Ba Ni O5 Tm2 Garcia-Matres E, Rodriguez-Carvajal J, Martinez J, Alonso J, Salinas-Sanchez A, Saez-Puche R Solid State Ionics 63 (1993) 915-921 Polymorphism in the oxides R2NaNiO5 (R= Tm, Yb, Lu) _cod_database_code 1006059 _database_code_amcsd 0015513 3.75124 5.72140 11.2456 90 90 90 Immm atom x y z Ba1 .5 .5 0 Tm1 .5 0 .2033 Ni1 0 0 0 O1 0 .2399 .1499 O2 .5 0 0