Ba32[Li15Si9W16N67O5]: A Barium‐Containing Oxonitridolithotungstosilicate with a Highly Condensed Network Structure

Abstract

The oxonitridolithotungstosilicate Ba32[Li15Si9W16N67O5] was synthesized by metathesis reaction of the reactive starting compounds Si(NH)2, LiNH2, LiF, and BaH2 in a radiofrequency furnace at 1000 °C by using tungsten crucibles. Single crystals of Ba32[Li15Si9W16N67O5] were obtained as a byproduct from reaction of the starting materials with the crucible. The crystal structure was solved and refined on the basis of single‐crystal X‐ray diffraction data [P21/n (no. 14), a = 8.3402(3), b = 8.5465(3), c = 16.6736(6) Å, β = 99.1950(10)°, Z = 1, R1(all) = 0.0302]. Ba32[Li15Si9W16N67O5] is the first oxonitridolithotungstosilicate containing a three‐dimensional network of vertex‐ (WN4) and edge‐sharing (LiN3O, Li/SiN3O, and SiN3O) tetrahedra with Ba2+ ions that fill the voids of the structure. The network is characterized by channels of fünfer rings running along [100] as well as channels of sechser and achter rings along [010]. Magnetic measurements verified an oxidation state of +VI for W. X‐ray spectroscopy, lattice energy calculations with MAPLE, and X‐ray diffraction confirmed the chemical composition and the structural model of Ba32[Li15Si9W16N67O5]. IR spectra corroborated the absence of N–H bonds. The optical band gap of Ba32[Li15Si9W16N67O5] has been determined by UV/Vis spectroscopy.