Synthesis and Crystal Structure of Cesium Hexamminesodium Decahydro‐closo‐decaborate‐Ammonia(1/1), Cs[Na(NH3)6][B10H10]·NH3

Cs[Na(NH₃)₆][B₁₀H₁₀]·NH₃ was synthesised from cesium and disodium‐decahydro‐closo‐decaborate Na₂B₁₀H₁₀ in liquid ammonia, from which it crystallized in form of temperature sensitive colorless plates (triclinic, P1¯, a = 8.4787(7) Å, b = 13.272(1) Å, c = 17.139(2) Å, α = 88.564(1)°, β = 89.773(1)°, γ = 81.630(1)°, V = 1907.5(3) ų, Z = 4). The compound is the first example of an alkali metal boranate with two different types of cations. The decahydro‐closo‐decaborate dianions [B₁₀H₁₀]^2— and the cesium cations form a equation/tex2gif-stack-1.gif[Cs₂(B₁₀H₁₀)₂]^2— layer parallel to the ac plane. These layers are separated by N—H···N‐hydrogen bonded hexamminesodium cations.     

First Characterization of an Extended Ammonium‐Ammonia Complex [{NH4(NH3)4}+(μ‐NH3)2] in the Crystal Structure of [NH4(NH3)4][Co(C2B9H11)2] · 2 NH3

The compound [NH₄(NH₃)₄][Co(C₂B₉H₁₁)₂] · 2 NH₃ ( 1 ) was prepared by the reaction of Na[Co(C₂B₉H₁₁)₂] with a proton‐charged ion‐exchange resin in liquid ammonia. The ammoniate 1 was characterized by low temperature single‐crystal X‐ray structure analysis. The anionic part of the structure consists of [Co(C₂B₉H₁₁)₂]^‐ complexes, which are connected via C‐H···H‐B dihydrogen bonds. Furthermore, 1 contains an infinite equation/tex2gif-stack-2.gif[{NH₄(NH₃)₄}⁺(μ‐NH₃)₂] cationic chain, which is formed by [NH₄(NH₃)₄]⁺ ions linked by two ammonia molecules. The N‐H···N hydrogen bonds range from 1.92 to 2.71Å (DHA = Donor···Acceptor angles: 136‐176°). Additional N‐H···H‐B dihydrogen bonds are observed (H···H: 2.3‐2.4Å).     

A S8‐like [Sb8]8− Zintl Anion in the Ammoniate [K17(Sb8)2(NH2)] · 17.5NH3

The ammoniate [K₁₇(Sb₈)₂(NH₂)] · 17.5NH₃ was synthesized by reduction of antimony with potassium in liquid ammonia. Single crystals were isolated and characterized by low temperature X‐ray structure analysis. [K₁₇(Sb₈)₂(NH₂)] · 17.5NH₃ crystallizes in the space group P2₁/c (No. 14) with a = 12.976(1) Å, b = 24.536(1) Å, c = 22.858(1) Å and β = 99.17(1)°. The ammoniate contains crown‐shaped [Sb₈]^8? Zintl anions which are analogous to S₈ rings. The presence of amide NH₂^? as an additional anion is deduced from coordination observations and the close similarity of structural features to the structure of KNH₂.     

[Sb11]3− and [As11]3−: Synthesis and Crystal Structure of Two New Ammoniates containing Trishomocubane‐like Polyanions

The ammoniates [K(18‐crown‐6)(NH₃)₂]₃Sb₁₁ · 5.5NH₃ ( 1 ) and [Cs(18‐crown‐6)]₂CsAs₁₁ · 8NH₃ ( 2 ) (18‐crown‐6 = 18C6: 1,4,7,10,13,16‐Hexaoxacyclooctadecan) were synthesized by either the reaction of K₃Sb₇ with SbPh₃ in liquid ammonia or by extraction of Cs₃As₁₁ with liquid ammonia. Single crystals were isolated and characterized by low temperature X‐ray structure analysis. [K(18‐crown‐6)(NH₃)₂]₃Sb₁₁ · 5.5NH₃ crystallizes in the space group with a = 13.31(2) Å, b = 15.161(2) Å, c = 22.521(3) Å, α = 99.23(1)°, β = 100.99(1)° and γ = 105.03(1)°. [Cs(18‐crown‐6)]₂CsAs₁₁ · 8NH₃ crystallizes in the monoclinic space group C2/c with a = 20.009(3) Å, b = 17.024(1) Å, c = 19.838(2) Å and β = 119.732(9)°. While 1 contains isolated [Sb₁₁]^3? anions and [K(18‐crown‐6)(NH₃)₂]⁺ complexes, cesium–arsenic contacts lead to one–dimensionally infinite chains in 2 .     

Solvothermal Synthesis and Crystal Structures of Two Thioantimonate(V) Compounds with the [SbS4]3— Anion Acting as a Monodentate Ligand: [Mn(C6H18N4)(C6H19N4)]SbS4 and [Mn(C6H14N2)3]2[Mn(C6H14N2)2(SbS4)2]·6H2O

The two novel thioantimonate(V) compounds [Mn(C₆H₁₈N₄)(C₆H₁₉N₄)]SbS₄ ( I ) and [Mn(C₆H₁₄N₂)₃][Mn(C₆H₁₄N₂)₂(SbS₄)₂]·6H₂O ( II ) were synthesized under solvothermal conditions by reacting elemental Mn, Sb and S in the stoichiometric ratio in 5 ml tris(2‐aminoethyl)amine (tren) at 140 °C or chxn (trans‐1, 2‐diaminocyclohexane, aqueous solution 50 %) at 130 °C. Compound I crystallises in the triclinic space group P1¯, a = 9.578(2), b = 11.541(2), c = 12.297(2)Å, α = 62.55(1), β = 85.75(1), γ = 89.44(1)°, V = 1202.6(4)ų, Z = 2, and II in the monoclinic space group C2/c, a = 32.611(2), b = 13.680(1), c = 19.997(1)Å, β = 117.237(5)°, V = 7931.7(8)ų, Z = 4. In I the Mn²⁺ cation is surrounded by one tetradentate tren molecule, one protonated tren acting as a monodentate ligand and a monodentate [SbS₄]^3— anion yielding a distorted octahedral environment. In II one unique Mn²⁺ ion is in an octahedral environment of three bidentate chxn molecules and the second independent Mn²⁺ ion is coordinated by two chxn ligands and two monodentate [SbS₄]^3— units leading to a distorted octahedral surrounding. The compounds were investigated and characterized with thermal and spectroscopic methods.     

Darstellung,Eigenschaften und Kristallstruktur von Na3[Yb(NH2)6]

Preparation, properties, and crystal structure of Na₃[Yb(NH₂)₆] Na₃[Yb(NH₂)₆] was prepared by the reaction of Na and Yb in the atomic ration 3:1 with ammonia at 150°C and 200 atm as a light grey microcrystalline powder. Colourless single crystals were obtained at 180°C and ～6000 atm. It decomposes rapidly at temperature above 140°C. At 250°C NaNH₂ nd a nitride phase results which crystallizes in the Nacl lattice type with a = 4.86 Å. Na₃[Yb(NH₂)₆] crystallizes orthorhombically with the lattice spacings a = 6.492 Å, b = 12.24 Å, and c = 21.33 Å with 8 formula units per unit cell. The space group is D–Pbca (No.61). The amide ions have a distorted close-packed arrangement with the layer sequence ABAC in the direction [010]. Ytterbium occupies on sixth, sodium one half of the octahedral interstices.     

Three New Thioantimonates(V): Solvothermal Syntheses and Crystal Structures of [M(chxn)3]3(SbS4)2·4H2O (M = Ni,Co) and [Co(dien)2][Co(tren)SbS4]2·4H2O

The three new thioantimonates(V) [Ni(chxn)₃]₃(SbS₄)₂·4H₂O ( I ), [Co(chxn)₃]₃(SbS₄)₂·4H₂O ( II ) (chxn is trans‐1,2‐diaminocyclohexane) and [Co(dien)₂][Co(tren)SbS₄]₂·4H₂O ( III ) (dien is diethylenetriamine and tren is tris(2‐aminoethyl)amine) were synthesized under solvothermal conditions. Compounds I and II are isostructural crystallizing in space group C2/c. The structures are composed of isolated [M(chxn)₃]²⁺ complexes (M = Ni, Co), [SbS₄]^3? anions and crystal water molecules. Short S···N/S···O/O···O separations indicate hydrogen bonding interactions between the different constituents. Compound III crystallizes in space group and is composed of [Co(dien)₂]²⁺ and [Co(tren)SbS₄]^? anions and crystal water molecules. In the cationic complex the Co²⁺ ion is in an octahedral environment of two dien ligands whereas in [Co(tren)SbS₄]^? the Co²⁺ ion is in a trigonal bipyramidal coordination of four N atoms of tren and one S atom of the [SbS₄]^3? anion, i.e., two different coordination polyhedra around Co²⁺ coexist in this compound. Like in the former compounds an extended hydrogen bonding network connects the complexes and the water molecules into a three‐dimensional network.     

Darstellung und Strukturaufklärung von Ammonium‐tetraamminlithium‐amidotrithiophosphat‐Ammoniak(1/1) (NH4) [Li(NH3)4] [P(NH2)S3] · NH3

Synthesis and Crystal Structure of Ammonium Tetraamminelithium Amidotrithiophosphate‐Ammonia(1/1)(NH₄)[Li(NH₃)₄][P(NH₂)S₃]·NH₃ Colourless crystals of (NH₄)[Li(NH₃)₄][P(NH₂)S₃]·NH₃ were prepared by the reduction of P₄S₁₀ with a solution of lithium in liquid ammonia. The X‐ray structure determination shows them to contain the pseudo‐tetrahedral amidotrithiophosphate anion [P(NH₂)S₃]²⁻ (point group C_S), which is the hitherto unknown final member of a series of previously characterized amidothiophosphates. The ammonium ion and the ammonia molecule of solvation form an diamminehydrogen(1+)‐ion N₂H₇⁺ with a short, nearly linear hydrogen bond of 2.864(3) Å.     

The Complex Amide K2[Zr(NH2)6]

We present the low‐temperature synthesis of potassium hexaamido zirconate(IV) from the transition metal tetrafluoride and thealkali metal dissolved in liquid ammonia at –40 °C. Potassium hexaamido zirconate(IV) K₂[Zr(NH₂)₆] is the first ternary amide reported for elements of group 4 of the periodic table It crystallizes with a novel structure type in the trigonal space group R$\bar{3}$ c with a = 6.5422(2) Å, c = 32.824(2) Å, V = 1216.66(9) Å³, Z = 6 and c/a = 5.017. The structure can be derived from the K₂PtCl₆ type. The compound contains discrete D₃‐symmetric [Zr(NH₂)₆]^2– anions which differ significantly from octahedral shape. Quantum chemical calculations show the distortion to arise from a splitting of degenerate d‐orbitals on the zirconium atom leading to a significant gain in energy.     

Synthesis and Structure of a One‐Dimensional Aluminum Phosphate, [NH3(CH2)2NH2(CH2)3NH3]3+ [Al(PO4)2]3—

A one‐dimensional aluminum phosphate, [NH₃(CH₂)₂NH₂(CH₂)₃NH₃]³⁺ [Al(PO₄)₂]^3—, has been synthesized hydrothermally in the presence of N‐(2‐Aminoethyl‐)1, 3‐diaminopropane (AEDAP) and its structure determined by single crystal X‐ray diffraction. Crystal data: space group = Pbca (no. 61), a = 16.850(2), b = 8.832(1), c = 17.688(4)Å, V = 2632.4(2)ų, Z = 8, R₁ = 0.0389 [5663 observed reflections with I > 2σ(I)]. The structure consists of anionic [Al(PO₄)₂]^3— chains built up from AlO₄ and PO₄ tetrahedra, in which all the AlO₄ vertices are shared and each PO₄ tetrahedron possesses two terminal P=O linkages. The cations, which balances the negative charge of the chains, are located in between the chains and interact with the oxygen atoms through strong N—H···O hydrogen bonds. Additional characterization of the compound by powder XRD and MAS‐NMR has also been performed and described.     

Darstellung und Kristallstrukturen von [P(C6H5)4][1-(NH3)B10H9] und Cs[(NH3)B12H11] · 2CH3OH

Synthesis and Crystal Structures of [P(C₆H₅)₄][1-(NH₃)B₁₀H₉] and Cs[(NH₃)B₁₂H₁₁] · 2CH₃OH The reduction of [1-(NO₂)B₁₀H₉]^2? with aluminum in alkaline solution yields [1-(NH₃)B₁₀H₉]^? and by treatment of [B₁₂H₁₂]^2? with hydroxylamine-O-sulfonic acid [(NH₃)B₁₂H₁₁]^? is formed. The crystal structures of [P(C₆H₅)₄][1-(NH₃)B₁₀H₉] (triclinic, space group P1 , a = 7.491(2), b = 13.341(2), c = 14.235(1) Å, α = 68.127(9), β = 81.85(2), γ = 86.860(3)°, Z = 2) and Cs[(NH₃)B₁₂H₁₁] · 2CH₃OH (monoclinic, space group P2₁/n, a = 14.570(2), b = 7.796(1), c = 15.076(2) Å, β = 111.801(8)°, Z = 4) reveal for both compounds the bonding of an ammine substituent to the cluster anion.     

Amminelithium Amidoborane Li(NH3)NH2BH3: A New Coordination Compound with Favorable Dehydrogenation Characteristics

The monoammoniate of lithium amidoborane, Li(NH₃)NH₂BH₃, was synthesized by treatment of LiNH₂BH₃ with ammonia at room temperature. This compound exists in the amorphous state at room temperature, but at ?20 °C crystallizes in the orthorhombic space group Pbca with lattice parameters of a=9.711(4), b=8.7027(5), c=7.1999(1) Å, and V=608.51 ų. The thermal decomposition behavior of this compound under argon and under ammonia was investigated. Through a series of experiments we have demonstrated that Li(NH₃)NH₂BH₃ is able to absorb/desorb ammonia reversibly at room temperature. In the temperature range of 40–70 °C, this compound showed favorable dehydrogenation characteristics. Specifically, under ammonia this material was able to release 3.0 equiv hydrogen (11.18 wt %) rapidly at 60 °C, which represents a significant advantage over LiNH₂BH₃. It has been found that the formation of the coordination bond between ammonia and Li⁺ in LiNH₂BH₃ plays a crucial role in promoting the combination of hydridic B? H bonds and protic N? H bonds, leading to dehydrogenation at low temperature.     

Konformation und Vernetzung von (CuCN)6‐Ringen in polymeren Cyanocupraten(I) [Cu2(CN)3—] (n = 2, 3)

Conformation and Cross Linking of (CuCN)₆‐Rings in Polymeric Cyanocuprates(I) equation/tex2gif-stack-8.gif [Cu₂(CN)₃^—] (n = 2, 3) The alkaline‐tricyano‐dicuprates(I) Rbequation/tex2gif-stack-9.gif[Cu₂(CN)₃] · H₂O ( 1 ) and Csequation/tex2gif-stack-10.gif[Cu₂(CN)₃] · H₂O ( 2 ) were synthesized by hydrothermal reaction of CuCN and RbCN or CsCN. The dialkylammonium‐tricyano‐dicuprates(I) [NH₂(Me)₂]equation/tex2gif-stack-11.gif[Cu₂(CN)₃] ( 3 ), [NH₂(iPr)₂]equation/tex2gif-stack-12.gif[Cu₂(CN)₃] ( 4 ), [NH₂(Pr)₂]equation/tex2gif-stack-13.gif[Cu₂(CN)₃] ( 5 ) and [NH₂(secBu)₂]equation/tex2gif-stack-14.gif[Cu₂(CN)₃] ( 6 ) were obtained by the reaction of dimethylamine, diisopropylamine, dipropylamine or di‐sec‐butylamine with CuCN and NaCN in the presence of formic acid. The crystal structures of these compounds are built up by (CuCN)₆‐rings with varying conformations, which are connected to layers ( 1 ) or three‐dimensional zeolite type cyanocuprate(I) frameworks, depending on the size and shape of the cations ( 2 to 6 ). Crystal structure data: 1 , monoclinic, P2₁/c, a = 12.021(3)Å, b = 8.396(2)Å, c = 7.483(2)Å, β = 95.853(5)°, V = 751.4(3)ų, Z = 4, d_c = 2.728 gcm^—1, R₁ = 0.036; 2 , orthorhombic, Pbca, a = 8.760(2)Å, b = 6.781(2)Å, c = 27.113(5)Å, V = 1610.5(5)ų, Z = 8, d_c = 2.937 gcm^—1, R₁ = 0.028; 3 , orthorhombic, Pna2₁, a = 13.504(3)Å, b = 7.445(2)Å, c = 8.206(2)Å, V = 825.0(3)ų, Z = 4, d_c = 2.023 gcm^—1, R₁ = 0.022; 4 , orthorhombic, Pbca, a = 12.848(6)Å, b = 13.370(7)Å, c = 13.967(7)Å, V = 2399(2)ų, Z = 8, d_c = 1.702 gcm^—1, R₁ = 0.022; 5 , monoclinic, P2₁/n, a = 8.079(3)Å, b = 14.550(5)Å, c = 11.012(4)Å, β = 99.282(8)°, V = 1277.6(8)ų, Z = 4, d_c = 1.598 gcm^—1, R₁ = 0.039; 6 , monoclinic, P2₁/c, a = 16.215(4)Å, b = 13.977(4)Å, c = 14.176(4)Å, β = 114.555(5)°, V = 2922(2)ų, Z = 8, d_c = 1.525 gcm^—1, R₁ = 0.070.     

Poly[tetrasodium(I)‐tetra‐μ2‐bis(butane‐1,4‐diyldioxy)borato‐μ2‐1,4‐butane­diol]

In the title compound, [Na₄(C₈H₁₆BO₄)₄(C₄H₁₀O₂)]_n, there are two coordination types for the four independent Na⁺ cations: two Na⁺ cations bond to six diolate O atoms [Na—O = 2.305 (2)–2.609 (2) Å], while the other two are five‐coordinate via one 1,4‐butane­diol [2.289 (2) and 2.349 (3) Å] and four diolate O atoms [2.295 (2)–2.408 (2) Å]. Corresponding to this, there are three‐ and four‐coordinate diolate O atoms, the latter bridging Na atoms. The 1,4‐butane­diol mol­ecules lie on inversion centres. The boron stereochemistry shows minor local perturbations from its usual tetrahedral state [B—O = 1.457 (4)–1.503 (4) Å]. The resulting polymer packs as sheets parallel to the (10) plane crosslinked by the butane­diol mol­ecules. The structure was solved using data from a multiple crystal.     

Inorganic−Organic Hybrid Polymers via Hydrothermal Syntheses: Tetraaquahexakis(pyrazine‐2‐carboxylato)pentacopper(4+) Hexacosaoxooctamolybdate(4−) Polymer ({[Cu5(pzca)6(H2O)4][Mo8O26]}n; pzca=Pyrazine‐2‐carboxylate) and Dicopperdecaoxo(pyrazine)trimolybdenum Polymer ([Mo3Cu2O10(pz)]n; pz=pyrazine)

Hydrothermal reactions of MoO₃, CuO, and pyrazine‐2‐carboxylic acid (Hpzca) resulted in two polymeric complexes, {[Cu₅(pzca)₆(H₂O)₄][Mo₈O₂₆]}_n ( 1 ; pzca=pyrazine‐2‐carboxylate) and [Mo₃Cu₂O₁₀(pz)]_n ( 2 ; pz=pyrazine). The former crystallized in the monoclinic space group P2₁/c with a=10.805(3) Å, b=13.061(5) Å, c=13.337(10) Å, β=90.20(4)°, V=2729(2) ų, and Z=2. The later crystallized in the orthorhombic space group Pnma with a=12.385(2) Å, b=7.6044(9) Å, c=12.7880(14) Å, V=1204.4(2) ų, and Z=4. X‐Ray diffraction analysis revealed that 1 possesses a two‐dimensional wave‐like structure, formed from a zigzag one‐dimensional chain, and 2 is a three‐dimensional network structure formed from a one‐dimensional chain and a pz bridging ligand. The temperature‐dependent magnetic behavior of 1 was studied.     

(LiI)2Li3SbS3: A mixed Alkali Metal Halide Thioantimonate with a novel Tetrahedron Network

(LiI)₂Li₃SbS₃ was prepared by solid‐state reaction of stoichiometric amounts of LiI, Li, Sb, and S in the ratio 2 : 3 : 1 : 3. The product is air and moisture sensitive. The crystal structure was determined from single crystals at room temperature. Colourless to pale yellow (LiI)₂Li₃SbS₃ crystallizes in the orthorhombic system, space group Pnnm (no. 58) with a = 10.436(1)Å, b = 13.509(1)Å, c = 7.530(1)Å, V = 1061.6(1)ų, and Z = 4 (data at 20 °C). The crystal structure of (LiI)₂Li₃SbS₃ is closely related to that of (CuI)₂Cu₃SbS₃ and (AgI)₂Ag₃SbS₃, at least for the positions of I, Sb, and S. Thus, iodine forms an eutactic arrangement which resembles the structure of hexagonal diamond. [SbS₃]^3— units are embedded in this framework in a way that the sulphur atoms of two adjacent trigonal pyramids form distorted octahedral voids. The lithium ions are tetrahedrally coordinated and fully ordered within the anionic framework. The three‐dimensional connectivities in (LiI)₂Li₃SbS₃ are significantly different from the homologous copper and silver compound due to the bonding necessities of Li and slightly different radii of the monovalent cations. Thus, a novel three‐dimensional network of edge sharing tetrahedra is observed in (LiI)₂Li₃SbS₃. It exhibits strands of eight‐membered rings of edge sharing tetrahedra which are linked by common vertices and cross linked by double tetrahedra.     

The Neutral Complex (NH3)Ag(NCO)

Dissolution of solid AgNCO (silver isocyanate) in aqueous ammonia (25 %) and subsequent crystal growth at T = –9 °C furnished the new ammoniate (NH₃)Ag(NCO) as colorless crystals [P2₁/c (no. 14); a = 4.1817(3) Å, b = 14.445(1) Å, c = 6.1988(5) Å, β = 102.0(4)°, V = 365,6(2) ų; Z = 4]. In the molecular monammine complex, which is only stable at temperatures below T = 0 °C, silver is in a twofold, however, asymmetrical coordination by the isocyanate anion and ammonia. At the reaction conditions applied, AgNCO does not form an ionic diammine species (e.g. [Ag(NH₃)₂]⁺) as known from related silver salts. In this sense, the solvation chemistry of AgNCO exhibits a rarely observed feature.     

Co(NH3)2Cl2 and Co(ND3)2Cl2: Order‐Disorder Behaviour of N(H, D)3 and Antiferromagnetic Structure

Diammine cobalt(II) chloride, Co(N(H, D)₃)₂Cl₂ was prepared by decomposition of the corresponding hexaammines at 120 °C in dynamical vacuum. Crystal structures and magnetic properties of these materials were characterised by X‐ray and neutron powder diffraction, and heat capacity measurements. At ambient temperatures Co(N(H, D)₃)₂Cl₂ crystallises in the Cd(NH₃)₂Cl₂ type structure: space group Cmmm, Z = 2, a = 8.0512(2) Å, b = 8.0525(2) Å, c = 3.73318(9) Å (X‐ray data of the H compound). This structure consists of chains of edge‐sharing octahedra [CoCl_4/2(NH₃)₂] running along the c‐axis. Neutron diffraction confirms that that the ND₃ groups are rotationally disordered at ambient temperatures. At 1.5 K and 20 K neutron diffraction data reveal rotational ordering of the ND₃ groups leading to doubling of the c‐axis and to Ibmm symmetry: a = 7.9999(6) Å, b = 7.9911(5) Å, c = 7.4033(3) Å (Z = 4, values for T = 1.5 K). Furthermore, antiferromagnetic ordering is present at these temperatures. It is caused by a ferromagnetic coupling of the magnetic moments at Co²⁺ (3.60(5) μ_B at 1.5 K, 3.22(5) μ_B at 20 K) along the octahedra chains [CoCl_4/2(NH₃)₂] and antiferromagnetic coupling between neighbouring chains. According to heat capacity measurements the phase transition antiferromagnetic‐paramagnetic takes place at T_N = 26 K.     

Solid State Structure of [Na4(μ‐dioxane)8/2(μ‐dioxane)(PPh2)4]∞: Unprecedented Supramolecular Arrangement of Na and P Atoms in Eight‐membered Na4P4 Rings

NaPPh₂, prepared from sodium and PClPh₂ in refluxing dioxane, crystallises from dioxane as [Na₄(μ‐dioxane)_8/2(μ‐dioxane)(PPh₂)₄]_∞ ( 1 ), in which the basic structural features are eight‐membered Na₄P₄ rings, linked by intermolecularly bridging dioxane molecules to give a three‐dimensional network, and inclusion of one dioxane molecule inside the eight‐membered ring. 1 crystallises in the orthorhombic space group Cmc2₁ (no. 36), T = 203(2) K, a = 27.377(1) Å, b = 10.579(1) Å, c = 23.608(1) Å, V = 6837.3(6) ų, Z = 4, and the absolute structure parameter 0.3(2). The refinement converged to R1 = 0.0632, wR2 = 0.1701 (for reflections with I > 2σ(I)), R1 = 0.0707, wR2 = 0.1781 (all data).     

Vergleich der Kristallstrukturen der Tetraammoniakate von Lithiumhalogeniden,LiBr·4NH3 und LiI·4NH3, mit der Struktur von Tetramethylammoniumiodid,N(CH3)4I

A Comparison of the Crystal Structures of the Tetraammoniates of Lithium Halides, LiBr·4NH₃ and LiI·4NH₃, with the Structure of Tetramethylammonium Iodide, N(CH₃)₄I Crystals of the tetraammoniates of LiBr and LiI sufficient in size for X‐ray structure determinations were obtained by slow evaporation of NH₃ at room temperature from a clear solution of the halides in liquid ammonia. The compounds crystallize in the space group Pnma (No. 62) with four formula units in the unit cell: LiBr·4NH₃: a = 11.947(5)Å, b = 7.047(4)Å, c = 9.472(3)Å LiI·4NH₃: a = 12.646(3)Å, b = 7.302 (1)Å, c = 9.790(2)Å For N(CH₃)₄I the structure was now successfully solved including the hydrogen positions of the methyl groups. N(CH₃)₄I: P4/nmm (No. 129), Z = 2, a = 7.948(1)Å, c = 5.738(1)Å The ammoniates of LiBr and LiI crystallize isotypic in a strongly distorted arrangement of the CsCl motif. Even N(CH₃)₄I has an CsCl‐like structure. Both structure types differ mainly in their orientation of the [Li(NH₃)₄]⁺ — resp. [N(CH₃)₄]⁺ — cations with respect to the surrounding “cube” of anions.