)(2)(SO(4))(2)(H(2)O)(2)

We present the synthesis, characterization by DT-TGA and IR, single crystal X-ray nuclear structure at 300 K, nuclear and magnetic structure from neutron powder diffraction on a deuterated sample at 1.4 K, and magnetic properties as a function of temperature and magnetic field of Ni(3)(OH)(2)(SO(4))(2)(H(2)O)(2). The structure is formed of chains, parallel to the c-axis, of edge-sharing Ni(1)O(6) octahedra, connected by the corners of Ni(2)O(6) octahedra to form corrugated sheets along the bc-plane. The sheets are connected to one another by the sulfate groups to form the 3D network. The magnetic properties measured by ac and dc magnetization, isothermal magnetization at 2 K, and heat capacity are characterized by a transition from a paramagnet (C = 3.954 emu K/mol and theta = -31 K) to a canted antiferromagnet at T(N) = 29 K with an estimated canting angle of 0.2-0.3 degrees. Deduced from powder neutron diffraction data, the magnetic structure is modeled by alternate pairs of Ni(1) within a chain having their moments pointing along [010] and [010], respectively. The moments of Ni(2) atoms are oppositely oriented with respect to their adjacent pairs. The resulting structure is that of a compensated arrangement of moments within one layer, comprising one ferromagnetic and three antiferromagnetic superexchange pathways between the nickel atoms.     

A new organic-inorganic hybrid layered molybdenum(V) cobalt phosphate constructed from [H24(Mo16O32)Co16(PO4)24(OH)4(C5H4N)2(H2O)6](4-) wheels and 4,4'-bipyridine linkers

A new layered molybdenum cobalt phosphate, Na(2)[Co(H(2)O)(6)][(Mo(16)O(32))Co(16)(PO(4))(4) (HPO(4))(16)(H(2)PO(4))(4)(OH)(4)(C(10)H(8)N(2))(4)(C(5)H(4)N)(2)(H(2)O)(6)]·4H(2)O (1), has been hydrothermally synthesized and structurally characterized. 1 crystallizes in the monoclinic space group P2(1)/n with a = 15.6825(18) ?, b = 39.503(4) ?, c = 17.2763(17) ?, β = 93.791(2)°, V = 10679.4(18) ?(3), and Z = 2. A polyoxoanion of 1 exhibits an unusual organic-inorganic hybrid wheel-type cluster, in which two pyridine ligands link to the surface Co(II) atoms of a [H(24)(Mo(16)O(32))Co(16)(PO(4))(24)(OH)(4)(H(2)O)(6)] (namely, {Mo(16)Co(16)P(24)}) wheel via the Co-N bonds. Furthermore, each {Mo(16)Co(16)P(24)} wheel is connected to four adjacent wheels by four pairs of 4,4'-bipyridine linkers, forming a 2D layered network. The susceptibility measurement shows the existence of dominant antiferromagnetic interactions in 1.     

On the thermal decomposition of Zn(NO3)2·6H2O and its deuterated analogue

The thermal dehydration and decomposition of Zn(NO₃)₂·6H₂O (I) were studied via DTA, TG and DSC, quantitative analysis and IR spectroscopy, and compared with those of Zn(NO₃)₂·6D₂O (II). The following phase transitions were observed: melting of the salts; partial dehydration to tetrahydrate; formation of basic nitrate-hydrate; and formation of ZnO.The sum of the enthalpies of dehydration and thermal decomposition for I was 286 kJ/mol, while that for II was 299 kJ/mol (data from DSC). The probable mechanisms were determined from the TG curves and the formal kinetic parameters were calculated for the two stages of thermal decomposition. Calculations with an equation of the accelerating-type exponential law gave for the formation of basic zinc nitrate-hydrateE ^*=59 kJ/mol for I andE ^*=64 kJ/mol for II. For the decomposition of the basic salt, the equation for bidimentional diffusion yieldedE ^*=127 kJ/mol for I andE ^*=138 kJ/mol for II.

---

Zusammenfassung Mittels DTA, TG, DSC, Elementaranalyse und IR-Spektroskopie wurde die thermische Dehydratation und Zersetzung von Zn(NO₃)₂ · 6H₂O (I) untersucht und mit der von Zn(NO₃)₂· 6D₂O (II) verglichen. Folgende Phasenumwandlungen konnten beobachtet werden: Schmelzen des Salzes; teilweise Dehydratation zu Tetrahydrat; Bildung von basischem Nitrathydrat; und Bildung von ZnO. Die Summe der Enthalpien für Dehydratation und Zersetzung betrug für I 286 kJ/mol und für II 299 kJ/mol (berechnet aus DSC). Die wahrscheinlichen Mechanismen wurden auf Grundlage der TG-Kurven festgelegt und die formalen kinetischen Parameter für die zwei Schritte der thermischen Zersetzung berechnet. Berechnungen ergaben für die Bildung des basischen ZinknitrathydratesE _m ^* =59 kJ/mol bei I undE ^*=64 kJ/mol für II. Für die Zersetzung des basischen Salzes lieferte eine Gleichung für zweidimensionale DiffusionE ^*=127 kJ/mol für I undE ^*=138 kJ/mol für II.

---

, , , (I). (II). ; , , - . , I 286 · ^–1, II 299 · ^–1. , . , , ^* I - 59 · ^–1, II- 64 · ^–1. ^* , , I II, , 127 138 · ^–1.

     

Syntheses, structures, ionic conductivities, and magnetic properties of three new transition-metal borophosphates Na5(H3O){M(II)3[B3O3(OH)]3(PO4)6}.2H2O (M(II) = Mn, Co, Ni)

Three new open-framework transition-metal borophosphates Na5(H3O){M(II)3[B3O3(OH)]3(PO4)6}.2H2O (M(II) = Mn, Co, Ni) (denoted as MBPO-CJ25) have been synthesized under mild hydrothermal conditions. Single-crystal X-ray diffraction analyses reveal that the three compounds possess isostructural three-dimensional (3D) open frameworks with one-dimensional 12-ring channels along the [001] direction. Notably, the structure can also be viewed as composed of metal phosphate layers [M(II)(PO4)2]4- with Kagomé topology, which are further connected by [B3O7(OH)] triborates, giving rise to a 3D open framework. The guest water molecules locate in the 12-ring channels. Partial Na+ ions reside in the 10-ring side pockets within the wall of the 12-ring channels, and the other Na+ ions and protonated water molecules locate in the 6-ring windows delimited by MO6 and PO4 polyhedra to compensate for the negative charges of the anionic framework. These compounds show a high thermal stability and are stable upon calcinations at ca. 500 degrees C. Ionic conductivities, due to the motion of Na+ ions, are measured for these three compounds. They have similar activation energies of 1.13-1.25 eV and conductivities of 2.7 x 10(-7)-9.9 x 10(-7) S cm(-1) at 300 degrees C. Magnetic measurements reveal that there are very weak antiferromagnetic interactions among the metal centers of the three compounds. Crystal data: MnBPO-CJ25, hexagonal, P6(3)/m (No. 176), a = 11.9683(5) A, c = 12.1303(6) A, and Z = 2; CoBPO-CJ25, hexagonal, P6(3)/m (No. 176), a = 11.7691(15) A, c = 12.112(2) A, and Z = 2; NiBPO-CJ25, hexagonal, P6(3)/m (No. 176), a = 11.7171(5) A, c = 12.0759(7) A, and Z = 2.     

Die Kristallstruktur von Dikalium-trikobalt(II)-dihydroxid-trisulfat-dihydrat,K2Co3(OH)2(SO4)3·2H2O

Crystals of K₂Co₃(OH)₂(SO₄)₃·2H₂O were synthesized under hydrothermal conditions. The crystal structure [a=17.945 (4) Å,b=7.557 (2) Å,c=9.760 (3) Å, space group Cmc2₁,Z=4] was determined by direct methods and refined with single crystal X-ray data. The H atoms were located byFourier syntheses. Their structural parameters were refined, too. The finalR-values areR=0.025 andR _w =0.028 (w=1/) for 612 reflections withF ₀>3 (F ₀). Both Co(II) atoms are octahedral six coordinated and form zigzag chains running parallel [001]. These chains are connected via sulfate groups to built up sheets parallel (100). The KO₉ polyhedron and one of the four hydrogen bonds link these sheets.

     

Die Kristallstruktur von Trikobalt(II)-dihydroxidsulfat-dihydrat,Co3(OH)2(SO4)2 · 2 H2O

Tricobalt (II)-dihydroxidesulfate-dihydrate, Co₃(OH)₂(SO₄)₂ · 2H₂O, is orthorhombic: a = 7.21, b = 9.77, c = 12.86 Å, V = 905.9 ų, space group D-Pbcm with four formula units per cell. The atomic positions have been determined by threedimensional Patterson and Fourier synthesis and full-matrix least-squares refinement of single crystal X-ray diffraction data. The structure shows infinite chains [001] of Co? O octahedra sharing one edge with each other. These chains are linked together by alternating SO₄ tetrahedra and additional Co? O octahedra, thus giving rise to a three-dimensional network of polyhedra. There is no similarity to the well known layer structures of most hydroxide salts of divalent metals. The SO₄ tetrahedra are regular while the Co? O octahedra show considerable distortion. The water molecule is coordinated to one Co atom and bonded to sulfate oxygen by two weak hydrogen bridges.     

The thermal dehydration,decomposition and kinetics of Mn(NO3)2 · 6H2O and its deuterated analogue

The processes of thermal dehydration and decomposition of Mn(NO₃)2 ·.6H₂O and its deuterated analogue were studied by DTA, TG and DSC. Comparisons were made between the data obtained for the two compounds. The following phase transitions were observed: melting of the compound; dehydration to monohydrate; dehydration of the monohydrate, accompanied by its partial decomposition to MnO₂; and decomposition of the anhydrous nitrate to MnO₂.The DSC data were used to determine the enthalpies of the phase transitions, and those corresponding to the partial dehydration were compared with the calculated ones. The formal kinetic parameters (E ^* andA) for the three stages (without the melting stage) were calculated from the TG curves, and the corresponding kinetic equations are reported.

---

Zusammenfassung Mittels DTA, TG und DSC wurde der Verlauf der thermischen Dehydratation und Zersetzung von deuteriertem und undeuteriertem Mn(NO₃)₂·6H₂O untersucht und die erhaltenen Ergebnisse beider Verbindungen miteinander verglichen. Folgende Phasenumwandlungen konnten beobachtet werden: Schmelzen der Verbindung; Dehydratation bis zum Monohydrat; Dehydratation des Monohydrates unter teilweiser Zersetzung zu MnO₂; Zersetzung von wasserfreiem Nitrat zu MnO₂. DSC-Daten wurden zur Bestimmung der Enthalpien für die Phasenumwandlungen benutzt, die so ermittelten Ergebnisse für die partielle Dehydratation wurden mit den berechneten verglichen. Anhand der TG-Kurven wurden die formellen kinetischen Parameter (E ^* undA) der drei Schritte (ohne Schmelzvorgang) berechnet und die entsprechenden kinetischen Gleichungen beschrieben.

     

Triethylenetetramine(3-sulfinatopropanoato-O,S)cobalt(III) isomers: Synthesis and structure of α-cis-[Co(Trien)(O2CC2H4SO2)]ClO4 · 2H2O and β-cis-[Co(Trien)(O2CC2H4SO2)]ClO4

The α-cis-and β-cis-isomers of (triethylenetetramine)(3-sulfinatopropanoato-O,S)cobalt(III) cation were synthesized and crystal structures of their perchlorates were established. The 3-sulfinatopropanoate anion, which forms six-membered ring with the Co atom, is bonded to the latter through the S atom and the carboxyl O atom.     

On the thermal decomposition of [Ni(H2O)6](NO3)2 and its deuterated analogue

The methods of TG, DTA and DSC were used to study the thermal decompositions of [Ni(H₂O)₆](NO₃)₂ and [Ni(D₂O)₆](NO₃)₂ in an atmospheric air medium. Intermediates were isolated at 145, 230 and 245°, and were identified by quantitative analysis and IR spectroscopy. The following phase transitions were observed under the conditions of the experiment: melting of the salts, partial dehydration to the tetrahydrate, formation of basic nickel nitrate hydrate stable within a narrow temperature interval, and formation of NiO.

---

Zusammenfassung Mittels TG, DTA und DSC wurde die thermische Zersetzung von [Ni(H₂O)₆](NO₃)₂ und [Ni(D₂O)₆](NO₃)₂ in Luft untersucht. Bei Temperaturen von T=145°C, 230°C un 245°C konnten Intermediäre festgestellt werden, welche mittels quantitativer Analyse und IR-Spektroskopie identifiziert wurden. Unter den gegebenen experimentellen Bedingungen wurden folgende Phasenumwandlungen beobachtet: Schmelzen der Salze, partielle Dehydratation zu Tetrahydrat, Bildung von basishem Nickelnitrat-hydrat (stabil innerhalb eines schmalen Temperaturintervalles), schließliche Bildung von NiO.Aus den DSC-Daten wurden die Enthalpien der Phasenumwaldungen berechnet. DTA- und DSC-Daten zeigen, daß die Phasenunwandlungen bei [Ni(H₂O)₆](NO₃)₂ bei etwas niedrigeren Temperaturen liegen als bei [Ni(D₂O)₆](NO₃)₂.

     

Co(en)3[B4O5(OH)4]Cl·3H2O和[Ni(en)3][B5O6(OH)4]2·2H2O的合成、结构以及热力学性质

利用水热法合成了两种过渡金属配合物为模板剂的含水硼酸盐晶体Co(en)3[B4O5(OH)4]Cl·3H2O(1) 和 [Ni(en)3][B5O6(OH)4]2·2H2O (2),并通过元素分析、X射线单晶衍射、红外光谱及热重分析对其进行了表征。化合物1晶体结构的主要特点是在所有组成Co(en)33+, [B4O5(OH)4]2–, Cl– 和 H2O之间通过O–H…O、O–H…Cl、N–H…Cl和N–H…O四种氢键连接形成网状超分子结构。化合物2晶体结构的特点是[B5O6(OH)4]–阴离子通过O–H…O氢键连接形成沿a方向有较大通道的三维超分子骨架,模板剂[Ni(en)3]2+阳离子和结晶水分子填充在通道中。     

Thermal decomposition of hydronium jarosite (H3O)Fe3(SO4)2(OH)6

Thermogravimetry combined with mass spectrometry has been used to study the thermal decomposition of a synthetic hydronium jarosite. Five mass loss steps are observed at 262, 294, 385, 557 and 619°C. The mass loss step at 557°C is sharp and marks a sharp loss of sulphate as SO₃ from the hydronium jarosite. Mass spectrometry through evolved gases confirms the first three mass loss steps to dehydroxylation, the fourth to a mass loss of the hydrated proton and a sulphate and the final step to the loss of the remaining sulphate. Changes in the molecular structure of the hydronium jarosite were followed by infrared emission spectroscopy. This technique allows the infrared spectrum at the elevated temperatures to be obtained. Infrared emission spectroscopy confirms the dehydroxylation has taken place by 400 and the sulphate loss by 650°C. Jarosites are a group of minerals formed in evaporite deposits and form a component of the efflorescence. The minerals can function as cation and heavy metal collectors. Hydronium jarosite has the potential to act as a cation collector by the replacement of the proton with a heavy metal cation.