New Ternary Compounds Sc3B0.75C3, Sc2B1.1C3.2, ScB15C1.60 and Subsolidus Phase Relations in the Sc–B–C System at 1700°C

摘要: Abstract The phase relations in the ternary system scandium–boron–carbon with special emphasis on boron-rich section have been investigated an isothermal at 1700°C. Ternary compounds following stoichiometries were identified: Sc 2 BC , 3 B 0.75 C 1.1 3.2 ScB 17 0.25 15 0.80 and 1.60 . Four of them, synthesized for first time. three could be indexed, i.e., shows tetragonal symmetry a =3.3308(3) A c =7.680(2) A; basic hexagonal unit cell is =3.3991(2) A, =6.7140(6) two-dimensional incommensurate structure magnitude ∣ q i ∣=(2/7+0.005) 100 −1 along 〈100〉 directions; body centered orthorhombic lattice =10.027(1) b =8.0138(9) =5.6668(6) A. crystal was grown by floating zone method refined from single data, which crystallizes symmetry: I 4/ mmm =3.3259(2) =10.6741(8) Z =2, R =0.011 263 unique reflections 10 variables.