Crystal Structure and Ionic Conductivity of Three Polymorphic Phases of Rubidium Trifluoromethyl Sulfonate, RbSO₃CF₃

Abstract

The crystal structures of three polymorphic phases of rubidium trifluoromethyl sulfonate (RbSO3CF3, rubidium 'triflate') were solved from X-ray powder diffraction data. At room temperature, rubidium triflate crystallizes in the monoclinic space group Cm with lattice parameters of a = 19.9611(5) A, b = 23.4913(7) A, c = 5.1514(2) A, beta = 102.758(2) degrees; Z = 16. At T = 321 K, a first-order phase transition occurs toward a monoclinic phase in space group P2(1) with lattice parameters at T = 344 K of a = 10.3434(5) A, b = 5.8283(3) A, c = 5.1982(3) A, beta = 104.278(6) degrees; Z = 2). At T = 461 K, another phase transition, this time of second order, occurs toward an orthorhombic phase in space group Cmcm with lattice parameters at T = 510 K of a = 5.3069(2) A, b = 20.2423(10) A, c = 5.9479(2) A; Z = 4. As a common feature within all three crystal structures of rubidium triflate, the triflate anions are arranged in double layers with the lipophilic CF3 groups facing each other. The rubidium ions are located between the SO3 groups. The general packing is similar to the packing in cesium triflate. Rubidium triflate can be classified as a solid electrolyte with a specific ionic conductivity of sigma = 9.89 x 10(-9) S/cm at T = 384 K and sigma = 3.84 x 10(-6) S/cm at T = 481 K.

On the Use of Aqueous Metal-Aqua pKa Values as a Descriptor of Lewis Acidity

“…RbOTf was synthesized by following a modified literature procedure. 47 A three-necked flask was loaded with rubidium carbonate (Rb 2 CO 3 , 4.05 g, 17.5 mmol) and water, forming a turbid solution. Under an inert atmosphere of N 2 , triflic acid (CF 3 SO 3 H, 5.0 g, 33 mmol) was added dropwise to the solution.…”

“…RbOTf was synthesized by following a modified literature procedure . A three-necked flask was loaded with rubidium carbonate (Rb 2 CO 3 , 4.05 g, 17.5 mmol) and water, forming a turbid solution.…”

Alkali Metal Control over N–N Cleavage in Iron Complexes

“…Rubidium trifluoromethanesulfonate was prepared according to the literature procedure. 42 Potassium trifluoromethanesulfonate was purchased from Sigma-Aldrich and dried under a vacuum (0.2 mTorr) for 24 h at 160 °C. Metals were obtained from the following vendors: lithium from ACROS (99+%, granular, dry), sodium from TJ Baker (Baker analyzed Na lump); potassium (98% pure) from Sigma-Aldrich; rubidium from Alfa Aesar (99.75% pure); cesium from Strem (99.9% pure).…”

(18-Crown-6)(trifluoromethanesulfonato)sodium

“…For the reaction of Na 2 [Fe(CO) 4 ] with tBu 3 SiO 3 SCF 3 , see: Lerner et al (2002). For the structure of similar complexes with trifluoromethanesulfonate, see: Bolte & Lerner (2001); Lerner & Bolte (2003); Sofina et al (2003); Dinnebier et al (2004); Hildebrandt et al (2006).…”