The structure of a triclinic form of octafluoroselenanthrene, (C6F4)2Se2
5
Citation
1
Reference
10
Related Paper
Keywords:
Triclinic crystal system
Monoclinic crystal system
Abstract Present study has been carried out to develop a facile synthetic methodology for preparing single phase monoclinic and triclinic forms of GdBO 3 , a potential phosphor material. This is achieved by varying annealing temperatures and annealing steps. Detailed structural studies, using X‐ray diffraction (XRD), Fourier transform infrared (FTIR) and Raman spectroscopic techniques confirmed that, Gd 3+ ‐boric acid complexes formed initially at low temperatures (300 °C or less) get converted to monoclinic and triclinic forms of GdBO 3 depending upon annealing temperatures, annealing steps and heating rates. Multiple steps with slow heating rates (∼3 °C/min) lead to the formation of single phase triclinic form of GdBO 3 . Two step heating with relatively faster heating rates (5 °C/min and above) results in single phase monoclinic GdBO 3 . FTIR and Raman studies also confirmed that boron exists only as BO 4 structural units (in the form of B 3 O 9 3− rings) in monoclinic GdBO 3 and as BO 3 structural units in triclinic GdBO 3 . Luminescence studies carried out with Eu 3+ as a probe species confirmed more covalent nature around Eu 3+ /Gd 3+ ions with improved red colour emission from triclinic form of GdBO 3 compared to the monoclinic form.
Triclinic crystal system
Monoclinic crystal system
Cite
Citations (5)
Abstract The structures of the four new telluridoindates (II) (monoclinic, space group C2/c, Z = 4), (III) (monoclinic, P2 1 /c, Z = 4), (IV) (triclinic, P $\bar 1$ , Z = 2), and (V) (tetragonal, I $\bar 4$ m2, Z = 4) are determined by single crystal XRD.
Monoclinic crystal system
Triclinic crystal system
Tetragonal crystal system
Bar (unit)
Cite
Citations (0)
The inherently oxygen-deficient compounds Ln26O27 square(BO3)8 (Ln=La, Nd) react with water vapor leading to Ln26O26(OH)2(BO3)8 phases, and this reaction is reversible. The crystal structure of Nd26O27 square(BO3)8 has been determined from single-crystal data (space group P with a=6.7643(10) A, b=12.663(2) A, c=14.271(2) A, alpha=90.553(8) degrees, beta=99.778(10) degrees, and gamma=90.511(9) degrees). It is a triclinic distorted version of the monoclinic structure of La26O27 square(BO3)8. The Ln26O26(OH)2(BO3)8 phases both crystallize in the monoclinic system (space group P21/c with a=6.7445(4) A, b=12.6177(9) A, c=14.4947(10) A, and beta=100.168(7) degrees for Nd26O26(OH)2(BO3)8 and a=6.9130(15) A, b=12.896(3) A, c=14.792(4) A, beta=99.698(16) degrees for La26O26(OH)2(BO3)8), and their crystal structure has been determined from single-crystal data, showing that the hydroxyl groups are localized mainly on one of the oxygen sites at room temperature (RT). For the Nd phases, the change in crystal system can result from two different phenomena depending on the atmosphere, either a phase transformation corresponding to a water uptake under wet conditions (triclinic Nd26O27 square(BO3)8 at RT-->monoclinic Nd26O26(OH)2(BO3)8) or a phase transition at approximately 300 degrees C for the anhydrous phase under dry conditions (triclinic Nd26O27 square(BO3)8 at RT-->monoclinic Nd26O27 square(BO3)8 at T>300 degrees C). For Nd26O26(OH)2(BO3)8, the conductivity measured under wet conditions at 300 degrees C is sigma300 degrees C approximately 0.5x10(-5) S cm(-1). Due to the dehydration process, the proton contribution to the total conductivity of the Nd phase is no longer observed above 500 degrees C whereas it was still clearly visible at 600 degrees C for the La phase.
Triclinic crystal system
Monoclinic crystal system
Anhydrous
Crystal (programming language)
Cite
Citations (19)
In our article, we reported the observation of monoclinic M2 to M1 structural phase transition in VO 2 single crystal near the temperature of ∼49 °C. However, the re‐examination of Laue patterns reveals that previously defined monoclinic M1 and M2 phases can be interpreted as monoclinic M2 and triclinic T phases instead. Careful experimental geometry calibration and further refinement of the lattice parameter ratios and angles show that monoclinic M2 and triclinic T phases fit better with the experimental data. On the other hand, our previous misidentification of the insulating phases does NOT affect the conclusions of our article. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)
Monoclinic crystal system
Triclinic crystal system
Lattice (music)
Cite
Citations (7)
Abstract Trielinic modification: C 12 N 4 O 3 H 16 . M r = 264.26, triclinic P 1 , a = 7.702(3), b = 9.420(11), c = 10.893(8) A, α = 73.37(8), β = 82.22(5), γ = 66.30(6)°, V = 638(1) A 3 , Z = 2, D m = 1.360 Mg m −3 , D x = 1.362 Mg m −3 , λ(MoK α ) = 0,71062 A, μ = 0.1084 mm −1 , F (000) = 280, T = 296 K, final R = 0.0742, w R = 0.0758 for 1842 reflections. Monoclinic modification: C 12 N 4 O 3 H 16 ·, 3/2H 2 O, M r = 291.28, monoclinic P 2 1 ,/c, α = 14.075(5), b = 12.631(6), c = 16.234(5) A, β = 99.25(3)°, V = 2849(1) A 3 , Z = 8, D m = 1.338 Mg m −3 , D m = 1.359 Mg m −3 , λ(MoK α ) = 0.71062 A, μ = 0.1134 mm −1 , F(000) = 1240, T = 296 K, final R = 0.0557, wR = 0.0691 for 1266 reflections. Comparison of the two independent Divascan® molecules of the monoclinic modification with the one of the triclinic modification demonstrates good agreement of related bond distances and angles in the molecules. Disorder of the hydroxyl groups of one Divascan® molecule of the monoclinic modification is announced by high vibration parameters of the related oxygen atom and a very short CO distance, which is not adequate to a real CO bond length.
Triclinic crystal system
Monoclinic crystal system
Cite
Citations (1)
Organometallic Chemistry
Cite
Citations (4)
Crystals of disodium succinate have two distinct modifications, monoclinic and triclinic. These were recognized by electron spin resonance (e.s.r.) studies of. the free radicals produced by γ-irradiation. In the monoclinic crystals, e.s.r. spectra and radiation processes appear similar to those observed in γ- (or x-) irradiated succinic acid. The situation in triclinic crystals is more complex (see Part 2). In monoclinic crystals irradiated at 77 °K, two types of radical coexist. They were identified as − O 2 CCH 2 CH 2 ĊO 2 2− , 1, together with a distorted conformation of the radical − O 2 C(ĊHCH 2 )*CO 2 − , 2. On warming to room temperature the former species disappears while the latter changes irreversibly to a stable conformation − O 2 CĊHCH 2 CO 2 − , 3.
Triclinic crystal system
Monoclinic crystal system
Succinic acid
Cite
Citations (13)
Abstract In the course of synthetic studies in the system CuO‐SeO2‐H2O in a temp. range up to 503 K four copper(II)‐oxid‐selenites (I)‐(IV) are obtained.
Triclinic crystal system
Monoclinic crystal system
Crystal (programming language)
Cite
Citations (1)
Abstract Single crystal XRD results are reported for (I) (monoclinic, space group C2/c), (IIc) (monoclinic, P2 1 /n, Z = 4), and (IVb, c) (triclinic, P $\bar 1$ , Z = 1).
Triclinic crystal system
Monoclinic crystal system
Bar (unit)
Cite
Citations (0)
A monoclinic modification of chloridomercurioferrocene, [FeHgCl(C5H4)(C5H5)], was found on its crystallization from acetonitrile. A triclinic form of the title compound [Sunkel & Kiessling (2001). J. Organomet. Chem. 637, 796–799] was crystallized from chloroform. Both forms have two molecules per asymmetric unit. In the monoclinic form, both molecules have an eclipsed conformation, while in the triclinic form one of them has an eclipsed and the other a staggered conformation. In the monoclinic crystals, molecules form infinite ribbons due to intermolecular secondary coordination between Hg and Cl atoms, while in the triclinic form molecules are arranged in tetramers.
Triclinic crystal system
Monoclinic crystal system
Cite
Citations (1)