Synthese und Kristallstruktur von Hydrogensulfaten einwertiger Metalle – Ag(H3O)(HSO4)2, Ag2(HSO4)2(H2SO4), AgHSO4 und Hg2(HSO4)2

Synthesis and Crystal Structure of Metal(I) Hydrogen Sulfates – Ag(H₃O)(HSO₄)₂, Ag₂(HSO₄)₂(H₂SO₄), AgHSO₄, and Hg₂(HSO₄)₂ Hydrogen sulfates Ag(H₃O)(HSO₄)₂, Ag₂(HSO₄)₂ · (H₂SO₄), and AgHSO₄ have been synthesized from Ag₂SO₄ and sulfuric acid. Hg₂(HSO₄)₂ was obtained from metallic mercury and 96% sulfuric acid as starting materials. The compounds were characterized by X‐ray single crystal structure determination. Ag(H₃O)(HSO₄)₂ belongs to the structure type of Na(H₃O)(HSO₄). The silver atom is coordinated by 6 + 2 oxygen atoms. In the structure, there are dimers and chains of hydrogen bonded HSO₄^– tetrahedra. Dimers and chains are connected by the H₃O⁺ ion to form a three dimensional hydrogen network. Ag₂(HSO₄)₂(H₂SO₄) crystallizes isotypic to Na₂(HSO₄)₂(H₂SO₄). The coordination number of silver is 6 + 1. The structure of Ag₂(HSO₄)₂(H₂SO₄) is characterized by hydrogen bonded trimers of HSO₄^– tetrahedra, which are further connected to chains. For the recently published structure of AgHSO₄ the hydrogen bonding system was discussed. There are tetrameres and chains, connected by bifurcated hydrogen bonds. The structure of Hg₂(HSO₄)₂ contains Hg₂²⁺ cations with Hg–Hg distance of 2.509 Å. Every mercury atom is coordinated by one oxygen atom at shorter distance (2.18 Å) and three ones at longer distances (2.57 to 3.08 Å). The HSO₄^– tetrahedra form zigzag chains by hydrogen bonds.     

Synthesis of platinum-mercury clusters and the molecular structure of Pt4(HgBr)2(μ-CO)4(PPh3)4

New platinum-mercury clusters, Pt₄(HgX)₂(μ-CO)₄(PR₃)₄ (X=Cl, Br, I, CF₃, or CCl₃; R=Ph or Et), were synthesized. The molecular and crystal structure of the Pt₄(HgBr)₂(μ-CO)₄(PPh₃)₄ cluster was established by X-ray structural analysis.     

Neue phosphidoverbrückte Mehrkernkomplexe des Ag und Zn. Die Kristallstrukturen von [Ag3(PPh2)3(PnBu2tBu)3], [Ag4(PPh2)4(PR3)4] (PR3 = PMenPr2, PnPr3), [Ag4(PPh2)4(PEt3)4]n, [Zn4(PPh2)4Cl4(PRR2)2] (PRR′2 = PMenPr2, PnBu3, PEt2Ph), [Zn4(PhPSiMe3)4Cl4(C4H8O)2] und [Zn4(PtBu2)4Cl4]

New Phosphido-bridged Multinuclear Complexes of Ag and Zn. The Crystal Structures of [Ag₃(PPh₂)₃(PⁿBu₂^tBu)₃], [Ag₄(PPh₂)₄(PR₃)₄] (PR₃ = PMeⁿPr₂, PⁿPr₃), [Ag₄(PPh₂)₄(PEt₃)₄]_n, [Zn₄(PPh₂)₄Cl₄(PRR′₂)₂] (PRR′₂ = PMeⁿPr₂, PⁿBu₃, PEt₂Ph), [Zn₄(PhPSiMe₃)₄Cl₄(C₄H₈O)₂] and [Zn₄(P^tBu₂)₄Cl₄] AgCl reacts with Ph₂PSiMe₃ in the presence of tertiary Phosphines (PⁿBu₂^tBu, PMeⁿPr₂, PⁿPr₃ and PEt₃) to form the multinuclear complexes [Ag₃(PPh₂)₃(PⁿBu₂^tBu)₃] 1 , [Ag₄(PPh₂)₄(PR₃)₄] (PR₃ = PMeⁿPr₂ 2 , PⁿPr₃ 3 ) and [Ag₄(PPh₂)₄(PEt₃)₄]_n 4 . In analogy to that ZnCl₂ reacts with Ph₂PSiMe₃ and PRR′₂ to form the multinuclear complexes [Zn₄(PPh₂)₄Cl₄(PRR′₂)₂] (PRR′₂ = PMeⁿPr₂ 5 , PⁿBu₃ 6 , PEt₂Ph 7 ). Further it was possible to obtain the compounds [Zn₄(PhPSiMe₃)₄Cl₄(C₄H₈O)₂] 8 and [Zn₄(P^tBu₂)₄Cl₄] 9 by reaction of ZnCl₂ with PhP(SiMe₃)₂ and ^tBu₂PSiMe₃, respectively. The structures were characterized by X-ray single crystal structure analysis. Crystallographic data see “Inhaltsübersicht”.     

Synthesis and Characterization of Gd2[Pt2(SO4)4(HSO4)2](HSO4)2

Red single crystals of Gd₂[Pt₂(SO₄)₄(HSO₄)₂](HSO₄)₂ (triclinic, , Z = 1, a = 844.02(9), b = 908.50(9), c = 939.49(8) pm, α = 107.73(1)°, β = 112.10(1)°, γ = 103.53(1)°) were obtained by the reaction of [Gd(NO₃)(H₂O)₇][PtCl₆]·4H₂O with sulfuric acid at 320 °C in a sealed glass ampoule. In the crystal structure, Pt₂ dumbbells are coordinated by four chelating sulfate groups and two monodentate hydrogensulfate ions. Two further HSO₄^? ions are not bonded to the Pt₂ dumbbell. The Gd³⁺ ions are eightfold coordinated by oxygen atoms. The IR data of Gd₂[Pt₂(SO₄)₄(HSO₄)₂](HSO₄)₂ are typical for these type of compounds. The thermal decomposition of the compound leads to elemental platinum and Gd₂O₃.     

(Hg2)Hg(OH)2(ClO4)2: Das erste gemischtvalente Quecksilberperchlorat

(Hg₂)Hg(OH)₂(ClO₄)₂: The First Mixed Valent Mercury Perchlorate Colorless single crystals of (Hg₂)Hg(OH)₂(ClO₄)₂ (C2/c, Z = 4, a = 1847.7(5), b = 490.8(1), c = 1086.2(3) pm, β = 93.80(2)°, R_all = 0.0610) were obtained as a side product during the dehydration of Hg₂(ClO₄)₂ · 2H₂O. The crystal structure consists of infinite zig‐zag chains {_∞¹[(Hg₂)_1/2(OH)Hg_1/2]⁺}₂ which are separated by the ClO₄^— ions.     

Pt2(HSO4)2(SO4)2, the First Binary Sulfate of Platinum

Red single crystals of Pt₂(HSO₄)₂(SO₄)₂ were obtained by the reaction of elemental platinum with conc. sulfuric acid at 350 °C in sealed glass ampoules. The crystal structure (monoclinic, P2₁/c, Z = 2, a = 868.6(2), b = 826.2(1), c = 921.8(2) pm, β=116.32(1)°, R_all = 0.0348) shows dumbbell shaped Pt₂⁶⁺ cations which are coordinated by four SO₄^2— and two HSO₄^— ions. Each of the sulfate ions is attached to another Pt₂⁶⁺ ion yielding layers according to equation/tex2gif-stack-1.gif[Pt₂(SO₄)_4/2(HSO₄)_2/1]. The layers are connected by hydrogen bonds with the OH group of the hydrogensulfate ion as donor and the non‐bonding oxygen atom of the sulfate ion as acceptor.     

Synthese und Kristallstruktur von K2(HSO4)(H2PO4), K4(HSO4)3(H2PO4) und Na(HSO4)(H3PO4)

Synthesis and Crystal Structure of K₂(HSO₄)(H₂PO₄), K₄(HSO₄)₃(H₂PO₄), and Na(HSO₄)(H₃PO₄) Mixed hydrogen sulfate phosphates K₂(HSO₄)(H₂PO₄), K₄(HSO₄)₃(H₂PO₄) and Na(HSO₄)(H₃PO₄) were synthesized and characterized by X‐ray single crystal analysis. In case of K₂(HSO₄)(H₂PO₄) neutron powder diffraction was used additionally. For this compound an unknown supercell was found. According to X‐ray crystal structure analysis, the compounds have the following crystal data: K₂(HSO₄)(H₂PO₄) (T = 298 K), monoclinic, space group P 2₁/c, a = 11.150(4) Å, b = 7.371(2) Å, c = 9.436(3) Å, β = 92.29(3)°, V = 774.9(4) ų, Z = 4, R₁ = 0.039; K₄(HSO₄)₃(H₂PO₄) (T = 298 K), triclinic, space group P 1, a = 7.217(8) Å, b = 7.521(9) Å, c = 7.574(8) Å, α = 71.52(1)°, β = 88.28(1)°, γ = 86.20(1)°, V = 389.1(8)ų, Z = 1, R₁ = 0.031; Na(HSO₄)(H₃PO₄) (T = 298 K), monoclinic, space group P 2₁, a = 5.449(1) Å, b = 6.832(1) Å, c = 8.718(2) Å, β = 95.88(3)°, V = 322.8(1) ų, Z = 2, R₁ = 0,032. The metal atoms are coordinated by 8 or 9 oxygen atoms. The structure of K₂(HSO₄)(H₂PO₄) is characterized by hydrogen bonded chains of mixed H_nS/PO₄^– tetrahedra. In the structure of K₄(HSO₄)₃(H₂PO₄), there are dimers of H_nS/PO₄^– tetrahedra, which are further connected to chains. Additional HSO₄^– tetrahedra are linked to these chains. In the structure of Na(HSO₄)(H₃PO₄) the HSO₄^– tetrahedra and H₃PO₄ molecules form layers by hydrogen bonds.     

Coordination Chemistry of [Nb2(S2)2]4+ Clusters: Preparation and Crystal Structures of K4[Nb2(S2)2(C2O4)4] · 6 H2O and (NH4)6[Nb2(S2)2(C2O4)4](C2O4)

Bis(disulfido)bridged Nb^IV cluster oxalate complexes [Nb₂(S₂)₂(C₂O₄)₄]^4– were prepared by ligand substitution reaction from the aqua ion [Nb₂(μ‐S₂)₂(H₂O)₈]⁴⁺ and isolated as K₄[Nb₂(S₂)₂(C₂O₄)₄] · 6 H₂O ( 1 ), (NH₄)₆[Nb₂(S₂)₂(C₂O₄)₄](C₂O₄) ( 2 ) and Cs₄[Nb₂(S₂)₂(C₂O₄)₄] · 4 H₂O ( 3 ). The crystal structures of 1 and 2 were determined. The crystals of 1 belong to the space group P1, a = 720.94(7) pm, b = 983.64(10) pm, c = 1071.45(10) pm, α = 109.812(1)°, β = 91.586(2)°, γ = 105.257(2)°. The crystals of 2 are monoclinic, space group C2/c, a = 1567.9(2) pm, b = 1906.6(3) pm, c = 3000.9(4) pm, β = 95.502(2)°. The packing in 2 shows alternating layers of cluster anions and of ammonium/uncoordinated oxalates perpendicular to the [1 0 1] direction. Vibration spectra, electrochemistry and thermogravimetric properties of the complexes are also discussed.     

Syntheses and Structures of Na2Mg3(OH)2(SO4)3·4H2O and K2Mg3(OH)2(SO4)3·2H2O

The crystal structures of Na₂Mg₃(OH)₂(SO₄)₃ · 4H₂O and K₂Mg₃(OH)₂(SO₄)₃ · 2H₂O, were determined from conventional laboratory X‐ray powder diffraction data. Synthesis and crystal growth were made by mixing alkali metal sulfate, magnesium sulfate hydrate, and magnesium oxide with small amounts of water followed by heating at 150 °C. The compounds crystallize in space group Cmc2₁ (No. 36) with lattice parameters of a = 19.7351(3), b = 7.2228(2), c = 10.0285(2) Å for the sodium and a = 17.9427(2), b = 7.5184(1), c = 9.7945(1) Å for the potassium sample. The crystal structure consists of a linked MgO₆–SO₄ layered network, where the space between the layers is filled with either potassium (K⁺) or Na⁺‐2H₂O units. The potassium‐bearing structure is isostructural to K₂Co₃(OH)₂(SO₄)₃ · 2(H₂O). The sodium compound has a similar crystal structure, where the bigger potassium ion is replaced by sodium ions and twice as many water molecules. Geometry optimization of the hydrogen positions were made with an empirical energy code.     

Synthese und Kristallstrukturen von [Cu4(As4Ph4)2(PRR′2)4], [Cu14(AsPh)6(SCN)2(PEt2Ph)8], [Cu14(AsPh)6Cl2(PRR′2)8], [Cu12(AsPh)6(PPh3)6], [Cu10(AsPh)4Cl2(PMe3)8], [Cu12(AsSiMe3)6(PRR′2)6] und [Cu8(AsSiMe3)4(PtBu3)4] (R,R′ = organische Gruppen)

Syntheses and Crystal Structures of [Cu₄(As₄Ph₄)₂(PRR′₂)₄], [Cu₁₄(AsPh)₆(SCN)₂(PEt₂Ph)₈], [Cu₁₄(AsPh)₆Cl₂(PRR′₂)₈], [Cu₁₂(AsPh)₆(PPh₃)₆], [Cu₁₀(AsPh)₄Cl₂(PMe₃)₈], [Cu₁₂(AsSiMe₃)₆(PRR′₂)₆], and [Cu₈(AsSiMe₃)₄(P^tBu₃)₄] (R, R′ = Organic Groups) Through the reaction of CuSCN with AsPh(SiMe₃)₂ in the presence of tertiary phosphines the compounds [Cu₄(As₄Ph₄)₂(PRR′₂)₄] ( 1 – 3 ) ( 1 : R = R′ = ⁿPr, 2 : R = R′ = Et; 3 : R = Me, R′ = ⁿPr) and [Cu₁₄(AsPh)₆(SCN)₂(PEt₂Ph)₈] ( 4 ) can be synthesised. Using CuCl instead of CuSCN results to the cluster complexes [Cu₁₄(AsPh)₆Cl₂(PRR′₂)₈] ( 5–6 ) ( 5 : R = R′ = Et; 6 : R = Me, R′ = ⁿPr), [Cu₁₂(AsPh)₆(PPh₃)₆] ( 7 ) and [Cu₁₀(AsPh)₄Cl₂(PMe₃)₈] ( 8 ). Through reactions of CuOAc with As(SiMe₃)₃ in the presence of tertiary phosphines the compounds [Cu₁₂(AsSiMe₃)₆(PRR′₂)₆] ( 9 – 11 ) ( 9 : R = R′ = Et; 10 : R = Ph, R′ = Et; 11 : R = Et, R′ = Ph) and [Cu₈(AsSiMe₃)₄(P^tBu₃)₄] ( 12 ) can be obtained. In each case the products were characterised by single‐crystal‐X‐ray‐structure‐analyses. As the main structure element 1 – 3 each have two As₄Ph₄^2–‐chains as ligands. In contrast 4 – 12 contain discrete AsR^2–ligands.     

Structure and spectral characteristics of (NH4)2[Re2(HPO4)4 · 2H2O]

The compound (NH₄)₂[Re₂(HPO₄)₄ · 2H₂O] has been synthesized and characterized by electronic and vibrational spectroscopy. The molecular structure has been determined by X-ray diffraction (MoK _α radiation, λ = 0.71073 Å). The (NH₄)₂[Re₂(HPO₄)₄ · 2H₂O] coordination units form centrosymmetrical binuclear ordering with each metal atom being coordinated in a distorted octahedron incorporating one rhenium atom, one oxygen atom of the water molecule, and four phosphate oxygen atoms in the equatorial plane. The rhenium-rhenium bond length (2.2207 Å) corresponds to a quadruple bond between the atoms. The [Re₂(HPO₄)₄ · 2H₂O]^2- complex anions in the crystal are associated through strong hydrogen bonds formed by the phosphate O-H···O groups. The stability of dirhenium(III) tetra-μ-phosphates in aqueous solutions is considered.     

Sur un nouveau Complexe entre l'oxyfluorure d'antimoine et l'oxalate. Structure cristalline de (NH4)4H2(C2O4)3(SbOF) 2 · H2O

On a New Complex of Antimony Oxide Fluoride and Oxalate. Crystal Structure of (NH₄)₄H₂(C₂O₄)₃(SbOF) ₂ · H₂O The crystal structure of (NH₄)₄H₂(C₂O₄)₃(SbOF) ₂ · H₂O has been fixed by X-ray diffraction on single crystal (R = 0.025 for 2124 planes). The antimony atom is complexed by the oxalate anions which are bidendate chelates. Antimony coordination is seven (five oxygen atoms, one fluorine atom, and the lone pair E). Antimony environment is a pentagonal bipyramid, one of the axial positions is occupied by the lone pair, the other one by the fluorine atom.     

Neue Phosphido-verbrückte Mehrkernkomplexe des Ag,Cd und Zn Die Kristallstrukturen von [Ag4(PPh2)4(PMe3)4], [Ag6(PPh2)6(PtBu3)2] und [M4Cl4(PPh2)4(PnPr3)2] (M = Zn,Cd)

New Phosphido-bridged Multinuclear Complexes of Ag, Cd and Zn. The Crystal Structures of [Ag₄(PPh₂)₄(PMe₃)₄], [Ag₆(PPh₂)₆(P^tBu₃)₂] and [M₄Cl₄(PPh₂)₄(PⁿPr₃)₂] (M = Zn, Cd) AgCl reacts with Ph₂PSiMe₃ in the presence of a tertiary Phosphine PMe₃ or P^tBu₃ to form the multinuclear complexes [Ag₄(PPh₂)₄(PMe₃)₄] ( 1 ) and [Ag₆(PPh₂)₆(P^tBu₃)₂] ( 2 ). In analogy to that MCl₂ reacts with Ph₂PSiMe₃ in the presence of PⁿPr₃ to form the two multinuclear complexes [M₄Cl₄(PPh₂)₄(PⁿPr₃)₂] (M = Zn ( 3 ), Cd ( 4 )). The structures were characterized by X-ray single crystal structure analysis ( 1 : space group Pna2₁ (Nr. 33), Z = 4, a = 1 313.8(11) pm, b = 1 511.1(6) pm, c = 4 126.0(18) pm, 2 : space group P–1 (Nr. 2), Z = 2, a = 1 559.0(4) pm, b = 1 885.9(7) pm, c = 2 112.4(8) pm, α = 104.93(3)°, β = 94.48(3)°, γ = 104.41(3)°; 3 : space group C2/c (Nr. 15), Z = 4, a = 2 228.6(6) pm, b = 1 847.6(6) pm, c = 1 827.3(6) pm, β = 110.86(2); 4 : space group C2/c (Nr. 15), Z = 4, a = 1 894.2(9) pm, b = 1 867.9(7) pm, c = 2 264.8(6) pm, β = 111.77(3)°). 3 and 4 may be considered as intermediates on the route towards polymeric [M(PPh₂)₂]_n (M = Zn, Cd).     

AgCo3PO4(HPO4)2

The structure of the hydro­thermally synthesized compound AgCo₃PO₄(HPO₄)₂, silver tricobalt phosphate bis­(hydrogen phosphate), consists of edge‐sharing CoO₆ chains linked together by the phosphate groups and hydrogen bonds. The three‐dimensional framework delimits two types of tunnels which accommodate Ag⁺ cations and OH groups. The title compound is isostructural with the compounds AM₃H₂(XO₄)₃ (A = Na or Ag, M = Co or Mn, and X = P or As) of the alluaudite structure type.     

A chiral mixed carboxylate, [Nd4(H2O)2(OOC(CH2)3COO)4(C2O4)2], exhibiting NLO properties

Reaction of a mixture of neodymium carbonate, HCl, oxamic acid and glutaric acid under hydrothermal conditions gives rise to a new mixed carboxylate of neodymium, [Nd₄(H₂O)₂(OOC(CH₂)₃COO)₄(C₂O₄)₂], I. The structure, determined using single crystal X-ray diffraction, comprises a helical column formed by the grafting of the oxalate unit on to helical NdO₉ chains, cross-linked by the glutarate anions. It is noteworthy that the pitch of the helix is equivalent to the length of the oxalate unit. Furthermore, I shows about 1.1 times the SHG activity of urea.     

Phase equilibria in the Tl2MoO4-Nd2(MoO4)3-Hf(MoO4)2 system and the crystal structure of double molybdate TlNd(MoO4)2

The Tl₂MoO₄-Nd₂(MoO₄)₃-Hf(MoO₄)₂ system was studied in the subsolidus region using X-ray powder diffraction. New triple molybdates were found to exist in this system: Tl₅NdHf(MoO₄)₆ (5: 1: 2), TlNdHf_0.5(MoO₄)₃ (1: 1: 1), and Tl₂NdHf₂(MoO₄)_6.5 (2: 1: 4). The first TlNd(MoO₄)₂ single crystals were grown from melt solutions with spontaneous nucleation. Their crystal structure was refined from X-ray diffraction data (Bruker X8 Apex automated diffractometer, MoK _α radiation, 386 F(hkl), R = 0.0136). The tetragonal unit cell parameters are as follows: a = 6.3000(2) Å, c = 9.5188(5) Å, V = 377.80(3) ų, Z = 2, ρ_calcd = 5.876 g/cm³, space group P4/nnc. The structure is a framework built of NdO₈ and TlO₈ tetragonal antiprisms linked via shared lateral edges and alternating in the checkerboard order. Layers share oxygen vertices with MoO₄ interlayer tetrahedra and are linked into the framework.     

Isopropylammonium Layered Uranyl Chromates: Syntheses and Crystal Structures of [(CH3)2CHNH3]3[(UO2)3(CrO4)2O(OH)3] and[(CH3)2CHNH3]2[(UO2)2(CrO4)3(H2O)]

Two novel isopropylamine‐templated uranyl chromates, [(CH₃)₂CHNH₃]₃[(UO₂)₃(CrO₄)₂O(OH)₃] ( 1 ) and [(CH₃)₂CHNH₃]₂[(UO₂)₂(CrO₄)₃(H₂O)] ( 2 ) were prepared by hydrothermal method at 100 °C. The compounds were characterized by electron microprobe analysis and X‐ray diffraction crystal structure analysis [ 1 : trigonal, P31m, a = 9.646(4), c = 8.469(4) Å, V = 682.4(5) ų; 2 : monoclinic, P2₁/c, a = 11.309(3), b = 11.465(3), c = 17.055(5) Å, β = 99.150(6)°, V = 2183.2(11) ų]. The structure of 1 is based upon trimers of uranyl bipyramids interlinked by CrO₄ tetrahedra to form [(UO₂)₃(CrO₄)₂O(OH)₃]^3– layers, whereas, in the structure of 2 , UO₇ and UO₆(H₂O) pentagonal bipyramids are linked through CrO₄ tetrahedra into the [(UO₂)₂(CrO₄)₃(H₂O)]^2– layers. The structures show many similarities to related uranyl selenate compounds, thus providing additional data on similarities and differences between uranyl sulfates, chromates, selenates, and molybdates.     

Zur Reaktion von NiCl2 mit PhP(SiMe3)2 Die Kristallstruktur von [Ni12Cl2(PPh)2(P2Ph2)4(PHPh)8]

Reaction of NiCl₂ with PhP(SiMe₃)₂, The Crystal Structure of [Ni₁₂Cl₂(PPh)₂(P₂Ph₂)₄(PHPh)₈] [Ni₁₂Cl₂(PPh)₂(P₂Ph₂)₄(PHPh)₈] ( 1 ) has been prepared by the reaction of NiCl₂ with PhP(SiMe₃)₂. The structure has been characterized by X-ray crystal structure analysis. 1 contains a Ni₁₂-cluster with m?₄-PPh- and m?₆-P₂Ph₂- as bridging ligands. The terminal PHPh- and Cl-ligands are bound to Ni-atoms. The Ni₁₂-cluster can be described as an Ni₈-cube, in which four edges are bridged by Ni-atoms.     

[CrBr2(NH3)4][CrBr4(NH3)2], a new chromium(III) complex

Green single crystals of trans‐tetraamminedibromidochromium(III) trans‐diamminetetrabromidochromate(III), [CrBr₂(NH₃)₄][CrBr₄(NH₃)₂], are found to contain two symmetry‐independent sixfold coordinated Cr^III cations on centres of inversion. The structure is composed of octahedral trans‐[CrBr₂(NH₃)₄]⁺ cations and octahedral trans‐[CrBr₄(NH₃)₂]⁻ anions, and adopts a distorted CsCl‐type lattice. The cations and anions are linked by N—H...Br interactions. This is the first example in which both ions are mixed ammine–bromide Cr^III complexes.     

Glass formation in the systems Al2(SO4)3-MSO4-H2O (M = Cd2+, Zn2+, Mg2+) and Al2(SO4)3-Fe2(SO4)3-H2O

The glass formation region boundaries were found in the systems Al₂(SO₄)₃-MSO₄-H₂O, where M = Cd²⁺, Zn²⁺, and Mg²⁺, and Al₂(SO₄)₃-Fe₂(SO₄)₃-H₂O. The causes of the differences in glass-forming ability between the studied systems were analyzed. The structures and properties of glassy Al₂(SO₄)₃ · 11H₂O and Fe₂(SO₄)₃ · 11H₂O were compared.