W. Buchmeier

Zur Polymorphie des Cadmiumsulfits, Kristallstrukturen von CdSO3-I, CdSO3-II und CdSO3-III / Polymorphic Cadmium Sulfites, Crystal Structures of CdSO3-I, CdSO3 -II, and CdSO3-III

The crystal structures of the anhydrous cadmium sulfites CdSO3-I (P21/c, Z=4), CdSO3-II (P21/c, Z=8), and CdSO3-III (R3̄̄, Z=18 for the hexagonal cell) have been determined by means of single crystal X-ray diffraction data. The final R for the 1475, 2349, and 2138 observed reflections are 0.040, 0.034, and 0.073. Coordination of Cd is trigonal-prismatic, a hitherto unknown coordination of Cd in salts of oxoacids, in CdSO3-I and CdSO3-II, and octahedral in CdSO3-III. The CdO6-polyhedra are arranged in two-dimensional (CdSO3-I) and three-dimensional (CdSO3-II and CdSO3-III) networks. SO32- groups act as monodentate and in CdSO3-I and CdSO3-II also as bidentate ligands. Cd−O distances range from 224.5(3) to 244.6(3) pm, with an average of 231.5 pm for the trigonal-prismatic and of 231.0 pm for the octahedral coordination. S−O dis-tances range from 152.3(3) to 155.3(3) pm with an average of 153.7 pm, the O−S−O angles from 99.2(2) to 106.7(3)° with an average of 103.2°.

Kristallstruktur von MgSO3·H2O/Crystal Structure of Mg SO3·H2O

Abstract The crystal structure of MgSO3·H2O , space group P21 /ln, Z = 4, Dx = 2.415 g·cm-3 , a = 4.699(1), b = 12.751(3), c = 5.618(1) Å, β = 90.49(3)°, was determined by single crystal X-ray diffraction. MgSO3·H2O crystallizes in the MnSO3·H2O type. The structure consists of buckled trans layers ∞[MgSO3·H2O], which are built up from strongly distorted MgO5(H2O) octahedra sharing four equatorial vertices, and of trigonal pyramidal SO32- ions. It is closely related to the structures of orthorhombic MnSeO3·D2O and monoclinic ZnSeO3·H2O . The Mg-O distances range from 2.051(3) to 2.175(4) Å. The S-O distances (1.543(3), 1.547(3) and 1.493(3) Å) and the O-S-O angles (98.4(2) and 2x 106.0(2)°) correspond to those in MnSO3·H2O . The distortion of the MO5(H2O) octahedra (M = Mg, Mn) and of the SO32- ions is smaller in MgSO3·H2O , but with greater deviations from m symmetry. The distances between the H-connected ∞2[MSO3·H2O] layers are greater in MgSO3·H2O , indicating weaker inter-layer hydrogen bonds. The lateral arrangement of the ∞2[MSO3·H2O] layers is nearly the same in both sulfite monohydrates.

P3Se4I: 5-Iodo-2,3,6,7-tetraselena-1,4,5-triphosphabicyclo[221]heptan, ein neues Phosphorselenaiodid / P3Se4I: 5-Iodo-2,3,6,7-tetraselena-1,4,5-triphosphabicyclo[221]heptan, a New Phosphorus Selena Iodide

P3Se4I is formed by the reaction of molten P4Se3 and I2. P3Se4I is monoclinic, space group P21/c with the lattice parameters of a = 1130.3(3) pm, b = 654.5(2) pm, c =1420.5(4) pm, β - 117.64(2)°. d = 3.87 g cm-3 and dx = 3.82 g cm-3 for Z = 4. The structure of the molecule is derived from the structure of α-or β-P4Se3I2 by the substitution of a P−I group by a Se-atom. The P−I, P−P and Se−Se bond lengths are 249.9, 219.2 and 236.9 pm. resp. The mean P−Se bond length is 225.0 pm. The molecule is stabilized by two weak intramolecular P−Se and P−I bonds, comparable to the bonding situation in α-P4Se3I2 . The 31P NMR spectra reveal a coalescence effect, due to equilibrium between two isomeric forms of the molecules.

Kristallstrukturen von NaMg2OH(SO3)2 · H2O, NaMn2OH(SO3)2 · H2O , NaFe2OH(SO3)2 · H2O, NaCo2OH (SO3)2 H2O und NaZn2OH(SO3)2H2O/ Crystal Structures of NaMg2OH(SO3)2-H2O, NaMn2OH(SO3)2 · H2O,NaFe2OH(SO3)2H2O, NaCo2OH(SO3)2 · H2O, and NaZn2OH(SO3)2 · H2O

Abstract The crystal structures of the isotypic hydroxosulfitometalates NaM2OH(SO3)2 ·1H2O with M = Mg, Mn, Fe, Co, and Zn were determined by means of X-ray single crystal data (triclinic space group P1̄ - Qi1, Z = 2). The final R for the 2223, 2496, 2440, 1461, and 3433 observed reflections are 0.043, 0.068, 0.025, 0.055, and 0.028, respectively. The bivalent metal ions (three types) are octahedrally coordinated by the oxygen atoms of adjacent SO32- ions (two types, both monodentate), OH- groups, and water molecules. The arrangement of the two OH- groups is trans, and of OH- and H2O cis with respect to the octahedral coordination. The mean metal oxygen distances are in the order M - OH2 > M -OSO22-> M - OH . The MO6 -octahedra are both vertex and edge sharing, forming two-dimensional networks parallel to (010), which are connected via hydrogen bonds. The water molecules form strong, linear, nearly symmetric (mm 2) hydrogen bonds to SO32- ions, the hydroxide ions weak bonds to water molecules.