Single crystal diffraction study of Ba[HCO][HCO][HCO][HCO], a hydrous mixed sp/sp-carbonate.

We have synthesized the first hydrous sp-carbonate by laser-heating Ba[CO], CO and HO in a diamond anvil cell at 40(3) GPa. The crystal structure of Ba[HCO][HCO][HCO][HCO] was determined by synchrotron single crystal X-ray diffraction. The experiments were complemented by DFT-based calculations.

Automated pipeline processing X-ray diffraction data from dynamic compression experiments on the Extreme Conditions Beamline of PETRA III.

Presented and discussed here is the implementation of a software solution that provides prompt X-ray diffraction data analysis during fast dynamic compression experiments conducted within the dynamic diamond anvil cell technique. It includes efficient data collection, streaming of data and metadata to a high-performance cluster (HPC), fast azimuthal data integration on the cluster, and tools for controlling the data processing steps and visualizing the data using the software package. This data processing pipeline is invaluable for a great number of studies.

A role for subducting clays in the water transportation into the Earth's lower mantle.

Subducting sedimentary layer typically contains water and hydrated clay minerals. The stability of clay minerals under such hydrous subduction environment would therefore constraint the lithology and physical properties of the subducting slab interface. Here we show that pyrophyllite (AlSiO(OH)), one of the representative clay minerals in the alumina-silica-water (AlO-SiO-HO, ASH) system, breakdowns to contain further hydrated minerals, gibbsite (Al(OH)) and diaspore (AlO(OH)), when subducts along a water-saturated cold subduction geotherm.

High-pressure Synthesis of Cobalt Polynitrides: Unveiling Intriguing Crystal Structures and Nitridation Behavior.

In this study, we conduct extensive high-pressure experiments to investigate phase stability in the cobalt-nitrogen system. Through a combination of synthesis in a laser-heated diamond anvil cell, first-principles calculations, Raman spectroscopy, and single-crystal X-ray diffraction, we establish the stability fields of known high-pressure phases, hexagonal NiAs-type CoN, and marcasite-type CoN within the pressure range of 50-90 GPa. We synthesize and characterize previously unknown nitrides, CoN, Pnma-CoN and two polynitrides, CoN and CoN, within the pressure range of 90-120 GPa.

Oxidation of iron by giant impact and its implication on the formation of reduced atmosphere in the early Earth.

Giant impact-driven redox processes in the atmosphere and magma ocean played crucial roles in the evolution of Earth. However, because of the absence of rock records from that time, understanding these processes has proven challenging. Here, we present experimental results that simulate the giant impact-driven reactions between iron and volatiles (HO and CO) using x-ray free electron laser (XFEL) as fast heat pump and structural probe.

High-pressure synthesis of acentric sodium pyrocarbonate, Na[CO].

The inorganic pyrocarbonate salt Na[CO] crystallizes in the acentric, monoclinic space group 2 with = 2. It contains monovalent alkali metal cations together with isolated pyrocarbonate anions. The [CO]-groups consist of two planar [CO]-groups which are slightly tilted with respect to each other around the bridging oxygen atom.

Simultaneous measurements of volume, pressure, optical images, and crystal structure with a dynamic diamond anvil cell: A real-time event monitoring system.

The dynamic diamond anvil cell (dDAC) technique has attracted great interest because it possibly provides a bridge between static and dynamic compression studies with fast, repeatable, and controllable compression rates. The dDAC can be a particularly useful tool to study the pathways and kinetics of phase transitions under dynamic pressurization if simultaneous measurements of physical quantities are possible as a function of time. We here report the development of a real-time event monitoring (RTEM) system with dDAC, which can simultaneously record the volume, pressure, optical image, and structure of materials during dynamic compression runs.

Graphite resistive heated diamond anvil cell for simultaneous high-pressure and high-temperature diffraction experiments.

High-pressure and high-temperature experiments using a resistively heated diamond anvil cell have the advantage of heating samples homogeneously with precise temperature control. Here, we present the design and performance of a graphite resistive heated diamond anvil cell (GRHDAC) setup for powder and single-crystal x-ray diffraction experiments developed at the Extreme Conditions Beamline (P02.2) at PETRA III, Hamburg, Germany.

A MHz X-ray diffraction set-up for dynamic compression experiments in the diamond anvil cell.

An experimental platform for dynamic diamond anvil cell (dDAC) research has been developed at the High Energy Density (HED) Instrument at the European X-ray Free Electron Laser (European XFEL). Advantage was taken of the high repetition rate of the European XFEL (up to 4.5 MHz) to collect pulse-resolved MHz X-ray diffraction data from samples as they are dynamically compressed at intermediate strain rates (≤10 s), where up to 352 diffraction images can be collected from a single pulse train.

Evidence for a rosiaite-structured high-pressure silica phase and its relation to lamellar amorphization in quartz.

When affected by impact, quartz (SiO) undergoes an abrupt transformation to glass lamellae, the planar deformation features (PDFs). This shock effect is the most reliable indicator of impacts and is decisive in identifying catastrophic collisions in the Earth´s record such as the Chicxulub impact. Despite the significance of PDFs, there is still no consensus how they form.

Dynamic compression of Ce and Pr with millisecond time-resolved X-ray diffraction.

Both cerium (Ce) and praseodymium (Pr) undergo a volume collapse transition under compression that originate from similar electronic mechanisms. Yet the outcome could not be more different. In the case of Ce with one affected 4f electron the volume collapse leaves the crystal symmetry intact, whereas for Pr with two 4f electrons the crystal symmetry changes from a distorted face centered cubic structure to a lower symmetry orthorhombic structure.

FeSiB metallic glass gaskets for high-pressure research beyond 1 Mbar.

A gasket is an important constituent of a diamond anvil cell (DAC) assembly, responsible for the sample chamber stability at extreme conditions for X-ray diffraction studies. In this work, we studied the performance of gaskets made of metallic glass FeSiB in a number of high-pressure X-ray diffraction (XRD) experiments in DACs equipped with conventional and toroidal-shape diamond anvils. The experiments were conducted in either axial or radial geometry with X-ray beams of micrometre to sub-micrometre size.

Synthesis and Structure of Pb[CO]: An Inorganic Pyrocarbonate Salt.

We have synthesized Pb[CO], an inorganic pyrocarbonate salt, in a laser-heated diamond anvil cell (LH-DAC) at 30 GPa by heating a Pb[CO] + CO mixture to ≈2000(200) K. Inorganic pyrocarbonates contain isolated [CO] groups without functional groups attached. The [CO] groups consist of two oxygen-sharing [CO] groups.

Testing the performance of secondary anvils shaped with focused ion beam from the single-crystal diamond for use in double-stage diamond anvil cells.

The success of high-pressure research relies on the inventive design of pressure-generating instruments and materials used for their construction. In this study, the anvils of conical frustum or disk shapes with flat or modified culet profiles (toroidal or beveled) were prepared by milling an Ia-type diamond plate made of a (100)-oriented single crystal using the focused ion beam. Raman spectroscopy and synchrotron x-ray diffraction were applied to evaluate the efficiency of the anvils for pressure multiplication in different modes of operation: as single indenters forced against the primary anvil in diamond anvil cells (DACs) or as pairs of anvils forced together in double-stage DACs (dsDACs).

Sr[CO] is an Inorganic Pyrocarbonate Salt with [CO] Complex Anions.

The synthesis of a novel type of carbonate, namely of the inorganic pyrocarbonate salt Sr[CO], which contains isolated [CO]-groups, significantly extends the crystal chemistry of inorganic carbonates beyond the established - and -carbonates. We synthesized Sr[CO] in a laser-heated diamond anvil cell by reacting Sr[CO] with CO. By single crystal synchrotron diffraction, Raman spectroscopy, and density functional theory (DFT) calculations, we show that it is a pyrocarbonate salt.

Structural Diversity of Magnetite and Products of Its Decomposition at Extreme Conditions.

Magnetite, FeO, is the oldest known magnetic mineral and archetypal mixed-valence oxide. Despite its recognized role in deep Earth processes, the behavior of magnetite at extreme high-pressure high-temperature (HPHT) conditions remains insufficiently studied. Here, we report on single-crystal synchrotron X-ray diffraction experiments up to ∼80 GPa and 5000 K in diamond anvil cells, which reveal two previously unknown FeO polymorphs, γ-FeO with the orthorhombic YbS-type structure and δ-FeO with the modified ThP-type structure.

Laser heating system at the Extreme Conditions Beamline, P02.2, PETRA III.

A laser heating system for samples confined in diamond anvil cells paired with in situ X-ray diffraction measurements at the Extreme Conditions Beamline of PETRA III is presented. The system features two independent laser configurations (on-axis and off-axis of the X-ray path) allowing for a broad range of experiments using different designs of diamond anvil cells. The power of the continuous laser source can be modulated for use in various pulsed laser heating or flash heating applications.

Sr[CO]O Antiperovskite with Tetrahedrally Coordinated sp-Hybridized Carbon and OSr Octahedra.

We have synthesized the orthocarbonate Sr[CO]O in a laser-heated diamond anvil cell at 20 and 30 GPa by heating to ≈3000 (300) K. Afterward, we recovered the orthocarbonate with [CO] groups at ambient conditions. Single-crystal diffraction shows the presence of [CO] groups, i.

The High Energy Density Scientific Instrument at the European XFEL.

The European XFEL delivers up to 27000 intense (>10 photons) pulses per second, of ultrashort (≤50 fs) and transversely coherent X-ray radiation, at a maximum repetition rate of 4.5 MHz. Its unique X-ray beam parameters enable groundbreaking experiments in matter at extreme conditions at the High Energy Density (HED) scientific instrument.

Compression-rate dependence of pressure-induced phase transitions in Bi.

It is qualitatively well known that kinetics related to nucleation and growth can shift apparent phase boundaries from their equilibrium value. In this work, we have measured this effect in Bi using time-resolved X-ray diffraction with unprecedented 0.25 ms time resolution, accurately determining phase transition pressures at compression rates spanning five orders of magnitude (10-10 GPa/s) using the dynamic diamond anvil cell.

X-ray Free Electron Laser-Induced Synthesis of ε-Iron Nitride at High Pressures.

The ultrafast synthesis of ε-FeN in a diamond-anvil cell (DAC) from Fe and N under pressure was observed using serial exposures of an X-ray free electron laser (XFEL). When the sample at 5 GPa was irradiated by a pulse train separated by 443 ns, the estimated sample temperature at the delay time was above 1400 K, confirmed by transformation of α- to γ-iron. Ultimately, the Fe and N reacted uniformly throughout the beam path to form FeN, as deduced from its established equation of state (EOS).

The stability of subducted glaucophane with the Earth's secular cooling.

The blueschist to eclogite transition is one of the major geochemical-metamorphic processes typifying the subduction zone, which releases fluids triggering earthquakes and arc volcanism. Although glaucophane is an index hydrous mineral for the blueschist facies, its stability at mantle depths in diverse subduction regimes of contemporary and early Earth has not been experimentally determined. Here, we show that the maximum depth of glaucophane stability increases with decreasing thermal gradients of the subduction system.

High-Pressure Synthesis of Metal-Inorganic Frameworks Hf N ⋅N , WN ⋅N , and Os N ⋅3 N with Polymeric Nitrogen Linkers.

Polynitrides are intrinsically thermodynamically unstable at ambient conditions and require peculiar synthetic approaches. Now, a one-step synthesis of metal-inorganic frameworks Hf N ⋅N , WN ⋅N , and Os N ⋅3 N via direct reactions between elements in a diamond anvil cell at pressures exceeding 100 GPa is reported. The porous frameworks (Hf N , WN , and Os N ) are built from transition-metal atoms linked either by polymeric polydiazenediyl (polyacetylene-like) nitrogen chains or through dinitrogen units.

Intense Reactivity in Sulfur-Hydrogen Mixtures at High Pressure under X-ray Irradiation.

Superconductivity near room temperature in the sulfur-hydrogen system arises from a sequence of reactions at high pressures, with X-ray diffraction experiments playing a central role in understanding these chemical-structural transformations and the corresponding S:H stoichiometry. Here we document X-ray irradiation acting as both a probe and as a driver of chemical reaction in this dense hydride system. We observe a reaction between molecular hydrogen (H) and elemental sulfur (S) under high pressure, induced directly by X-ray illumination, at photon energies of 12 keV using a free electron laser.

Single-crystal diffractometer coupled with double-sided laser heating system at the Extreme Conditions Beamline P02.2 at PETRAIII.

Combination of in situ laser heating with single-crystal X-ray diffraction (scXRD) in diamond anvil cells (DACs) provides a tool to study crystal structures and/or chemistry of materials at simultaneous high pressures and high temperatures. Here, we describe the first dedicated single-crystal X-ray diffractometer coupled with double-sided laser heating (dsLH) system. The scXRD/dsLH setup was developed for the P02.