Ca0.75 K6.5 Nb14 O47 Si4 Borel M, Chardon J, Grandin A, Leclaire A, Raveau B Acta Crystallographica C49 (1993) 570-571 Structure of a new siliconiobate K6.5 Ca0.75 Nb14 Si4 O47 _cod_database_code 1001861 _database_code_amcsd 0010283 9.046 9.046 27.883 90 90 120 P6_3/mcm atom x y z occ Nb1 .24520 0 .04437 Nb2 .23777 0 .18222 Nb3 1/3 2/3 0 Si1 1/3 2/3 .19176 K1 .5924 0 .10739 K2 .6018 0 .25 .1667 Ca1 .6018 0 .25 .25 O1 .2172 0 .1106 O2 .2752 0 .25 O3 .1973 0 .5328 O4 .1744 0 .6862 O5 1/3 2/3 .25 O6 .1817 .4856 .1731 O7 .1684 .4815 .4584