Combeite Ohsato H, Maki I, Takeuchi Y Acta Crystallographica C41 (1985) 1575-1577 Structure of Na2CaSi2O6 Locality: synthetic high-temperature form _database_code_amcsd 0010016 10.500 10.500 13.184 90 90 120 R-3m atom x y z occ Biso Na1 0 0 .2485 .705 1.04 Ca1 0 0 .2485 .295 1.04 Na2 .5 0 0 .972 2.69 Na3 .5 0 .5 .501 1.34 Ca3 .5 0 .5 .499 1.34 Ca4 0 0 0 .81 Si .1502 -.1502 .5636 .58 O1 .2533 .0131 .5147 .5 2.81 O2 .1161 -.1161 .6734 2.68 O3 .2373 -.2373 .5510 2.62