Rb2Lu[Si4O10]F, a tubular chain silicate.
Single crystals of Rb2Lu[Si4O10]F (dirubidium lutetium tetra-silicate fluoride) were obtained in flux-synthesis experiments in the system SiO2-Lu2O3-RbF. The compound belongs to the group of tubular chain silicates, i.e. it is based on multiple chains of condensed [SiO4] tetra-hedra forming closed columns. The periodicity of the unbranched multiple chains is four and corresponds to the length of the b axis. Adjacent columns are connected by Lu(3+) cations, which are coordinated by four oxide and two fluoride anions in the form of slightly distorted octa-hedra. By sharing common fluoride corners, the single octa-hedra are linked into chains running parallel to the silicate tubes. Electroneutrality is achieved by the incorporation of additional Rb(+) cations. All four symmetrically independent rubidium ions, four out of twelve oxide as well as the two fluoride anions are located on mirror planes. The remaining atoms reside on general positions.
University of Innsbruck, Institute of Mineralogy & Petrography, Innrain 52, A-6020 Innsbruck, Austria.
Volker
V
Kahlenberg
University of Innsbruck, Institute of Mineralogy & Petrography, Innrain 52, A-6020 Innsbruck, Austria.
Tanja
T
Manninger