Tricaesium dimolybdate(VI) bromide

The title compound, Cs3(Mo2O7)Br, was synthesized by the reaction of CsNO3, MoO3 and 1-ethyl-3-methyl­imidazolium bromide. Its crystal structure is isotypic with K3(Mo2O7)Br and contains (MoO4)2− tetra­hedra which share an O atom to produce a [Mo2O7]2− dimolybdate(VI) anion with a linear bridging angle and m2 symmetry. The anions are linked by Cs atoms (site symmetry m2), forming sheets parallel to (001). Br atoms (site symmetry m2) are also part of this layer. Another type of Cs atom (3m site symmetry) is located in the inter­layer space and connects the layers via Cs—O and Cs—Br inter­actions into a three-dimensional array

Polyoxometalate chemistry at volcanoes: discovery of a novel class of polyoxocuprate nanoclusters in fumarolic minerals

Polyoxometalate (POM) chemistry is an important avenue of comprehensive chemical research, due to the broad chemical, topological and structural variations of multinuclear polyoxoanions that result in advanced functionality of their derivatives. The majority of compounds in the polyoxometalate kingdom are synthesized under laboratory conditions. However, Nature has its own labs with the conditions often unconceivable to the mankind. The striking example of such a unique environment is volcanic fumaroles – the natural factories of gas-transport synthesis. We herein report on the discovery of a novel class of complex polyoxocuprates grown in the hot active fumaroles of the Tolbachik volcano at the Kamchatka Peninsula, Russia. The cuboctahedral nanoclusters {[MCu$_{12}$O$_{8}$](AsO$_{4}$)$_{8}$} are stabilized by the core Fe(III) or Ti(IV) cations residing in the unique cubic coordination. The nanoclusters are uniformly dispersed over the anion- and cation-deficient NaCl matrix. Our discovery might have promising implications for synthetic chemistry, indicating the possibility of preparation of complex polyoxocuprates by chemical vapor transport (CVT) techniques that emulate formation of minerals in high-temperature volcanic fumaroles