The crystal structure of melamine diborate

The crystal structure of melamine diborate (C3N6H6 . 2H(3)BO(3)), well known as raw material of boron nitride, was determined by single crystal. X-ray analysis, Molecules are packed in a monoclinic crystal system, space group P2(1)/c, with a=0.3596 (1)nm, b=2.0111 (2)nm, c=1.41092 (9)nm, beta=92.12 (2)degrees, Z=4 and crystal density is 1.627 g/cm(3). Molecules in the crystal are linked together by hydrogen-bonds, and form spirally stacked quasi-sheets parallel to a-axis, Bond lengths of hydrogen-bonds range from 0.181(2)nm to 0.209 (2)nm. The crystal shows needlelike habit and its longitudinal direction is also parallel to a-axis, The preferred orientation, which was elucidated from powder X-ray diffraction pattern, is presumably due to the needlelike habit and is attenuated by grinding.