New x-ray powder diffraction data for Fe, B substituted Rb-leucites (RbFeSi2O6 and RbBSi2O6)

The boron and iron for aluminum substitution in the Rb-leucite structure (RbAlSi2O6, ICDD card 38-201) has been examined by sol-gel preparation of different samples along the three compositional joins Rb(X,Y)Si2O6, where X and Y are any two of the elements Al, Fe, B. The compound RbBSi2O6 (a(0) = 12.831 Angstrom) is here described and characterized by X-ray powder diffraction for the first time, while the compound RbFeSi2O6 is reexamined with a more precise determination of lattice parameters and diffraction intensities with respect to ICDD card 31-1189. The lattice parameters and the space groups of different selected terms of the three solid solutions are reported. (C) 1997 International Centre for Diffraction Data.