Ca2[BN2]H: The First Nitridoborate Hydride — Synthesis,Crystal Structure,and Vibrational Spectra

Ca₂[BN₂]H was synthesized from a mixture of the binary components Ca₃N₂, CaH₂ and BN (molar ratio 1 : 1 : 2) in a sealed steel ampoule encapsulated in an evacuated silica tube at 1273 K. Ca₂[BN₂]H crystallizes in the orthorhombic space group Pnma (no. 62) with a = 9.2015(8)Å, b = 3.6676(2)Å and c = 9.9874(12)Å (Z = 4; Pearson symbol oP24). The crystal structure is a filled variant of the Co₂P type and can be formulated as Co₂P(□^t)₃(□^py)₃ ≡ Ca₂[N—B—N]H(□^t)₂(□^py)₃ (□^t and □^py = tetrahedral and square‐pyramidal hole, respectively). The d(B—N) bond lengths and bond angle for the linear [N—B—N]^3— anion are: d(B—N1) = 1.324(3)Å, d(B—N2) = 1.350(2)Å and ∠N—B—N = 177.2(2)°. The vibrational spectra of Ca₂[BN₂]H confirm the presence of [N—B—N]^3— groups deviating only slightly from the ideal D_∞h symmetry. The vibrational frequencies and the ?(B—N) force constants are discussed and compared with those of the isotypic compound Ca₂[BN₂]F.     

Ca3[BN2]I3: The First Halide‐Rich Alkaline Earth Nitrido­borate with Isolated [BN2]3– Units

The title compound Ca₃[BN₂]I₃ was obtained from reactions of mixtures of the starting materials Ca₃[BN₂]₂ and CaI₂ in a 1:4 ratio in sealed Nb tubes at 1223 K. The crystal structure was solved from powder synchrotron diffraction data. Ca₃[BN₂]I₃ is the first example of a halide‐rich nitridoborate crystallizing in the rhombohedral space group R32 [no. 155, Pearson code: hR96; Z = 12; a = 16.70491(2) Å, c = 12.41024(2) Å]. The crystal structure is built up by two interpenetrating networks of condensed edge‐sharing [BN₂]@Ca₆ and [□]@I₆ trigonal antiprisms (□ = void). In Ca₃[BN₂]I₃ two crystallograhically distinct [BN₂]^3– anions are present with d(B1–N) = 1.393(2) Å and d(B2–N) = 1.369(9) Å. Their bond angles are practically linear, varying only slightly: N–B1–N = 179(1)° and N–B2–N = 180°. Vibrational spectra were interpreted based on the D_∞h symmetry of the discrete linear [N–B–N]^3– moieties, considering the site symmetry reduction and the presence of two distinct [BN₂]^3– groups.     

Na3[BN2] and Na2K[BN2]: A Known and a Novel Alkali Metal Dinitridoborate Obtained via Mild Thermal Dehydrogenation

Na₃[BN₂] and Na₂K[BN₂] were obtained as white polycrystalline powders from the reaction of the respective binary mixtures NaNH₂:NaBH₄ and NaNH₂:KBH₄ in molar ratio 2:1 at 873 K and 683 K, respectively, in an argon stream. According to the results of thermal analysis measurements, both compounds are thermally stable only up to 954 K (Na₃[BN₂]) and 712 K (Na₂K[BN₂]), respectively, decomposing under evolution of alkali metal and nitrogen to yield hexagonal BN as final residue, which was identified from powder patterns. The crystal structure of Na₃[BN₂] {β‐Li₃[BN₂] type; P2₁/c (No. 14); Z = 4} was confirmed and the unit cell parameters redetermined: a = 5.724(1) Å, b = 7.944(1) Å, c = 7.893(1) Å, β = 111.31(1)°. According to X‐ray powder data, Na₂K[BN₂] crystallizes isotypic to Na₂KCuO₂ in the tetragonal space group I4/mmm (No. 139) with a = 4.2359(1) Å, c = 10.3014(2) Å and Z = 2. The crystal structure of Na₂K[BN₂] is composed of linear [N–B–N]^3– anions centering elongated M₁₄ rhombic dodecahedra, which are formed by 8 sodium and 6 potassium atoms. The [BN₂]@Na_8/4K_6/6 polyhedra are stacked along [001] and condensed via common tetragonal faces to generate a space‐filling 3D arrangement. The B–N bond lengths for the strictly linear [N–B–N]^3– units are 1.357(4) Å. Vibrational spectra of the title compounds were measured and analyzed based on D_∞h symmetry of the relevant [N–B–N]^3– groups taking into account the site symmetry effects for Na₃[BN₂]. Both the wavenumbers, as well as the calculated valence force constants f(B–N) = 7.29 N · cm^–1 (Na₃[BN₂]) and 7.33 N · cm^–1 (Na₂K[BN₂]), respectively, are in good agreement with those of the known alkali and alkaline earth dinitridoborates.     

The Cluster Compounds Ag[W6Br14] and Ag2[W6Br14]

The reaction of W₆Br₁₂ with AgBr in evacuated silica tubes (temperature gradient 925 K/915 K) yielded brownish black octahedra of Ag[W₆Br₁₄] ( I ) and yellowish green platelets of Ag₂[W₆Br₁₄] ( II ) both in the low temperature zone. ( I ) crystallizes cubically (Pn3 (no. 201); a = 13.355 Å, Z = 4) and ( II ) monoclinically (P2₁/c (no. 14); a = 9.384 Å, b = 15.383 Å, c = 9.522 Å, β = 117.34°, Z = 2). Both crystal structures contain isolated cluster anions, namely [(W₆Brⁱ₈)Br^a₆]^1– and [(W₆Brⁱ₈)Br^a₆])]^2–, respectively, with the mean distances and angles: ( I ) d(W–W) = 2.648 Å, d(W–Brⁱ) = 2.617 Å, d(W–Br^a) = 2.575 Å, d(Brⁱ…Brⁱ) = 3.700 Å, d(Brⁱ…Br^a) = 3.692 Å, ∠W–Brⁱ–W = 60.78°. ( II ) d(W–W) = 2.633 Å, d(W–Brⁱ) = 2.624 Å, d(W–Br^a) = 2.613 Å, d(Brⁱ…Brⁱ) = 3.710 Å, d(Brⁱ…Br^a) = 3.707 Å, ∠W–Brⁱ–W = 60.23°. The Ag⁺ cations are trigonal antiprismatically coordinated in ( I ) with d(Ag–Br) = 2.855 Å, but distorted trigonally planar in ( II ) with d(Ag–Br) = 2.588–2.672 Å. The structural details of hitherto known compounds with [W₆Br₁₄] anions will be discussed.     

Vibrational Spectra and Magnetic Properties of Eu3[BN2]2 and LiEu4[BN2]3

Eu₃[BN₂]₂ and LiEu₄[BN₂]₃ were synthesized from a stoichiometric mixture of EuN, BN, europium metal and Li₃N, EuN and BN (ratio: 1:4:3) in sealed niobium ampoules at 1475 and 1275 K, respectively. Temperature dependent susceptibility measurements of Eu₃[BN₂]₂ and LiEu₄[BN₂]₃ show Curie‐Weiss behavior with experimental magnetic moments of 8.03(5) and 8.5(1) μ_B/Eu atom, respectively, compatible with divalent europium. Both nitridoborates order ferromagnetically at T_C = 32.0(5) K (Eu₃[BN₂]₂) and 22.0(5) K (LiEu₄[BN₂]₃). The saturation magnetizations of 5.73(5) μ_B/Eu atom at 5 K and 7 T for Eu₃[BN₂]₂ and 4.2 μ_B/Eu atom at 5 K and 2 T for LiEu₄(BN₂)₃ are smaller than the maximum value of 7 μ_B. ¹⁵¹Eu Mössbauer data of Eu₃[BN₂]₂ at 4.2 K show an isomer shift of —11.4(1) mm/s and an experimental line width of 3.1(2) mm/s. Full magnetic hyperfine field splitting with 26.2(3) T at the europium nuclei is detected. Vibrational spectra of Eu₃[BN₂]₂ are interpreted on the basis of discrete [BN₂]^3— units with symmetry D_∞h by taking into account the existence of two crystallographically independent [BN₂]^3— anions and their dynamic coupling in the unit cell (factor group splitting).     

Diversity of Strontium Nitridogermanates(IV): Novel Sr4[GeN4], Sr8Ge2[GeN4], and Sr17Ge2[GeN3]2[GeN4]2

Single crystals of three new strontium nitridogermanates(IV) were grown in sealed niobium ampules from sodium flux. Dark red Sr₄[GeN₄] crystallizes in space group P2₁/c with a = 9.7923(2) Å, b = 6.3990(1) Å, c = 11.6924(3) Å and β = 115.966(1)°. Black Sr₈Ge₂[GeN₄] contains Ge^4– anions coexisting with [Ge^IVN₄]^8– tetrahedra and adopts space group Cc with a = 10.1117(4) Å, b = 17.1073(7) Å, c = 10.0473(4) Å and β = 115.966(1)°. Black Sr₁₇Ge₆N₁₄ features the same anions alongside trigonal planar [Ge^IVN₃]^5– units. It crystallizes in P1 with a = 7.5392(1) Å, b = 9.7502(2) Å, c = 11.6761(2) Å, α = 103.308(1)°, β = 94.651(1)° and γ = 110.248(1)°.     

K2[O(HgSO3)3], a new sulfitomercurate with an [OHg3] core

The structure of dipotassium μ₃‐oxido‐tris[sulfitomercurate(II)], K₂[O(HgSO₃)₃], is characterized by segregation of the K⁺ cations and complex [O(HgSO₃)₃]²⁻ anions into layers parallel to (010). The anion has m symmetry and is a new example of a μ₃‐oxido‐trimercurate complex with a central [OHg₃] core. This unit adopts the shape of a flat, almost trigonal, pyramid (mean O—Hg = 2.072 Å and mean Hg—O—Hg = 110.8°). The two independent Hg—S bonds have nearly the same length (mean Hg—S = 2.335 Å). Due to intermolecular O...Hg donor–acceptor interactions greater than 2.65 Å, the O—Hg—S fragments are slightly bent. The [KO₉] coordination polyhedron of the K⁺ cation approaches a distorted tricapped trigonal prism with a [6+1+2] coordination.     

Synthesis,Crystal Structure and Properties of [Mn(hdpa)2(N(CN)2)2] and [Co(hdpa)2(N(CN)2)2] (hdpa = 2, 2'‐Dipyridylamine)

Two new transition metal(II) complexes [M(hdpa)₂(N(CN)₂)₂] (M = Mn ( 1 ), Co ( 2 ); hdpa = 2, 2'‐dipyridylamine) have been prepared and characterized structurally and magnetically. Both compounds crystallize in the monoclinic space group C2/c. 1 and 2 are isotypic with the unit cell parameters a = 8.634(9), b = 13.541(14), c = 21.99(2) Å, β = 94.806(18)°, and V = 2562(5) ų for 1 , a = 8.617(3) Å, b = 13.629(5)Å, c = 21.598(8)Å, β = 94.593(6)°, and V = 2528.4(15)ų for 2 , and Z = 4 for both. According to X‐ray crystallographic studies, each metal(II) ion was six‐coordinated with four nitrogen atoms from two bidentate hdpa ligand and two nitrogen atoms from two N(CN)^— anions to form slightly distorted octahedrons. Adjacent complex molecules are connected by hydrogen bonds or π···π interactions to form three‐dimensional network. The IR and UV spectroscopy were measured and the magnetic behaviors were investigated.     

Lithium Ion Motion in Lithium Nitridoborate Chalcogenides Li5(BN2)Ch (Ch = Se,Te)

The compounds Li₅(BN₂)Se and Li₅(BN₂)Te were synthesized at 900 °C in a closed system utilizing weld shut niobium ampoules and obtained as white microcrystalline powders. Their crystal structures were solved and refined on the basis of single‐crystal X‐ray diffraction data with the space group I4₁md [a = 6.3983(4) Å, c = 11.1072(9) Å for Li₅(BN₂)Se and a = 6.5878(3) Å, c = 11.4382(7) Å for Li₅(BN₂)Te]. The temperature dependent Li⁺ motion was investigated by ⁷Li MAS NMR spectroscopy.     

Crystal Structure,Phase Transition and Ferroelastic Properties of [N(CH3)4]3[As2Cl9]

The crystal structure of [N(CH₃)₄]₃[As₂Cl₉] is determined at 293 K. It crystallizes in trigonal space group P31c: a = 9.2199(8), c = 21.065(3)Å, Z = 2, R₁ = 0.0505, wR₂ = 0.1283. The crystal is built of the discrete bioctahedral [As₂Cl₉]^3— anions and the deformed tetramethylammonium cations. A structural phase transition in [N(CH₃)₄]₃[As₂Cl₉] is detected by the DSC and dilatometric techniques at 146/151 K (on cooling/heating). Dielectric relaxation studies in the frequency range 75 kHz — 5 MHz indicate reorientations of the tetramethylammonium cations within the high temperature phase. Optical observations show the existence of the ferroelastic domain structure below 146 K. The possible mechanism of phase transition is discussed on the basis of the presented results.     

La6(BN3)O6, ein Nitridoborat‐Oxid des Lanthans

La₆(BN₃)O₆, a Nitridoborate Oxide of Lanthanum Single‐crystals of La₆(BN₃)O₆ were formed in reactions of Li₃BN₂, Li₃N, and LaOCl at 950 °C. The structure was solved by single‐crystal X‐ray diffraction. La₆(BN₃)O₆crystallizes with the space group Cmcm (no. 63) containing Z = 4 formula units in the unit cell, with lattice parameters of a = 366.88(3) pm, b = 2509.2(3) pm, and c = 1101.1(1) pm (R1 = 0.054, wR2 = 0.065 for all collected symmetry independant reflections). The crystal structure reflects typical patterns obtained in structures of nitridoborates. Tri‐nitridoborate ions are coordinated by La³⁺ ions in a tricapped trigonal prismatic arrangement, being stacked via shared trigonal faces to form columns. The arrangement of the columns in the structure provides space for O^2— ions with CN = 4, 5, and 6.     

Beiträge zum Koordinationsverhalten von Oxidionen in anorganischen Feststoffen. IV [1] Darstellung,Kristallstruktur und spektroskopische Charakterisierung von NiP4O11 und CaNiP2O7

Synthesis, Crystal Structures, and Spectroscopic Characterization of NiP₄O₁₁ and CaNiP₂O₇ From melts single crystals of NiP₄O₁₁ and CaNiP₂O₇ have been grown. These allowed refinement of the crystal structures (NiP₄O₁₁: C1¯, Z = 8, a = 12, 753(4)Å, b = 12.957(3)Å, c = 10.581(4)Å, α = 89.42(2)°, β = 116.96(2)°, γ = 90.20(2)°, R1 = 0.027, wR2 = 0.072 for 3058 I_o > 2σ (I_o), 3291 independent reflections, 290 parameters; CaNiP₂O₇: P1¯, Z = 2, a = 6.433(3)Å, b = 6.536(4)Å, c = 6.515(2)Å, α = 66.4(2)°, β = 87.5(2)°, γ = 82.7(2)°, R1 = 0.026, wR2 = 0.062 for 1624 I_o > 2σ (I_o), 2189 independent reflections, 101 parameter) and measurement of polarized electronic absorption spectra in the uv/vis/nir region (6000—32000 cm^—1). NiP₄O₁₁ is isotypic to the series of ultraphosphates MP₄O₁₁ (M = Mn, Fe, Co, Cu, Zn, Cd) that exhibit a two‐dimensional network formed from ten‐membered phosphate rings. CaNiP₂O₇ completes the series of diphosphates AMP₂O₇ (A: Ca, Sr, Ba; M = Cr — Zn) and is isotypic to CaCoP₂O₇. Ni²⁺ ions in both phosphates show distorted octahedral coordination. The electronic transitions associated with the chromophores [Ni²⁺O₆] are nicely reproduced by calculations within the framework of the angular overlap model (AOM). The parametrisation scheme leads to e_{σ, norm}(2.0Å) = 3690 cm^—1 and B = 896 cm^—1 (C/B = 4.2) for CaNiP₂O₇ and e_{σ, norm}(2.0Å) = 4150 cm^—1 and B = 948 cm^—1 (C/B = 4.5) for NiP₄O₁₁ (Δ_o(CaNiP₂O₇) = 6800 cm^—1; Δ_o(NiP₄O₁₁) = 7100 cm^—1).     

Alkoxo‐Verbindungen des dreiwertigen Eisen: Synthese und Charakterisierung von [Fe2(OtBu)6], [Fe2Cl2(OtBu)4], [Fe2Cl4(OtBu)2] und [N(nBu)4]2[Fe6OCl6(OMe)12]

Alkoxo Compounds of Iron(III): Syntheses and Characterization of [Fe₂(OtBu)₆], [Fe₂Cl₂(OtBu)₄], [Fe₂Cl₄(OtBu)₂] and [N(nBu)₄]₂[Fe₆OCl₆(OMe)₁₂] The reaction of iron(III)chloride in diethylether with sodium tert‐butylat yielded the homoleptic dimeric tert‐‐butoxide Fe₂(OtBu)₆ ( 1 ). The chloro‐derivatives [Fe₂Cl₂(OtBu)₄] ( 2 ), and [Fe₂Cl₄(OtBu)₂] ( 3 ) could be synthesized by ligand exchange between 1 and iron(III)chloride. Each of the molecules 1 , 2 , and 3 consists of two edge‐sharing tetrahedrons, with two tert‐butoxo‐groups as μ₂‐bridging ligands. For the synthesis of the alkoxides 1 , 2 , and 3 diethylether plays an important role. In the first step the dietherate of iron(III)chloride FeCl₃(OEt₂)₂ ( 4 ) is formed. The reaction of iron(III)chloride with tetrabutylammonium methoxide in methanol results in the formation of a tetrabutylammonium methoxo‐chloro‐oxo‐hexairon cluster [N(nBu)₄]₂[Fe₆OCl₆(OMe)₁₂] ( 5 ). Crystal structure data: 1 , triclinic, P1¯, a = 9.882(2) Å, b = 10.523(2) Å, c = 15.972(3) Å, α = 73.986(4)°, β = 88.713(4)°, γ = 87.145(4)°, V = 1594.4(5) ų, Z = 2, d_c = 1.146 gcm^—1, R₁ = 0.044; 2 , monoclinic, P2₁/n, a = 11.134(2) Å, b = 10.141(2) Å, c = 12.152(2) Å und β = 114.157(3)°, V = 1251.8(4) ų, Z = 2, d_c = 1.377 gcm^—1, R₁ = 0.0581; 3 , monoclinic, P2₁/n, a = 6.527(2) Å, b = 11.744(2) Å, c = 10.623(2), β = 96.644(3)°, V = 808.8(2) ų, Z = 2, d_c = 1.641 gcm^—1, R₁ = 0.0174; 4 , orthorhombic, Iba2, a = 23.266(5) Å, b = 9.541(2) Å, c = 12.867(3) Å, V = 2856(2) ų, Z = 8, d_c = 1.444 gcm^—1, R₁ = 0.0208; 5 , trigonal, P3₁, a = 13.945(2) Å, c = 30.011(6) Å, V = 5054(2) ų, Z = 6, d_c = 1.401 gcm^—1; R_c = 0.0494.     

The molecular structures of cis-3-hexene and trans-3-hexene in the gas phase by electron diffraction and molecular mechanical calculations

The molecular structures of cis-3-hexene and of trans-3-hexene in the gas phase have been determined by electron diffraction combined with molecular mechanical calculations. For cis-3-hexene the data indicate the presence of the (+ac, +ac) and the (?ac, +ac) forms. In trans-3 -hexene three rotamers were observed, with an energy sequence E(+ac, +ac) ≈ E(?ac, +ac) < E(ac, sp). The refined r_α⁰-structural parameters are: cis-3-hexene: C-H = 1.073 Å, CC = 1.330 Å, C(sp²)-C(sp³) = 1.505 Å, ∠CCH(in CH₂) = 111.1°, ∠CCC = 111.4°, ∠(CC-C) = 129.1° trans-3-hexene: C-H = 1.078 Å, CC = 1.342 Å, C(sp²)-C(sp³) = 1.506 Å, ∠CCH(in CH₂) = 109.3°, ∠CCC = 112.8, ∠CC—C = 124.1°The agreement between calculated and experimental geometries and vibrational amplitudes is good.     

Tt‐Tt (Tt = Si,Ge) Dumb‐Bell Structures at Different Valence Electron Concentrations: Ln2MgSi2 (Ln = La,Ce), Yb2Li0.5Ge2, and Yb1.75Mg0.75Si2

The isostructural compounds Yb₂MgSi₂, La_2.05Mg_0.95Si₂, and Ce_2.05Mg_0.95Si₂, as well as Yb₂Li_0.5Ge₂ and Yb_1.75Mg_0.75Si₂, respectively, were synthesized from stoichiometric mixtures of the corresponding elements in sealed Nb‐ ampoules under argon atmosphere. The structures were determined by single crystal X‐ray diffraction: Yb₂MgSi₂ (P4/mbm (No. 127), a = 7.056(1), c = 4.130(1) ų, Z = 2), La_2.05Mg_0.95Si₂ (P4/mbm, a = 7.544(1), c = 4.464(1) ų, Z = 2), and Ce_2.05Mg_0.95Si₂ (P4/mbm, a = 7.425(1), c = 4.370(1) ų, Z = 2), Yb₂Li_0.5Ge₂ (Pnma (No. 62), a = 7.0601(6), b = 14.628(1), c = 7.6160(7) Å, V = 786.5ų, Z = 4), Yb_1.75Mg_0.75Si₂ (Pnma, a = 6.9796(1), b = 14.4009(1), c = 7.5357(1) Å, V = 757.43(2) ų, Z = 4). All compounds contain exclusively Tt‐Tt dumb‐bells (Tt = Si, Ge). The Si‐Si Zintl anions exhibit only very small variations of bond lengths which seem to be more due to cation matrix effects than to effective bond orders.     

Two New Quaternary Thiophosphates with Pseudo One‐dimensional Structures: Syntheses and Crystal Structures of Cs3Sm[PS4]2 and Rb3Sm[PS4]2

The new thiophosphates Rb₃Sm[PS₄]₂ and Cs₃Sm[PS₄]₂ were obtained as pale yellow needles using an in‐situ formed thiophosphate flux. Rb₃Sm[PS₄]₂ crystallizes in the space group P2₁ with a = 9.7061(19) Å, b = 6.7517(14) Å, c = 11.395(2) Å, β = 90.63(3)°, (Z = 2); Cs₃Sm[PS₄]₂ in space group P2₁/n with a = 15.311(3) Å, b = 6.8762(14) Å, c = 15.352(3) Å, β = 99.49(3)°, (Z = 4). The crystal structures are characterized by the formation of complex anionic chains, which run along the [010] direction in both structures. One of the two independent thiophosphate groups connects three Sm³⁺ cations to form an infinite zigzag like arrangement, while the other acts as a terminal ligand to one Sm³⁺ions. Such a μ₃ or face‐grafting coordination mode of a [PS₄]³⁻ anion is not very common. The Sm³⁺ ions are in bicapped trigonal prismatic chalcogen coordination. The average Sm–S distances within the trigonal prisms are close to 2.88Å, while the bonds to the capping atoms are distinctly longer. The chains are chiral yet their symmetry is close to 2₁/m. In contrast to the rubidium compound, Cs₃Sm[PS₄]₂ contains both enantiomorphs. In both structures the chains are arranged as a distorted hexagonal rod packing.     

Synthesis and Crystal Structure of Hexakis(N—allylthiourea)tetracopper(I) Tetratrifluoromethanesulfonate, [Cu4{CH2=CHCH2NHC(S)NH2}6](SO3CF3)4

Hexakis(N—allylthiourea)tetracopper(I) Tetratrifluoromethanesulfonate, [Cu₄{CH₂=CHCH₂NHC(S)NH₂}₆](CF₃SO₃)₄ (sp.gr.P2₁/n, a = 13.5463(8), b = 24.129(2), c = 19.128(1)Å, β = 108.053(6)°, Z = 4, R = 0.0440 for 13548 unique reflections) was obtained by reduction of Cu(CF₃SO₃)₂ with excess of N—allylthiocarbamide in benzene medium. Four crystallographical independent Cu atoms possess trigonal environment of three S atoms of CH₂=CHCH₂NHC(S)NH₂ moiety and form Cu₄S₆⁴⁺ adamantane—like fragments. The latteres are connected with CF₃SO₃^— anions via (C)—H···F hydrogen bonds.     

Darstellung,Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalyse von [PtX2ox]2−, X = Cl,Br

Synthesis, Crystal Structure, Vibrational Spectra, and Normal Coordinate Analysis of [PtX₂ox]²⁻, X = Cl, Br By treatment of [PtX₄]^2— (X = Cl, Br) with C₂O₄^2— (ox^2—) in water [PtCl₂ox]^2— and [PtBr₂ox]^2— are formed which have been isolated by ion exchange chromatography on diethylaminoethyl cellulose. The crystal structures of [(C₅H₅N)₂CH₂][PtCl₂ox]·2H₂O ( 1 ) (orthorhombic, space group Pbca, a = 18.451(1), b = 18.256(1), c = 19.913(1)Å, Z = 16) and [(C₅H₅N)₂CH₂][PtBr₂ox] ( 2 ) (monoclinic, space group P2₁/c, a = 7.249(1), b = 10.180(1), c = 21.376(1)Å, β = 93.415(9)°, Z = 4) reveal nearly planar complex anions with C_2v point symmetry. The bond lengths are Pt‐Cl = 2.286, Pt‐Br = 2.405 und Pt‐O = 2.016 ( 1 ) und 2.030Å ( 2 ). In the vibrational spectra the PtX stretching vibrations are observed at 335 and 336 ( 1 ) and 219 and 231 cm^—1 ( 2 ). The PtO stretching vibrations are coupled with internal modes of the oxalato ligands and appear in the range of 350 — 800 cm^—1. Using the molecular parameters of the X‐Ray determinations the IR and Raman spectra of the (n‐Bu₄N) salts are assigned by normal coordinate analysis. The valence force constants are f_d(PtCl) = 1.97, f_d(PtBr) = 1.78 and f_d(PtO) = 2.48 ( 1 ) and 2.38 mdyn/Å ( 2 ). Taking into account increments of the trans influence a good agreement between observed and calculated frequencies is achieved. The NMR shifts are δ(¹⁹⁵Pt) = 3603.9 ( 1 ) and 3318.1 ppm ( 2 ).     

Darstellung,Kristallstruktur, Schwingungsspektren und Normalkoordinatenanalyse von [Co(NH3)6][Os(SCN)6]

Synthesis, Crystal Structure, Vibrational Spectra, and Normal Coordinate Analysis of [Co(NH₃)₆][Os(SCN)₆] From the mixture of the linkage isomers [Os(NCS)_n(SCN)_6–n]^3–, n = 0–2, pure [Os(SCN)₆]^3– has been isolated by ion exchange chromatography on diethylaminoethyl cellulose. The X‐ray structure determination on a single crystal of [Co(NH₃)₆][Os(SCN)₆] (trigonal, space group R 3, a = 12.368(2), c = 11.830(2) Å, Z = 3) reveals that the thiocyanate ligands are exclusively S‐coordinated with the Os–S distance of 2.388 Å and the Os–S–C angle of 108.8°. The IR and Raman spectra of (n‐Bu₄N)₃[Os(SCN)₆] are assigned by normal coordinate analysis based on the molecular parameters of the X‐ray determination. The valence force constant f_d(OsS) is 1.42 mdyn/Å.     

Synthesis and Structure of Lithium Cadmium Selenite Hydroxide,LiCd2(SeO3)2(OH)

The new compound LiCd₂(SeO₃)₂(OH) has been hydrothermally synthesized and characterized by single‐crystal X‐ray diffraction and IR spectroscopy. It is built up from a network of edge‐ and vertex‐sharing pyramidal [SeO₃]^2— groups, distorted CdO₆ octahedra, and CdO₇ monocapped trigonal prisms. The cadmium‐centred groups form infinite columns, onto which Se atoms (as [SeO₃]^2— groups) are grafted. Cross‐linking between the columns results in a three‐dimensional framework which encapsulates [100] channels occupied by the tetrahedrally‐coordinated lithium cations. The H atom of the hydroxyl group appears to participate in a weak, bifurcated, hydrogen bond. Crystal data: LiCd₂(SeO₃)₂(OH), M_r = 502.67, monoclinic, P2₁/c (No. 14), a = 5.8184 (3)Å, b = 10.2790 (5)Å, c = 11.5021 (5)Å, β = 90.446(1)°, V = 687.89 (9)ų, Z = 4, R(F) = 0.021, wR(F²) = 0.046.