Mixed Valence Tungsten (IV, V) Compounds with Layered Structures (Part IV): Syntheses, Crystal Structures, and Conductivity of BiX₂[W₂O₂X₆] (X = Cl, Br)

Abstract

The reaction of metallic bismuth with either tungsten tetrachlorideoxide WOCl 4 at 650 K or tungsten tetrabromideoxide WOBr 4 at 670 K, respectively, leads to BiX 2 [W 2 O 2 X 6 ] (X = Cl, Br) as black, lustrous crystal needles. The crystal structure determinations (triclinic, P1) show the two isotypic structures to be closely related to Hg 0.55 [W 2 O 2 Cl 6 ] with the presence of 1D-polymeric W 2 O 2 X 6 double strands. Dinuclear [Bi 2 X 4 ] 2+ cations are embedded in the host structure via secondary W-X···Bi bonds. Unlike the other members of the M y [W 2 O 2 X 6 ] structure family, which crystallize monoclinic and show crystallographic equivalent tungsten atoms, BiX 2 [W 2 O 2 X 6 ] has indeAll steps of preparation were performed in an argon filled glove box. Ampoules were made of borosilicate glass or silica glass, if required, and flame-dried in vacuo prior to use. WOCl 4 was prepared by heating freshly precipitated WO 3 , obtained by spiking a saturated NaWO 4 solution with concentrated hydrochloric acid, with SOCl 2 under reflux.

Heteroanionic LaBrVIO4 (VI = Mo, W): Excellence in Both Nonlinear Optical Properties and Photoluminescent Properties

“…The 4 + 1 coordination environment for W and Mo is uncommon. Some selected Mo- and W-constituted oxybromides are summarized in Table S5. − The four or six coordination environments for Mo and W atoms are the most common. Our study also confirmed that the distortion degree of 1D [WO 5 ] strands plays a critical role in determining NLO and PL properties (vide infra).…”

“…Oxybromides are compounds constructed by O 2– and Br – as anions. The chemically distinct O 2– (ionic size: 126 pm; electronegativity: 3.4) and Br – (ionic size: 182 pm; electronegativity: 3.0) made most oxybromides as ordered heteroanionic compounds, − which results in pliable structural chemistry and fruitful physical phenomena, such as nonlinear optical properties. − In this work, we report the crystal structure and growth, electronic structures, chemical bonding pictures, linear and NLO properties, and photoluminescent (PL) properties of LaBrMoO 4 and LaBrWO 4 . LaBrMoO 4 was structurally characterized without any property measurements.…”