Compressibility and equation of state of beryl (Be3Al2Si6O18) by using a diamond anvil cell and in situ synchrotron X-ray diffraction

Abstract

K ′ 0 = 4.2 ± 0.3. With K ′ 0 fixed to 4.0, we also obtained V 0 = 675.2 ± 0.1 Å 3 and K 0 = 182 ± 1 GPa. Consequently, we fitted the P-V-T data with high-temperature BM-EoS approach using the resultant K ′ 0 (4.2) from room-temperature BM-EoS and then obtained the thermoelastic parameters of V 0 = 675.3 ± 0.2 Å 3 , K 0 = 180 ± 1 GPa, temperature derivative of the bulk modulus (∂K/∂T) P = −0.01 7 ± 0.004 GPa K −1 , and thermal expansion coefficient at ambient conditions α 0 = (2.82 ± 0.74) × 10 −6 K −1 . Present results were also compared with previous studies for beryl. From the comparison of these fittings, we propose to constrain K 0 = 180 GPa and K ′ 0 = 4.2 for beryl. And we also observed that beryl exhibits anisotropic thermal expansion at relatively low temperatures, which is very consistent with previous studies. Furthermore, no phase transition was observed in the entire pressure and temperature range (up to 16.84 GPa and 750 K) of this study for the natural beryl.

Hydroxylherderite (Ca2Be2P2O8(OH)2) stability under extreme conditions (up to 750°C/100 GPa)

“…Besides, this information could help to explain beryllium deposit formation. 18 As far as we know, less than 10 Be-containing minerals were studied under high-pressure conditions, among them are beryl Be 3 Al 2 Si 6 O 18 , 19,20 chrysoberyl BeAl 2 O 4 , 21,22 phenakite Be 2 SiO 4 and bertrandite Be 4 Si 2 O 7 (OH) 2 , 23 behoite Be(OH) 2 , 24 londonite CsBe 4 Al 4 (B 11 Be)O 28 , 25 hurlbutite CaBe 2 P 2 O 8 , 26 and hingganite-(Y) Y 2 □Be 2 Si 2 O 8 (OH) 2 . 27 Of these, only hurlbutite was studied up to the amorphization (above 90 GPa), whereas all other minerals were studied up to 5-50 GPa, and these pressures are not their whole stability range.…”

High-pressure behavior and structural transition of beryl-type johnkoivulaite, Cs(Be2B)Mg2Si6O18

“…M' = ¶M0/ ¶P » -8 for the c-axis, and even negative values for the volume with K' = ¶K0/ ¶P » -2 ± 3. The occurrence of axial negative values has been previously reported for irradiated and non-irradiated cordierite (Miletich et al 2014a,b;Scheidl et al 2014), and pezzottaite (Ende et al 2021), while studies on beryl itself did not report any anomalous behavior (Fan et al 2015). Structural instabilities have been reported for isostructural materials associated with remarkable elastic-softening behavior, which can be interpreted as a precursor effect of an impending transition in beryl-type phases (Miletich et al 2014a,b;Ende et al 2021).…”

“…The P dependency of unit-cell parameters (Figure 3) reveals a compressional anisotropy with the structure being ~10 % less compressible along the c-axis than along the a-axis (Table 1), following a pattern of anisotropy similar to that of pezzottaite but different from that of beryl or cordierite (Miletich et al 2014a,b;Scheidl et al 2014;Fan et al 2015;O'Bannon and Williams 2016;Ende et al 2021). An obvious change in the compression behavior can be observed from the critical pressure of ~4 GPa, as described in the high-pressure Raman spectroscopic investigations.…”

“…Referring to the Anderson-Anderson relationship (Anderson and Anderson 1970), the bulk modulus of the low-P form is very similar to that reported for pezzottaite (K0 = 152 GPa at V/Z = 341.3 Å 3 per formula unit Z), and plots between those of beryl [K0 = 180 GPa, V0/Z = 337.7 Å 3 p.f.u. (Fan et al 2015)]…”

Dehydration kinetics of nanoconfined water in beryl probed by high temperature single crystal synchrotron X-ray diffraction

“…Cordierite, when heated to 800 °C expands along the a-axis, but contracts along the c-axis 17 . Beryl, when heated below ~ 300 °C, contracts along the c-axis, but expands at higher temperatures 18 – 20 . Cordierite has widespread industrial uses as a ceramic material, for instance as the substrate in catalytic converters, driving interest in its high temperature transformation.…”