Using synchrotron radiation, X-ray diffraction patterns of LnSb (Ln = Pr, N
d, Sm, Gd and Tb) with a NaCl-type structure have been measured up to 30 GP
a at room temperature. First-order phase transitions with a crystallographi
c change occur at around 13 GPa for PrSb and 15 GPa for NdSb. The structure
of the high-pressure phases of both antimonides is tetragonal (Ln: 0,0,0;
Sb: 1/2, 1/2, 1/2; space group P4/mmm), and can be viewed as a distorted Cs
Cl structure. The structure of the high-pressure phase of LnSb (Ln = La, Ce
, Pr and Nd) is more anisotropic compared with that of corresponding LnP. P
ressure-induced phase transitions of SmSb, GdSb and TbSb are observed at ar
ound 19, 22 and 21 GPa, respectively. (C) 2000 Published by Elsevier Scienc
e Ltd. All rights reserved.