Rubidiumhexaamidolanthanat und -neodymat,Rb3[La(NH2)6] und Rb3[Nd(NH2)6]; Strukturverwandtschaft zu K3[Cr(OH6)] und K4CdCl6

Rubidium Hexaamidolanthanate and -neodymate, Rb₃[La(NH₂)₆] and Rb₃[Nd(NH₂)₆]; Compounds. Structurally Related to K₃[Cr(OH)₆] and K₄CdCl₆ Colourless Rb₃[La(NH₂)₆] (a = 12.298(4) Å, c = 13.759(2) Å, N = 6, R3 c) and pale blue Rb₃[Nd(NH₂)₆] (a = 12.199(6) Å, c = 13.626(4) Å, N = 6, R32) have been prepared by the reaction of the corresponding metals (Rb: La resp. Nd = 3:1) with NH₃(P(NH₃) = 4–4.5 kbar) at 300°C. Single crystal x-ray methods gave their structures. It is shown by space group relations that these compounds are structurally related to one another and to further ternary amides as well as to K₃[Cr(OH)₆] and K₄CdCl₆.     

Untersuchung des Systems Na/La/NH3

Inhaltsübersicht. Im System Na/La/NH₃ warden Amidpräparate durch Umsetzung der Metalle Na und La mit Ammoniak bei 3000–5000 atm NH₃-Druck und bei Temperaturen von 250–500°C dargestellt. Das Molverhältnis der Ausgangsmetalle reichte von Na: La = 9:1 bis 1:2. Na₃La(NH₂)₆ ließ sich mit einer röntgenographischen Einkristalluntersuchung charakterisieren: A = 22,11 ± 0,01 Å, b = 11,15 ± 0,01 Å und c = 7,375 ± 0,006 Å; N = 8, Fddd (Nr. 70). Neben dieser Verbindung und dem binären Amid des Lanthans existiert wahrscheinlich bei tiefen Reaktions-temperaturen ein schlecht kristallisierendes Na-ärmeres Amidometallat. Die thermische Zersetzung von Amidpraparaten (Na: La = 3:1 und 1:1) führte zu zwei mikro-kristallinen ternaren Phasen, einem Amid — Imid sowie zu einem Imid — Nitrid; als Endprodukte ergaben sich LaN neben unzersetztem NaNH₂. Investigation of the System Na/La/NH₃ Abstract. In the system Na/La/NH₃ amides were prepared by the reaction of the metals Na and La with ammonia. The ammonothermal synthesis was used starting with a molar ratio of the metals ranging from Na: La = 9:1 to 1:2 at NH₃-pressures from 3000 to 5000 atm and temperatures from 250 to 500°C. Na₃La(NH₂)₆ was characterized by an x-ray single crystal inv estigation: A = 22.11 ± 0.01 Å, b = 11.15 ± 0.01 Å, and c = 7.375 ± 0.006 Å; N = 8, Fddd (No. 70). Beside this compound and the binary Lanthanum amide another bad crystallizing compound with a lower sodium content may exist. The thermal degradation of the amides (Na: La = 3:1, and 1:1) led to two microcrystalline ternary phases, an amide – imide and an imide – nitride; binary LaN and undecomposed NaNH₂ are the endproducts.     

Synthese und Struktur von Ammin- und Amidokomplexen des Iridiums

Synthesis and Structure of Ammine and Amido Complexes of Iridium The reaction of (NH₄)₂[IrCl₆] with NH₄Cl at 300 °C in a sealed glass ampoule yields the iridium(III) ammine complex (NH₄)₂[Ir(NH₃)Cl₅], which crystallizes isotypically with K₂[Ir(NH₃)Cl₅] in the orthorhombic space group Pnma with Z = 4, and a = 1350.0(2); b = 1028.5(3); c = 689.6(2) pm. The reaction of (NH₄)₂[IrCl₆] with NH₃ at 300 °C, however, gives the already known [Ir(NH₃)₅Cl]Cl₂ beside a small amount of [Ir(NH₃)₄Cl₂]Cl₂. In pure form [Ir(NH₃)₅Cl]Cl₂ is obtained by ammonolysis of (NH₄)₂[Ir(NH₃)Cl₅] at 300 °C with NH₃. [Ir(NH₃)₄Cl₂]Cl₂ crystallizes triclinic (P1, Z = 1, a = 660,2(3); b = 680,4(3); c = 711,1(2) pm; α = 103,85(2)°, β = 114,54(3)°, γ = 112,75(2)°). The structure contains Cl^– anions and [Ir(NH₃)₄Cl₂]²⁺ cations with a trans position of the Cl atoms. Upon reaction of [Ir(NH₃)₅Cl]Cl₂ with Cl₂ one ammine ligand is eliminated yielding [Ir(NH₃)₄Cl₂]Cl, which is transformed to orthorhombic [Ir(NH₃)₄(OH₂)Cl]Cl₂ (Pnma, Z = 4, a = 1335,1(3); b = 1047,9(2); c = 673,4(2) pm) by crystallization from water. In the octahedral complex [Ir(NH₃)₄(OH₂)Cl]²⁺ the four ammine ligands have an equatorial position, whereas the Cl atom and the aqua ligand are arranged axial. Oxidation of (NH₄)₂[Ir(NH₃)Cl₅] with Cl₂ at 330 °C affords the tetragonal Ir^IV complex (NH₄)[Ir(NH₃)Cl₅] (P4nc, Z = 2, a = 702.68(5); c = 912.89(9) pm). Its structure was determined using the powder diagram. Oxidation of (NH₄)₂[Ir(NH₃)Cl₅] with Br₂ in water, on the other hand, gives (NH₄)₂[IrBr₆] crystallizing in the K₂[PtCl₆] type. Oxidation of (PPh₄)₂[Ir(NH₃)Cl₅] with PhI(OAc)₂ in CH₂Cl₂ affords the Ir^V amido complex (PPh₄)[Ir(NH₂)Cl₅].     

Zeit- und temperaturaufgelöste Röntgenpulverdiffraktometrie: Die Reaktion von (NH4)2SnF6 mit Ammoniak

Time and Temperature Resolved in situ X-Ray Powder Diffractometry. The Reaction of (NH₄)₂SnF₆ with Ammonia The thermal decomposition of (NH₄)₂SnF₆ under an atmosphere of ammonia is reported. The complicated reaction paths were illucidated by time and temperature resolved in situ x-ray powder diffractometry. It is shown that this technique is a powerful tool to observe structural changes during reaction. It offers also a valuable access to thermodynamic and kinetic data for solid state and gas phase reactions. (NH₄)₂SnF₆ decomposes under ammonia below room temperature to NH₄F and amorphous SnF₄ · x NH₃. At a temperature of 80°C an intermediate product, (NH₄)₄SnF₈, is formed, which decomposes at 140°C into (NH₄)₂SnF₆ and NH₄F. At 250°C (NH₄)[Sn(NH₃)F₅] and Sn(NH₃)₂F₄ are formed. The latter crystallises C-centered monoclinic with lattice constants a = 844.1(5) pm, b = 630.5(3) pm, c = 520.2(3) pm and b? = 114.02(7)°. At 330°C a further decomposition yields SnF₂(NH₂)₂ with a C-centered monoclinic cell and lattice constants a = 1 069(7), b = 325.3(2), c = 504.8(3) pm and b? = 105.83(7)°. Finally above 500°C tin metal is formed.     

Kaliumamidotrioxogermanate(IV) – Wasserstoff-Brückenbindungen in K3GeO3NH2 und K3GeO3NH2 · KNH2

Potassium Amido Trioxo Germanates(IV) – Hydrogen Bridge Bonds in K₃GeO₃NH₂ and K₃GeO₃NH₂ · KNH₂ Colorless crystals of K₃GeO₃NH₂ and of K₃GeO₃NH₂ · KNH₂ were obtained by the reaction of KNH₂ with GeO₂ in supercritical ammonia at 450°C and p = 6 kbar in high-pressure autoclaves within 15 resp. 5 days. The crystal structures of both compounds were solved by X-ray single crystal methods. K₃GeO₃NH₂: P1 , a = 6.390(1) Å, b = 6.684(1) Å, c = 7.206(1) Å, α = 96.47(1)°, β = 101.66(1)°, γ = 91.66(1)°, Z = 2, R/R_w = 0.020/0.022, N(I) ≥ 2σ(I) = 3023, N(Var.) = 82 K₃GeO₃NH₂ · KNH₂: P2₁/c, a = 10.982(6) Å, b = 6.429(1) Å, c = 12.256(8) Å, β = 106.12(1)°, Z = 4, R/R_w = 0.022/0.029, N(F) ≥ 3σ(F) = 1745, N(Var.) = 107. In K₃GeO₃NH₂ tetrahedral ions GeO₃NH₂^3? are connected to chains by N? H …? O bridge bonds with 2.18 Å ≤ d(H …? O) ≤ 2.40 Å for d(N? H) ? 1.0 Å and by potassium ions while in K₃GeO₃NH₂ · KNH₂ bridge bonds between NH₂ groups of GeO₃NH₂^3? and NH₂^? ions as acceptors occur with 2.41 Å ≤ d((N? )H …? NH₂^?) ≤ 2.61 Å for d(N? H) ? 1.0 Å.     

Penta‐Ammoniates of Aluminium Halides: The Crystal Structures of AlX3·5NH3 with X = Cl,Br, I

Colourless crystals grow in the colder part of a glass ampoule when AlX₃·5NH₃ with X = Cl, Br, I is heated for 3—6 d to 330 °C (Cl), 350 °C (Br) and 400 °C (I), respectively. The chloride forms hexagonal prisms while the bromide and iodide were obtained as a bunch of lancet‐like crystals. The chloride and bromide crystallize isotypic whereas the iodide has an own structure type. All three are related to the motif of the K₂PtCl₆ type. So the formula of the ammoniates may be written as X₂[Al(NH₃)₅X] ≙ [Al(NH₃)₅X]X₂. The compounds are characterized by the following crystallographic data AlCl₃·5NH₃: Pnma, Z = 4, a = 13.405 (1)Å, b = 10.458 (1)Å, c = 6.740 (2)Å AlBr₃·5NH₃: Pnma, Z = 4, a = 13.808 (2)Å, b = 10.827 (1)Å, c = 6.938 (1)Å AlI₃·5NH₃: Cmcm, Z = 4, a = 9.106 (2)Å, b = 11.370 (2)Å, c = 11.470 (2)Å For the chloride and the bromide the structure determinations were successful including hydrogen positions. All three compounds contain octahedral molecular cations [Al(NH₃)₅X]²⁺ located in distorted cubes formed by the remaining 2X^— ions. The orientation of the octahedra to each other is clearly different for those with X = Cl, Br in comparison to the one with X = I.     

Kaliumhexahydroxochromat(III), K3[Cr(OH)6]: Beispiel eines neuen Syntheseweges für Metallhydroxide und Hydroxometallate

Potassium Hexaydroxochromate(III), K₃[Cr(OH)₆]: An Example for a New Synthetic Way to Metal Hydroxides and Hydroxometallates The comproportionation of nitrate with amide ions in supercritical ammonia leads to the formation of hydroxide ions and elementary nitrogen: [Cr(NH₃)₆](NO₃)₃ reacts with KNH₂ at 250°C and 6 kbar NH₃-pressure to K₃[Cr(OH)₆], K(H₂O)OH and an unknown yellow microcrystalline phase. The bluegreen hydroxochromate is well crystallized. The x-ray structure determination on K₃[Cr(OH)₆] gave the atomic arrangement inclusive the hydrogen position. The unit cell with a = 10.672(4) Å and c = 11.083(3) Å contains six formular units; the space group is R3 c. The chemical bonding in this compound is discussed.     

Zur Struktur und Reaktivität des Diammoniumhexafluoromanganats(IV)

About the Structure and Reactivity of Diammonium Hexafluoromanganate(IV) Electrolytic oxidation of an aqueous suspension of MnF₂ containing NH₄F, and subsequent crystallization in 40% HF yields yellow crystals of (NH₄)₂MnF₆. It crystallizes in the hexagonal K₂MnF₆ type structure with the space group P6₃mc and a = 5.903; c = 9.565 Å; Z = 2. With in situ powder diffraction studies it is shown, that (NH₄)₂MnF₆ is gradually reduced in a NH₃ atmosphere between 30 and 230 °C to afford (NH₄)₃MnF₆, (NH₄)₂MnF₅, and finally NH₄MnF₃. (NH₄)₃MnF₆, thereby, forms a hitherto unknown cubic (a = 9.082 Å) high temperature modification with the cryolite type structure. Under N₂ the thermal decomposition of (NH₄)₂MnF₆ proceeds via NH₄MnF₄ to yield MnF₂.     

The ammonium-bromide route to anhydrous rare earth bromides MBr3

The use of NH₄Br in the conversion of rare earth oxides (M₂O₃), hydrated bromides (MBr₃ · xH₂O) or the metals scandium, yttrium and lanthanum to lutetium, to anhydrous tribromides (MBr₃) provides a plethora of chemistry. In general, the two-step procedures start with the synthesis of a ternary bromide: (NH₄)₂MBr₅ for M ≡ La to Nd and (NH₄)₃MBr₆ for M ≡ Sm to Lu, Y, Sc. This is achieved at 200–250 °C from hydrated ternary bromides in an HBr gas stream, at 280 °C from NH₄Br and M₂O₃ (a 10:1 molar ratio for M ≡ La to Nd and a 12:1 molar ratio for M ≡ Sm to Lu, Y, Sc) or at 300 °C from NH₄Br and M mixtures. The subsequent step is the decomposition of the ternary bromide to the binary tribromide MBr₃ in a vacuum at 350–400 °C. The actual decomposition pathways are dependent upon the size of the trivalent cation and may pass through the intermediate NH₄M₂Br₇ (M ≡ Nd to Dy).     

Hexamincyclotriphosphazenhemiammoniakat,P3N3(NH2)6 · 0,5 NH3, ein Produkt der Hochdruckammonolyse von weißem Phosphor

Hexaminecyclotriphosphazenehemiammoniate, P₃N₃(NH₂)₆ · 0.5 NH₃, a Product of High Pressure Ammonolysis of White Phosphorus White phosphorus gives at NH₃-pressures ≥5 kbar and temperatures above 250°C in a disproportionation reaction P₃N₃(NH₂)₆ · 0.5 NH₃; besides these products red phosphorus is formed. The yield on P₃N₃(NH₂)₆ · 0.5 NH₃ increases with T and is about 70–80% at 400°C as to the disproportionation reaction of the amount of white phosphorus. X-ray structure determination was successful on single crystals of P₃N₃(NH₂)₆ · 0.5 NH₃. Pbca, N = 8 a = 11.395(3) Å, b = 12.935(4) Å, c = 12.834(4) Å R = 0.035, R_w = 0.041 with w = 1, N (F_o²) ≥ 3σ(F_o²) = 1371, N(Var.) = 166. The molecules are connected by N? H? N-bridgebonds with 3.04 Å ≤ d(N …? N) ≤ 3,19 Å and d (N? H) = 0.87 Å. The compound is furthermore characterized by IR-data and its thermical behaviour.     

Darstellung und Kristallstruktur von KLa2(NH2)7

Preparation and Crystal Structure of KLa₂(NH₂)₇ KLa₂(NH₂)₇ was prepared by the reaction of the pure metals K and La in the atomic ratio 1:2 with ammonia as reagent and solvent. At 350°C and 5000 atm NH_3- pressure single crystals of the compound can be obtained. KLa₂(NH₂)₇ is orthorhombic with the following spacings a = 6.89, b = 10.33 and c = 15.85 Å. The lattice contains four formula units. The space group is Pnnm (No. 58). The positions of K, La and N were obtained by x-ray single crystal examination. The structure of KLa₂(NH₂)₇ may not be explained starting with one of the possible close-packings of the anions.     

Protonenlagen bei Kaliumtetraamidozinkat,K2Zn(NH2)4

Positions of the Protons in Potassium Tetraamidozincate, K₂Zn(NH₂)₄ X-ray single crystal data for K₂Zn(NH₂)₄ allowed the determination of the so far unknown positions of the protons: P1 , Z = 2, a = 6.730(1) Å, b = 7.438(1) Å, c = 8.019(2) Å, α = 72.03(2)°, β = 84.45(2)°, γ = 63.82(1)°, Z(F₀) with (F₀)² ≥ 3σ(F₀)² = 2166, Z(parameters) = 96, R/R_W = 0.032/0.039. In the structure of K₂Zn(NH₂)₂ the amide ions are nearly hexagonal close packed. One layer of octahedral holes parallel to (010) is fully occupied by potassium atoms and zinc is in an ordered way in a quarter of the tetrahedral holes of the next layer. The orientation of the protons of the amide ions is characteristic for this type of structure (filled up CdI₂ type).     

(NH4)3[M2NCl10] (M = Nb,Ta): Synthese,Kristallstruktur und Phasenumwandlung

(NH₄)₃[M₂NCl₁₀] (M = Nb, Ta): Synthesis, Crystal Structure, and Phase Transition The nitrido complexes (NH₄)₃[Nb₂NCl₁₀], and (NH₄)₃[Ta₂NCl₁₀] are obtained in form of moisture-sensitive, tetragonal crystals by the reaction of the corresponding pentachlorides with NH₄Cl at 400 °C in sealed glass ampoules. Both compounds crystallize isotypically in two modifications, a low temperature form with the space group P4/mnc and a high temperature form with space group I4/mmm. In case of (NH₄)₃[Ta₂NCl₁₀] a continuous phase transition occurs between –70 °C and +60 °C. For the niobium compound this phase transition is not yet fully completed at 90 °C. The structure of (NH₄)₃[Nb₂NCl₁₀] was determined at several temperatures between –65 °C und +90 °C to carefully follow the continuous phase transition. For (NH₄)₃[Ta₂NCl₁₀] the structure of the low temperature form was determined at –70 °C, and of the high temperature form at +60 °C. The closely related crystal structures of the two modifications contain NH₄⁺ cations and [M₂NCl₁₀]^3– anions. The anions with the symmetry D_4h are characterized by a symmetrical nitrido bridge M=N=M with distances Nb–N = 184.5(1) pm at –65 °C or 183.8(2) pm at 90 °C, and Ta–N = 184.86(5) pm at –70 °C or 184.57(5) pm at 60 °C.     

Spezielle Alkylammoniumhexachlorometallate. I. Kristallisationsverhalten und Kristallstruktur von Diethylentriammoniumhexachlororhodat, [H3N(CH2)2NH2(CH2)2NH3][RhCl6]

Alkylammonium Hexachlorometallates. I. Crystallization Properties and Crystal Structure of Diethylenetriammonium Hexachlororhodate, [H₃N(CH₂)₂NH₂(CH₂)₂NH₃][RhCl₆] The reaction of RhCl₃ · 3H₂O with diethylenetriamine in 12 m hydrochloric acid yielded diethylenetriammonium hexachlororhodate [H₃N(CH₂)₂NH₂(CH₂)₂NH₃][RhCl₆] ( 1 ). Dark red single crystals of the compound were grown under hydrothermal conditions at a temperature interval of 180°C to 125°C in closed glass ampoules over several weeks (space group C2/c, a = 30.956(4) Å, b = 7.371(2) Å, c = 12.9736(15) Å, β = 113.787(11)°, Z = 8, 2385 reflections with I > 0, wR²(obs.) = 0.0279, R¹(I > 2σ(I)) = 0.0271). The crystal structure is determined by a complex framework of hydrogen bonds between the hexachlororhodate anions and the diethylenetriammonium cations.     

Bildung des „superoktaedrischen”︁ Heteropolyanions [Ni(TaF6)6]4− bei der Oxidation von Tantal mit Ammoniumfluorid an der Monel-Wand

Formation of the “Superoctahedral” Heteropolyanion [Ni(TaF₆)₆]^4? through Oxidation of Tantalum with Ammonium Fluoride at the Monel-Container Wall A few single crystals of (NH₄)₄[Ni(TaF₆)₆] are obtained besides (NH₄)[TaF₆] as the main product of the reaction of (NH₄)F with tantalum powder in an He-are-welded Monel metal container at 400°C. The crystal structure (trigonal, R-3c (Nr. 167), Z = 6, a = 1723,0(2); c = 2166,6(2) pm; R1 = 0,0303, _WR2 = 0,0609) contains the superoctahedral heteropolyanion [Ni(TaF₆)₆]^4? and (NH₄)⁺ ions; it may be recognized as a derivative structure of the K₄CdCl₆ type according to (NH₄)₄[Ni(TaF₆)₆]?K₄[Cd(Cl)₆].     

Analytical applications of the reaction of thorium with benzenephosphonic acid

Benzenephosphonic acid quantitatively precipitates thorium as Th(C₆H₅PO₃)₂·3H₂O at pH values as low as 0.5. The compound may be dried at 140° to 180° C and weighed, as a gravimetric means of determining thorium. On ignition, Th (C₂H₅PO₃)₂ 3 H₂O undergoes decomposition at 240° to 300° C to form Th(C₆H₅PO₃)₂·2H₂O, at 450° to 650° C to form Th(HPO₄)₂·2H₂O and finally at 800° to 1000° C to form Th(HPO₄)₂. The latter compound is stable to 1200° C.Potentiometrically (pK₁' = 0.91, pK₂' = 6.41) and spectrophotometrically (pK₁' = 0.96, pK₂' = 6.51) determined pK' values are reported. Absorption spectra of C₆H₅PO₃H₂, C₆H₅PO₃H^- and C₆H₅PO₃^-2 are reported. The solubility of Th (C₆H₅PO₃)₂·3H₂O was studied as a function of pH and the average value of the solubility product (K_sp = 4s³) was found to be 3.24·10^-31.     

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.     

Kristallstruktur von Hexamincyclotriphosphazen,P3N3(NH2)6

Crystal Structure of Hexamine Cyclotriphosphazene, P₃N₃(NH₂)₆ In the presence of KNH₂ hexamine cyclotriphosphazene semi ammoniate (molar ratio 12:1) in NH₃ gives crystals of solvent free P₃N₃(NH₂)₆ within 5 d at 130°C and p(NH₃) = 110 bar. The structure was solved by X-rax methods: P₃N₃(NH₂)₆: P2₁/c, Z = 4, a = 10.889(6) Å, b = 5.9531(6) Å, c = 13.744(8) Å, β = 97.83(3)°, Z(F_o) = 1 721 with (F_o)² ≥ 3σ(F_o)², Z(var.) = 157, R/R_w = 0,036/0,041 The structure contains columns of molecules P₃N₃(NH₂)₆ all in the same orientation. The six-membered rings within one molecule have boat conformation. The columns are stacked together in a way that one is surrounded by four others shifted by half a lattice constant in direction [010]. Strong hydrogen bridge-bonds N? H…?N connect molecules within the columns and between them.     

The X‐ray Crystal Structures of Hg(C6F4X‐p)2 (X = NH2, OMe,or Me) – Two Examples of Supramolecular Lewis Acid/Base Complexes

The X‐ray crystal structures of Hg(C₆F₄X‐p)₂ (X = NH₂, OMe, or Me) show the compounds to have almost linear C–Hg–C stereochemistry (X = NH₂, 176.3(4)°; X = OMe, 179.5(2)°; X = Me, 176.3(2)°), and the two tetrafluoroaryl rings rotated ca. 52–62° with respect to each other. Substantial conjugation of NH₂ and OMe groups with the aromatic rings is evident from N–C and O–C(Ar) distances. For X = NH₂ or OMe, two weak N(O)–Hg coordination interactions per mercury lead to a two dimensional supramolecular chain structure containing pairs of π‐stacked aromatic rings at near van der Waals contact distances rotated at 62.2° (X = NH₂) or 52.9° (X = OMe) to each other. In Hg(C₆F₄Me‐p)₂, which does not have potential donor atoms, no supramolecular structure is obtained, the molecules being laterally displaced from one another.