New technique for the determination of trace noble metal content in geological and process materials

RbBrF4 Revisited

“…140). Since the RbBrF 4 crystal structure is not expected to be non-centrosymmetric and also taking the structures of NaBrF 4 and KBrF 4 into account, the Rietveld refinement of rubidium tetrafluoridobromate(III) was performed in the space group I4/mcm (no. 140).…”

“…[21] A section of the structure is shown in Figure 2, and the crystal structure in Figure 3. The rubidium atoms occupy the Wyckoff position 4a, and the square planar BrF 4 -anions with their bromine atoms the Wyckoff position 4d. This arrangement makes the structure chemically more plausible and isotypic to KBrF 4 of which the structure was previously well-characterized using also neutron diffraction.…”

“…It is interesting to note that the physical and chemical properties of some tetrafluoridobromates(III) are still not fully established, whereas some others, mainly KBrF 4 and Ba(BrF 4 ) 2 are well documented. [8][9][10][11][12][13][14] The single crystal structures of KBrF 4 , [15][16][17] RbBrF 4 , [8] and CsBrF 4 [12] have been determined.…”

“…[8][9][10][11][12][13][14] The single crystal structures of KBrF 4 , [15][16][17] RbBrF 4 , [8] and CsBrF 4 [12] have been determined. Single crystal structures are not only of purely theoretical interest but are a precondition to obtain technologically important parameters by computer simulations, such as the values of thermodynamic functions (enthalpy of formation, entropy, heat capacity, etc.)…”

“…reported for RbBrF 4 that the rubidium atoms occupy the special position 4c (0; 0; 0) of the space group I4/mcm. [8,9] This leads to a square prismatic coordination of the Rb atoms, which is in contrast to the K + coordination of KBrF 4 .…”