Syntheses and Crystal Structures of Sr7H12X2 (X = Cl, Br)

2008 ◽  
Vol 63 (5) ◽  
pp. 513-518 ◽  
Author(s):  
Olaf Reckeweg ◽  
Jay C. Molstad ◽  
Scott Levy ◽  
Constantin Hoch ◽  
Francis J. DiSalvo

Dichroic, pink to blue single crystals of Sr7H12Cl2 and Sr7H12Br2 were obtained by reacting Sr with SrX2 or NaX and NaNH2 or NH4X (X = Cl, Br) as hydrogen sources in a Na melt at 900 °C for 12 h in silica-jacketed stainless-steel or Ta ampoules. The crystal structures of the new compounds were determined by means of single crystal X-ray diffraction. Both title compounds crystallize isotypically to Ba7Cl2F12 in the hexagonal space group P6̅ (no. 174) with the lattice parameters a = 998.06(3), c = 392.84(3) pm for Sr7H12Cl2 and a = 1004.62(3), c = 399.68(3) pm for Sr7H12Br2. The hydride positions taken from the difference Fourier map agree with those of the fluorides of the isotypic compound Ba7F12Cl12. The validity of our structural results is corroborated by EUTAX calculations and the comparison to SrH2, SrX2 and SrHX.

2010 ◽  
Vol 65 (4) ◽  
pp. 493-498 ◽  
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo

Single crystals of Ca7H12Cl2 and Ca2H3Br were obtained by reacting stoichiometric amounts of CaH2 and CaX2 (X = Cl, Br) at 1300 K in the presence of surplus Ca metal for 13 h in silicajacketed Nb ampoules. The crystal structures of the new compounds were determined by means of single-crystal X-ray diffraction. Ca7H12Cl2 crystallizes isotypical to Ba7Cl2F12 and Sr7H12Cl2 in the hexagonal space group P¯6 (no. 174) with the lattice parameters a = 936.51(8), c = 368.65(2) pm, while Ca2H3Br crystallizes in a stuffed anti-CdI2 structure isotypical to Ba2H3Cl and therefore adopts the space group P¯3m1 (no. 164) with the lattice parameters a = 391.37(6) and c = 697.04(13) pm. The structural results are corroborated by EUTAX calculations on the title compounds and the comparison of these results to those for CaH2, CaX2 and CaHX (X = Cl, Br). Similar calculations on the hypothetical compound “Ca7H12Br2” give a possible explanation for the preferred formation of the compound Ca2H3Br.


2011 ◽  
Vol 66 (1) ◽  
pp. 21-26
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo

Single crystals of Sr2H3I andBa5H2I3.9(2)O2 were obtained by reacting Sr or Ba, respectively, with dried and sublimed NH4I in a 4 : 1 molar ratio in silica-jacketed Nb ampoules for 13 h at 1200 K. The crystal structures of the new compounds have been determined by means of single-crystal X-ray diffraction. Sr2H3I crystallizes in a stuffed anti-CdI2 structure isotypic to Ba2H3Cl in the space group P3m1 (no. 164) with the lattice parameters a = 426.0(1) and c = 774.9(2) pm, while Ba5H2I3.9(2)O2 crystallizes in a new structure type in the space group Cmcm (no. 63) with the lattice parameters a = 1721.0(2), b = 1452.5(2) and c = 639.03(9) pm. The structural results for Sr2H3I are corroborated by EUTAX calculations. For the disordered compound Ba5H2I3.9(2)O2, EUTAX calculations on an approximated, ordered structural model were used to find possible insights into the disorder


2011 ◽  
Vol 66 (4) ◽  
pp. 359-365 ◽  
Author(s):  
Olaf Reckeweg ◽  
Armin Schulz ◽  
Francis J. DiSalvo

Single crystals of Eu5(BO3)3Cl were obtained by serendipity by reacting Eu2O3 and Mg with B2O3 at 1300 K in the presence of an NaCl melt for 13 h in silica-jacketed Nb ampoules. Ba5(BO3)3X (X = Cl, Br) crystals were formed by direct synthesis from appropriate amounts of Ba(OH)2, H3BO3 and the respective barium halide (hydrate) in alumina crucibles kept in the open atmosphere at 1300 K for 13 h. The crystal structures of the title compounds were determined with single-crystal X-ray diffraction. All compounds crystallize isotypically to Sr5(BO3)3Cl in the orthorhombic space group C2221 (no. 20, Z = 4) with the lattice parameters a = 1000.34(7), b = 1419.00(9), c = 739.48(5) pm for Eu5(BO3)3Cl, a = 1045.49(5), b = 1487.89(8), c = 787.01(4) pm for Ba5(BO3)3Cl, and a = 1048.76(7), b = 1481.13(9) and c = 801.22(5) pm for Ba5(BO3)3Br. The Raman spectra of all compounds were acquired and are presented and compared to literature data. The incremental volume of the orthoborate (BO3)3− anion has been determined and is compared to the Biltz volume


Author(s):  
Michel Fleck ◽  
Ekkehart Tillmanns ◽  
Ladislav Bohatý ◽  
Peter Held

AbstractThe crystal structures of eight different L-malates have been determined and refined from single-crystal X-ray diffraction data. The compounds are the monoclinic (space groupIn addition, for all the compounds, powder diffraction data were collected, analysed and submitted to the powder diffraction file (PDF).


1996 ◽  
Vol 51 (6) ◽  
pp. 806-810 ◽  
Author(s):  
Rainer Pöttgen

Abstract EuPdSn and EuPtSn were prepared from the elements in tantalum tubes at 1070 K and investigated by X-ray diffraction on both powder as well as single crystals. They crystallize with the TiNiSi type structure of space group Pnma and with Z = 4 formula units per cell. Both structures were refined from single-crystal diffractometer data: a = 751.24(9), b = 469.15(6), c = 804.31(9) pm, V = 0.2835(1) nm3 for EuPdSn, and a = 753.38(7), b = 467.72(4), c = 793.08(7) pm, V = 0.2795(1) nnr for EuPtSn. The structures consist of three-dimensional [PdSn] and [PtSn] polyanionic networks in which the europium atoms are embedded. The crystal chemistry of these stannides is briefly discussed


2015 ◽  
Vol 71 (11) ◽  
pp. 1325-1327 ◽  
Author(s):  
Maxim Bykov ◽  
Elena Bykova ◽  
Vadim Dyadkin ◽  
Dominik Baumann ◽  
Wolfgang Schnick ◽  
...  

Hitherto, phosphorus oxonitride (PON) could not be obtained in the form of single crystals and only powder diffraction experiments were feasible for structure studies. In the present work we have synthesized two polymorphs of phosphorus oxonitride, cristobalite-type (cri-PON) and coesite-type (coe-PON), in the form of single crystals and reinvestigated their crystal structures by means of in house and synchrotron single-crystal X-ray diffraction. The crystal structures ofcri-PON andcoe-PON are built from PO2N2tetrahedral units, each with a statistical distribution of oxygen and nitrogen atoms. The crystal structure of thecoe-PON phase has the space groupC2/cwith seven atomic sites in the asymmetric unit [two P and three (N,O) sites on general positions, one (N,O) site on an inversion centre and one (N,O) site on a twofold rotation axis], while thecri-PON phase possesses tetragonalI-42dsymmetry with two independent atoms in the asymmetric unit [the P atom on a fourfold inversion axis and the (N,O) site on a twofold rotation axis]. In comparison with previous structure determinations from powder data, all atoms were refined with anisotropic displacement parameters, leading to higher precision in terms of bond lengths and angles.


Author(s):  
Hidetomo Hongu ◽  
Akira Yoshiasa ◽  
Massimo Nespolo ◽  
Tsubasa Tobase ◽  
Makoto Tokuda ◽  
...  

Petzite, Ag3AuTe2, crystallizes in the space group I4132, which is a Sohncke type of space group where chiral crystal structures can occur. The structure refinement of petzite reported long ago [Frueh (1959). Am. Mineral. 44, 693–701] did not provide any information about the absolute structure. A new single-crystal X-ray diffraction refinement has now been performed on a sample from Lake View Mine, Golden Mile, Kalgoorlie, Australia, which has resulted in a reliable absolute structure [a Flack parameter of 0.05 (3)], although this corresponds to the opposite enantiomorph reported previously. The minimum Te–Te distance is 3.767 (3) Å, slightly shorter than the van der Waals bonding distance, which suggests a weak interaction between the two chalcogens. XANES spectra near the Au and Te L III edges suggest that the chemical-bonding character of Au in petzite is more metallic than in other gold minerals.


2004 ◽  
Vol 59 (3) ◽  
pp. 281-285 ◽  
Author(s):  
Matthias Weil

Colourless single crystals of the compounds CdXO4 · 2 HgO (X = S, Se) were obtained under hydrothermal conditions (250 °C, 5 d), starting from stoichiometric amounts of HgO, CdSO4 ·7H2O and CdSeO4 ·2H2O, respectively. The crystal structures were determined from X-ray diffraction data sets. The CdXO4 · 2HgO compounds crystallise isotypically with two formula units in space group P1̅ (# 2) [CdSO4 · 2HgO (CdSeO4 · 2HgO): a = 6.793(2) (6.9097(5)) Å , b = 7.205(2) (7.1786(6)) Å , c=7.359(2) (7.4556(6)) Å ,α =73.224(6) (74.586(2))°, β =66.505(6) (68.229(1))°, γ =63.054(5) (63.886(1))°, 1670 (1786) structure factors, 92 parameters, R[F2 > 2σ(F2)] = 0.0379 (0.0244)] and are made up from zig-zag [O-Hg-O]∞ chains with very short bonds of d̅(Hg-O) 2.025 Å , distorted [CdO6] octahedra (d̅(Cd-O)= 2.297 Å ), and XO4 tetrahedra (d̅(S-O)= 1.458 Å , d̅(Se-O)= 1.633 Å ) as the main building blocks. The CdXO4 ·2HgO compounds reveal no structural relationship with the corresponding HgXO4 ·2HgO phases


2015 ◽  
Vol 70 (4) ◽  
pp. 207-214 ◽  
Author(s):  
Daniela Vitzthum ◽  
Stefanie A. Hering ◽  
Lukas Perfler ◽  
Hubert Huppertz

AbstractOrthorhombic dysprosium orthogallate DyGaO3 and trigonal gallium orthoborate GaBO3 were synthesized in a Walker-type multianvil apparatus under high-pressure/high-temperature conditions of 8.5 GPa/1350 °C and 8 GPa/700 °C, respectively. Both crystal structures could be determined by single-crystal X-ray diffraction data collected at room temperature. The orthorhombic dysprosium orthogallate crystallizes in the space group Pnma (Z = 4) with the parameters a = 552.6(2), b = 754.5(2), c = 527.7(2) pm, V = 0.22002(8) nm3, R1 = 0.0309, and wR2 = 0.0662 (all data) and the trigonal compound GaBO3 in the space group R3̅c (Z = 6) with the parameters a = 457.10(6), c = 1419.2(3) pm, V = 0.25681(7) nm3, R1 = 0.0147, and wR2 = 0.0356 (all data).


2011 ◽  
Vol 66 (11) ◽  
pp. 1087-1091 ◽  
Author(s):  
Olaf Reckeweg ◽  
Francis J. DiSalvo

Colorless and transparent single crystals of Ba2H3I were obtained by reacting Ba with dried and sublimed NH4I in a 4 : 1 molar ratio in silica-jacketed Nb ampoules at 1100 K for 13 h. The crystal structure of the title compound was determined and refined by means of single-crystal X-ray diffraction. Ba2H3I crystallizes in a stuffed anti-CdI2 structure isotypic to Sr2H3I in the space group P3̄m1 (no. 164) with the lattice parameters a = 451.86(12) and c = 811.84(23) pm. The structural results for Ba2H3I are consistent with bond lengths and coordination geometries of related binary and ternary hydrides


Sign in / Sign up

Export Citation Format

Share Document