Ni Distance Research Articles

Characterization of an ultrafine β-nickel hydroxide from supersonic co-precipitation method

Nickel hydroxide is a well known electrode active material for nickel-based batteries. Compared with a commercial spherical Ni(OH) 2, characteristics of an ultrafine Ni(OH) 2 made from supersonic co-precipitation method were studied. SEM showed that the prepared Ni(OH) 2 exhibited a worm-like structure, compared to the ball-like shape of spherical Ni(OH) 2. By XRD, the sample was found to be β-type Ni(OH) 2, with more structure distortion due to a shortening in Ni–Ni distances and a prolongation in distances between NiO 2 layers as the lattice constants for the sample are a = 3.123 Å, c = 4.655 Å. XANES testified a severe structure distortion for the prepared Ni(OH) 2, and EXAFS showed expansion in Ni–O and contraction in Ni–Ni distances when compared to perfect crystal Ni(OH) 2. Electrochemical impedance spectroscopy (EIS) determined that proton diffusion coefficient of the ultrafine powder (6.0 × 10 −16 cm 2 s −1) was about two orders larger than that of spherical Ni(OH) 2 (5.6 × 10 −18 cm 2 s −1). The badly crystallized ultrafine Ni(OH) 2 may have more electrochemical activities and thus could be applied in nickel-based batteries.

EXAFS study of LaNi 5 and LaNi 4.5Al 0.5

We report extended X-ray absorption fine structure measurements in the temperature range between 20 and 300 K at the Ni K absorption edge on LaNi 5 and LaNi 4.5Al 0.5 before and after hydrogen charging. In agreement with previous studies, an increase of the Ni–Ni distance has been found when Ni atoms are partially substituted by Al. For all the samples, the Debye–Waller factors of the Ni–Ni first sub-shells have been fitted with a correlated Debye model plus a temperature independent static disorder, obtaining a Debye temperature dependence on the Al content. Even a small hydrogen content has been found to increase the static contribution to the local disorder around Ni atoms.

Synthesis, crystal structure and thermoanalysis of bis{[μ-bis-N,N′-(2-hydroxybenzoyl)-1,3-propandiaminato](N,N′-dimethyl formamide) (μ-benzoato)nickel(II)}nickel(II)

The title compound is a centrosymmetric, linear, homotrinuclear nickel(II) complex and has been characterized by elemental and thermogravimetric analysis, IR spectroscopy and single-crystal X-ray diffraction. The complex is monoclinic, space group P21/n, with a = 13.707(4), b = 13.455(2), c = 14.620(3) Å, β = 101.300(2)°, V = 2644.1(10) Å3 and Z = 2. The central and terminal nickel(II) ions have distorted octahedral geometry with a Ni ··· Ni distance of 3.047(1) Å.

Syntheses, crystal structures, and magnetic properties of Ni(mnt) 2-based molecular solids containing substituted isoquinolinium

Two novel ion-pair complexes, [RBzIQl] +[Ni(mnt) 2] − (mnt 2− = maleonitriledithiolate, [RBzIQl] + = 4-R-benzylisoquinolinium; R = H ( 1), Cl ( 2)) have been characterized structurally and magnetically. The Ni ( mnt ) 2 - anions and [BzIQl] + cations of 1 form 1D column of alternating between cations and anions via π⋯π stacking interaction between Ni(mnt) 2 plane and isoquinoline ring, and the Ni(mnt) 2 anions between adjacent columns exist C⋯N, C⋯N, and N⋯N interaction. The anions and cations of 2 stack into well-segregated columns in the solid state; and the Ni(III) ions form a 1D zigzag chain in a Ni(mnt) 2 column through intermolecular Ni⋯S, S⋯S, Ni⋯Ni or π⋯π interactions. The chain is uniform in 2 with the Ni⋯Ni distances of 3.784 Å. Magnetic susceptibility measurements for these complexes in the temperature range 1.8–300 K show that 1 exhibits antiferromagnetic coupling behavior, and 2 exhibits unusual magnetic phase transitions around 45 K. The overall magnetic behavior for 2 indicates the presence of antiferromagnetic interaction in the high-temperature phase (HT) and spin gap in the low-temperature phase (LT).

Dinuclear terephthalato-bridged nickel(II) complexes. Structural characterization and magnetic properties

The dinuclear terephthalato-bridged nickel(II) complexes [Ni 2(cyclen) 2(μ-tp)](ClO 4) 2 ( 1) [Ni 2(trpn) 2(μ-tp)(H 2O) 2](ClO 4) 2 ( 2) and [Ni 2(3,3,3-tet) 2(μ-tp)(H 2O) 2](ClO 4) 2 · 2H 2O ( 3), where tp = terephthalate dianion, cyclen = 1,4,7,10-tetraazacyclododecane, trpn = tris(3-aminopropyl)amine and 3,3,3-tet = 1,5,9,13-tetraazatridecane, were synthesized and structurally characterized by X-ray crystallography. Their magnetic susceptibilities were also determined at variable temperatures over the range 2–300 K. The structures of these complexes consist of μ-tp bridging two Ni(II) centers in a bis(bidentate) bonding fashion in 1 and in bis(monodentate) bonding fashion in 2 and 3. The coordination geometry around the Ni(II) ions in these compounds has a distorted octahedral geometry with four nitrogen atoms from the amine ligand (cyclen, trpn or 3,3,3-tet) and two coordinated oxygen atoms supplied by the chelated carboxylate group of the bridged terephthalate ligand in 1, and by one tp-carboxylate-oxygen in 2 and 3. The sixth coordination site in the last two complexes 2 and 3 is achieved via an oxygen atom from a coordinated water molecule. The intradimer Ni…Ni distances in these complexes are 10.740, 11.428 and 11.537 Å for 1, 2 and 3, respectively. The electronic spectra of the complexes in aqueous solutions are in complete agreement with the assigned X-ray geometry around the Ni(II) centers. Also, the analysis of the infrared spectral data for the ν(COO −) stretching frequencies of the tp-carboxalato groups reveals the existence of the bis(bidentate) and bis(monodentate) coordination modes for the bridged terephthalate ligand in 1, 2 and 3, respectively. Despite the different coordination modes of the tp bridging ligand in these complexes, they all exhibit very weak antiferromagnetic coupling. The coupling constants J were found to be −2.2, −0.6 and −1.5 cm 3 K mol −1 for the complexes 1, 2 and 3, respectively. The structural and magnetic results of 1– 3 are discussed in relation to the other related published μ-terephthalato dinuclear Ni(II) compounds.

Di-μ-acetato-bis[μ-2-hydroxy-N,N′-bis(2-oxidobenzyl)propane-1,3-diamine]bis(N,N′-dimethylformamide)trinickel(II)N,N′-dimethylformamide disolvate

The title compound, [Ni3(C17H20N2O2)2(C2H3O2)2(C3H7NO)2]·2C3H7NO, is a centrosymmetric trinuclear nickel(II) complex. The central and terminal nickel(II) atoms have distorted octa­hedral coordination, the central NiII atom by six O atoms, and the terminal NiII atoms by four O atoms and two N atoms each. The average Ni—O and Ni—N distances for the terminal Ni ions are 2.062 (17) and 2.082 (2) Å, respectively. The Ni⋯Ni distance is 3.035 (2) Å.

Two quasi-one-dimensional molecular solids based on Ni(mnt) 2 anion: Crystal structures, spectra, and magnetic properties

Two new molecular solids, [DiClBzPyNH 2][Ni(mnt) 2] ( 1) and [DiClBzPyN(CH 3) 2][Ni(mnt) 2] ( 2) ([DiClBzPyNH 2] + = 1-(2′,4′-dichlorobenzyl)-4-aminopyridinium, [DiClBzPyN(CH 3) 2] + = 1-(2′,4′-dichlorobenzyl)-4-dimethylaminopyridinium, and mnt 2− = maleonitriledithiolate) have been prepared and characterized by elemental analyses, IR, MS spectra, single-crystal X-ray diffraction and magnetic susceptibility. The Ni(III) ions of both 1 and 2 form a 1D zigzag magnetic chain within a Ni ( mnt ) 2 - column through Ni⋯S, S⋯S, Ni⋯Ni, or π⋯π interactions. The chain is alternating in 1 with Ni⋯Ni distances of 3.869 and 4.074 Å, while it is uniform in 2 with Ni⋯Ni distances of 4.159 Å. Magnetic susceptibility measurements in the temperature range 1.8–300 K show that 1 exhibits antiferromagnetic behavior, while 2 shows an unusual magnetic phase transition around 140 K, and antiferromagnetic interaction in the high-temperature (HT) phase and spin gap in the low-temperature (LT) phase. The phase transition for 2 is second order by determination of DSC analyses.

Unusual magnetic transition in a new 1D molecular solid [1-(4′-iodobenzyl)pyridinium][Ni(mnt) 2]( [formula omitted

A new molecular solid, [1-(4′-iodobenzyl)pyridinium]-bis(maleonitriledithiolato)nickel, [IBzPy][Ni(mnt) 2] ( 1), has been prepared and characterized. The Ni ( mnt ) 2 − anions and [IBzPy] + cations of 1 form completely segregated uniform stacking columns with the Ni⋯Ni distance 3.956 Å in the column. The temperature dependence of the magnetic susceptibility reveals that 1 undergoes a magnetic transition around 120 K, and exhibits an antiferromagnetic interaction in the high-temperature phase and a spin gap in the low-temperature phase. The DSC analyses further reveals that the phase transition is first order.

Zirconium–aluminium ordering in Zr 5Ni 4Al—a new superstructure in the family of U 3Si 2 related intermetallics

Zr 5Ni 4Al was synthesized by arc-melting of the elements and subsequent annealing in an induction furnace at 1360–1440 K. This aluminide crystallizes according to X-ray diffraction data of a twinned crystal with an ordered version of the Zr 3Al 2 type: P4 2/ m, a=716.7(3), c=659.8(4) pm, w R2=0.1174, 824 F 0 2 values, 28 variables. Due to the ordering of the zirconium and aluminium atoms, the space group symmetry is reduced from P4 2/ mnm (Zr 3Al 2) to P4 2/ m (Zr 5Ni 4Al), leading to merohedric twinning with a twin ratio of 52.5: 47.5 ( twin matrix 010 100 00 1 ¯ ) . The Zr 5Ni 4Al structure is an intergrowth of slightly distorted AlB 2 and CsCl/W related slabs of compositions ZrNi 2, ZrAl, and Zr 2 with an Ni–Ni distance of 257 pm in the distorted AlB 2 slab. A metastable Zr 3Al 2 type ( P4 2/ mnm) form of Zr 5Ni 4Al showing a disordered distribution of ZrAl and Zr 2 slabs was obtained by crystallizing a metallic glass of the composition Zr 50Ni 40Al 10 at 770 K. Further annealing at higher temperature led to the formation of ordered Zr 5Ni 4Al. The crystal chemical peculiarities of the different forms of Zr 5Ni 4Al are discussed on the basis of a group-subgroup scheme.

Unusual magnetic property and theoretical analysis of 1D molecular solid [1-(4′-iodobenzyl)-4-aminopyridinium][Ni(mnt) 2] (mnt 2− = maleonitriledithiolate)

A novel molecular solid, [1-(4′-iodobenzyl)-4-aminopyridinium][Ni(mnt) 2] (mnt 2− = maleonitriledithiolate), [IBzPyNH 2][Ni(mnt) 2] ( 1), has been structurally characterized and its magnetic properties investigated. The Ni ( mnt ) 2 - anions and [IBzPyNH 2] + cations of 1 form completely segregated uniform stacking columns with the Ni⋯Ni distances 4.001 Å in the Ni ( mnt ) 2 - stacking column through intermolecular Ni⋯S, S⋯S, Ni⋯Ni or π⋯π interactions. The temperature dependences of the magnetic susceptibilities of 1 reveal that 1 exhibits antiferromagnetic interaction ( J = −13.8 cm −1) above 100 K and ferromagnetic interaction ( J = 5.5 cm −1) below 100 K. The weak ferromagnetism in low temperature may result from spin canting.

An oxido-bridged dinickel(II) complex with L-alanine derived spiro ligand from an unusual mannich aminomethylation

The crystal structure of a centrosymmetric dinuclear nickel(II) complex, formed from the reaction of bis(L-alaninato)nickel(II) with formaldehyde and methylamine, shows two bridging 2,4,8,10-tetramethyl-5-oxido-5′-carboxylato-2λ5,4,8,10-tetraazaspiro[5.5]undec-2-en(234-del)-ylium ligands, L, and two formato ligands; each nickel atom exists in a trans-N2O4 octahedral geometry with an average (μ-O)–Ni distance of 2.033(1) Å and Ni···Nii distance of 2.894(1) Å. Formation of L implicates an unprecedented deamination step involving activation of both the α-carbon and the α-methyl hydrogen atoms of the L-alaninato moiety.

Magnesium‐Tin Substitution in NiMg2

AbstractThe binary intermetallic compound NiMg2 (own structure type) forms a pronounced solid solution NiMg2−xSnx. The structure of NiMg1.85(1)Sn0.15(1) was refined on the basis of single crystal X‐ray data: P6422, a = 520.16(7), c = 1326.9(1) pm, wR2 = 0.0693, 464 F2 values, and 20 variables. With increasing magnesium/tin substitution, the structure type changes. Crystals with x = 0.22 and 0.40 adopt the orthorhombic CuMg2 type: Fddd, a = 911.0(2), b = 514.6(1), c = 1777.0(4) pm, wR2 = 0.0427, 394 F2 values for NiMg1.78(1)Sn0.22(1), and a = 909.4(1), b = 512.9(1), c = 1775.6(1) pm, wR2 = 0.0445, 307 F2 values for NiMg1.60(1)Sn0.40(1) with 19 variables per refinement. The nickel atoms build up almost linear chains with Ni–Ni distances between 260 and 263 pm in both modifications where each nickel atom has coordination number 10 with two nickel and eight Mg/Sn neighbors. Both magnesium sites in the NiMg2 and CuMg2 type structures show Mg/Sn mixing. The Ni polyhedra are condensed leading to dense layers which show a different stacking sequence in both structure types. The crystal chemical peculiarities of these intermetallics are briefly discussed.

Synthesis, crystal structure and magnetic properties of a new ion-pair complex benzyltriphenylphosphinium-bis(maleonitriledithiolato)nickel

The crystal structure of a new ion-pair complex, benzyltriphenylphosphinium-bis(maleonitriledithiolato)nickel (1) ([BzTPP][Ni(mnt)2]) was determined. The anions and [BzTPP]+ cations of complex 1 stack into well-segregated columns in the solid state, and the Ni(III) ions form a one-dimensional alternating chain with Ni ··· Ni distances between 4.192 and 4.386 Å within a Ni(mnt)2− anion through Ni ··· S, S ··· S or π ··· π interactions. Anion–anion, anion–cation and cation–cation contacts may play important roles in crystal packing and stabilizing. Variable-temperature magnetic susceptibilities of 1 in the temperature range 75–300 K have been interpreted in terms of a simple dimer model approximation (H = 2JS A S B). Complex 1 exhibits a strong antiferromagnetic interaction, with g = 1.93 and J = − 273.1 cm−1.

Syntheses, crystal structures, and magnetic properties of two new 1D molecular solids based on Ni(mnt) 2 ion

Two novel ion-pair complexes, 1-(4′-bromo-2′-fluorobenzyl)isoquinolinium-bis(maleonitrile dithiolato)nickel(III), [BrFBzIQl] · Ni(mnt) 2 · 0.5MeCN ( 1) and 1-(4′-bromo-2′-flourobenzyl)-quinolinium-bis(maleonitriledithiolato)nickel(III), [BrFBzQl] · Ni(mnt) 2 ( 2) have been characterized structurally and magnetically. The anions and cations of 1 stack into columns in the solid state, respectively; and the Ni(III) ions form uniform stacking column with the Ni⋯Ni distances 4.061 Å within a Ni ( mnt ) 2 - column through intermolecular Ni⋯S, S⋯S, Ni⋯Ni or π⋯π interactions, while 2 forms 1D column of alternating between cations and anions via the hydrogen bonds, C⋯N, C⋯N, N⋯C, and π⋯π interactions. The changes of coupling constants were observed in these two complexes at 85 K for 1 and 70 K for 2. It is interesting that 1 undergoes a transition from antiferromagnetic to ferromagnetic phase and 2 does counter to that of 1.

Two cyano-bridged heterotrinuclear complexes built from [(Tp)Fe(CN) 3] − (Tp = hydrotris(pyrazolyl)borate): synthesis, crystal structures and magnetic properties

Using an anionic precursor [(Tp)Fe III(CN) 3] − ( 1) as a building block, two cyano-bridged centrosymmetric heterotrinuclear complexes, [ ( Tp ) 2 Fe 2 III ( CN ) 6 Mn II ( C 2 H 5 OH ) 4 ] · 2 C 2 H 5 OH ( 2) and [ ( Tp ) 2 Fe 2 III ( CN ) 6 Ni ( en ) 2 ] ( 3) (en = ethylenediamine), have been synthesized and structurally characterized. In each complex, [TpFe(CN) 3] − acts as a monodentate ligand toward a central [Mn(C 2H 5OH) 4] 2+ or [Ni(en) 2] 2+ core through one of its three cyanide groups, the other two cyanides remaining terminal. The intramolecular Fe–Mn and Fe–Ni distances are 5.2354(4) and 5.0669(11) Å, respectively. The magnetic properties of complexes 2 and 3 have been investigated in the temperature range of 2.0–300 K. A weak antiferromagnetic interaction between the Mn(II) and Fe(III) ions has been found in complex 2. The magnetic data of 2 can be fitted with the isotropic Hamiltonian: H ˆ = - 2 J ( S ˆ 1 · S ˆ 2 + S ˆ 2 · S ˆ 3 ) - 2 J ′ S ˆ 1 · S ˆ 3 where J and J′ are the intramolecular exchange coupling parameters between adjacent and peripheral spin carriers, respectively. This leads to values of J = −1.37 cm −1 and g = 2.05. The same fitting method is applied to complex 3 to give values of J = 1.2 cm −1 and g = 2.25, showing that there is a ferromagnetic interaction between the Fe(III) and Ni(II) ions.

Preparation, crystal structure and magnetic properties of a maleonitriledithiolate salt of the 1-methyl-3-benzylimidazolium cation with a novel structural motif

A new ion-pair complex, 1-methyl-3-benzylimidazolium bis(maleonitriledithiolato)nickelate(III), has been synthesized and characterized by IR spectroscopy and X-ray crystallography. The compound crystallizes in the triclinic space group P with a = 13.280(1), b = 14.906(1), c = 17.949 (2) Å, α = 108.02(1), β = 101.55(1), γ = 90.51(1)° and Z = 6. There are three inequivalent [Ni(mnt)2]− anions in the structure of the complex, two of them are stacked along the b axis with an AACC-type repeat unit, the other lies approximately orthogonal to the stack. Anions form three kinds of dimers with short Ni···Ni distances, leading to such strong spin coupling interactions that the complex is diamagnetic.

Towards the Design of Linear Homo‐Trinuclear Metal Complexes Based on a New Phenol‐Functionalised Diazamesocyclic Ligand: Structural Analysis and Magnetism

AbstractThe formation of two novel phenoxo‐bridged linear trimetallic CuII and NiII complexes, [Cu3(μ‐L)2](CH3OH)2(ClO4)2 (1) and [Ni3(μ‐L)2(CH3OH)2](ClO4)2 (2), with a new diazamesocyclic ligand functionalised by additional phenol donor pendants (H2L = N,N′‐ bis(2‐hydroxybenzyl)‐1,4‐diazacycloheptane), has been achieved and both complexes have been characterised by IR spectroscopy, elemental analyses, conductivity measurements, thermal analyses and UV/Vis techniques. Single‐crystal X‐ray diffraction analyses revealed that both 1 and 2 have the similar phenoxo‐bridged linear trinuclear cores. For 1, two terminal and the central CuII ion are in square‐planar environments with the adjacent intramolecular Cu···Cu separation of 2.9376(9) Å. For 2, however, two terminal NiII ions are in square‐planar environments and the central NiII ion assumes an octahedral geometry by axial coordination of two methanol ligands, the adjacent intramolecular Ni···Ni distance being 3.007(3) Å. In both cases, the 1,4‐diazacycloheptane (DACH) ring adopts the normal boat configuration. The magnetic properties of complexes 1 and 2 have been investigated by variable‐temperature magnetic susceptibility measurements in the solid state. Complex 1 displays a very strong antiferromagnetic coupling interaction between the neighbouring μ‐phenoxo CuII centres with a J parameter of −314 cm−1 and the magneto‐structural correlation for such complexes is discussed in detail. For complex 2, the result indicates that both terminal NiII ions are diamagnetic and the central NiII shows typical paramagnetic behaviour. The presence of zero‐field splitting for NiII with a D parameter of 11 cm−1, being active at low temperature, is further corroborated by the magnetisation measurement at 2 K. Additionally, the interesting ESR spectra of 1 at different temperatures (from 298 K to 8 K) were investigated and interpreted. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

Synthesis, crystal structure and magnetic property of a new 1D molecular material [1-(4′-chlorobenzyl)–4-aminopyridinium](+) bis(maleonitriledithiolato)nickel(–)

A new ion-pair complex, [1-(4′-chlorobenzyl)–4-aminopyridinium](+)bis(maleonitrile-dithiolato)nickel(−),[ClbzPyNH 2][Ni(mnt) 2] ( 1), has been prepared and characterized. X-ray single crystal structure conforms that the Ni(mnt) 2 − anions and [ClbzPyNH 2] + cations of 1 form completely segregated uniform stacking columns with the Ni⋯Ni distance 3.944 Å in the Ni(mnt) 2 − stacking column. The temperature dependence of the magnetic susceptibility reveals that 1 undergoes a magnetic transition, and exhibits ferromagnetic interaction in the high-temperature phase and spin gap system in the low-temperature phase.

Unusual magnetic transition around 210 K in a new 1D molecular solid based on [formula omitted] ion

A new ion-pair complex, [CNBzPyNH 2][Ni(mnt) 2] ( 1), where [CNBzPyNH 2] + = 1-(4′-cyanobenzyl)-4-aminopyridinium and mnt 2− = maleonitriledithiolate, forms a completely segregated uniform stacking column with the Ni⋯Ni distance 3.863 Å and shows a peculiar magnetic transition from paramagnetism in the high-temperature (HT) phase to spin gap in low-temperature (LT) phase around 210 K. The DSC analysis reveals that the phase transition is first order.

Unusual magnetic property associated with a structural phase transition within a new ion-pair complex

A novel ion-pair complex, [BrbzPyNH 2][Ni(mnt) 2], where [BrbzPyNH 2] + = 1-(4′-bromobenzyl)-4-aminopyridinium and mnt 2− = maleonitriledithiolate, forms a completely segregated uniform stacking column with the Ni⋯Ni distance 3.952 Å and undergoes a magnetic phase transition from paramagnetism in the high-temperature (HT) phase to diamagnetism in the low-temperature (LT) phase at around 105 K.