Abstract. orthorhombic, P212~21, a=

M r= 120.22, monoclinic, P2/n, a= 14.656(5), b=4.945(1), c=10.432(3)A, fl= 1 11.27 (3) °, V = 704.55 A 3, Z = 4, D x = 1.13 Mg m -a, 2(Cu Ka) = 1.5418 A, a = 2.12 mm -1, F(000) = 264, T= 293 K, R = 0.062 for 944 unique observed reflections. The full three-dimensional structure, first described by Kakudo & Watase [Technol. Rep. Osaka Univ. (1952). 5, 247-250], has been redetermined, using the space group P2/n not P21/a, and the positions of the hydrogen atoms determined from difference Fourier maps. The hydroxyl hydrogen atoms occur in two alternative arrangements with hydrogen bonds of normal type, O...O distances 2.679 (6)-2.727 (6) A.