Brès E F, Cherns D, Vincent R, Morniroli J P
Max-Planck-Institut für Metallforschung, Institut für Werkstoffwissenschaft, Stuttgart, Germany.
Acta Crystallogr B. 1993 Feb 1;49 ( Pt 1):56-62. doi: 10.1107/s0108768192006566.
In the present work, we have determined the space group of human tooth-enamel crystals using--for the first time for a biological crystal--convergent beam electron diffraction (CBED). The symmetries observed in the different patterns we have obtained lead us to the P6(3)/m hydroxyapatite space group. Disorder, most likely situated in the columns formed by the hydroxyl ions of the crystals, is suggested as a cause of weak intensity in the otherwise forbidden 000l (l odd) reflections and low visibility of first-order Laue zone (FOLZ) reflections in the CBED pattern from crystals oriented along the [0001] zone axis. A monoclinic phase was not observed.
