The New Mercury Vanadium Phosphate Hg4VO(PO4)2 Containing Hg2+2 Dumbbells: Crystal Structure and Thermal and Magnetic Properties

Synthesis and Crystal Structure of Hg2V8O20 – the First Ternary Mercury Vanadate with Mixed-valent Vanadium (IV/V)

“…With the possible exceptions of the ternary phases with the tentative com-0932-0776 / 07 / 1100-1390 $ 06.00 © 2007 Verlag der Zeitschrift für Naturforschung, Tübingen · http://znaturforsch.com positions Hg x V 2 O 5 (0.16 ≤ x ≤ 0.20), Hg 4 V 18 O 39 , α P -and β P -HgV 2 O 4 , and HgV 2 O 5 , which were obtained as microcrystalline products in the system HgO-V 2 O 3 -V 2 O 5 at high-pressure conditions (2.5 to 7.7 GPa) [7], all reported ternary mercury vanadates [1,8] comprise vanadium in oxidation state +5. However, lower oxidation states for vanadium were also observed for quaternary mixed metal/non-metal framework structures in the system Hg-V-P-O-(H) where the crystal structures have recently been determined for the orthophosphates (Hg 2 ) 2 VO(PO 4 ) 2 [9] and Hg 4−x O 1−y (VO)(PO 4 ) 2 · (H 2 O) [10] with vanadium in oxidation state +4 and the diphosphate HgV 2 (P 2 O 7 ) 2 [11] with vanadium in oxidation state +3.…”

New Mercury Vanadium Phosphate Hydrate Hg4-xO1-y((VO)(PO4)2·H2O with Unprecedented Tetrahedral Oxo-Cluster [Hg∼4O∼5]

“…The initial mixture was placed in a 23 mL Parr bomb, then heated at 463 K for 60 h under autogenous pressure, and slowly cooled to room temperature over a 2 day period. The final product was filtered off and recovered as a green powder that turned out to be in the majority Hg 4 VO(PO 4 ) 2 from X-ray powder diffraction analysis . Single crystals were isolated under the microscope with different size, morphology (rods and needles), and color.…”

“…The various dimensionality and topology of the latter species (isolated Hg 3 4+ , linear or planar clusters Hg n x + , and so forth) make the mercury a promising template for the working out of new open framework solids. To the best of our knowledge, only two HgVPO phases have been isolated, namely HgV 2 (P 2 O 7 ) (high-temperature solid-state reactions) and Hg 4 VO(PO 4 ) 2 (hydrothermal synthesis) . Our investigations on the Hg−V−P−O system under hydrothermal conditions resulted in the synthesis of the title compound.…”