Synthesis,structure, and conductivity of molecular conductor (PyEt)[Ni(dmit)<Subscript>2</Subscript>]<Subscript>2</Subscript>

A new electrical conductive crystal PyEt[Ni(dmit)₂]₂ (dmit = 4,5-dimercapto-1,3-dithiole-2-thione) has been synthesized and its X-ray structure has been determined to be in monoclinic system, C2/c space group. In PyEt[Ni(dmit)₂]₂ crystal, the conducting component [Ni(dmit)₂]^0.5- is face-to-face packed forming molecular column along the c-direction, and these molecular columns are then side-by-side extended along the a-direction forming a kind of two-dimensional conducting sheet on (010). The measured conductivity at room temperature along a certain direction on (010) plane is 10 S · cm^-1. From 282 to 269 K, the crystal shows metallic behavior but changes to semiconductor below 269 K. Based on the measured crystal structure and calculated band structure, this conductor-semiconductor phase transformation can be primarily interpreted: The metallic conductivity is corresponding to the uniform molecular column and the atomic-lattice-chain structure of Ni chain, while the semi-conductive behavior to staggered molecular column and the atomic-zigzag-chain structure of Ni chain.     

Towards Single-component Molecular Conductor [Ni(dmit)_2] by Charge Disproportionation:2[Ni(dmit)_2]~(-0.5)[Ni(dmit)_2]+[Ni(dmit)_2]~-

It was commonly thought that a molecular conductor or semiconductor should be composed of at least two components to make the conducting component in partially charged state. However, this idea became questionable by the recent report of the single-component molecular conductor [Ni(tmdt)2]1 as well as several reports about single-component molecular semiconductors such as [Ni(ptdt)2]2 and [Ni(C10H10S8)2]3. In fact, as early as 1985, [Ni(dmit)2] as a by-product in synthesizing TTF[Ni(dmit…     

Towards Single-component Molecular Conductor [Ni（dmit）2 ] by Charge Disproportionation： 2[Ni（dmit）2]^0.5→[Ni（dmit）2 ]＋ [Ni（dmit）2]^-

A new method of synthesizing single-component molecular conductor [Ni(dmit)2] bythe reaction 2(Me4N)[Ni(dmit)2]2→ [Ni(dmit)2] (Me4N)[Ni(dmit)2] is reported. [Ni(dmit)2]exhibits a semiconductive behavior above 167 K, while from 167 K down to the measuring limit of 60 K, it exhibits metallic conductivity.     

Crystal structures and magnetic properties of (4,4'-phenylazophenyl)diammonium(crown ethers)[Ni(dmit)2]2 crystals

Sandwich-type hydrogen-bonded supramolecular dications (DAAz(2+))([18]crown-6)(2) and (DAAz(2+))(dicyclohexane[18]crown-6)(2) (DAAz(2+) = 4,4'-(phenylazophenyl)diammonium) were introduced into [Ni(dmit)(2)](-) anions via a diffusion method to form novel single crystals (DAAz(2+))([18]crown-6)(2)[Ni(dmit)(2)](2) (1) and (DAAz(2+))(dicyclohexane[18]crown-6)(2)[Ni(dmit)(2)](2) (2), respectively, which were characterized based on their crystal structures and magnetic susceptibilities. The molecular assembly structures and its physical properties were expanded in the use of a three component molecular network system. The two ammonium groups (-NH(3)(+)) of the DAAz(2+) dication formed N-H(+)-O hydrogen-bonding interactions with the oxygen atoms of [18]crown-6 and dicyclohexane[18]crown-6. In the case of crystal 1, an alternating π-stacking interaction was observed for the [Ni(dmit)(2)](-) anions, whereas orthogonal linear π-S interactions were detected for crystal 2. Temperature-dependent magnetic susceptibilities of crystals 1 and 2 followed the alternate Heisenberg antiferromagnetic chain (J = -15.8 K) and linear Heisenberg antiferromagnetic chain (J = -13.7 K) models, respectively.     

Molecular rotor of Cs2([18]crown-6)3 in the solid state coupled with the magnetism of [Ni(dmit)2

Nanoscale molecular rotors that can be driven in the solid state have been realized in Cs2([18]crown-6)3[Ni(dmit)2]2 crystals. To provide interactions between the molecular motion of the rotor and the electronic system, [Ni(dmit)2]- ions, which bear one S=1/2 spin on each molecule, were introduced into the crystal. Rotation of the [18]crown-6 molecules within a Cs2([18]crown-6)3 supramolecule above 220 K was confirmed using X-ray diffraction, NMR, and specific heat measurements. Strong correlations were observed between the magnetic behavior of the [Ni(dmit)2]- ions and molecular rotation. Furthermore, braking of the molecular rotation within the crystal was achieved by the application of hydrostatic pressure.     

A convenient route to synthesize the fully conjugated bimetallic complex (Bu4N)2[tto[Ni(dmit)2]] (tto = tetrathiooxalate,C2S4(2-), and dmit = 1,3-dithiole-2-thione-4,5-dithiolate,C3S5(2-) and the crystal structure of a new crystal form

A novel route for the conversion of (Bu4N)2[Ni(dmit)2] to (Bu4N)2[tto[Ni(dmit)2]] is reported here. This provides a much more efficient way of synthesizing (Bu4N)2[tto[Ni(dmit)2]] than the literature method. During the process, the conversion of dmit2- to tto2- was realized for the first time. This new synthesis should facilitate further research on the conducting bimetallic complexes [C]x[tto[Ni(dmit)2]]. In addition, a new crystal form of (Bu4N)2[tto[Ni(dmit)2]]. In addition, a new crystal form of (Bu4N)2[tto[Ni(dmit)2]] was determined by X-ray crystallographic analysis.     

Structural phase transition of magnetic [Ni(dmit)2]- salts induced by supramolecular cation structures of (M+)([12]crown-4)2

Sandwich-type supramolecular cation structures of (M(+))([12]crown-4)(2) complexes (M(+) = Li(+), Na(+), K(+), and Rb(+)) were introduced as countercations to the [Ni(dmit)(2)](-) anion, which bears an S = (1)/(2) spin, to form novel magnetic crystals (dmit(2-) = 2-thione-1,3-dithiole-4,5-dithiolate). The zigzag arrangement of Li(+)([12]crown-4)(2) cations in Li(+)([12]crown-4)(2)[Ni(dmit)(2)](-) salt induced weak intermolecular interactions of [Ni(dmit)(2)](-) dimers, whose magnetic spins were isolated from each other. The molecular arrangements of cations and anions in M(+)([12]crown-4)(2)[Ni(dmit)(2)](-) salts (M(+) = Na(+), K(+), and Rb(+)) were isostructural to each other. In the case of Na(+)([12]crown-4)(2)[Ni(dmit)(2)](-), the space group C2/m changed to C2/c with a lowering in temperature from 298 to 100 K. This structural change occurred at 222.5 K as a first-order phase transition. The space group C2/m (T = 298 K) in the salt K(+)([12]crown-4)(2)[Ni(dmit)(2)](-) also changed to C2/c (T = 100 K), which transition occurred at 270 K. Crystal structural analyses at 298 and 100 K revealed changes in both supramolecular cation conformation and [Ni(dmit)(2)](-) anion arrangements. The transition from C2/m to C2/c crystals generated a dipole moment in the Na(+)([12]crown-4)(2) and K(+)([12]crown-4)(2) structures, which were reconstructed to cancel the net dipole moment of the C2/c crystals. These cation transformations led to changes in intermolecular interactions between the [Ni(dmit)(2)](-) anions via structural rearrangements. The crystal structure of C2/c was stabilized in Rb(+)([12]crown-4)(2)[Ni(dmit)(2)](-) at 298 K. The [Ni(dmit)(2)](-) configuration in these salts with the C2/c space group was a one-dimensional uniform chain, which showed the temperature-dependent magnetic susceptibility of a one-dimensional linear Heisenberg antiferromagnetic chain.     

M+(12-crown-4) supramolecular cations (M+ = Na+, K+, Rb+, and NH4+) within Ni(2-thioxo-1,3-dithiole-4,5-dithiolate)2 molecular conductor

Monovalent cations (M+ = Na+, K+, Rb+, and NH4+) and 12-crown-4 were assembled to new supramolecular cation (SC+) structures of the M+(12-crown-4)n (n = 1 and 2), which were incorporated into the electrically conducting Ni(dmit)2 salts (dmit = 2-thioxo-1,3-dithiole-4,5-dithiolate). The Na+, K+, and Rb+ salts are isostructural with a stoichiometry of the M+(12-crown-4)2[Ni(dmit)2]4, while the NH4+ salt has a stoichiometry of NH4+(12-crown-4)[Ni(dmit)2]3(CH3CN)2. The electrical conductivities of the Na+, K+, Rb+, and NH4+ salts at room temperature are 7.87, 4.46, 0.78, and 0.14 S cm-1, respectively, with a semiconducting temperature dependence. The SC+ structures of the Na+, K+, and Rb+ salts have an ion-capturing sandwich-type cavity of M+(12-crown-4)2, in which the M+ ion is coordinated by eight oxygen atoms of the two 12-crown-4 molecules. On the other hand, the NH4+ ion is coordinated by four oxygen atoms of the 12-crown-4 molecule. Judging from the M(+)-O distances, thermal parameters of oxygen atoms, and vibration spectra, the thermal fluctuation of the Na+(12-crown-4)2 structure is larger than those of K+(12-crown-4)2 and Rb+(12-crown-4)2. The SC+ unit with the larger alkali metal cation gave a stress to the Ni(dmit)2 column, and the SC+ structure changed the pi-pi overlap mode and electrically conducting behavior.     

Magnetism of [Ni(dmit)2] salts with [meso- and (1S, 2S)-diphenyl-1,2-ethanediammonium]([18]crown-6)2 supramolecular cations

Meso- and (1S, 2S)-diphenyl-1,2-ethanediammonium (DPEDA2+) complexed with [18]crown-6 were introduced into [Ni(dmit)2]-based magnetic salts as countercations. The configurational difference of DPEDA2+ modulated the crystal structure and magnetic behavior of the salts. A two-dimensional (2D) Heisenberg antiferromagnetic square lattice was observed in (meso-diphenyl-1,2-ethane diammonium2+)([18]crown-6)2[Ni(dmit)2](-)2, which was the first example of a 2D magnetic lattice in [Ni(dmit)2]- salts.     

Supramolecular rotor: adamantylammonium([18]crown-6) in [Ni(dmit)2]- salt

Adamantylammonium (ADNH3+) was complexed with [18]crown-6, forming a supramolecular cation of (ADNH3+)([18]crown6), which was introduced into a [Ni(dmit)2]- salt as a supramolecular rotor. The cation layers were alternately arranged with [Ni(dmit)2]- layers in the crystal, in which the molecular rotation of (ADNH3+)([18]crown-6) was confirmed from the temperature-dependent solid-state 1H NMR.     

Cooperativity of dynamics of 18-crown-6 molecule forming one-dimensional chain in Cs2(18-crown-6)3[Ni(dmit)2]2

Heat capacity of Cs2(18-crown-6)3[Ni(dmit)2]2 was measured by adiabatic calorimetry. A broad thermal anomaly was observed around 225 K. The entropy gain (about 52 J K(-1) mol(-1)) is much larger than that expected for twofold disordering of 18-crown-6 assumed in the previous structure analysis. The shape of thermal anomaly was qualitatively explained by a linear Ising model developed for cooperative disordering in polymers. The 18-crown-6 molecules forming a one-dimensional chain in the crystal are orientationally disordered with moderate cooperativity.     

Solid-state molecular rotators of anilinium and adamantylammonium in [Ni(dmit)2](-) salts with diverse magnetic properties

Supramolecular rotators of hydrogen-bonding assemblies between anilinium (Ph-NH 3 (+)) or adamantylammonium (AD-NH 3 (+)) and dibenzo[18]crown-6 (DB[18]crown-6) or meso-dicyclohexano[18]crown-6 (DCH[18]crown-6) were introduced into [Ni(dmit) 2] salts (dmit (2-) is 2-thioxo-1,3-dithiole-4,5-dithiolate). The ammonium moieties of Ph-NH 3 (+) and AD-NH 3 (+) cations were interacted through N-H (+) approximately O hydrogen bonding with the six oxygen atoms of crown ethers, forming 1:1 supramolecular rotator-stator structures. X-ray crystal-structure analyses revealed a jackknife-shaped conformation of DB[18]crown-6, in which two benzene rings were twisted along the same direction, in (Ph-NH 3 (+))(DB[18]crown-6)[Ni(dmit) 2] (-) ( 1) and (AD-NH 3 (+))(DB[18]crown-6)[Ni(dmit) 2] (-) ( 3), whereas the conformational flexibility of two dicyclohexyl rings was observed in (Ph-NH 3 (+))(DCH[18]crown-6)[Ni(dmit) 2] (-) ( 2) and (AD-NH 3 (+))(DCH[18]crown-6)[Ni(dmit) 2] (-) ( 4). Sufficient space for the molecular rotation of the adamantyl group was achieved in the crystals of salts 3 and 4, whereas the rotation of the phenyl group in salts 1 and 2 was rather restricted by the nearest neighboring molecules. The rotation of the adamantyl group in salts 3 and 4 was evidenced from the temperature-dependent wide-line (1)H NMR spectra, dielectric properties, and X-ray crystal structure analysis. ab initio calculations showed that the potential energy barriers for the rotations of adamantyl groups in salts 3 (Delta E approximately 18 kJmol (-1)) and 4 (Delta E approximately 15 kJmol (-1)) were similar to those of ethane ( approximately 12 kJmol (-1)) and butane (17-25 kJmol (-1)) around the C-C single bond, which were 1 order of magnitude smaller than those of phenyl groups in salts 1 (Delta E approximately 180 kJmol (-1)) and 2 (Delta E approximately 340 kJmol (-1)). 1D or 2D [Ni(dmit) 2] (-) anion arrangements were observed in the crystals according to the shape of crown ether derivatives. The 2D weak intermolecular interactions between [Ni(dmit) 2] (-) anions in salts 1 and 3 led to Curie-Weiss behavior with weak antiferromagnetic interaction, whereas 1D interactions through lateral sulfur-sulfur atomic contacts between [Ni(dmit) 2] (-) anions were observed in salts 2 and 4, whose magnetic behaviors were dictated by ferromagnetic (salt 2) and singlet-triplet (salt 4) intermolecular magnetic interactions, respectively.     

A unique new multiband molecular conductor: [BDTA][Ni(dmit)2]2

A new molecular conducting material, [BDTA][Ni(dmit)2]2, with a novel multiband electronic structure has been prepared by simple mixing of precursor salts of the components.     

[Co(C~5H~5)~2]~n.[M(dmit)~2](M=Ni,Pd;n=0,1,2)型配合物的合成及表征

二茂金属[M'(C~5H~5)~2]^1^+的盐与(NBu~4)~n[M(dmit)~2](M=Ni, Pd; N=1,2)反应, 当M'=Fe, Ni; n=1时, 分别得到了导电配合物[Ni(dmit)~2]和[Pd(dmit)~2]; 当M'=Co, n=1,2时, 分别得到的是电荷几乎不转移的4个盐[Co(C~5H~5)~2]~n[Ni(dmit)~2]和[Co(C~5H~5)~2]~n[Pd(dmit)~2]。用ESCA、Raman谱及循环伏安图讨论了上述化合物形成时的电荷转移量。尽管[M(dmit)~2]的室温电导率相当大, 但其电导率随温度的变化曲线表明它们属于半导体。EHCO能带计算给出[Ni(dmit)~2]的能隙0.112eV, 与实测的电导活化能相当接近。     

Supramolecular cation assemblies of hydrogen-bonded (NH4+/NH2NH3+)(crown ether) in [Ni(dmit)2]-based molecular conductors and magnets

Hydrogen-bonded supramolecular cation assemblies of (NH4+/NH2-NH3+)(crown ether), where the crown ether is [12]crown-4, [15]crown-5, or [18]crown-6, were incorporated into electrically conducting [Ni(dmit)2] salts (dmit2- = 2-thioxo-1,3-dithiole-4,5-dithiolate). (NH4+)([12]crown-4)[Ni(dmit)2]3(CH3CN)2 had a pyramidal shape, while ionic channels were observed in (NH4+)(0.88)([15]crown-5)[Ni(dmit)(2)]2 and (NH4+)(0.70)([18]crown-6)[Ni(dmit)(2)]2. Both (NH4+)(0.88)([15]crown-5) and (NH4+)(0.70)([18]crown-6) contained regularly spaced [Ni(dmit)(2)] stacks formed by N-H.O hydrogen bonding between the oxygen atoms in crown ethers and the NH4+ ion. NH4+ occurred nonstoichiometrically; there were vacant ionic sites in the ionic channels. The ionic radius of NH4+ is larger than the cavity radius of [15]crown-5 and [18]crown-6. Therefore, NH4+ ions could not pass through the cavity and were distributed randomly in the ionic channels. The static disorder caused the conduction electrons to be randomly localized to the [Ni(dmit)2] stacks. Hydrazinium (NH2-NH3+) formed the supramolecular cations in (NH2-NH3+)([12]crown-4)2[Ni(dmit)2]4 and (NH2-NH3+)2([15]crown-5)3[Ni(dmit)2]6, possessing a sandwich and club-sandwich structure, respectively. To the best of our knowledge, these represent the first hydrazinium-crown ether assemblies to be identified in the solid. In the supramolecular cations, hydrogen bonding was detected between the ammonium or the amino protons of NH2-NH3+ and the oxygen atoms of crown ethers. The sandwich-type cations coexisted with the [Ni(dmit)2] dimer stacks. Although the assemblies were typically semiconducting, ferromagnetic interaction (Weiss temperature = +1 K) was detected in the case of (NH2-NH3+)2([15]crown-5)3[Ni(dmit)2]6. The (NH2-NH3+)0.8([18]crown-6)[Ni(dmit)2]2 and (NH4+)0.76([18]crown-6)[Ni(dmit)2]2 crystals were isomorphous. The large and flexible [18]crown-6 allowed for maintaining the same ionic channel structure through replacement of the NH4+ cation by NH2-NH3+.     

Synthesis, Structure and Conductivity of （PyH）[Ni（dmit）2]2

A new molecular conductor (PyH)[Ni(dmit)2]2 (dmit = 4, 5-dimercapto-1, 3-dithiole-2-thione) has been prepared and its crystal structure has been determined. Crystallographic parameters for (PyH)[Ni(dmit)2]2: C17H6NNi2S20; triclinic system; P-1 space group; a = 5.9227 (4) , b =8.2279 (6), c = 16.7535 (9) A, a = 90.233 (5) , 0 = 92.107 (6) , y= 104.654 (6) ; V= 789.25 (9) A3; Z = 1; Dc = 2.068 g/cm3; F (000) = 491. The conductivity at one direction on (001) plane at room temperature was measured to be 0.13 ii^-cmf1. The resistivity-temperature curve in the temperature range of 90-290 K shows that this compound behaves as a semiconductor.     

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.     

Magnetic semiconductor: structural,magnetic, and conducting properties of the salts of the 6-oxoverdazyl radical cation with M(dmit)(2) anions (M = Ni,Zn, Pd,and Pt,dmit = 1,3-dithiol-2-thione-4,5-dithiolate)

Five kinds of (1:1), (1:3), and (2:1) salts of 3-[4-(diethylmethylammonio)phenyl]-1,5-diphenyl-6-oxoverdazyl radical cation [V](+) with M(dmit)(2) anions (M = Ni, Zn, Pd, and Pt, dmit = 1,3-dithiol-2-thione-4,5-dithiolate) ([V](+)[Ni(dmit)(2)](-) (1), [V](+)[Ni(dmit)(2)](3)(-) (2), [V](+)(2)[Zn(dmit)(2)](2-) (3), [V](+)(2)[Pd(dmit)(2)](2-) (4), and [V](+)(2)[Pt(dmit)(2)](2-) (5)) and an iodide salt of [V](+) ([V](+)[I](-) (6)) have been prepared, and the magnetic susceptibilities (chi(M) values) have been measured between 1.8 and 300 K. The chi(M) of the (1:1) Ni salt (1) can be well reproduced by the sum of the contributions from (i) a Curie-Weiss system with a Curie constant (C) of 0.376 K emu/mol and a negative Weiss constant (theta) of -1.5 K and (ii) the one-dimensional Heisenberg antiferromagnetic alternating chain system with 2J(A-B)/k(B) = -274 K (alternation parameter alpha = J(A-C)/J(A-B) = 0.2). The chi(M) of the (1:3) Ni salt (2) can be well explained by the two-term contributions from (i) the Curie-Weiss system with C = 0.376 K emu/mol and theta = -5.0 K and (ii) the dimer system with 2J/k(B) = -258 K. The magnetic properties of 1 and 2 were discussed based on the results obtained by crystal structure analysis and ESR measurements of 1 and 2. The chi(M) values of the (2:1) Zn, Pd, Pt salts 3, 4, and 5 and [V](+)[I](-) salt 6 follow the Curie-Weiss law with C = 0.723, 0.713, 0.712, and 0.342 K emu/mol and theta = -2.8, -3.1, -2.6, and +0.02 K, respectively, indicating that only the spins of the verdazyl radical cation contribute to the magnetic property of these salts. The salts 1, 3, and 5 are insulators. On the other hand, the conductivity (sigma) of the Ni salt 2 and Pd salt 4 at 20 degrees C was sigma = 8.9 x 10(-2) and 1.3 x 10(-4) S cm(-)(1) with an activation energy E(A) = 0.11 and 0.40 eV, respectively. The salts 2 and 4 are new molecular magnetic semiconductors.     

Structures, energy bands and conductivities of (Me_3NEt)[Pd(dmit)_2]_2 and (NEt_4)[Pd(dmit)_2]_2

The electrical conductive molecular crystals (Me3NEt)[Pd(dmit)2]2 and (NEt4)[Pd (dmit)2]2 (dmit = 4,5-dimercapto-1,3-dithiole-2-thione) have been prepared, and their crystal structures and conductivity-temperature curves have been determined. The fact that the conductivity at room temperature of (Me3NEt)[Pd(dmit)2]2 (a = 58 Ω· cm-1) is much higher than that of (NEt4)-[Pd(dmit)2]2(cr= 2.2 Q~1 ?cm'1) has been rationally explained by the results of energy band calculations. (MeNEt3)[Pd(dmit)2]2 belongs to monoclinic system, P21/m space group and (NEt4)[Pd (dmit)2]2 belongs to triclinic system, P1 space group. The structural conducting component of the crystals is the planar coordinative anion [Pd(dmit)2]05- which forms the face-to-face dimmer [Pd(dmit)2]2-. These dimers have been further constructed to be a kind of two-dimensional (2-D)conductive molecular sheet by means of S…S intermolecular interactions. The tiny difference of the above 2-D molecular sheets of the two title crystals has resulted in one     

Two Polymorphs of (Anilinium)(18-Crown-6)[Ni(dmit)2]: Structure and Magnetic Properties

Two polymorphs of monovalent [Ni(dmit)₂]⁻ (dmit²⁻=2-thioxo-1,3-dithiole-4,5-dithiolate) crystals A and B, (anilinium)(18-crown-6)[Ni(dmit)₂], were prepared, and the structure and magnetic properties were investigated. In these crystals, the [Ni(dmit)₂]⁻ molecules form dimers, which arranged into chains between the supramolecular cation structure (anilinium)(18-crown-6). In crystal A, supramolecular cation formed a regular stack, inducing ladder structure of [Ni(dmit)₂], whose magnetism had been well fitted by spin ladder equation with the spin gap of Δ=190 K. Crystal B is ca. 3% more densely packed compared to crystal A. Due to the dense packing, supramolecular cation stack is distorted, which prevented the intermolecular interaction between [Ni(dmit)₂]⁻ dimers in direction corresponds to the ladder-leg direction in crystal A. Reflecting the [Ni(dmit)₂]⁻ arrangement, crystal B showed a temperature dependence of magnetic susceptibility well reproduced by the singlet-triplet thermal activation model, whose antiferromagnetic exchange interaction (2J) was 140 K.