Non-Prussian blue structures and magnetic ordering of Na2Mn(II)[Mn(II)(CN)6] and Na2Mn(II)[Mn(II)(CN)6]·2H2O

The aqueous reaction of Mn(II) and NaCN leads to the isolation of the 3-D Prussian blue analogue (PBA) Na(2)Mn[Mn(CN)(6)]·2H(2)O (1·H(2)O), which under careful dehydration forms 1. 1·H(2)O is monoclinic [P2(1)/n, a = 10.66744(32) ?, b = 7.60223(23) ?, c = 7.40713(22) ?, β = 92.4379(28)°], while 1 is rhombohedral [R ?3, a = 6.6166(2) ?, c = 19.2585(6) ?], and both structures are atypical for PBAs, which are typically face centered cubic. Most notably, the average ∠Mn-N-C angles are 165.3(3)° and 142.4(4)° for 1·H(2)O and 1, respectively, which are significantly reduced from linearity. This is attributed to the ionic nature of high-spin Mn(II) accommodating a reduced ∠Mn-N-C to minimize void space. Both 1 and 1·H(2)O magnetically order as ferrimagnets below their ordering temperature, T(c), of 58 and 30 K, respectively, as determined from the average of several independent methods. 1 and 1·H(2)O are hard magnets with 5 K coercive fields of 15,300 and 850 Oe, and remnant magnetizations of 9075 and 102 emu·Oe/mol, respectively. These data along with previous T(c)'s reported for related materials reveal that T(c) increases as the ∠Mn-N-C deviates further from linearity. Hence, the bent cyanide bridges play a crucial role in the superexchange mechanism by increasing the coupling via shorter Mn(II)···Mn(II) separations, and perhaps an enhanced overlap.     

Syntheses and Crystal Structures of Two Cyano-bridged Bimetallic Complexes [Ce(DMSO)4(H2O)3Fe(CN)6]·H2O and [La(DMSO)4(H2O)3Co(CN)6]·H2O (DMSO = Dimethylsulfoxide)

Two new bimetallic cyano-bridged complexes [Ce(DMSO)4(H2O)3Fe(CN)6]·H2O 1 and [La(DMSO)4(H2O)3Co(CN)6]·H2O 2 have been prepared by the ball milling reaction method and structurally characterized by X-ray single-crystal structure analyses. Crystallographic data for 1:C14H32CeFeN6O8S4, Mr = 736.67, monoclinic, space group P21/n, a = 14.952(1), b =13.7276(9), c = 15.392(1) (A), β = 108.288(1)°, V = 2999.6(4) (A)3, Z = 4, Dc= 1.631 g/cm3,μ =2.304 mm-1, F(000) = 1480, R = 0.0593 and wR = 0.1611; and those for 2: C14H32CoLaN6O8S4,Mr=738.54, monoclinic, space group P21/n, a = 14.945(3), b = 13.731(3), c = 15.300(3) (A), β=107.806(1)°, V= 2989.3(11) (A)3, Z = 4, Dc = 1.641 g/cm3,μ = 2.288 mm-1, F(000) = 1480, R =0.0383 and wR = 0.1132. In both complexes the lanthanide ion is eight-coordinated in a square antiprism arrangement, and the Fe(Ⅲ) or Co(Ⅲ) ion in a nearly regular octahedral environment.The [LnM(CN)6(DMSO)4(H2O)3]·H2O (Ln = Ce and M = Fe for 1; Ln = La and M = Co for 2)species are held together via hydrogen bonds by coordinated water molecules, lattice water molecules and nitrogen atoms of cyanide groups to form a three-dimensional framework.     

Crystal structure of [{Cu(H2O)(en)2}{Cu(en)2}Re6Te8(CN)6]·3H2O

The reaction of Cs₄[Re₆Te₈(CN)₆]·2H₂O with Cu(en)₂Cl₂ in water affords crystals of a cluster complex [{Cu(H₂O)(en)₂}{Cu(en)₂}Re₆Te₈(CN)₆]·3H₂O. The structure of the compound is determined by single crystal X-ray diffraction (a = 10.8082(4) Å, b = 16.5404(6) Å, c = 24.6480(7) Å, β = 92.696(1)°, V = 4401.5(3) ų, Z = 4, space group P2₁/n, R ₁ = 0.0331, wR ₂ (all data) = 0.0652). In the complex, cluster [Re₆Te₈(CN)₆]^4? anions are linked by Cu²⁺ cations into zigzag chains through cyanide bridges. The coordination environment of the copper cations is complemented by ethylenediamine molecules. Each of the cluster anions is additionally coordinated by a terminal fragment {Cu(H₂O)(en)₂}.     

Novel inorganic ionic compounds based on Re6 chalcocyanide cluster complexes: synthesis and crystal structures of [CuNH3(trien)]2[Re6S8(CN)6] · 7H2O, [CuNH3(trien)]2[Re6Se8(CN)6] and [CuNH3(trien)]2[Re6Te8(CN)6] · H2O

Three new octahedral rhenium chalcocyanide cluster compounds [CuNH₃(trien)]₂[Re₆S₈(CN)₆] · 7H₂O (1), [CuNH₃(trien)]₂[Re₆Se₈(CN)₆] (2) and [CuNH₃(trien)]₂[Re₆Te₈(CN)₆] · H₂O (3) exhibiting ionic structures have been obtained by the diffusion of an ammonia solution of KCs₃[Re₆S₈(CN)₆] (for 1), K₄[Re₆Se₈(CN)₆] · 3.5H₂O (for 2) or Cs₄[Re₆Te₈(CN)₆] · 2H₂O (for 3) into a glycerol solution of CuCl₂ · 2H₂O in the presence of trien (trien=triethylenetetramine). The compounds have been characterized by single-crystal X-ray diffraction. All three compounds contain a cationic complex [CuNH₃(trien)]²⁺ which was not described previously.     

Crystal structure of CsLnFe(CN)6·5H2O (Ln=Ce,Pr, Nd), CsCeFe(CN)6·4H2O,and TlTmRu(CN)6·3H2O

We have investigated the crystal structures of CsLnFe(CN)₆·nH₂O (Ln=lanthanide, n=4,5), as well as TlTmRu(CN)₆·3H₂O. These phases can be thought of as derivatives of LnFe(CN)₆·4H₂O, where, simultaneously, an alkali ion (or Tl⁺) is introduced while the valence of Fe is reduced from Fe³⁺ to Fe²⁺. A new arrangement of the structural units is observed in the CsLnFe(CN)₆·5H₂O, where the coordination of the Ln-ion is changed to a bisdisphenoid. The resulting LnN₅O₃ units alternate with Fe(CN)₆ units to form an overall rocksalt-type ralted lattice that accommodates the alkali ions in interstitial sites. Due to the arrangement of the water molecules, a layer structure results.     

New Layered Polymer [{Mn(H2O)3}2{Re6Se8(CN)6}] · 3.3H2O: Synthesis and Properties

The [{Mn(H₂O)₃}₂{Re₆Se₈(CN)₆}] · 3.3H₂O complex was produced on slow evaporation of an aqueous solution containing the salt of a cluster complex K₄Re₆Se₈(CN)₆ · 3.5H₂O and a 23-fold excess of Mn²⁺. The cluster complexes [Re₆Se₈(CN)₆]^4– are linked in a crystal into the charged coordination layers [{Mn(H₂O)₃}₄{Re₆Se₈(CN)₆}₃]^4– ₂ through the Mn²⁺ cations. The Mn²⁺ cations are coordinated in a layer by three cyano nitrogen atoms of the cluster complexes; the Mn–N bond lengths are 2.13(4) and 2.21(2) Å. Each [Re₆Se₈(CN)₆]^4– anion is bonded to three manganese cations Mn(1). The anions are bonded additionally to the Mn(2) cations disordered over two close positions.     

Synthesis and structure of the organoantimony peroxide solvates [Sb4(μ2-O)4(O2)2(C6H3MeO-2,Br-5)8]·1.5C4H8O2 and [Sb4(μ2-O)4(O2)2(C6H3MeO-2,Br-5)8]·6C4H8O2

The organoantimony peroxide (Ar₂SbO)₄(O₂)₂ (Ar = C₆H₃OMe-2, Br-5) was synthesized by the oxidation of Ar3Sb with hydrogen peroxide in the presence or acetoxime or acetophenone oxime in dioxane. The product crystallizes with various content of the solvent molecules in the crystal unit cell [1.5 (I) and 6 (II), respectively]. An X-ray diffraction analysis of the solvates was performed. Four antimony atoms in the peroxide are in the octahedral coordination, and are linked through bridging oxygen atoms and two peroxide groups. The distances Sb-C, Sb-O_bridge, Sb-O_peroxide, O-O and Sb...Sb are 2.117–2.122, 1.960–1.972, 2.193–2.235, 1.461, 1.465 and 3.223–3.237 Å in I, and 2.112, 2.119, 1.957, 1,966, 2.204, 2,246, 1,467, and 3.2439 Å in II.     

Synthesis, properties, and thermal decomposition of compounds [Co(En)3][Fe(CN)6] · 2H2O and [Co(En)3]4[Fe(CN)6]3 · 15H2O

Binary complex salts, [Co(En)₃][Fe(CN)6] · 2H₂O and [Co(En)₃]₄[Fe(CN)₆]₃ · 15H₂O, are synthesized. The properties of the salts and their thermolysis in air, dihydrogen, and argon are studied. Oxides of the central ions of the binary complex salts are found to be the thermolysis products in an oxidative atmosphere. Solid solutions (intermetallic compounds) CoFe are the thermolysis products in the reductive atmosphere, whereas intermetallides containing considerable amounts of C and N and an impurity of Co and Fe oxides are the thermolysis products in an inert atmosphere. Gaseous thermolysis products in dihydrogen and argon are NH₃, hydrocarbons, and ethylenediamine.     

Syntheses and Crystal Structures of (H3O)(C3H5N2)[Mn(OH)6 Mo6O18]·3.5H2O and (H3O)3[Co(OH)6Mo6O18]·7H2O

The crystals of the title compounds (H3O)(C3H5N2)[Mn(OH)6Mo6O18]·3.5H2O 1 and (H3O)3[Co(OH)6Mo6O18]·7H2O 2 have been prepared and structurally determined by X-ray single-crystal diffraction. Compound 1 crystallizes in monoclinic, space group C2/c with a = 21.5018(9), b = 10.9331(5), c = 11.8667(5)A,β = 95.3570(10)o, V = 2777.5(2)A3, Z = 4, Dc = 2.802 g/cm3, Mr = 1171.80,μ(MoKα) = 3.173 mm-1, F(000) = 223, the final R = 0.0458 and wR = 0.1041 for 2093 observed reflections (I>2σ(I)); Compound 2 crystallizes in monoclinic, space group P21/c with a = 11.4042(12), b = 10.9481(11), c = 11.6722(12)A, β= 99.948(2)o, V = 1435.4(3)A3, Z = 2, Dc = 2.794 g/cm3, Mr = 1207.80,μ(MoKα) = 3.223 mm-1, F(000) = 1160, the final R = 0.0544 and wR = 0.1066 for 1906 observed reflections (I > 2σ(I)). Both compounds 1 and 2 adopt the Anderson structure, in which the anion is of centrosymmetry and formed by six octahedral edge-sharing MoO6 units surrounding the central MO6 (M = Mn or Co) octahedron.     

Unique seven-node rare-earth octacyanomolybdate(IV) three-dimensional molecular frameworks: {[Er(H2O)5(Er(H2O)4)3][Mo(CN)8]3·11H2O}n and {[Eu(H2O)5(Eu(H2O)4)3][Mo(CN)8]3·11H2O}n

The crystal structure analyses of {[Er(H₂O)₅(Er(H₂O)₄)₃][Mo(CN)₈]₃·11H₂O}_n (1) and {[Eu(H₂O)₅(Eu(H₂O)₄)₃][Mo(CN)₈]₃·11H₂O}_n (2), show that they are not only new neutral three-dimensional rare-earth octacyanomolybdate(IV) molecular frameworks, but that they also belong to an unknown structure type having seven different nodes. To the best of our knowledge this is different to any other known molybdenum(IV) octacyanide complexes published to date. Both compounds crystallize in the triclinic system, space group P-1, and are isostructural and isotypic. The coordination polyhedra of the molybdenum atoms in the three different [Mo(CN)₈]⁴⁻ anions are trigonal prisms, with two additional atoms. A new bridging mode for octacyanometallates is also observed with five of the eight cyanide groups involved in bridging either three or four rare-earth atoms, while the three remaining cyanide groups are terminal and are involved in hydrogen bonding. The four rare-earth atoms in 1 and 2 have different coordination polyhedra in the form of trigonal prisms with two additional atoms. The three-dimensional structures are made up of infinite two-dimensional slabs linked by one of the rare-earth metal atoms. In both compounds, apart from the 17 coordinated water molecules, there are 11 lattice water molecules of crystallization present in the cavities of the three-dimensional frameworks. The 28 water molecules and the terminal CN⁻ groups are involved in an extensive O–H⋯O and O–H⋯N hydrogen bonding network.     

Syntheses and structures of p-HOOCC6F4COOH · H2O (H2L · H2O) and luminescent coordination polymers [Tb2(H2O)4(L)3 · 2H2O] n and Tb2(Phen)2(L)3 · 2H2O

Compounds p-HOOCC₆F₄COOH · H₂O (H₂L · H₂O), [Tb₂(H₂O)₄(L)₃ · 2H₂O] _n (I), and Tb₂(Phen)₂(L)₃ · 2H₂O (II) are synthesized. According to the X-ray structure analysis data, the crystal structure of H₂L · H₂O is built of centrosymmetric molecules H₂L and molecules of water of crystallization. The crystal structure of compound I is built of layers of coordination 2D polymer [Tb₂(H₂O)₄(L)₃] _n and molecules of water of crystallization. The ligands are the L^2? anions performing both the tetradentate bridging and pentadentate bridging-chelating functions. The coordination polyhedron TbO₉ is a distorted three-capped trigonal prism. Acid H₂L manifests photoluminescence in the UV region (??_max = 368 nm). Compounds I and II have the green luminescence characteristic of the Tb³⁺ ions, and the band with ??_max = 545 nm (transition ⁵ D ₄?? ⁷ F ₅) is maximum in intensity. The photoluminescence intensity of compound II is higher than that for compound I.     

Syntheses and structural determination of mononuclear nine-coordinate (MnH)[GdIII(EDTA)(H2O)3] · 4H2O and 2D ladder-like binuclear nine-coordinate (MnH)2[Gd 2 III (H2TTHA)2] · 4H2O

Two title rare earth metal coordination compounds, (MnH)[Gd^III(Edta)(H₂O)₃] · 4H₂O (I) and (MnH)₂[Gd ₂ ^III (H₂Ttha)₂] · 4H₂O (II), where Mn = methylamine, H₄Edta = ethylenediamine-N,N,N′,N′-tetraacetic acid, H₆Ttha = triethylenetetramine-N,N,N′,N″,N′″,N′″-hexaacetic acid), have been successfully synthesized through direct heating reflux and characterized by FT-IR spectroscopy, thermal analysis and single-crystal X-ray diffraction techniques. In complex I, the Gd³⁺ ion is nine-coordinated by an Edta ligand and three water molecules, yielding a pseudo-monocapped square antiprismatic (MC-SAP) conformation. Complex I crystallizes in the orthorhombic crystal system with space group Fdd2. The cell dimensions are as follows: a = 19.5207(17), b = 35.387(3), c = 12.5118(11) Å, and V = 8642.8(13) ų. The central Gd³⁺ ion of II is also ninecoordinate, forming tricapped trigonal prismatic (TC-TP) conformation with three amine nitrogen atoms and six oxygen atoms. Complex II crystallizes in the monoclinic crystal system with P2/c space group. The crystal data are as follows: a = 14.4301(13), b = 11.2400(11), c = 17.7102(16) Å, β = 112.606(2)°, and V = 2651.8(4) ų. There retain outer-protonated and inner-protonated carboxyl oxygen atoms in the [Gd ₂ ^III (H₂Ttha)₂]^2? complex anion. In II, there are only one type of methylamine cation (MnH⁺) as the counter ion, which connects [Gd ₂ ^III (H₂Ttha)₂]^2? complex anions and lattice water molecules through hydrogen bonds, leading to the formation of 2D ladder-like layer structure.     

The system of hydrogen bonds in Ba2Re6Te8(CN)6·12H2O: Simulation and NMR study

The crystal hydrate Ba₂Re₆Te₈(CN)₆· 12H₂O whose structural fragments are the cluster onions [Ba₂Re₆Te₈(CN)₆]^4? is studied by¹H NMR. In the triclinic cell (space group P-1), the barium atoms coordinated by six water molecules are united into the dimers [Ba· 5H₂O] ₂ ⁴⁺ by two bridging H₂O molecules; the water molecules lying outside the coordination sphere of Ba are located in the structure channels running along the [001] direction. Diffusion of H₂O molecules was found in the range of temperatures 100?C below the temperature of intense dehydration of the crystal. The structure of the water lattice of the compound is modeled by calculating Coulomb interactions between hydrogen and surrounding atoms and analyzing the NMR spectra recorded under translational diffusion conditions for H₂O. Half of the protons in H₂O molecules are involved in the formation of hydrogen bonds whose lengths lie within 2.78–2.86 å (O-H…O) and 2.92-3.13 å (O-H…N). The water lattice structure is preserved up to ≈100?C. The water subsystem is radically rearranged upon subsequent heating followed by partial dehydration of the crystal.     

ChemInform Abstract: Unique Seven-Node Rare-Earth Octacyanomolybdate(IV) Three-Dimensional Molecular Frameworks: {[Er(H2O)5(Er (H2O)4)3] [Mo(CN)8]3·11H2O}n and {[Eu(H2O)5(Eu (H2O)4)3] [Mo(CN)8]3·11H2O}n.

Good quality single crystals of the title compound are obtained by reaction of H₄[Mo(CN)₈] with the rare earth carbonates.     

Tetranuclear bismuth complexes Bi4(O)2(O2CC6H2F3-3,4,5)8 · 2C6H6 and Bi4(O)2(O2CC6H2F3-3,4,5)8 · 2C6H4Me2-1,4: Synthesis and structures

X-ray diffraction study of tetranuclear organobismuth complexes Bi₄(O)₂(O₂CC₆H₂F₃-3,4,5)₈ · 2⁶-C₆H₆ and Bi₄(O)₂(O₂CC₆H₂F₃-3,4,5)₈ · 2(C₆H₄Me₂-1,4) revealed four Bi atoms connected through the bridging carboxylate ligands and the O atoms. The coordination sphere of the terminal Bi atoms includes the chelate carboxylate ligand and the 6-arene molecule. The bridging O atoms are tricoordinated, the distances between the terminal Bi atom and the center of benzene molecule (1,4-dimethylbenzene) are 3.024 Å(3.131 Å).Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 1, 2005, pp. 4–11.Original Russian Text Copyright © 2005 by Sharutin, Egorova, Sharutina, Ivanenko, Adonin, Starichenko, Pushilin, Gerasimenko.     

Synthesis and Crystal Structure of a Cyano-bridged Bimetallic Complex [La(betaine)2(H2O)6Fe(CN)6]·2H2O

The title complex [La(betaine)2(H2O)6Fe(CN)6](2H2O (betaine = (CH3)3NCH2CO2) has been synthesized and characterized by X-ray single-crystal structure analysis. The crystal crystallizes in monoclinic, space group P21/n with a = 15.793(5), b = 8.927(3), c = 22.257(7) (A), β = 110.147(5)°, C16H38FeLaN8O12, Mr = 729.31, Z = 4, V = 2946.0(15) (A)3, Dc = 1.640 g/m3, μ(MoKα) = 1.988 mm-1, F(000) =1476, R = 0.0388 and wR = 0.0827 for 4237 observed reflections (I > 2σ(I)). The La3+ ion is nine-coordinated by one cyano nitrogen atom and eight oxygen atoms of two betaine and six water molecules. Each complex molecule is connected to form a 3D network structure by some O-H…O and O-H…N hydrogen bonds.     

Synthesis and structure of two molybdovanadates containing coordinatively bound oxalato ligands: (NH4)6[Mo6V2O24(C2O4)2]·6H2O and (NH4)4[H2Mo2V2O12(C2O4)2]·2H2O

The compounds (NH₄)₆[Mo₆V₂O₂₄(C₂O₄)₂]·6H₂O (I) and (NH₄)₄[H₂Mo₂V₂O₁₂(C₂O₄)₂]·2H₂O (II) have been prepared from molybdenum(VI) oxide and ammonium vanadate in aqueous solution through the addition of ammonium oxalate, and their structures determined by X-ray structure analysis. Whereas the molybdovanadate anion [Mo₆V₂O₂₄(C₂O₄)₂]⁶⁻ found in (I) consists of six MoO₆ and two VO₆ edge-sharing octahedra of the γ-[Mo₈O₂₆]⁴⁻ type structure, the tetranuclear anion [H₂Mo₂V₂O₁₂(C₂O₄)₂]⁴⁻ of (II) adopts the structure with a M₄O₁₆ core. Both complexes contain bidentate oxalato ligands bonded to the vanadium ions. In both crystal structures the molybdovanadate anions are mutually hydrogen bonded by ammonium ions and water molecules.     

Syntheses and Structural Researches of Nine-Coordinated (NH4)[EuIII(Edta)(H2O)3] · H2O and (NH4)3[EuIII(Ttha)] · 5H2O1

The crystal and molecular structures of the (NH₄)[Eu^III(Edta)(H₂O)₃] · H₂O (I); Edta^4– is an ethylenediaminetetraacetate anion) and (NH₄)₃[Eu^III(Ttha)] · 5H₂O (II); Ttha^6– is a triethylenetetraminehexaacetate anion) complexes have been determined by single-crystal X-ray structure analysis. The crystal of complex I is orthorhombic with Fdd2 space group. The crystal data are as follows: a = 1.9505(8) nm, b = 3.5445(14) nm, c = 1.2442(5) nm, V = 8.602(6) nm³, Z = 16, M = 531.29, p = 1.579 g cm^–3, = 2.970 mm^–1, and F(OOO) = 3924. The final R and wR values are 0.0378 and 0.1030 for 2799 (I > 2.0(I)) unique reflections, and 0.0495 and 0.1072 for all 6237 reflections, respectively. The nine-coordinated [Eu^III(Edta)(H₂O)₃]^– complex anion has a pseudo-monocapped square antiprismatic structure in which the nine coordinated atoms, two N and four O are from one Edta ligand and three O atoms from water molecules. The crystal of complex II is monoclinic with P2₁/c space group. The crystal data are as follows: a = 1.0387(3) nm, b = 1.2737(4) nm, c = 2.3031(7) nm, = 90.870(5)°, V = 3.047(2) nm³, Z = 4, M = 784.58, C 51.83, H 4.32, N 115.12. = 1.710 g cm^–3, = 2.143 mm^–1 and F(000) = 1608. The final R and wR are 0.0400 and 0.0720 for 5909 (I > 2.0(I)) unique reflections, and 0.0747 and 0.0799 for all 13825 reflections, respectively. The nine-coordinated [Eu^III(Ttha)]^3– complex anion has a pseudo-monocapped square antiprismatic structure in which the Ttha acts as an ninedentate ligand with four N atoms of amino groups and five O atoms of carboxylic groups actually, in addition, there is a non-coordinated free carboxylic group in the structure.     

The Oxalato-Titanium-Containing Tungstophosphate(V) Dimers, [Ti8(C2O4)8P2W18O76(H2O)4]18− and [Ti6(C2O4)4P4W32O124]20−

The oxalato-titanium(IV)-containing, dimeric 18-tungsto-2-phosphate [Ti₈(C₂O₄)₈P₂W₁₈O₇₆(H₂O)₄]^18? (1) and the 32-tungsto-4-phosphate [Ti₆(C₂O₄)₄P₄W₃₂O₁₂₄]^20? (2) are formed upon reaction of the oxalato-titanium complex [TiO(C₂O₄)₂]^2? with the trilacunary Keggin precursor [A-α-PW₉O₃₄]^9? and the hexalacunary Wells–Dawson precursor [H₂P₂W₁₂O₄₈]^12?, respectively. Polyanion 1 consists of two {PW₉} units encapsulating eight titanium centers and connected to each other via two Ti–O–Ti bridges, and crystallizes as a mixed potassium-sodium-lithium salt in the triclinic space group $P{\bar{1}}$ . Polyanion 2 comprises two {P₂W₁₆} units containing each two titanium atoms, and the two half-units are connected via two titanium atoms decorated by two oxalate groups each, and crystallizes as a mixed potassium-lithium salt in the rhombohedral space group $R{\bar{3}}c$ . Polyanions 1 and 2 were characterized in the solid state by single-crystal XRD, FT-IR, and TGA, whereas polyanion 2 was also investigated by ³¹P and ¹⁸³W NMR.