Structural Science

 

Acta Cryst. (2002). B58, 1-7  [ doi:10.1107/S0108768101017918 ]

The self-hosting structure of -Ta

A. Arakcheeva, G. Chapuis and V. Grinevitch

Synopsis: Single crystals of tetragonal -Ta could be obtained from electrodeposition in a bath of molten fluorides. This -phase-type structure has been refined in space group P2₁m from normal temperature and pressure X-ray data. This structure exhibits many features common to the high-pressure phases of Ba^IV, Bi^III and Rb^IV.

Online 24 January 2001

 

Acta Cryst. (2002). B58, 8-33  [ doi:10.1107/S0108768101018936 ]

Structure solution of the basic decagonal Al-Co-Ni phase by the atomic surfaces modelling method

A. Cervellino, T. Haibach and W. Steurer

Synopsis: The structure of the basic decagonal phase of Al-Co-Ni has been solved by applying the atomic surface modelling method to refine a high-resolution synchrotron X-ray data set. A solution proposed for the 8 Å superstructure is compared with several earlier models, showing significant differences and solving some apparent contradictions. The stabilization mechanism of quasicrystals appears to be energetic but assisted by entropy.

Online 24 January 2001

    

Acta Cryst. (2002). B58, 34-37  [ doi:10.1107/S0108768101017062 ]

Structurally ferroelectric SrMgF₄

S. C. Abrahams

Synopsis: SrMgF₄ is predicted to be a new ferroelectric, with a Curie temperature of 1450 K and a spontaneous polarization of 11 × 10^-2 C m^-2, on the basis of its recently published crystal structure.

Online 24 January 2001

 

Acta Cryst. (2002). B58, 38-51  [ doi:10.1107/S0108768101019310 ]

Structural relationships between cations and alloys; an equivalence between oxidation and pressure

A. Vegas and M. Jansen

Synopsis: Cations in oxides tend to reproduce the structure of their corresponding alloys. In many instances, the structure adopted is that of the high-pressure phases of the alloys, but when oxides are heated (a way of eliminating the pressure effects) the cations recover the structure of the ambient pressure phases of the alloys. An analogy between oxidation and pressure is established.

Online 24 January 2001

 

Acta Cryst. (2002). B58, 52-61  [ doi:10.1107/S0108768101016688 ]

Structure of compounds E(SnMe₃)₄ (E = Si, Ge) as seen by high-resolution X-ray powder diffraction and solid-state NMR

R. E. Dinnebier, P. Bernatowicz, X. Helluy, A. Sebald, M. Wunschel, A. Fitch and S. van Smaalen

Synopsis: The crystal and molecular structures of tetrakis(trimethylstannyl)germane, Ge(Sn(CH₃)₃)₄, and tetrakis(trimethylstannyl)silane, Si(Sn(CH₃)₃)₄, have been determined for low- and high-temperature phases by Rietveld refinement. Dynamical aspects of the phase transitions have been characterized by NMR.

Online 24 January 2001

 

Acta Cryst. (2002). B58, 62-77  [ doi:10.1107/S0108768101017128 ]

Some 60 new space-group corrections

R. E. Marsh, M. Kapon, S. Hu and F. H. Herbstein

Synopsis: Some 60 examples of crystal structures are presented which can be better described in space groups different from those used in the original publications.

Online 24 January 2001

    

Acta Cryst. (2002). B58, 78-93  [ doi:10.1107/S010876810101850X ]

[Ni(cyclam)(OCOR)₂], a finite molecular complex: hydrogen-bonded supramolecular aggregation in one, two and three dimensions, and coordination polymers in one and two dimensions

C. M. Zakaria, G. Ferguson, A. J. Lough and C. Glidewell

Synopsis: In complexes [Ni(cyclam)(OCOR)₂], where (RCOO)^- represents an aromatic carboxylate or dicarboxylate(2-) anion, the (RCOO)^- acts as a monodentate ligand to Ni, and hard hydrogen bonds of N-HO and O-HO types can link the neutral complexes into supramolecular arrays in one, two or three dimensions.

Online 24 January 2001

 

Acta Cryst. (2002). B58, 94-108  [ doi:10.1107/S0108768101016858 ]

Iodo-nitroarenesulfonamides: interplay of hard and soft hydrogen bonds, IO interactions and aromatic stacking interactions

C. J. Kelly, J. M. S. Skakle, J. L. Wardell, S. M. S. V. Wardell, J. N. Low and C. Glidewell

Synopsis: In iodo-nitroarenesulfonamides of the type RNH(SO₂R') or RN(SO₂R')₂ the supramolecular aggregation can exhibit four types of hydrogen bond, N-HO(nitro), N-HO=S, C-HO(nitro) and C-HO=S; three types of IO interaction, involving two- or three-centre IO₂N interactions or IO=S interactions; and aromatic interactions. The resulting supramolecular structures can be one-, two- or three-dimensional.

Online 24 January 2001

 

Acta Cryst. (2002). B58, 109-115  [ doi:10.1107/S0108768101016548 ]

Structure of N,4-dinitroaniline and its complex with sulfolane at 85 K; on the proton donor-acceptor affinity of the primary nitramine (HNNO₂) group

J. Zaleski, Z. Daszkiewicz and J. B. Kyziol

Synopsis: The primary nitramino group acts as a proton donor in hydrogen bonds formed with the weak proton acceptors of the nitro or sulfonyl group.

Online 24 January 2001

 

Acta Cryst. (2002). B58, 116-124  [ doi:10.1107/S0108768101014744 ]

5-Chloro- and 5-bromobenzfurazan 1-oxide revisited

M. Pink and D. Britton

Synopsis: At room temperature the two title compounds are isomorphous with a disordered structure that includes a major component and a minor component, the 6-halo isomer, occurring at the same site in the crystal. When the bromo compound is cooled, it undergoes a second-order phase transition at 282 K to a second polymorph.

Online 24 January 2001

    

Acta Cryst. (2002). B58, 125-133  [ doi:10.1107/S0108768101017955 ]

Coupling of the lactone-ring conformation with crystal symmetry in 6-hydroxy-4,4,5,7,8-pentamethyl-3,4-dihydrocoumarin

A. Budzianowski and A. Katrusiak

Synopsis: Two phase transitions driven by the conformational transformations of the lactone ring in 6-hydroxy-4,4,5,7,8-pentamethyl-3,4-dihydrocoumarin molecules have been observed: the transition at 225 K is first-order and that at 300 K is a continuous phase transition. Crystal structures and calorimetric studies in the range 110-330 K, and the intriguing relationships between the molecular conformation and crystal symmetry, are reported.

Online 24 January 2001

 

Acta Cryst. (2002). B58, 134-139  [ doi:10.1107/S0108768101016330 ]

Structure of C₁₅-, C₁₇- and C₁₉-mono-acid -triacylglycerols

R. B. Helmholdt, R. Peschar and H. Schenk

Synopsis: The crystal structures of -1,2,3-tris(pentadecanoyl)glycerol (-C₁₅C₁₅C₁₅), -1,2,3-tris(heptadecanoyl)glycerol (-C₁₇C₁₇C₁₇) and -1,2,3-tris(nonadecanoyl)glycerol (-C₁₉C₁₉C₁₉) have been determined from high-resolution X-ray powder diffraction data using grid search and Rietveld refinement, resulting in final R_p values of 0.079, 0.065 and 0.070, respectively.

Online 24 January 2001

 

Acta Cryst. (2002). B58, 140-147  [ doi:10.1107/S0108768101018043 ]

Z' = 4 structure without obvious pseudosymmetry: implications for the formation of solid-state compounds

H.-J. Lehmler, L. W. Robertson, S. Parkin and C. P. Brock

Synopsis: The asymmetric unit of 4-chloro-2'-biphenylol at 293 and 142 K contains four molecules that do not seem to be related by any approximate symmetry operation. The unusual, and inefficient, crystal packing is a consequence of the ortho position of the hydroxyl substituent. A link between large values of Z', poor crystal packing and the likelihood of solid-state compound formation is suggested.

Online 24 January 2001

 

Acta Cryst. (2002). B58, 148-152  [ doi:10.1107/S0108768101019322 ]

Quasi-three-dimensional network of molecular interactions and electronic structure of a new organic semiconductor, ET(NCS)_0.77

O. N. Kazheva, E. Canadell, G. G. Aleksandrov, N. D. Kushch and O. A. Dyachenko

Synopsis: The crystal and electronic structures of ET(NCS)_0.77 have been determined, using an X-ray diffraction method and tight-binding band structure calculations. The ET(NCS)_0.77 salt has a partial three-dimensional architecture of intermolecular interactions, that is a very rare phenomenon in molecular conductors.

Online 24 January 2001

 

Acta Cryst. (2002). B58, 153  [ doi:10.1107/S0108768102000927 ]

Systematic generation of all nonequivalent closest-packed stacking sequences of length N using group theory. Erratum

R. M. Thompson and R. T. Downs

Synopsis: Erratum to Acta Cryst. (2001), B57, 766-771.

Online 24 January 2001

 

Acta Cryst. (2002). B58, 154  [ doi:10.1107/S0108768101014835 ]

Liquid crystals

Online 24 January 2001

 

Acta Cryst. (2002). B58, 155-160  [ doi:10.1107/S0108768101019450 ]

Notes for Authors

Online 24 January 2001