The solid state reaction between hexaamminechromium(III) complexes and L-α-alanine

The solid reaction between [Cr(NH₃)₆]X₃(X^? = Cl, I, SCN and NO₃) and L-α-alanine was studied under continuous rise in temperature and isothermal heating. Under continuous rise in temperature, the main products were [Cr(NCS)₃-(NH₃)₃] (X^? = NCS) and [Cr(L-ala)₃] (X^? = NO₃), when [Cr(NH₃)₆]Cl₃ and [Cr(NH₃)₆]I₃ as starting complexes were used; in both cases only the decomposition proceeds. Under isothermal heating at 150°C the main products were [CrCl(NH₃)₅]-Cl₂ (X^? = Cl), [Cr(NH₃)₆]I₂ (X^? = I), [Cr(NCS)₃(NH₃)₃] (X^? = SCN) and [Cr(L-ala)₃] (X^? = NO₃). In those matrix reactions, the ease of anion coordination was: SCN^? > Cl^? > I^? > alanine. For the synthesis of tris(alaninato)chromium(III) complex the most desirable starting complex was [Cr(NH₃)₆](NO₃)₃.The solid state reaction between [Cr(en)₃]X₃ type complexes and NH₄X (X^? = F, Cl, Br, I and SCN), KX (X^? = Cl, Br and I), and NaSCN have been reported by Wendlandt and Stembridge¹. They reported that the reaction product in most cases, was cis-[Cr(en)₂Y₂]X, where Y and X are the same or different anions, depending upon the matrix material employed and the thermal matrix method appears to be a useful new route for the synthesis of bis(ethylendiamine(chromium(III) complexes.In the previous paper², the solid state reaction between [Cr(NH₃)₆](NO₃)₃ and L-amino acids has been utilized in the preparation of tris(amino acidato)chromium(III) complexes. The preparation of [Cr(L-ala)₃] by the solid state reaction between [Cr(NH₃)₆](NO₃)₃ and L-alanine have been reported. No studies on the effect of the counter-ion have been reported.In this paper, various hexaamminechromium(III) complexes, [Cr(NH₃)₆]X₃ (X^? = Cl, I, SCN and NO₃), were heated with L-α-alanine under continuous rise in temperature and under isothermal heating at 150°C for studies on the ease of anion coordination. It will seen that the anion which replaces the ammonia in the hexaamminechromium(III) complex comes from either the alanine or counter-ion.     

Biocidal Organotin Compounds. Part 2. Synthesis,Characterization and Biocidal Properties of Triorganotin(IV) Hydantoic Acid Derivatives and the Crystal Structures of Triphenyltin and Tricyclohexyltin Hydantoates

The preparation and spectroscopic (¹H NMR, UV and IR) characterization of three R₃Sn(O₂CCH₂N(H)C(O)NH₂) [R=Ph, c-Hex (cyclohexyl) or n-Bu] compounds are reported. A different mode of coordination is indicated for the hydantoate ligand in the R=Ph compound compared with the R=c-Hex and R=n-Bu compounds, as confirmed by a crystallographic analysis. The structure of [Ph₃Sn(O₂CCH₂N(H)C(O)NH₂)] is polymeric owing to the presence of bridging hydantoate ligands such that each ligand coordinates one tin atom, via one of the carboxylate oxygen atoms, and a symmetry-related tin atom via the carbonyl group at the other end of the molecule. The structure features distorted trigonal-bipyramidal tin atom geometries with a trans -R₃SnO₂ motif. The structure of [c-Hex₃Sn(O₂CCH₂N(H)- C(O)NH₂)], by contrast, is monomeric, distorted tetrahedral, as the carboxylate group is monodentate and there are no additional tin–ligand interactions. The structures are each stabilized by a number of intermolecular hydrogen bonds. Fungitoxicity and phytotoxicity studies indicate that the R=n-Bu derivative is the more active compound.     

Organometallphosphin-substituierte übergangsmetallkomplexe XVII. Tetracarbonyl-di(organometallphosphin)-chrom-, -molybdän- und -wolfram-komplexe

Bicyclo[2.2.1]-2,5-heptadiene complexes of transition metal carbonyls have been treated with organometallic phosphines, to give the disubstituted compounds [(R₃M′)₃P]₂M(CO)₄ [R = CH₃; M′ = Ge, Sn; M = Cr, Mo, W] by exchange of ligands. The chemical and spectroscopic properties of the new compounds are reported.     

Thermal studies on the decomposition of aquopentamminecobalt(III) hexathiocyanatochromate(III)

The decomposition of [Co(NH₃)₅H₂O] [Cr(NCS)₆] has been studied using DSC and TG. The first step involves the loss of H₂O and NH₃ in a first-order process to produce [(NH₃)₅Co(SCN)₃Cr(NCS)₃]. A second step involves the loss of HSCN. Activation energies are presented and the mechanisms of the reactions are discussed in comparison to analogous cyanide complexes.     

Syntheses and structures of diorgano(halo- orpseudohalo-)(1,3-dithiole-2-thione-4,5-dithiolato)-stannates (1-), [Q][RSnX(dmit)] (Q=onium cation; X=halide orpseudohalide)

Ionic compounds, [Q] [R₂SnX(dmit)][dmit=1,3-dithiole-2-thione-dithiolate; Q=1,4-dimethylpyridinium or tetraalkylammonium; R=Phor alkyl; X=Cl, Br, I, NCS, NCSe, or N₃] have been obtained by (a) from R₂SnX₂ and [Q]₂[Zn(dmit)₂] in the presence of excess QX,(b) from halide exchange reactions in acetone solution between [Q] [R₂SnCl(dmit)]and a halide or pseudohalide source, or (c) by addition of QX to [R₂Sn(dmit)]. Crystalstructure determinations of [NEt₄] [Ph₂SnI(dmit)] and [1,4-Me₂pyridiniuml [Ph₂SnBr(dmit)] as well as of the mixed halides, [1a, 1b, 4a, 2] [Ph₂SnCl_nI₁₋n(dmit)] (n=0.57, 0.42 or0.22), indicated that the tin atoms have distorted trigonal bipyramidal geometries in the anions,with the X ligand and a dithiolato atom in the axial sites. The [R₂SnX(dmit)]⁻ anions remain essentially intact in organic solvents, but lose X⁻ on extractionwith H₂O to give the neutral species, R₂Sn(dmit).     

Über Cyanatverbindungen und deren reaktives Verhalten. XXXI [1]. Solvatfreies Titan(IV)-thiocyanat und einige abgeleitete Tetrathiocyanato-bis(ligand)-titan(IV)-Komplexe

Cyanates and Their Reactive Behaviour. XXXI. Solvate-free Titanium(IV) Thiocyanate and Some Related Tetrathiocyanato-bis(ligand) Titanium(IV) Complexes TiCl₄ and [TiCl_a(NCS)_bL₂] compounds react with alkali thiocyanates in tetrahydrofurane or acetonitrile to monomeric tetrathiocyanato-bis(ligand)titan(IV) complexes (a = 1, 2, 3; b = 3, 2, 1; L = CH₃CN, C₄H₈O), also NH₄[TiCl(NCS)₄(THF)] · 2 THF is formed. Desolvatation of [Ti(NCS)₄(THF)₂] leads to [Ti(NCS)₄]_x. The prepared compounds are characterized by analytical data, IR and electron spectra, and conductivity measurements.     

Über Cyanatverbindungen und deren reaktives Verhalten. X. 14N-NMR-Untersuchungen an einigen diamagnetischen Metall- und Triphenylzinnthiocyanatverbindungen sowie Kaliumselenocyanat

Chemical shifts and line-widths of the following soluble diamagnetic ¹⁴N-compounds are given: (NH₄)₂[Hg(SCN)₄], Sr(SCN)₂, K₂[Zn(NCS)₄] · 2 CH₃COCH₃, K₂[Zn(NCS)₄], K₄[Cd(NCS)₆], (C₆H₅)₃SnNCS, C₇H₇NH₃[(C₆H₅)₃Sn(NCS)₂], K[(C₆H₅)₃Sn(NCSe)₂] und KSeCN. Types of bonding of the NCY group (Y = S, Se) in these compounds are discussed and correlated to the measurements. Dependences of the line-widths upon different concentrations and temperatures are given for aqueous KSCN solutions.     

Organosilicon Amine Gels Based on 3-Aminopropyltriethoxysilane, Cobalt(II) or Chromium(III) Clorides, and Triethoxysilane

Organosilicon gels [Co(NH₂R²)₂Cl₂] and [Cr(NH₂R²)₃Cl₃], containing a diaminodichloride complex of cobalt(II) and triaminotrichloride complex of chromium(III) (R² = CH₂CH₂CH₂SiO(OEt)), were synthesized by the hydrolysis of complexes [Co(NH₂R¹)₂Cl₂] (I) and [Cr(NH₂R¹)₃Cl₃] (II) incorporating peripheral triethoxysilyl groups (R¹ = CH₂CH₂CH₂Si(OEt)₃). The coprecipitated [Co(NH₂R²)₂Cl₂] · 4NH₂R³, [Cr(NH₂R²)₃Cl₃] · 6NH₂R³, [Co(NH₂R²)₂Cl₂] · 2SiO₂, and [Cr(NH₂R²)₃Cl₃] ·xSiO₂ · (3 – x)SiHO_1.5 (R³ = CH₂CH₂CH₂SiO_1.5) gels were obtained by cohydrolysis of complexes I and II with 3-aminopropyltriethoxysilane or triethoxysilane. Interaction with SiH(OEt)₃ is accompanied by the decomposition of silicon hydride groups and the formation of tetraethoxysilane derivatives. The heating of dry gels in a flow of argon or oxygen to 600° results in the formation of amorphous silica having a specific surface area 2–467 m²/g and containing crystalline metals, their chlorides, oxides, silicates, or carbides.     

Mixed-ligand complexes [Cd(DMSO)5(NCS)][Cr(NH3)2(NCS)4] · 3DMSO and [Mn(DMSO)4(H2O)2][Cr(NH3)2(NCS)4]2 · 6DMSO · 2H2O: Syntheses and crystal structures

New mixed-ligand coordination compounds[Cd(DMSO)₅(NCS)][Cr(NH₃)₂(NCS)₄] · 3DMSO (I) and [Mn(DMSO)₄(H₂O)₂][Cr(NH₃)₂(NCS)₄]₂ · 6DMSO · 2H₂O (II) have been synthesized and studied by IR spectroscopy and X-ray diffraction analysis. The crystals of compound I are monoclinic, a = 14.5275(7), b = 23.1692(11), c = 14.6969(6) ?, β = 97.057(2)°, V = 4909.4(4) ?³, space group P2₁/c, Z = 4, ρ_calcd = 1.507 g/cm³, R = 0.0556. The crystals of compound II are triclinic, a = 11.7784(3), b = 12.1760(3), c = 13.1922(2) ?, α = 85.5420(10)°, β = 87.9000(10)°, γ = 70.3680(10)°, V = 1776.46(7) ?³, space group P , Z = 1, ρ_calcd = 1.444 g/cm³, R = 0.0350. Original Russian Text ? E.A. Gerasimova, T.V. Utkina, E.V. Peresypkina, A.V. Virovets, T.G. Cherkasova, 2009, published in Zhurnal Neorganicheskoi Khimii, 2009, Vol. 54, No. 5, pp. 751–755.     

Über Cyanatverbindungen und deren reaktives Verhalten. XXI. Reaktionsverhalten von Niob(V)- und Tantal(V)-thiocyanat gegenüber N-Donatoren

Cyanate Compounds and their Reactivity. XXI. Reactivity of Niobium(V) and Tantalum(V) Thiocyanates to N-Donators M₂(NCS)₁₀ reacts with ammonia or primary and secondary aliphatic amines to complexes of the types [M(NCS)(NH₂)₂NH]_x, [M(NCS)₃(NHR)₂ H₂NR], or [M(NCS)₃(NR′₂)₂ HNR′₂], with N-heterocyclic amines in a first step to [M(NCS)₅L]-complexes and in a further step through a redox mechanism to [M(NCS)₄L₂] complexes. [M(NCS)₅(CH₃CN)] mCH₃CN reacts with ammonia, or primary amines in acetonitrile over acetamidine and amidinolytic cleavage of M-NCS bonds to complexes of the type [M(NCS)_a(NC(NHR″)CH₃)_b(CH₃C(NH)NHR″)]_x. The prepared compounds are characterized by analytical data, derivatographic measurements, and IR or visible absorption spectra (M = Nb, Ta; x = 2; R = n-C₄H₉; R′ = C₂H₅; L = pyridine or 4-methyl-pyridine; m = 0, 1, 2; a = 1 or 4; b = 4 or 1; R″ = H, n-C₄H₉).     

Synthese und Kristallstruktur von [Cr(NH3)6][Cr(NH3)2F4][BF4]2

Synthesis and Crystal Structure of [Cr(NH₃)₆][Cr(NH₃)₂F₄][BF₄]₂ The action of ammonium fluoride on a mixture of boron and chromium in a sealed Monel ampoule at 300 °C yields single crystals of [Cr(NH₃)₆][Cr(NH₃)₂F₄][BF₄]₂. The crystal structure (tetragonal, P4/mbm, Z = 2, a = 1056.0(1), c = 781.7(1) pm; R₁ = 0.0414; wR₂ = 0.1087 for 411 reflections with I₀ > 2σ(I)) contains [Cr(NH₃)₆]³⁺ and [Cr(NH₃)₂F₄]^– octahedra and twice as many [BF₄]^– tetrahedra that are arranged in a quadrupled super‐structure of the CsCl‐type of structure.     

The first heterometallic Cu(II)/Cr(III) complex with an open-chain Schiff-base ligand self-assembled from copper powder,Reineckes salt,ethylendiamine and acetone

A novel supramolecular assembly [{Cu(enac)}₂Cr(NCS)₄(NH₃)₂][Cr(NCS)₄(NH₃)₂]₃ · 4(CH₃)₂CO (enac = 4,6,6-trimethyl-3,7-diazanon-3-ene-1,9-diamine), the first example of a Cu/Cr heterometallic compound containing a Schiff-base ligand such as enac, and an anion of Reineckes salt, Cr(NCS)₄(NH₃)₂⁻, as a building block, was obtained by the self-assembly reaction of copper powder and Reineckes salt in an acetone/methanol (1:4) solution of ethylenediamine in the open air. An X-ray study shows that the complex includes a trinuclear Cu₂Cr cation, constructed from two Cu(enac)²⁺ moieties and a trans-[Cr(NCS)₄(NH₃)₂]⁻ block as a two-linking bridging ligand. The metal–metal separations within the cation are Cu?Cr = 6.393(31) Å and Cu?Cu = 12.786(63) Å. The supramolecular architecture of the complex involves two types of H-bonded chains, the first chain is generated by trinuclear cations [{Cu(enac)}₂Cr(NCS)₄(NH₃)₂]²⁺, [Cr(NCS)₄(NH₃)₂]⁻ anions and (CH₃)₂CO molecules, while the second by crystallographically different anions of Reineckes salt and (CH₃)₂CO. Variable-temperature (1.8–300 K) magnetic susceptibilities show a slight change of the μ_B value at low temperature, indicative of weak antiferromagnetic interactions (J_CuCr = −0.9 cm⁻¹) between the paramagnetic centers.     

Synthesis,Properties, and Structures of Salts with the Reineckate Anion, [CrIII(NCS)4(NH3)2]–, and Large Organic Cations

A series of 9 new Reineckate salts, A[Cr^III(NCS)₄(NH₃)₂] with various large organic cations A = tetraalkylammonium, [R₄N]⁺, R = n‐butyl, n‐dodecyl; 1‐alkyl‐3‐methylimidazolium, (RMIm)⁺: R = methyl, ethyl, iso‐propyl, n‐butyl, and n‐hexyl; A = 1,3‐dimethyl‐2,4,5‐triphenylimidazolium and A = 1,2,3,4,5‐pentamethylimidazolium was synthesized. The melting point of each compound was measured to see if any belongs to the group of metal‐containing Ionic Liquids with low melting points. Each compound was further characterized by elemental analysis, NMR, IR, and UV/Vis spectroscopy. From NMR investigations information about the magnetic behavior was derivedusing the Evans method. It has been found that every compound is paramagnetic with effective magnetic moments of spin‐only Cr^III. The structures of the Reineckates with A = tetra‐n‐butyl‐ammonium, tetra‐n‐dodecyl‐ammonium, 1‐ethyl‐3‐methylimidazolium, and 1,2,3,4,5‐pentamethylimidazolium were determined by single‐crystal X‐ray diffraction measurements: (nBu₄N)[Cr(NCS)₄(NH₃)₂]: monoclinic, C2/c (no. 15), a = 12.0818(8), b = 10.2425(8), c = 24.222(2) Å, β = 98.324(3)°, Z = 4, R1(F)/wR2(F²) = 0.0332/0.0871; {(C₁₂H₂₅)₄N}[Cr(NCS)₄(NH₃)₂]·0.85H₂O: triclinic, P$\bar{1}$ (no. 2), a = 8.4049(1), b = 20.1525(4), c = 20.7908(4) Å, α = 67.487(1)°, β = 81.328(1)°, γ = 78.040(1)°, Z = 2, R1(F)/wR2(F²) = 0.0533/0.1343; (EMIm)[Cr(NCS)₄(NH₃)₂]: orthorhombic, Pbcm (no. 57), a = 8.765(2), b = 15.888(3), c = 14.191(3) Å, Z = 4, R1(F)/wR2(F²) = 0.0466/0.1271; (PeMIm)[Cr(NCS)₄(NH₃)₂]: monoclinic, P2₁/n (no. 14), a = 6.0817(2), b =13.9811(5), c = 25.2902(9) Å, β = 90.075(2)°, Z = 4, R1(F)/wR2(F²) = 0.0405/0.1111.     

Neue Substitutionsprodukte von K3[Cr(NCS)6] mit einigen heterocyclischen N-Basen

Substitution reactions of K₃[Cr(NCS)₆] with pyridine and alkyl-pyridine derivatives was studied. The formulas of three complex anions, [Cr(NCS)₄(pyridine)₂]^?, [Cr(NCS)₄(β-picoline)₂]^? and [Cr(NCS)₄(γ-picoline)₂]^?, was established by preparation. 33 new complex compounds of these types have been prepared from the hydrochlorides of aromatic and heterocyclic amines. Their thermal behaviour and the mechanism of pyrolysis of these salts was studied by TGA. From UV and IR spectra some structural problems are resolved and discussed.     

Crystal structures of Ti(NH<Subscript>4</Subscript>)<Subscript>2</Subscript>P<Subscript>4</Subscript>O<Subscript>13</Subscript> and Sn(NH<Subscript>4</Subscript>)<Subscript>2</Subscript>P<Subscript>4</Subscript>O<Subscript>13</Subscript>

The characteristics of crystal structures of the titanium(IV) diammonium (Ti(NH₄)₂P₄O₁₃) and tin(IV) diammonium (Sn(NH₄)₂P₄O₁₃) tetraphosphates, which are isostructural with similar silicon(IV) and germanium(IV) salts, have been obtained by the Rietveld method using X-ray powder diffraction data. The compounds crystallize in the triclinic system, space group P \(\overline 1 \), Z = 2, a = 15.0291(7) Å, b = 7.9236(4) Å, c = 5.0754(3) Å, α = 99.168(3)°, β = 97.059(3)°, γ = 83.459(3)° for Ti(NH₄)₂P₄O₁₃ and a = 15.1454(7) Å, b = 8.0103(5) Å, c = 5.1053(3) Å, α = 99.898(6)°, β = 96.806(3)°, γ = 83.881(4)° for Sn(NH₄)₂P₄O₁₃. The structure is refined in the isotropic approximation using the pseudo-Voigt function: R _p = 0.077, R _Bragg = 0.045, R _F = 0.057 for Ti(NH₄)₂P₄O₁₃; R _p = 0.082, R _Bragg = 0.044, R _F = 0.046 for Sn(NH₄)₂P₄O₁₃. The hydrogen atoms of the ammonium cations are placed in the calculated positions. A comparative analysis of the structures of the compounds of the M^IV(NH₄)₂P₄O₁₃ (M^IV = Si, Ge, Ti, Sn) series has been carried out.     

Darstellung und Struktur von Sn(NH2)2F2

Synthesis and Structure of Sn(NH₂)₂F₂ Diamido-difluoro-tin Sn(NH₂)₂F₂ can be produced by ammonolysis from (NH₄)₂SnF₆ at 613 K. The compound is a product from Sn(NH₃)₂F₄ formed during the ammonolysis reaction. Sn(NH₂)₂F₂ crystallizes in space group C2/m (No. 12) with lattice constants a = 1070.18(7), b = 325.38(3) pm, c = 505.02(3) pm and β = 105.728(3)° (V = 169.271(6) · 10⁶ pm³) containing two formula units per unit cell. Data refinement by the Rietveld method yields a Bragg R-value of R_Bragg = 0.0514 (Profile R-value R_wp = 0.177). Tin is octahedrally coordinated by two fluorine atoms and for amido groups. The octahedra are connected to one-dimensional strings by edge sharing. The NH₂ groups are in the bridging position whilst the fluorine atoms are terminal.     

Double complex salts [M(NH3)5Cl][M′Br4] (M = Rh, Ir, Co, Cr, Ru; M′ = Pt, Pd): Synthesis, x-ray diffraction characterization, and thermal properties

Double complex salts (DCSs) with [M(NH₃)₅Cl]²⁺ (M = Rh, Ir, Co, Cr, Ru) cations and [PtBr₄]^2? anions were prepared in high yields. The salts were two-phase mixtures of the anhydrous and monohydro DCSs. Anhydrous analogues containing [PdBr₄]^2? anions with M = Cr or Ru were synthesized. All the compounds were characterized using a set of physicochemical methods. The crystal structure of chloropentaamminechromium(III) tetrabromopalladate(II) was solved: space group Pnma, Z = 4, a = 17.068(2) Å, b = 8.315(12) Å, c = 9.653(14) Å. The [M(NH₃)₅Cl][M′X₄] (M = Rh, Ir, Co, Cr, Ru; M′ = Pd, Pt; X = Cl, Br) compounds were shown to be isostructural. The [M(NH₃)₅Cl][PtBr₄] · H₂O monohydrates are isostructural to the [M(NH₃)₅Cl][PdCl₄] · H₂O monohydrates (space group P2₁/c, z = 4). The properties of the compounds were comparatively analyzed. The tendencies of the thermal stability of the complexes were elucidated. The thermolysis products of the double complex salts obtained under a helium or hydrogen atmosphere were studied.     

Kobalt(III)ammin-derivate einiger Reineckesalz-Analoga mit Xylidinen

Zusammenfassung Es wurden 34 neue Komplexsalze durch doppelte Umsetzung aus wäßr.-alkohol. Lösungen der folgenden Reineckeat-Analoga: [Cr(NCS)₄(m-xylidin)₂]^–, [Cr(NCS)₄(p-xyl)₂]^– und Hexammin-, Monoacido-pentammin- und Diacido-tetramminkobalt(III)-komplexsalze erhalten. Es wurden in einigen Fällen Unterschiede in physiko-chemischen Eigenschaften, wie Farbtönung, Kristallform, Löslichkeit und papierchromatographischeR _f-Werte, bei den stellungsisomeren Salzen vom Typus: Kation · [Cr(NCS)₄(xyl)₂] und auch bei den Koordinationsisomerpaaren: [Co(DH)₂(m-xyl)₂] [Cr(NCS)₄(p-xyl)₂] und [Co(DH)₂(p-xyl)₂] [Cr(NCS)₄(m-xyl)₂] usw. beobachtet.

---

Cobalt(III)ammine derivatives of some reineckate analogues with xylidines

34 new complex salts were prepared by double conversion of the reineckate analogues [Cr(NCS)₄(m-xylidine)₂]^–, [Cr(NCS)₄(p-xyl)₂]^–, with the hexammine-, monoacido-pentammine- and diacidotetrammine-complexes of Co(III). In some of the position and coordination isomeres differences of the standard physico-chemical properties, i.e. color, crystal form, solubility and paper chromatographyR _f-values were observed.

     

Structural types of octa(ɛ-caprolactam)-lanthanide(III) hexa(isothiocyanato)chromates(III). Phase transition with reversible twinning

The compounds [LnL₈][Cr(NCS)₆] (Ln = La³⁺, Pr³⁺, Eu³⁺, Gd³⁺, Tb³⁺, Yb³⁺, L =?-C₆H₁₁NO) were obtained from aqueous solutions containing LnCl₃, K₃[Cr(NCS)₆], and ?-caprolactam at 4–6. All these compounds have thermochromic properties and reversibly changed color from pale violet to dark green when heated in air at 473–483 K. The compounds crystallized as one of the three related structural types with the mutual packing of ions topologically corresponding to the packing in the structure of NaCl. The [EuL₈][Cr(NCS)₆] single crystal underwent a reversible phase transition at T = 240–250 K, which was accompanied by reversible twinning.     

Kaliumtriamidostannat(II), K[Sn(NH2)3] – Synthese und Kristallstruktur

Potassium Triamidostannate(II), K[Sn(NH₂)₃] – Synthesis and Crystal Structure Rusty‐red crystals of K[Sn(NH₂)₃] were obtained by the reaction of SnBr₂ and KNH₂ in a 1 : 3 molar ratio in liquid ammonia at 233 K in the form of platelets. The structure was determined from single crystal X‐ray diffractometer data: Space group P3; Z = 2; a = 6.560(1) Å, c = 7.413(2) Å. The structure contains trigonal pyramidal complex anions [Sn(NH₂)₃]^– and potassium cations. These ions are arranged to one another following the motif of a strongly distorted hexagonal close packing of sequence A(Sn) B(Sn) A′(K) B′(K) …