Crystal Structures 1 (1963) 7-83 Second edition. Interscience Publishers, New York, New York Hexagonal closest packed, hcp, structure _database_code_amcsd 0011195 2.950 2.950 4.686 90 90 120 P6_3/mmc atom x y z Ti 1/3 2/3 .25 测得R1=0.447nm,R2=0.2503nm,R3=0.2231nm,<R1,R2>=90,<R1R3>=60,<R2R3>=30