Praseodymium Wyckoff R W G Crystal Structures 1 (1963) 7-83 Second edition. Interscience Publishers, New York, New York Hexagonal closest packed, hcp, structure _database_code_amcsd 0011189 3.669 3.669 5.920 90 90 120 P6_3/mmc atom x y z Pr 1/3 2/3 .25