Retraction: Carbon content drives high temperature superconductivity in a carbonaceous sulfur hydride below 100 GPa.

Retraction of 'Carbon content drives high temperature superconductivity in a carbonaceous sulfur hydride below 100 GPa' by G. Alexander Smith , , 2022, , 9064-9067, https://doi.org/10.

On the identification of hyperhydrated sodium chloride hydrates, stable at icy moon conditions.

Sodium chloride is expected to be found on many of the surfaces of icy moons like Europa and Ganymede. However, spectral identification remains elusive as the known NaCl-bearing phases cannot match current observations, which require higher number of water of hydration. Working at relevant conditions for icy worlds, we report the characterization of three "hyperhydrated" sodium chloride (SC) hydrates, and refined two crystal structures [2NaCl·17HO (SC8.

Carbon content drives high temperature superconductivity in a carbonaceous sulfur hydride below 100 GPa.

We report a previously unobserved superconducting state of the photosynthesized carbonaceous sulfur hydride (C-S-H) system with a maximum of 191(1) K below 100 GPa. The properties of C-S-H are dependent on carbon content, and X-ray diffraction and simulations reveal the system remains molecular-like up to 100 GPa.

Effect of synchrotron X-ray radiation damage on phase transitions in coordination polymers at high pressure.

The high-pressure phase-transition behaviour of metal-organic frameworks and coordination polymers upon varying degrees of X-ray irradiation are highlighted with four example studies. These show that, in certain cases, the radiation damage, while not extreme in changing unit-cell values, can impact the existence of a phase transition. In particular, pressure-induced phase transitions are suppressed after a certain absorbed dose threshold is reached for the sample.

Understanding multiscale structure-property correlations in PVDF-HFP electrospun fiber membranes by SAXS and WAXS.

Electrospinning is a versatile technique to produce nanofibrous membranes with applications in filtration, biosensing, biomedical and tissue engineering. The structural and therefore physical properties of electrospun fibers can be finely tuned by changing the electrospinning parameters. The large parameter window makes it challenging to optimize the properties of fibers for a specific application.

Host-Guest Hydrogen Bonding in High-Pressure Acetone Clathrate Hydrates: Single-Crystal X-ray Diffraction Study.

The phenomenon of host-guest hydrogen bonding in clathrate hydrate crystal structures and its effect on physical and chemical properties have become subjects of extensive research. Hydrogen bonding has been studied for cubic (sI and sII) and hexagonal (sH) binary clathrates, while it has not been addressed for clathrate structures that exist at elevated pressures. Here, four acetone hydrate clathrates have been grown at high-pressure and low-temperature conditions.

Enhancing the chemical flexibility of hybrid perovskites by introducing divalent ligands.

Herein we report the synthesis and structures of [(CH3)2NH2]Er(HCO2)2(C2O4) and [(NH2)3C]Er(HCO2)2(C2O4), in which the inclusion of divalent oxalate ligands allows for the exclusive incorporation of A+ and B3+ cations in an ABX3 hybrid perovskite structure for the first time. We rationalise the observed thermal expansion of these materials, including negative thermal expansion, and find evidence for weak antiferromagnetic coupling in [(CH3)2NH2]Er(HCO2)2(C2O4).

Probing the Influence of Defects, Hydration, and Composition on Prussian Blue Analogues with Pressure.

The vast compositional space of Prussian blue analogues (PBAs), formula AM[M'(CN)]·HO, allows for a diverse range of functionality. Yet, the interplay between composition and physical properties-e.g.

Pressure-Induced Polymerization of Polycyclic Arene-Perfluoroarene Cocrystals: Single Crystal X-ray Diffraction Studies, Reaction Kinetics, and Design of Columnar Hydrofluorocarbons.

Pressure-induced polymerization of aromatic compounds leads to novel materials containing sp carbon-bonded networks. The choice of the molecular species and the control of their arrangement in the crystal structures via intermolecular interactions, such as the arene-perfluoroarene interaction, can enable the design of target polymers. We have investigated the crystal structure compression and pressure-induced polymerization reaction kinetics of two polycyclic 1:1 arene-perfluoroarene cocrystals, naphthalene/octafluoronaphthalene (NOFN) and anthracene/octafluoronaphthalene (AOFN), up to 25 and 30 GPa, respectively, using single-crystal synchrotron X-ray diffraction, infrared spectroscopy, and theoretical computations based on density-functional theory.

Crystal Structure and Non-Hydrostatic Stress-Induced Phase Transition of Urotropine Under High Pressure.

High-pressure behavior of hexamethylenetetramine (urotropine) was studied in situ using angle-dispersive single-crystal synchrotron X-ray diffraction (XRD) and Fourier-transform infrared absorption (FTIR) spectroscopy. Experiments were conducted in various pressure-transmitting media to study the effect of deviatoric stress on phase transformations. Up to 4 GPa significant damping of molecular librations and atomic thermal motion was observed.

Effect of Alkali and Trivalent Metal Ions on the High-Pressure Phase Transition of [CHNH]M M (HCOO) (M = Na, K and M = Cr, Al) Heterometallic Perovskites.

We report the high-pressure behavior of two perovskite-like metal formate frameworks with the ethylammonium cation (EtAKCr and EtANaAl) and compare them to previously reported data for EtANaCr. High-pressure single-crystal X-ray diffraction and Raman data for EtAKCr show the occurrence of two high-pressure phase transitions observed at 0.75(16) and 2.

Spin crossover in the Prussian blue analogue FePt(CN) induced by pressure or X-ray irradiation.

The spin state of the Prussian blue analogue FePt(CN) is investigated in response to temperature, pressure, and X-ray irradiation. While cooling to 10 K maintains the high-spin state of Fe, compression at ambient temperature induces a first-order spin-crossover (SCO) transition with a small hysteresis loop (p↑ = 0.8 GPa, p↓ = 0.

Charting the Metal-Dependent High-Pressure Stability of Bimetallic UiO-66 Materials.

In theory, bimetallic UiO-66(Zr:Ce) and UiO-66(Zr:Hf) metal-organic frameworks (MOFs) are extremely versatile and attractive nanoporous materials as they combine the high catalytic activity of UiO-66(Ce) or UiO-66(Hf) with the outstanding stability of UiO-66(Zr). Using in situ high-pressure powder X-ray diffraction, however, we observe that this expected mechanical stability is not achieved when incorporating cerium or hafnium in UiO-66(Zr). This observation is akin to the earlier observed reduced thermal stability of UiO-66(Zr:Ce) compounds.

A versatile diamond anvil cell for X-ray inelastic, diffraction and imaging studies at synchrotron facilities.

We present a new diamond anvil cell design, hereafter called mBX110, that combines both the advantages of a membrane and screws to generate high pressure. It enables studies at large-scale facilities for many synchrotron X-ray techniques and has the possibility to remotely control the pressure with the membrane as well as the use of the screws in the laboratory. It is fully compatible with various gas-loading systems as well as high/low temperature environments in the lab or at large scale facilities.

Raman and single-crystal X-ray diffraction evidence of pressure-induced phase transitions in a perovskite-like framework of [(CH)N] [Mn(N(CN))].

We report complementary high-pressure Raman and single-crystal X-ray diffraction studies of a perovskite-like dicyanamide framework of [(C3H7)4N][Mn(N(CN)2)3] ([TPrA][Mn(dca)3]). Our studies show that the bulk modulus of the ambient pressure P4[combining macron]21c phase is B0 = 8.1(11) GPa, and the ab-plane compresses by 54.

Packing Rearrangements in 4-Hydroxycyanobenzene Under Pressure.

4-hydroxycyanobenzene (4HCB) is a dipolar molecule formed of an aromatic substituted benzene ring with the CN and OH functional groups at the 1 and 4 positions. In the crystalline state, it forms spiral chains via hydrogen bonding, which pack together through π - π interactions. The direct stacking of benzene rings down the - and -axes and its π - π interactions throughout the structure gives rise to its semiconductor properties.

Polymorphism in M(HPO) (M = V, Al, Ga) compounds with the perovskite-related ReO structure.

Trivalent metal hypophosphites with the general formula M(H2PO2)3 (M = V, Al, Ga) adopt the ReO3 structure, with each compound displaying two structural polymorphs. High-pressure synchrotron X-ray studies reveal a pressure-driven phase transition in Ga(H2PO2)3 that can be understood on the basis of ab initio thermodynamics.

Intrinsic Flexibility of the EMT Zeolite Framework under Pressure.

The roles of organic additives in the assembly and crystallisation of zeolites are still not fully understood. This is important when attempting to prepare novel frameworks to produce new zeolites. We consider 18-crown-6 ether (18C6) as an additive, which has previously been shown to differentiate between the zeolite EMC-2 (EMT) and faujasite (FAU) frameworks.

High-pressure behaviour of Prussian blue analogues: interplay of hydration, Jahn-Teller distortions and vacancies.

We report a high-pressure crystallographic study of four hydrated Prussian blue analogues: M[Pt(CN)] and M[Co(CN)] (M = Mn, Cu) in the range 0-3 GPa. Mn[Co(CN)] was studied by single-crystal X-ray diffraction, whereas the other systems were only available in polycrystalline form. The Mn-containing compounds undergo pressure-induced phase transitions from Fm3[combining macron]m to R3[combining macron] at ∼1.

Pressure dependence of spin canting in ammonium metal formate antiferromagnets.

High-pressure single-crystal X-ray diffraction at ambient temperature and high-pressure SQUID measurements down to 2 K were performed up to ∼2.5 GPa on ammonium metal formates, [NH][M(HCOO)] where M = Mn, Fe, and Ni, in order to correlate structural variations to magnetic behaviour. Similar structural distortions and phase transitions were observed for all compounds, although the transition pressures varied with the size of the metal cation.

Complete Set of Elastic Moduli of a Spin-Crossover Solid: Spin-State Dependence and Mechanical Actuation.

Molecular spin crossover complexes are promising candidates for mechanical actuation purposes. The relationships between their crystal structure and mechanical properties remain, however, not well understood. In this study, combining high pressure synchrotron X-ray diffraction, nuclear inelastic scattering, and micromechanical measurements, we assessed the effective macroscopic bulk modulus ( B = 11.

SiO_{2} Glass Density to Lower-Mantle Pressures.

The convection or settling of matter in the deep Earth's interior is mostly constrained by density variations between the different reservoirs. Knowledge of the density contrast between solid and molten silicates is thus of prime importance to understand and model the dynamic behavior of the past and present Earth. SiO_{2} is the main constituent of Earth's mantle and is the reference model system for the behavior of silicate melts at high pressure.

Neon-Bearing Ammonium Metal Formates: Formation and Behaviour under Pressure.

The incorporation of noble gas atoms, in particular neon, into the pores of network structures is very challenging due to the weak interactions they experience with the network solid. Using high-pressure single-crystal X-ray diffraction, we demonstrate that neon atoms enter into the extended network of ammonium metal formates, thus forming compounds Ne [NH ][M(HCOO) ]. This phenomenon modifies the compressional and structural behaviours of the ammonium metal formates under pressure.

Control of Multipolar and Orbital Order in Perovskite-like [C(NH2)3]CuxCd1-x(HCOO)3 Metal-Organic Frameworks.

We study the compositional dependence of molecular orientation (multipolar) and orbital (quadrupolar) order in the perovskite-like metal-organic frameworks [C(NH2)3]CuxCd1-x(HCOO)3. Upon increasing the fraction x of Jahn-Teller-active Cu(2+), we observe an orbital disorder/order transition and a multipolar reorientation transition, each occurring at distinct critical compositions xo = 0.45(5) and xm = 0.