Tarapacaite Zachariasen W, Ziegler G Zeitschrift fur Kristallographie 80 (1931) 164-173 The crystal structure of potassium chromate K2 Cr O4 _cod_database_code 1011186 _database_code_amcsd 0018061 5.92 10.4 7.61 90 90 90 Pmcn atom x y z K1 .25 .083 .355 K2 .25 -.306 .5 Cr1 .25 .083 -.231 O1 .25 .083 -.019 O2 .25 -.061 -.3 O3 .028 .156 -.3