Crystal growth and structure refinement of a new higher boride NaAlB14

Single crystal of a new ternary boride NaAlB14 was grown from a high temperature Al solution using Na2B4O7 and crystalline boron powders as raw materials under an Ar atmosphere. The crystals obtained showed a plate-like or a trapezoidal shape with well-developed {0 1 0} faces, and were reddish black with a metallic luster. The largest crystal prepared in the present work attained maximum dimensions of approximately 7.3 mm × 3.2 mm × 2.8 mm. The crystals were examined by powder X-ray diffraction and chemical analyses, and the crystal structure of NaAlB14 was refined using data of single crystal X-ray diffractometry. The structure refinement converged at an R1 (F2) value of 0.025 with 29 parameters for 381 independent reflections [F0 > 4σ(F0)] and 0.027 for all 426 independent reflections. The crystal structure is orthorhombic with the space group Imma (number 74), and lattice constants are a = 1.0465(1), b = 0.5844(1), and c = 0.8231(1) nm; V = 0.5034(1) nm3; Z = 4.