A new polymorph of the title compound, C(36)H(30)OSi(2)·2C(7)H(8), is reported, which is triclinic (P-1) instead of possessing the previously reported rhombohedral symmetry [Hönle et al. (1990). Acta Cryst. C46, 1982-1984]. Each of the -SiPh(3) units are related by the inversion center. The Si-O-Si moiety is linear with the O atom sitting on an inversion center, and the O-Si-(toluene ring centr...

A 1:1 co-crystal of rac-trans-1,2-C(6)H(10)(OH)(2) and (C(6)H(5))(3)PO has been found that is unusual because there are no strong interactions between the two kinds of molecules, which are segregated into layers. Furthermore, neither pure rac-1,2-cyclohexanediol (CHD) nor pure triphenylphosphine oxide (TPPO) has any obvious packing problem that would make the formation of inclusion complexes li...

The lattice of 5,7,12,14-tetrahydro-5,14:7,12-bis([1,2]benzeno)pentacene-6,13dione, C34H20O2, at 173 K has triclinic (P1) symmetry and crystallizes with four independent half-molecules in the asymmetric unit. Each molecule is generated from a C17H10O substructure through an inversion center at the centroid of the central quinone ring, generating a wide H-shaped molecule, with a dihedral angle b...

The first theoretical description of the experimentally often-observed isotropic-polar smectic phase transitions of symmetric and asymmetric bent-shape molecules is presented. The isotropic-tilted polar smectic phase transition requires a coupling among three types of ordering processes: polar packing, director tilt, and layer ordering. For explaining the unusual triclinic-monoclinic phase tran...

C11H12O2Se is triclinic, P1. Unit-cell dimensions at 293 K are a = 5.8450(10), b = 8.1490(10), c = 11.4620(10)A, alpha = 97.050(10), beta = 90.140(10), gamma = 90.120(10) degrees, V = 541.81(12)A3, Dx = 1.564 g/cm3, and Z = 2. The R value is 0.047 for 1388 observed reflections. The dihedral angle between the phenyl ring and the isobutenyl group is 72.3(2) degrees. There is an intermolecular hyd...

The previously reported room-temperature crystal structure [Jaud Baldy, Negrel, Poite & Chanon (1993 ▶). Z. Kristallogr.204, 289-291] of the title compound, C(20)H(8)Cl(12), is monoclinic with Z' = 1, whereas the 90 K structure reported herein is triclinic with Z' = 2 and shows a 2% volume contraction. The crystallographically independent unit chosen consists of both enanti-omers (Λ and Δ) of t...

The title compound, sodium bis(6-carboxy-1-hydroxy-3-oxo-1,3-dihydro-2,1-benzoxaborol-1-yl)oxidanium, Na(+)·C(16)H(15)B(2)O(13)(-), was prepared in two steps from 2-bromo-p-xylene. Its crystal structure was determined at 140 K and has triclinic ( ̅P1) symmetry. The compound presents a unique structural motif, including two units of the cyclic anhydride of boronoterephthalic acid, joined by a pro...

The crystal structure, electrical resistivity, magnetic susceptibility, and heat capacity of single crystals of BaFe2As2, BaNi2As2, and BaFeNiAs2 are reported. BaFe2As2 data indicate the equivalence of C T , d T /dT, and d /dT results in determining the antiferromagnetic transition at TN=132 1 K. BaNi2As2 shows a structural phase transition from a high-temperature tetragonal phase to a low-temp...

Three new cesium oxometallates with trigonal-planar [MO3]n− anions (M = Zn, Fe, B) were observed as products of reactions aimed at the formation of alkali metal suboxometallates A9MO4 (A = Rb, Cs; M = Al, Ga, In, Fe, Sc), or as decomposition products thereof. Cs4[FeO3], Cs4[ZnO3] and Cs3[BO3] crystallize with new structure types (Cs4[FeO3]: triclinic, space group P1̄, a = 7.0652(1), b = 7.125(1)...

We report the structural and magnetic phase transitions of triclinic Ca10(FeAs)10(Pt3As8), which is the parent compound of the 1038-type iron-arsenide superconductors. High-resolution x-ray diffraction reveals splitting of the in-plane (a,b) lattice parameters at T(s) ≈ 120 K. Platinum-doping weakens the distortion and shifts the transition temperature to 80 K in Ca10(Fe(1-x)Pt(x)As)10(Pt3As8) ...