Volume 235, Issue 8-9 - Special Issue: Dedicated to Professor Dr. Ulrich Müller on the occasion of his 80th birthday

Herein we present the synthesis, crystal structure, and the infrared and Raman spectra of K 3 Na 4 [SiF 6 ] 3 [BF 4 ]. The compound also occurs in nature as the mineral Knasibfite. We obtained it from the reaction of stoichiometric amounts of SiO 2 , Na[BF 4 ], K 2 CO 3 , and Na 2 CO 3 in hydrofluoric acid at room temperature. Hydrofluorothermal synthesis at 200 °C lead to a product of higher purity. Knasibfite is colorless and crystallizes in space group Im  2 m with a  = 5.546(2), b  = 9.261(2), c  = 17.184(4) Å, V  = 882.5(4) Å 3 , Z  = 2, at T  = 400(2) K. At 342 K a phase transition to a monoclinic structure was observed ( I  2, a  = 5.5003(6), b  = 9.0890(9), c  = 17.0048(2) Å, β  = 90.041(9)°, V  = 852.2(2) Å 3 , Z  = 2, T  = 100(2) K). By replacing SiO 2 with GeO 2 as a starting material K 3 Na 4 [GeF 6 ] 3 [BF 4 ] was obtained. This compound also crystallizes in form of two polymorphs, both of which are isotypic to the respective ones of K 3 Na 4 [SiF 6 ] 3 [BF 4 ].

Yellow prismatic crystals of rubidium bromido-antimonate(III) Rb 7 Sb 3 Br 16 and of two different modifications of thallium bromido-bismuthate(III) Tl 7 Bi 3 Br 16 were obtained by solvent-free synthesis and by precipitation from acidic aqueous solutions. X-ray diffraction analyses revealed the Tl 7 Bi 3 I 16 -type for α -Tl 7 Bi 3 Br 16 (orthorhombic, Cmcm , a  = 2324.31(8) pm, b  = 1346.69(4) pm, c  = 3460.0(1) pm; Pearson symbol oC 312) and a new structure type for β -Tl 7 Bi 3 Br 16 (monoclinic, C 2 /c , a  = 2331.87(5) pm, b  = 1343.33(3) pm, c  = 3546.01(7) pm, β  = 102.708(1)°; mC 312). The antimonate Rb 7 Sb 3 Br 16 adopts the Tl 7 Bi 3 I 16 -type, too (orthorhombic, Cmcm , a  = 2347.16(3) pm, b  = 1357.89(5) pm, c  = 3539.47(9) pm; oC 312). The crystal structures of α - and β -Tl 7 Bi 3 Br 16 comprise alternating slabs of isolated [BiBr 6 ] 3– octahedra and [Bi 2 Br 10 ] 4– octahedra pairs. Both structure types are hierarchically organized and can be regarded as sphere close packing with the same stacking sequence, if octahedra and octahedra pairs are replaced by spheres of equal size. The structural relationship between the Tl 7 Bi 3 I 16 -type and the hydrate Na 7 Bi 3 Br 16 · 18H 2 O, which comprises similar structural features, is discussed.

Beryllium and BeCl 2 were treated with trifluoromethanesulfonic acid and trimethylsilyltriflate, respectively to form beryllium triflates BeL 2 (OTf) 2 (L=H 2 O, THF, n Bu 2 O). The Be–O atomic distances (1.605–1.635 Å) between Be 2+ and the triflate anions in solid state are the shortest known distances of this kind in a metal triflate yet. Attempts to remove the solvate molecules led to the decomposition of the obtained compounds.

Cu(I) and Ag(I) iodidometalates have been investigated for both their rich structural chemistry, as well as for useful properties like luminescence. Here, we present the synthesis and crystal structure of (BzA)[MI 2 ] · 0.5 H 2 O (BzA = benzylammonium; M=Cu ( 1 ), Ag ( 2 )). The two compounds are isostructural and show a previously unknown layered anion motif that can be described as a 4 4 net constructed via corner-sharing of M 2 I 6 subunits, built from two edge-sharing MI 4 tetrahedra.

Four new mixed-valent chain alkali metal ( A ) sulfido ferrates of the general structure family A1+xFexIIFe1−xIIIS2${A}_{1+x}\left[{\text{Fe}}_{x}^{\text{II}}{\text{Fe}}_{1-x}^{\text{III}}{\text{S}}_{2}\right]$ were synthesized in the form of tiny green-metallic needles from nearly stoichiometric melts reacting elemental potassium with natural pyrite ( A  = K) or previously prepared Rb 2 S/Cs 2 S 2 with elemental iron and sulfur ( A  = Rb/Cs). The crystal structures of the compounds were determined by means of single crystal X-ray diffraction: In the (3+1)D modulated structure of K 7.15 [FeS 2 ] 4 (space group Ccce (00 σ 3 )0 s 0, a  = 1363.87(5), b  = 2487.23(13), c  = 583.47(3) pm, q  = 0,0,0.444, R 1 = 0.055/0.148, x  = 0.787), a position modulation of the two crystallographically different undulated [FeS4/2]∞1${}_{\infty }{}^{1}\left[{\text{FeS}}_{4/2}\right]$ tetrahedra chains and the surrounding K cations is associated with an occupation modulation of one of the three potassium sites. In the case of the new monoclinic rubidium ferrate Rb 4 [FeS 2 ] 3 ( x  = 13$\frac{1}{3}$; space group P 2 1 / c , a  = 1640.49(12), b  = 1191.94(9), c  = 743.33(6) pm, β  = 94.759(4)°, Z  = 4, R 1 = 0.1184) the undulation of the tetrahedra chain is commensurate, the repetition unit consists of six tetrahedra. In the second new Rb ferrate, Rb 7 [FeS 2 ] 5 ( x  = 0.4; monoclinic, space group C 2/ c , K 7 [FeS 2 ] 5 -type; a  = 2833.9(2), b  = 1197.36(9), c  = 744.63(6) pm, β  = 103.233(4)°, Z  = 4, R 1 = 0.1474) and its isotypic mixed Rb/Cs-analog Rb 3.6 Cs 3.4 [FeS 2 ] 5 ( a  = 2843.57(5), b  = 1226.47(2), c  = 759.890(10) pm, β  = 103.7170(9)°, R 1 = 0.0376) the chain buckling leads to a further increased repetition unit of 10 tetrahedra. For all mixed-valent ferrates, the Fe–S bond lengths continuously increase with the amount ( x ) of Fe(II). The buckling of the chains is controlled through the local coordination of the S atoms by the variable number of A cations of different sizes.

La 6 MnSb 15 is synthesized from the constituent elements in quartz ampoules at 973 K. Crucial for the quality of the obtained single-crystals was a slow cooling rate of 2 K h −1 . The crystal structure of La 6 MnSb 15 was investigated via single-crystal X-ray diffraction experiments, leading to the observation of superstructure reflections as described in the literature. Two crystals, with refined compositions of La 6 MnSb 15 (1) and La 6 MnSb 14.66(1) (2) were obtained from different batches, yet both showed an orthorhombic body centered unit cell as well as additional reflections at q 1  = (0,0,0.258(1)) for crystal (1) and q 1  = (0,0,0.244(1)) for crystal (2). The structure could be solved and refined in superspace group Immm (00 γ )000 (71.1.12.1), leading to a concise structural model. Due to γ not being exactly 1/4, an incommensurate modulation is present in the presented compounds. In order to describe the structural influence of the modulation in 3D, different approximants were chosen and the differences compared. Additionally, the temperature dependence of the electrical resistivity was investigated, indicating a metallic behavior of the title compound. This result is in line with the retro-theoretical investigation in the literature that counts excess electrons when using the Zintl – Klemm – Busmann concept. 121 Sb Mößbauer -spectroscopic investigations at 78 K show a broad signal with an average isomeric shift of δ  ∼ −10 mm s −1 , in line with a negatively charged Sb species. The massive line broadening can be explained by the large number of crystallographic antimony sites in the basic structure and the approximant.

The monoclinic α -polymorph of (V IV O)(PO 3 ) 2 is obtained reproducibly by reaction of V 2 O 5 and H 3 PO 4 (85%) (Au crucible, 380 °C, 4 d). Its crystal structure was refined from X-ray single-crystal data [ C 2/c, Z = 4, a  = 15.1038(7) Å, b  = 4.193(2) Å, c  = 9.573(9) Å, β  = 126.45(3), R 1  = 0.052, wR 2  = 0.189 for 976 unique reflections with F o  >  4σ ( F o ), 48 variables]. A single-phase powder of the β -polymorph is obtained by the reaction of V 2 O 5 , H 3 PO 4 (85%) and oxalic acid, evaporating the mixture, and subsequent annealing (porcelain crucible, 800 °C in air, 2 d). Single crystals of β -(V IV O)(PO 3 ) 2 were grown in a sealed silica ampoule with chlorine as mineralizer. The crystal structure of the orthorhombic (pseudo-tetragonal) β -polymorph was refined from X-ray single-crystal data [pseudo-merohedral twin, Fdd 2, Z = 8, a  = 15.536(2) Å, b  = 15.586(2) Å, c  = 4.2611(5) Å, R 1  = 0.032, wR 2  =  0.068 for 1072 unique reflections with F o  >  4σ ( F o ), 50 variables]. Earlier reports on a tetragonal polymorph with unusual geometric structure of the [(V≡O)O 5 ] polyhedron are corrected.

Pb5O2[WO6]${\text{Pb}}_{5}{\text{O}}_{2}\left[{\text{WO}}_{6}\right]$ was discovered as a frequently observed side phase during our investigation on lead tungstates. Its crystal structure was solved by single-crystal X-ray diffraction (P21/n$P{2}_{1}/n$, a=7.4379(2)$a=7.4379\left(2\right)$ Å, b=12.1115(4)$b=12.1115\left(4\right)$ Å, c=10.6171(3)$c=10.6171\left(3\right)$ Å, β=90.6847(8)$\beta =90.6847\left(8\right)$°, Z=4$Z=4$, Rint=0.038${R}_{\text{int}}=0.038$, R1=0.020${R}_{1}=0.020$, ωR2=0.029$\omega {R}_{2}=0.029$, 4188 data, 128 param.) and is isotypic with Pb5O2[Te6]${\text{Pb}}_{5}{\text{O}}_{2}\left[{\text{Te}}_{6}\right]$. Pb5O2[WO6]${\text{Pb}}_{5}{\text{O}}_{2}\left[{\text{WO}}_{6}\right]$ comprises a layered structure built up by non-condensed [WO 6 ]6−${}^{6-}$ octahedra and [O4Pb10]12+${\left[{\text{O}}_{4}{\text{Pb}}_{10}\right]}^{12+}$ oligomers. The compound was characterised by spectroscopic measurements (Infrared (IR), Raman and Ultraviolet–visible (UV/Vis) spectra) as well as quantum chemical and electrostatic calculations (density functional theory (DFT), MAPLE) yielding a band gap of 2.9 eV fitting well with the optical one of 2.8 eV. An estimation of the refractive index based on the Gladstone-Dale relationship yielded n≈2.31$n\approx 2.31$. Furthermore first results of the thermal analysis are presented.

Many Laves phases AM 2 takes up hydrogen to form interstitial hydrides in which hydrogen atoms partially occupy A 2 M 2 , AM 3 , and/or M 4 tetrahedral interstices. They often exhibit temperature-driven order-disorder phase transitions, which are triggered by repulsion of hydrogen atoms occupying neighboring tetrahedral interstices. Because of the phase widths with respect to hydrogen a complete ordering, i.e., full occupation of all hydrogen positions is usually not achieved. Order-disorder transitions in Laves phase hydrides are thus phase transitions between crystal structures with different degrees of hydrogen order. Comparing the crystal structures of ordered and disordered phases reveals close symmetry relationships in all known cases. This allows new insights into the crystal chemical description of such phases and into the nature of the phase transitions. Structural relationships for over 40 hydrides of cubic and hexagonal Laves phases ZrV 2 , HfV 2 , ZrCr 2 , ZrCo 2 , LaMg 2 , CeMg 2 , PrMg 2 , NdMg 2 , SmMg 2 , YMn 2 , ErMn 2 , TmMn 2 , LuMn 2 , Lu 0.4 Y 0.6 Mn 2 YFe 2 , and ErFe 2 are concisely described in terms of crystallographic group-subgroup schemes ( Bärnighausen trees) covering 32 different crystal structure types, 26 of which represent hydrogen-ordered crystal structures.

The new samarium germanide SmGe 3 is obtained by high-pressure high-temperature synthesis of pre-reacted mixtures of samarium and germanium at a pressure of 9.5 GPa and temperatures between 1073 and 1273 K. SmGe 3 decomposes at 470(5) K into SmGe 2 , α -Sm 3 Ge 5 and a hitherto unknown phase. SmGe 3 exhibits a superstructure of the cubic Cu 3 Au-type. Transmission electron microscopy measurements of crystalline particles and prepared lamellae indicate a high density of defects on the nanoscale. Selected area electron diffraction and elaborate X-ray powder diffraction measurements consistently indicate a 2 a 0  × 2 a 0  × 2 a 0 superstructure adopting space group Fm3¯m$Fm\overline{3}m$ with a  = 8.6719(2) Å.

The complete series of sodium rare-earth metal(III) chloride oxotellurates(IV) with the composition Na 2 RE 3 Cl 3 [TeO 3 ] 4 ( RE  = Y, La–Nd, Sm–Lu) has been synthesized via solid-state reactions. For these conversions mixtures of the respective rare-earth metal(III) oxides, tellurium dioxide and sodium chloride as flux and reactant were prepared, intimately ground and heated for 5 days at 1225 K. The almost colorless single crystals were characterized via single-crystal X-ray diffractometry. In the monoclinic crystal structure of these compounds two crystallographically different rare-earth metal(III), but only one sodium cation sites occur. [ RE O 8 ] 13− polyhedra around both RE 3+ positions as well as sodium-centered polyhedra [NaO 4 Cl 4 ] 8− form layers via different connectivity modes. These layers spread out parallel to the (001) plane and arrange alternatingly resulting in the three-dimensional network of the Na 2 RE 3 Cl 3 [TeO 3 ] 4 structure, where the Te 4+ lone-pair cations at two different sites work as linkers by forming isolated ψ 1 -tetrahedra [TeO 3 ] 2− . Some of these compounds were represented before in different settings of space group C 2/ c . Now the complete series of the Na 2 RE 3 Cl 3 [TeO 3 ] 4 representatives with RE  = Y, La–Nd, Sm–Lu is described consistently for a better comparison and understanding. Additionally, a single crystal of Na 2 Pr 3 Cl 3 [TeO 3 ] 4 was measured via energy dispersive X-ray analysis to verify the included elements, powder samples of Na 2 Nd 3 Cl 3 [TeO 3 ] 4 were characterized by X-ray diffractometer data for a phase-purity check and a single-crystal Raman spectrum of Na 2 Yb 3 Cl 3 [TeO 3 ] 4 served for proving the signature of discrete [TeO 3 ] 2− anions.

Three salts of the common composition [EuCl 2 ( X -tpy) 2 ][EuCl 4 ( X -tpy)]·nMeCN were obtained from EuCl 3 ·6H 2 O and the respective organic ligands ( X -tpy = 4′-phenyl-2,2′:6′,2″-terpyridine ptpy, 4′-(pyridin-4-yl)-2,2′:6′,2″-terpyridine 4-pytpy, and 4′-(pyridin-3-yl)-2,2′:6′,2″-terpyridine 3-pytpy). These ionic complexes are examples of salts, in which both cation and anion contain Eu 3+ with the same organic ligands and chlorine atoms coordinated. As side reaction, acetonitrile transforms into acetamide resulting in the crystallization of the complex [EuCl 3 (ptpy)(acetamide)] ( 4 ). Salts [EuCl 2 (ptpy) 2 ][EuCl 4 (ptpy)]·2.34MeCN ( 1 ), [EuCl 2 (4-pytpy) 2 ][EuCl 4 (4-pytpy)]·0.11MeCN ( 2 ), and [EuCl 2 (3-pytpy) 2 ][EuCl 4 (3-pytpy)]·MeCN ( 3 ) crystallize in different structures (varying in space group and crystal packing) due to variation of the rear atom of the ligand to a coordinative site. Additionally, we show and compare structural variability through the dimeric complexes [Eu 2 Cl 6 (ptpy) 2 ( N , N ′-spacer)]· N , N ′-spacer ( 5 , 6 , 7 ) obtained from [EuCl 3 (ptpy)(py)] by exchanging the end-on ligand pyridine with several bipyridines (4,4′-bipyridine bipy, 1,2-bis(4-pyridyl)ethane bpa, and 1,2-bis(2-pyridyl)ethylene bpe). In addition, photophysical (photoluminescence) and thermal properties are presented.

A set of imidazolium-based ionic liquids (ILs), 1-(2-hydroxyethyl)-3-methylimidazolium chloride ( 1 ), 1,3-bis-(2-hydroxyethyl)-imidazolium chloride ( 2 ), and 1-butyl-2,3,4,5-tetramethylimidazolium bromide ( 3 ), has been synthesized and their structural and thermal behavior studied. Organic halides are well-known IL formers with imidazolium halides being the most prominent ones. Functionalization of the imidazolium cation by enhancing its hydrogen bonding capacity, i.e. through introduction of –OH groups or by diminishing it, i.e. through substitution of the ring hydrogen atoms by methyl groups is expected to change the inter-ionic interactions. Consequently, the solid-state structures of 1 – 3 have been characterized with means of single X-ray diffraction to shed light on preferential inter-ionic interactions for obtaining valuable information on anti-crystal engineering, i.e. designing ion combinations that favor a low melting point and exhibit a low tendency for crystallization. The study reveals that endowing IL forming ions with an enhanced hydrogen bonding capacity leads to a depression in melting points and kinetically hinders crystallization. This study provides hints towards new design concepts for IL design, similar to the common strategy of employing conformationally flexible ions.

Single-crystals of the new manganese hydroxide halides Mn 5 (OH) 6 Cl 4 , Mn 5 (OH) 7 I 3 , and Mn 7 (OH) 10 I 4 were obtained by means of high-pressure/high-temperature synthesis in a Walker-type multianvil apparatus. The chloride crystallizes in the monoclinic space group P 2 1 / c (no. 14) with the lattice parameters (single-crystal data) a  = 592.55(8), b  = 1699.7(2), c  = 597.33(8) pm, and β  = 112.58(1)°. The iodides crystallize in the triclinic space group P 1‾$\bar{1}$ (no. 2) with a  = 653.16(2), b  = 905.98(3), c  = 1242.98(4) pm, α  = 114.21(1)°, β  = 99.91(1)°, and γ  = 94.37(1)° for Mn 5 (OH) 7 I 3 and a  = 656.90(3), b  = 906.59(4), c  = 909.32(4) pm, α  = 119.29(1)°, β  = 97.99(1)°, and γ  = 95.03(1)° for Mn 7 (OH) 10 I 4 . The crystal structures consist of edge-sharing Mn(OH) 6–n X n ( X  = Cl, I; n  = 1, 2, 3) octahedra arranged in stacked sheets. Adjacent layers are connected by hydrogen bonds of type O–H··· X , confirmed by further characterization of single-crystals by IR-spectroscopy. The crystal chemical relationship with the aristotype Mg(OH) 2 (brucite) is discussed on the basis of Bärnighausen trees (group–subgroup relations).

The binary Ru 4 Si 3 remained the only compound in its structure type for more than 60 years. Herein, we report the synthesis and crystal structure of the first ternary silicide (Ir 4− x CuSi 2 ) in the Ru 4 Si 3 -type structure, which can be derived from RuSi by unit cell twinning. According to single-crystal X-ray diffraction, Ir vacancies exist along the twin boundary. Ir 4− x CuSi 2 exhibits a distorted structure compared to Ru 4 Si 3 , as the larger Cu selectively replaces Si on only one of three possible sites, leading to zigzag chains with short Cu–Cu distances. Furthermore, DFT calculations show that the rigid band approximation does not apply to this structure type, but the similarities of electronic structures of the ideal binary and ternary compositions suggest that this structure type can accommodate a large variety of elemental substitutions without a significant change of its electronic structure if a similar valence electron count is maintained, hinting at a potentially rich substitutional chemistry.

The solvate complexes that can be obtained by either dissolving metal iodides in N , N -dimethylformamide (DMF) or by synthesising them in DMF have the general composition [ M (DMF) x ]I y . DMF shows to behave as simple monodentate ligand with low sterical impact, so that x in the composition follows the radius of M y + . We present here the crystal structures of the alkaline earth and lanthanoid metal iodide complexes [Mg(DMF) 6 ]I 2 , [Ca(DMF) 6 ]I 2 , [Sr(DMF) 7 ]I 2 , [Ba(DMF) 8 ]I 2 , [La(DMF) 9 ]I 3 , [ Ln (DMF) 8 ]I 3 (isotypic series for Ln  = Nd, Sm, Eu, Dy, Gd, Er, Yb and Lu) and for the tris-triiodide complex salt [Sc(DMF) 6 ](I 3 ) 3 . Their different crystal structure types can be compared on the basis of the packing topologies of the nearly spherical cationic entities which show simple sphere packing motifs.