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Single-crystal X-ray diffraction is an established method to constrain the structure and chemistry of crystalline minerals under high-pressure conditions. Partnership for eXtreme Xtallography (PX2) is a high-pressure crystallographic research program dedicated to diamond anvil cell research. Located at the experimental station 13-BM-C of the Advanced Photon Source, PX2 provides 10 µm-level focused X-rays at a fixed energy of 28.6 keV, a 6-circle heavy duty diffractometer and a state-of-the-art Pilatus3 1 M photon-counting detector, optimized for a variety of advanced crystallography experiments. A suite of auxiliary equipment including a compact multipurpose optical table and remote membrane-based pressure control has been installed to facilitate the experiments. Resistive and laser heating capabilities have been commissioned to provide high-temperature sample environments for the study of the planetary interior. In this manuscript we present a few examples to demonstrate the experimental capabilities at PX2. [ABSTRACT FROM AUTHOR]

Experimental studies on the phase transition and thermoelastic behavior of barite-group minerals are crucial to understand the recycle of sulfur in Earth's interior. Here, we present a high-pressure and high-temperature (high P–T) study on two barite-group minerals—barite (BaSO4) and celestite (SrSO4) up to ~ 59.5 GPa 700 K and ~ 22.2 GPa, 700 K, respectively, using in situ synchrotron-based X-ray diffraction (XRD) combined with diamond anvil cells (DACs). Our results show that BaSO4 undergoes a pressure-induced phase transition from Pbnm to P212121 at ~ 20.3 GPa, which is different from the previous results. Upon decompression, the high-pressure phase of BaSO4 transforms back into its initial structure, which indicates a reversible phase transition. However, no phase transitions have been detected in SrSO4 over the experimental P–T range. In addition, fitting a third-order Birch–Murnaghan equation of state to the pressure–volume data yields the bulk moduli and their pressure derivatives of BaSO4 and SrSO4. Simultaneously, the thermal expansion coefficients of BaSO4 and SrSO4 are also obtained, by fitting the temperature-volume data to the Fei-type thermal equation of state. Furthermore, the compositional effects on the phase transformation and thermoelastic behavior of barite-group minerals are also discussed, and the results suggest that the bond length of < M–O > (M=Ba, Sr, Pb) is an important factor that causes the phase transition pressure of SrSO4 to be the largest, PbSO4 is the second, and BaSO4 is the lowest. [ABSTRACT FROM AUTHOR]

Zoisite is a typical accessory mineral of eclogite; understanding its compressional behavior is important for the knowledge of the properties and processes within subduction zones. In this study, the compressional behavior of a natural eclogitic zoisite Ca1.99(Al2.87Fe0.11)Si3.00O12OH was investigated at ambient temperature and high pressure to 34 GPa, using a diamond anvil cell (DAC) combined with synchrotron-based single-crystal X-ray diffraction (XRD) method. Our results indicate that zoisite is stable over the experimental pressure range. The pressure–volume (P–V) data were fitted to a third-order Birch–Murnaghan equation of state (BM3 EoS), and the equation of state coefficients including zero-pressure unit-cell volume (V0), isothermal bulk modulus (KT0), and its pressure derivative ( K T 0 ′ ) were obtained as: V0 = 904.77(8) Å3, KT0 = 118(1) GPa, and K T 0 ′ = 6.3(2), respectively. The axial compressibilities (β) for a-, b-, and c-axes were also obtained using a parameterized form of the BM3 EoS, and the results show βa0 < βb0 < βc0 with βa0:βb0:βc0 = 1:1.28:1.50. In addition, the bulk modulus of this study is very consistent with previously studied zoisite with similar Fe content. However, the axial compressibility is significantly different with the previous study and the compression of zoisite in this study is more isotropic, which may result from the difference in the pressure-transmitting medium. [ABSTRACT FROM AUTHOR]

The compressibility and expansivity of anglesite (PbSO4) have been measured at high pressure up to 21.6 GPa and high temperature up to 700 K using in situ angle-dispersive X-ray diffraction and diamond anvil cell. The third-order Birch-Murnaghan equation of state (III-BM-EoS) was used to analyze the pressure-volume (P-V) data of PbSO4. We obtained the bulk modulus K0 = 59(1) GPa, and its pressure derivative K0′ = 5.3(4), respectively. Using Holland-Powell thermal EoS to fit the temperature-volume (T-V) data, the thermal expansion coefficient α0 = 4.59(2) × 10− 5 K− 1 for PbSO4 was also derived. Simultaneously, the ambient-pressure axial compressibilities (βa0 = 1.79(4) × 10− 3 GPa− 1, βb0 = 1.75(5) × 10− 3 GPa− 1, βc0 = 2.12(4) × 10− 3 GPa− 1) and axial thermal expansivities (αa0 = 1.23(4) × 10− 5 K− 1, αb0 = 1.93(2) × 10− 5 K− 1, and αc0 = 1.43(1) × 10− 5 K− 1) along a-axis, b-axis and c-axis were derived at 300 K, respectively. Furthermore, the potential influencing factors (e.g., the effective size of M2+ cation, polarizability and electronegativity) on the bulk moduli of barite-type (belonging to Pbnm space group) sulfates (anglesite, barite, and celestine) were discussed. We found that the polarizability might be the most important factor. Finally, the anisotropic linear compressibility and thermal expansivity in barite-type sulfates were also discussed, respectively. [ABSTRACT FROM AUTHOR]

The pressure-volume-temperature ( P- V- T) equation of state (EoS) of synthetic grossular (Grs)-andradite (And) solid-solution garnet sample have been measured at high temperature up to 900 K and high pressures up to 22.75 GPa for GrsAnd, by using in situ angle-dispersive X-ray diffraction and diamond anvil cell. Analysis of room-temperature P- V data to a third-order Birch-Murnaghan (BM) EoS yields: V = 1706.8 ± 0.2 Å, K = 164 ± 2 GPa and K′ = 4.7 ± 0.5. Fitting of our P- V- T data by means of the high-temperature third-order BM EoS gives the thermoelastic parameters: V = 1706.9 ± 0.2 Å, K = 164 ± 2 GPa, K′ = 4.7 ± 0.2, (∂K/∂T) = −0.018 ± 0.002 GPa K, and α = (2.94 ± 0.07) × 10 K. The results also confirm that grossular content increases the bulk modulus of the Grs-And join following a nearly ideal mixing model. The relation between bulk modulus and Grs mole fraction ( X ) in this garnet join is derived to be K (GPa) = (163.7 ± 0.7) + (0.14 ± 0.02) X ( R = 0.985). Present results are also compared to previously studies determined the thermoelastic properties of Grs-And garnets. [ABSTRACT FROM AUTHOR]

Synchrotron-based in situ angle-dispersive X-ray diffraction experiments were conducted on a natural uvite-dominated tourmaline sample by using an external-heating diamond anvil cell at simultaneously high pressures and temperatures up to 18 GPa and 723 K, respectively. The angle-dispersive X-ray diffraction data reveal no indication of a structural phase transition over the P-T range of the current experiment in this study. The pressure-volume-temperature data were fitted by the high-temperature Birch-Murnaghan equation of state. Isothermal bulk modulus of K = 96.6 (9) GPa, pressure derivative of the bulk modulus of $$K_{0}^{\prime } = 12.5 \;(4)$$ , thermal expansion coefficient of α = 4.39 (27) × 10 K and temperature derivative of the bulk modulus ( ∂K/∂T) = −0.009 (6) GPa K were obtained. The axial thermoelastic properties were also obtained with K = 139 (2) GPa, $$K_{a0}^{\prime }$$ = 11.5 (7) and α = 1.00 (11) × 10 K for the a-axis, and K = 59 (1) GPa, $$K_{c0}^{\prime }$$ = 11.4 (5) and α = 2.41 (24) × 10 K for the c-axis. Both of axial compression and thermal expansion exhibit large anisotropic behavior. Thermoelastic parameters of tourmaline in this study were also compared with that of the other two ring silicates of beryl and cordierite. [ABSTRACT FROM AUTHOR]

The high-pressure properties of natural azurite [Cu(CO)(OH)] have been investigated by in situ synchrotron powder X-ray diffraction and Raman spectroscopy up to 11 and 16 GPa at room temperature, respectively. The results indicate that azurite is stable within the pressure region in this study. The pressure-volume data from in situ X-ray diffraction experiments were described by a third-order Birch-Murnaghan equation of state with V = 304.5 (4) Å, K = 40 (2) GPa and K′ = 5.5 (6). The K was obtained as 45.1 (8) GPa when K′ was fixed at 4. The axial compressional behavior of azurite was also fitted with a linearized third-order Birch-Murnaghan equation of state, showing an intense anisotropy with K = 29.7 (9) GPa, K = 25.0 (7) GPa and K = 280 (55) GPa. In addition, the Raman spectroscopy of azurite in this study also presents the weak [OH] group and the rigid [CO] group. The different high-pressure behaviors of azurite and malachite combined with the smaller isothermal bulk modulus compared with certain anhydrous carbonates and the obvious compression anisotropy of azurite were discussed with the experimental results in this study together with the results from previous studies. Furthermore, the effect of hydroxyl on the high-pressure behaviors of carbonates was also discussed. [ABSTRACT FROM AUTHOR]

High-pressure single-crystal synchrotron X-ray diffraction was carried out on a single crystal of natural beryl compressed in a diamond anvil cell. The pressure-volume ( P- V) data from room pressure to 9.51 GPa were fitted by a third-order Birch-Murnaghan equation of state (BM-EoS) and resulted in unit-cell volume V = 675.5 ± 0.1 Å, isothermal bulk modulus K = 180 ± 2 GPa, and its pressure derivative $$K_{0}^{{\prime }}$$ = 4.2 ± 0.5. We also calculated V = 675.5 ± 0.1 Å and K = 181 ± 1GPa with fixed $$K_{0}^{{\prime }}$$ at 4.0 and then obtained the axial moduli for a ( K)-axis and c ( K)-axis of 209 ± 1 and 141 ± 2 GPa by 'linearized' BM-EoS approach. The axial compressibilities of a-axis and c-axis are β = 1.59 × 10 GPa and β = 2.36 × 10 GPa with an anisotropic ratio of β :β = 0.67:1.00. On the other hand, the pressure-volume-temperature ( P- V- T) EoS of the natural beryl has also been measured at temperatures up to 750 K and at pressures up to 16.81 GPa, using diamond anvil cell in conjunction with in situ synchrotron angle-dispersive powder X-ray diffraction. The P- V data at room temperature and at a pressure range of 0.0001-15.84 GPa were then analyzed by third-order BM-EoS and yielded V = 675.3 ± 0.1 Å, K = 180 ± 2 GPa, $$K_{0}^{{\prime }}$$ = 4.2 ± 0.3. With $$K_{0}^{{\prime }}$$ fixed to 4.0, we also obtained V = 675.2 ± 0.1 Å and K = 182 ± 1 GPa. Consequently, we fitted the P- V- T data with high-temperature BM-EoS approach using the resultant $$K_{0}^{{\prime }}$$ (4.2) from room-temperature BM-EoS and then obtained the thermoelastic parameters of V = 675.3 ± 0.2 Å, K = 180 ± 1 GPa, temperature derivative of the bulk modulus ( ∂K/∂T) = −0.017 ± 0.004 GPa K, and thermal expansion coefficient at ambient conditions α = (2.82 ± 0.74) × 10 K. Present results were also compared with previous studies for beryl. From the comparison of these fittings, we propose to constrain K = 180 GPa and $$K_{0}^{{\prime }}$$ = 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. [ABSTRACT FROM AUTHOR]

The pressure-volume-temperature ( P- V- T) equation of state (EoS) of two natural garnet samples along spessartine-almandine (Spe-Alm) join has been measured at high temperature up to 800 K and high pressures up to 15.46 and 16.17 GPa for SpeAlm and SpeAlm, respectively, using in situ angle-dispersive X-ray diffraction and diamond anvil cell. Analysis of room-temperature P- V data to a third-order Birch-Murnaghan EoS yields: V = 1,544.4 ± 0.4 Å, K = 180 ± 3 GPa and $$ K_{0}^{{\prime }} $$ = 4.0 ± 0.4 for SpeAlm, and V = 1,557.5 ± 0.3 Å, K = 176 ± 2 GPa and $$ K_{0}^{{\prime }} $$ = 4.0 ± 0.3 for SpeAlm. Fitting of our P- V- T data by means of the high-temperature third-order Birch-Murnaghan EoS gives the thermoelastic parameters: V = 1,544.6 ± 0.6 Å, K = 180 ± 4 GPa, $$ K_{0}^{{\prime }} $$ = 4.0 ± 0.4, (∂ K/∂ T) = −0.028 ± 0.005 GPa K and α = (3.16 ± 0.14) × 10 K for SpeAlm, and V = 1,557.7 ± 0.9 Å, K = 176 ± 4 GPa, $$ K_{0}^{{\prime }} $$ = 4.0 ± 0.5, (∂ K/∂ T) = −0.029 ± 0.005 GPa K and α = (3.04 ± 0.16) × 10 K for SpeAlm. The results confirm that almandine content increases the bulk modulus of the spessartine-almandine join following a nearly ideal mixing model. The relation between bulk modulus and almandine mole fraction ( X) in this garnet join is derived to be K(GPa) = 171.6(±2.6) + 10.9(±1.8) X. Present results are also compared with previously studies determined the thermoelastic properties of other garnets. [ABSTRACT FROM AUTHOR]

The compression behavior of natural adamite [ZnAsOOH] has been investigated up to 11.07 GPa at room temperature utilizing in situ angle-dispersive X-ray diffraction and a diamond anvil cell. No phase transition has been observed within the pressure range investigated. A third-order Birch-Murnaghan equation of state fitted to all of the data points yielded V = 430.1(4) Å, K = 80(3) GPa, K′ = 1.9(5). The K was obtained as 69(1) GPa when K′ was fixed at 4. Analysis of axial compressible moduli shows the intense compression anisotropy of adamite: K = 37(3) GPa, K = 153(6) GPa, K = 168(8) GPa; hence, a axis is the most compressible and the compressibility of b and c axis is comparable. Furthermore, the comparisons among the compressional properties of adamite, libethenite (CuPOOH, also belongs to olivenite group), and andalusite (AlSiOO has the similar structure with adamite) at high pressure were made. [ABSTRACT FROM AUTHOR]