Abstract. hopping mechanism is suggested while at higher temperatures a standard semi-conductivity with a band gap of 60 meV is present.

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.

No abstract

Mixed Valence Tungsten (IV,V) Compounds with Layered Structures. Part 3. Synthesis and Crystal Structure of Ag1-x[W2O2Cl6] and Investigations on the Ag + IonMobility. -Title compounds with x = 0, 0.38, and 0.82 are synthesized either by reaction of WOCl3 with AgCl in the presence of a small amount of WCl6 (510→700 K, 40 d), or by reaction of WOCl4 with metallic Ag (690 K, 7 d). Ag0.18[W2O2Cl6], Ag 0.62 [W 2 O 2 Cl 6 ], and Ag[W 2 O 2 Cl 6 ] crystallize in the monoclinic space group C2/m with Z = 2. The basic building blocks of the structure are ∞

BiCl2[W2O2Cl6] is prepared by reaction of metallic Bi and WOCl4 (sealed silica tube, 650 K, 7 d; 80% yield) and BiBr2[W2O2Br6] is obtained from Bi and WOBr4 (670 K, 50 d; 20% yield).