Hg 4 O 3 [ReO 4 ] 2 , Featuring a 2D Polycationic Framework [Hg 4 O 3 ] 2+ with Tetrahedral Rhenate(VII) Anions Embedded

New Hg 4 O 3 [ReO 4 ] 2 was obtained via low temperature synthesis, at 65–70 °C. The coarse crystalline, single phase product is pale yellow, starts to decompose at 540 °C and sublimes without leaving behind any solid residue at 685 °C in an argon atmosphere. Its crystal structure [ P 2 1 / n (14), a = 7.0104(10), b = 12.5046(18), c = 12.1692(18) Å, β = 91.838(3)°, Z = 4] can be rationalized as a stuffed HgRe 2 sub lattice, adopting the MgZn 2 Laves phase arrangement. The resulting structure after inserting the oxygen atoms consists of heavily corrugated 2D polycationic Hg/O networks stacked along [001] with the tetrahedral oxorhenate(VII) anions accommodated in the folds of individual layers.