BULK MODULUS AND HIGH-PRESSURE THERMAL-EXPANSION OF TLCL AND TLBR

The isothermal bulk modulus, K-T and its pressure derivative, K-T', fo r TlCl and TlBr have been determined up to 6 GPa with energy dispersiv e X-ray diffraction using synchrotron radiation. Room temperature K-0T , K-0T' values for TlCl and TlBr are 16.3 GPa, 7.8 and 16.2 GPa, 7.9, respectively. Thermal expansion was measured up to 500 degrees C and b oth TlCl and TlBr show a rapid decrease with temperature similar to is o-structural CsCl. Thermal expansion of all three halides at 6 GPa is similar to 3.7 x 10(-5) K-1 (C) 1998 Elsevier Science Ltd. All rights reserved.