Publications with shared reference: New Oxyfluoride Pyrochlores Li<sub>2–<i>x</i></sub>La<sub>(1+x)/3</sub>□<sub>(2<i>x</i>–1)/3</sub>B<sub>2</sub>O<sub>6</sub>F (B = Nb, Ta): Average and Local Structure Characterization by XRD, TEM and <sup>19</sup>F Solid‐State NMR Spectroscopy