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Materials Data on Ho3(Al3Os)4 by Materials Project

Ho3(OsAl3)4 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Ho is bonded in a 5-coordinate geometry to four equivalent Os and eleven Al atoms. All Ho–Os bond lengths are 3.37 Å. There are a spread of Ho–Al bond distances ranging from 2.96–3.22 Å. There are two inequivalent Os sites. In the first Os site, Os is bonded in a body-centered cubic geometry to eight Al atoms. There are two shorter (2.39 Å) and six longer (2.59 Å) Os–Al bond lengths. In the second Os site, Os is bonded in a 12-coordinate geometry to four equivalent Ho and eight Al atoms. There are a spread of Os–Al bond distances ranging from 2.55–2.68 Å. There are four inequivalent Al sites. In the first Al site, Al is bonded in a 3-coordinate geometry to three equivalent Ho and three equivalent Os atoms. In the second Al site, Al is bonded in a 3-coordinate geometry to three equivalent Ho and three Os atoms. In the third Al site, Al is bonded in a 2-coordinate geometry to two equivalent Ho and two equivalent Os atoms. In the fourth Al site, Al is bonded in a distorted linear geometry to three equivalent Ho and two equivalent Os atoms.

36 MATERIALS SCIENCE↗

2.07-micron CW diode-laser-pumped Tm,Ho:YLiF4 room-temperature

Continuous-wave action is obtained at 2.07 microns from a 2-mm-long Tm-sensitized Ho:YLiF4 crystal at room temperature when longitudinally pumped by a pair of diode-laser arrays. Laser output power at 300 K is 26 mW, with a 30-percent slope efficiency and a lasing threshold of 108 mW. A maximum output power of 187 mW is obtained from a 4-mm-long crystal at 77 K, with a 67 percent slope efficiency. A preliminary demonstration of cavity Q switching produced 165 microJ of pulse energy at a repetition rate of 100 Hz.

Hemmati, Hamid↗

Materials Data on Ho20Cu6(Pb3S14)3 by Materials Project

Ho20Cu6(Pb3S14)3 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twenty inequivalent Ho3+ sites. In the first Ho3+ site, Ho3+ is bonded to six S2- atoms to form HoS6 octahedra that share corners with three HoS6 octahedra, corners with two PbS7 pentagonal bipyramids, edges with five HoS6 octahedra, and edges with two CuS4 tetrahedra. The corner-sharing octahedra tilt angles range from 3–41°. There are a spread of Ho–S bond distances ranging from 2.70–2.80 Å. In the second Ho3+ site, Ho3+ is bonded to six S2- atoms to form HoS6 octahedra that share corners with three HoS6 octahedra, a cornercorner with one HoS7 pentagonal bipyramid, a cornercorner with one PbS7 pentagonal bipyramid, edges with five HoS6 octahedra, and edges with two CuS4 tetrahedra. The corner-sharing octahedra tilt angles range from 2–39°. There are a spread of Ho–S bond distances ranging from 2.71–2.75 Å. In the third Ho3+ site, Ho3+ is bonded to six S2- atoms to form HoS6 octahedra that share corners with three HoS6 octahedra, a cornercorner with one PbS7 pentagonal bipyramid, edges with five HoS6 octahedra, and edges with two CuS4 tetrahedra. The corner-sharing octahedra tilt angles range from 2–38°. There are a spread of Ho–S bond distances ranging from 2.70–2.77 Å. In the fourth Ho3+ site, Ho3+ is bonded to six S2- atoms to form HoS6 octahedra that share corners with three HoS6 octahedra, a cornercorner with one HoS7 pentagonal bipyramid, edges with five HoS6 octahedra, and edges with two CuS4 tetrahedra. The corner-sharing octahedra tilt angles range from 7–38°. There are a spread of Ho–S bond distances ranging from 2.71–2.77 Å. In the fifth Ho3+ site, Ho3+ is bonded to six S2- atoms to form HoS6 octahedra that share corners with three HoS6 octahedra, edges with five HoS6 octahedra, and edges with two CuS4 tetrahedra. The corner-sharing octahedra tilt angles range from 6–40°. There are a spread of Ho–S bond distances ranging from 2.71–2.77 Å. In the sixth Ho3+ site, Ho3+ is bonded to six S2- atoms to form HoS6 octahedra that share corners with three HoS6 octahedra, edges with five HoS6 octahedra, and edges with two CuS4 tetrahedra. The corner-sharing octahedra tilt angles range from 2–41°. There are a spread of Ho–S bond distances ranging from 2.70–2.78 Å. In the seventh Ho3+ site, Ho3+ is bonded to six S2- atoms to form HoS6 octahedra that share corners with two HoS6 octahedra, a cornercorner with one PbS7 pentagonal bipyramid, edges with two HoS6 octahedra, an edgeedge with one HoS7 pentagonal bipyramid, edges with two PbS7 pentagonal bipyramids, and edges with two CuS4 tetrahedra. The corner-sharing octahedra tilt angles range from 41–48°. There are a spread of Ho–S bond distances ranging from 2.67–2.75 Å. In the eighth Ho3+ site, Ho3+ is bonded to six S2- atoms to form HoS6 octahedra that share corners with two HoS6 octahedra, a cornercorner with one HoS7 pentagonal bipyramid, edges with two HoS6 octahedra, an edgeedge with one HoS7 pentagonal bipyramid, an edgeedge with one PbS7 pentagonal bipyramid, and edges with two CuS4 tetrahedra. The corner-sharing octahedra tilt angles range from 38–63°. There are a spread of Ho–S bond distances ranging from 2.69–2.82 Å. In the ninth Ho3+ site, Ho3+ is bonded to six S2- atoms to form HoS6 octahedra that share corners with two HoS6 octahedra, a cornercorner with one HoS7 pentagonal bipyramid, a cornercorner with one PbS7 pentagonal bipyramid, edges with two HoS6 octahedra, edges with two PbS7 pentagonal bipyramids, and edges with two CuS4 tetrahedra. The corner-sharing octahedra tilt angles range from 40–50°. There are a spread of Ho–S bond distances ranging from 2.66–2.78 Å. In the tenth Ho3+ site, Ho3+ is bonded to six S2- atoms to form HoS6 octahedra that share corners with two HoS6 octahedra, edges with two HoS6 octahedra, an edgeedge with one HoS7 pentagonal bipyramid, and edges with two CuS4 tetrahedra. The corner-sharing octahedra tilt angles range from 41–55°. There are a spread of Ho–S bond distances ranging from 2.64–2.81 Å. In the eleventh Ho3+ site, Ho3+ is bonded to six S2- atoms to form HoS6 octahedra that share corners with two HoS6 octahedra, a cornercorner with one PbS7 pentagonal bipyramid, edges with two HoS6 octahedra, and edges with two CuS4 tetrahedra. The corner-sharing octahedra tilt angles range from 39–56°. There are a spread of Ho–S bond distances ranging from 2.64–2.80 Å. In the twelfth Ho3+ site, Ho3+ is bonded to six S2- atoms to form HoS6 octahedra that share corners with two HoS6 octahedra, a cornercorner with one PbS7 pentagonal bipyramid, edges with two HoS6 octahedra, an edgeedge with one PbS7 pentagonal bipyramid, and edges with two CuS4 tetrahedra. The corner-sharing octahedra tilt angles range from 38–57°. There are a spread of Ho–S bond distances ranging from 2.70–2.77 Å. In the thirteenth Ho3+ site, Ho3+ is bonded to six S2- atoms to form HoS6 octahedra that share corners with three HoS6 octahedra, corners with three PbS7 pentagonal bipyramids, a cornercorner with one CuS4 tetrahedra, edges with five HoS6 octahedra, and an edgeedge with one HoS7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 2–48°. There are a spread of Ho–S bond distances ranging from 2.68–2.77 Å. In the fourteenth Ho3+ site, Ho3+ is bonded to six S2- atoms to form HoS6 octahedra that share corners with three HoS6 octahedra, a cornercorner with one PbS7 pentagonal bipyramid, corners with two equivalent HoS7 pentagonal bipyramids, a cornercorner with one CuS4 tetrahedra, and edges with five HoS6 octahedra. The corner-sharing octahedra tilt angles range from 4–63°. There are a spread of Ho–S bond distances ranging from 2.69–2.83 Å. In the fifteenth Ho3+ site, Ho3+ is bonded to six S2- atoms to form HoS6 octahedra that share corners with three HoS6 octahedra, a cornercorner with one HoS7 pentagonal bipyramid, corners with two equivalent PbS7 pentagonal bipyramids, a cornercorner with one CuS4 tetrahedra, edges with five HoS6 octahedra, and an edgeedge with one PbS7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 2–50°. There are a spread of Ho–S bond distances ranging from 2.66–2.80 Å. In the sixteenth Ho3+ site, Ho3+ is bonded to six S2- atoms to form HoS6 octahedra that share corners with three HoS6 octahedra, a cornercorner with one HoS7 pentagonal bipyramid, a cornercorner with one CuS4 tetrahedra, and edges with five HoS6 octahedra. The corner-sharing octahedra tilt angles range from 7–55°. There are a spread of Ho–S bond distances ranging from 2.63–2.85 Å. In the seventeenth Ho3+ site, Ho3+ is bonded to six S2- atoms to form HoS6 octahedra that share corners with three HoS6 octahedra, a cornercorner with one PbS7 pentagonal bipyramid, a cornercorner with one CuS4 tetrahedra, and edges with five HoS6 octahedra. The corner-sharing octahedra tilt angles range from 7–56°. There are a spread of Ho–S bond distances ranging from 2.62–2.85 Å. In the eighteenth Ho3+ site, Ho3+ is bonded to six S2- atoms to form HoS6 octahedra that share corners with three HoS6 octahedra, a cornercorner with one PbS7 pentagonal bipyramid, a cornercorner with one CuS4 tetrahedra, edges with five HoS6 octahedra, and an edgeedge with one PbS7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 3–57°. There are a spread of Ho–S bond distances ranging from 2.69–2.81 Å. In the nineteenth Ho3+ site, Ho3+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Ho–S bond distances ranging from 2.63–3.23 Å. In the twentieth Ho3+ site, Ho3+ is bonded to seven S2- atoms to form distorted HoS7 pentagonal bipyramids that share corners with eight HoS6 octahedra, a cornercorner with one CuS4 tetrahedra, edges with four HoS6 octahedra, and a faceface with one PbS7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 23–70°. There are a spread of Ho–S bond distances ranging from 2.62–3.19 Å. There are six inequivalent Cu1+ sites. In the first Cu1+ site, Cu1+ is bonded to four S2- atoms to form CuS4 tetrahedra that share a cornercorner with one HoS6 octahedra, a cornercorner with one PbS7 pentagonal bipyramid, corners with two CuS4 tetrahedra, and edges with four HoS6 octahedra. The corner-sharing octahedral tilt angles are 10°. There are a spread of Cu–S bond distances ranging from 2.33–2.37 Å. In the second Cu1+ site, Cu1+ is bonded to four S2- atoms to form CuS4 tetrahedra that share a cornercorner with one HoS6 octahedra, corners with two CuS4 tetrahedra, and edges with four HoS6 octahedra. The corner-sharing octahedral tilt angles are 8°. There are a spread of Cu–S bond distances ranging from 2.29–2.37 Å. In the third Cu1+ site, Cu1+ is bonded to four S2- atoms to form CuS4 tetrahedra that share a cornercorner with one HoS6 octahedra, corners with two CuS4 tetrahedra, and edges with four HoS6 octahedra. The corner-sharing octahedral tilt angles are 10°. There are a spread of Cu–S bond distances ranging from 2.33–2.38 Å. In the fourth Cu1+ site, Cu1+ is bonded to four S2- atoms to form CuS4 tetrahedra that share a cornercorner with one HoS6 octahedra, corners with two CuS4 tetrahedra, and edges with four HoS6 octahedra. The corner-sharing octahedral tilt angles are 9°. There are one shorter (2.32 Å) and three longer (2.36 Å) Cu–S bond lengths. In the fifth Cu1+ site, Cu1+ is bonded to four S2- atoms to form CuS4 tetrahedra that share a cornercorner with one HoS6 octahedra, a cornercorner with one PbS7 pentagonal bipyramid, corners with two CuS4 tetrahedra, and edges with four HoS6 octahedra. The corner-sharing octahedral tilt angles are 10°. There are a spread of Cu–S bond distances ranging from 2.33–2.36 Å. In the sixth Cu1+ site, Cu1+ is bonded to four S2- atoms to form CuS4 tetrahedra that share a cornercorner with one HoS6 octahedra, a cornercorner with one HoS7 pentagonal bipyramid, corners with two CuS4 tetrahedra, and edges with four HoS6 octahedra. The corner-sharing octahedral tilt angles are 9°. There are one shorter (2.33 Å) and three longer (2.36 Å) Cu–S bond lengths. There are nine inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Pb–S bond distances ranging from 2.85–3.45 Å. In the second Pb2+ site, Pb2+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Pb–S bond distances ranging from 2.84–3.44 Å. In the third Pb2+ site, Pb2+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Pb–S bond distances ranging from 2.88–3.40 Å. In the fourth Pb2+ site, Pb2+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Pb–S bond distances ranging from 2.85–3.49 Å. In the fifth Pb2+ site, Pb2+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Pb–S bond distances ranging from 2.82–3.45 Å. In the sixth Pb2+ site, Pb2+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Pb–S bond distances ranging from 2.85–3.37 Å. In the seventh Pb2+ site, Pb2+ is bonded to seven S2- atoms to form distorted PbS7 pentagonal bipyramids that share corners with eight HoS6 octahedra, a cornercorner with one CuS4 tetrahedra, edges with four HoS6 octahedra, a faceface with one HoS7 pentagonal bipyramid, and a faceface with one PbS7 pentagonal bipyramid. The corner-sharing octahedra tilt angles range from 21–74°. There are a spread of Pb–S bond distances ranging from 2.84–3.24 Å. In the eighth Pb2+ site, Pb2+ is bonded in a 7-coordinate geometry to seven S2- atoms. There are a spread of Pb–S bond distances ranging from 2.83–3.24 Å. In the ninth Pb2+ site, Pb2+ is bonded to seven S2- atoms to form distorted PbS7 pentagonal bipyramids that share corners with eight HoS6 octahedra, a cornercorner with one CuS4 tetrahedra, edges with four HoS6 octahedra, and a faceface with one PbS7 pentagonal bipy

36 MATERIALS SCIENCE↗

Materials Data on K2HoSbO7 by Materials Project

K2HoSbO7 crystallizes in the orthorhombic Imm2 space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded to eight O atoms to form KO8 hexagonal bipyramids that share corners with two equivalent KO8 hexagonal bipyramids, corners with two equivalent SbO6 octahedra, edges with four equivalent KO8 hexagonal bipyramids, edges with two equivalent SbO6 octahedra, and edges with four equivalent HoO6 octahedra. The corner-sharing octahedral tilt angles are 51°. There are a spread of K–O bond distances ranging from 2.63–3.07 Å. In the second K site, K is bonded to eight O atoms to form distorted KO8 hexagonal bipyramids that share edges with six KO8 hexagonal bipyramids, edges with two equivalent HoO6 octahedra, and edges with four equivalent SbO6 octahedra. There are a spread of K–O bond distances ranging from 2.78–3.14 Å. Ho is bonded to six O atoms to form HoO6 octahedra that share corners with two equivalent HoO6 octahedra, corners with four equivalent SbO6 octahedra, and edges with six KO8 hexagonal bipyramids. The corner-sharing octahedra tilt angles range from 35–50°. There are a spread of Ho–O bond distances ranging from 2.23–2.26 Å. Sb is bonded to six O atoms to form SbO6 octahedra that share corners with two equivalent KO8 hexagonal bipyramids, corners with four equivalent HoO6 octahedra, and edges with six KO8 hexagonal bipyramids. The corner-sharing octahedral tilt angles are 35°. There is two shorter (1.96 Å) and four longer (2.00 Å) Sb–O bond length. There are six inequivalent O sites. In the first O site, O is bonded in a distorted rectangular see-saw-like geometry to three K and one Sb atom. In the second O site, O is bonded in a 2-coordinate geometry to two K, one Ho, and one Sb atom. In the third O site, O is bonded in a 2-coordinate geometry to two K, one Ho, and one Sb atom. In the fourth O site, O is bonded in a 2-coordinate geometry to two equivalent K and two equivalent Ho atoms. In the fifth O site, O is bonded in a distorted rectangular see-saw-like geometry to three K and one Sb atom. In the sixth O site, O is bonded in a 2-coordinate geometry to two equivalent K and two equivalent Ho atoms.

36 MATERIALS SCIENCE↗

Materials Data on Ho2Fe14B by Materials Project

Ho2Fe14B is beta Uranium-derived structured and crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. there are two inequivalent Ho sites. In the first Ho site, Ho is bonded in a 10-coordinate geometry to sixteen Fe atoms. There are a spread of Ho–Fe bond distances ranging from 2.98–3.19 Å. In the second Ho site, Ho is bonded in a 1-coordinate geometry to sixteen Fe and one B atom. There are a spread of Ho–Fe bond distances ranging from 3.03–3.35 Å. The Ho–B bond length is 2.86 Å. There are six inequivalent Fe sites. In the first Fe site, Fe is bonded in a distorted L-shaped geometry to two equivalent Ho, four Fe, and two equivalent B atoms. There are two shorter (2.49 Å) and two longer (2.73 Å) Fe–Fe bond lengths. Both Fe–B bond lengths are 2.06 Å. In the second Fe site, Fe is bonded to three Ho and nine Fe atoms to form distorted FeHo3Fe9 cuboctahedra that share corners with fourteen FeHo3Fe9 cuboctahedra, edges with three FeHo3Fe9 cuboctahedra, and faces with twelve FeHo2Fe10 cuboctahedra. There are a spread of Fe–Fe bond distances ranging from 2.36–2.77 Å. In the third Fe site, Fe is bonded in a distorted single-bond geometry to two Ho, seven Fe, and one B atom. There are a spread of Fe–Fe bond distances ranging from 2.44–2.72 Å. The Fe–B bond length is 2.06 Å. In the fourth Fe site, Fe is bonded to four Ho and eight Fe atoms to form a mixture of face and corner-sharing FeHo4Fe8 cuboctahedra. All Fe–Fe bond lengths are 2.43 Å. In the fifth Fe site, Fe is bonded in a 2-coordinate geometry to two Ho and twelve Fe atoms. There are two shorter (2.61 Å) and two longer (2.63 Å) Fe–Fe bond lengths. In the sixth Fe site, Fe is bonded to two Ho and ten Fe atoms to form a mixture of distorted face, edge, and corner-sharing FeHo2Fe10 cuboctahedra. There are two shorter (2.54 Å) and one longer (2.55 Å) Fe–Fe bond lengths. B is bonded in a 6-coordinate geometry to one Ho and six Fe atoms.

36 MATERIALS SCIENCE↗

Permanent Electride Magnets Induced by Quasi‐Atomic Non‐Nucleus‐Bound Electrons

Abstract Interstitial quasi‐atomic electrons (IQEs) in the quantized energy levels of positively charged cavities possess a substantial own magnetic moment and control the magnetism of crystalline electrides depending on the interaction with surrounding cations. However, weak spin‐orbit coupling and gentle exchange interaction restricted by the IQEs preclude a large magnetic anisotropic, remaining a challenge for a hard magnetism. It is reported that 2D [ Re 2 C] 2+ ·2e − electrides (Re = Er, Ho, Dy, and Tb) show the permanent magnetism in a ferrimagnetic ground state, mimicking the ferrites composed of magnetic sublattices with different spin polarizations. Magnetic interaction between Re‐spin lattice and IQE‐spin lattice in the [ Re 2 C] 2+ ·2e − electrides results in a large magnetocrystalline anisotropy and high coercivity, giving a maximum energy product of 15 MGOe. It is demonstrated that the spontaneous breaking of magnetic IQE‐sublattice through substitution with paramagnetic elements produces a crossover into an antiferromagnetic spin ordering of Re‐sublattice, implying that the magnetic sublattice of IQEs drives the permanent magnetism.

Hwang, Jeong Yun [Department of Materials Science ↗

Materials Data on Ho2Fe14C by Materials Project

Ho2Fe14C crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. there are two inequivalent Ho sites. In the first Ho site, Ho is bonded in a 6-coordinate geometry to sixteen Fe atoms. There are a spread of Ho–Fe bond distances ranging from 2.95–3.23 Å. In the second Ho site, Ho is bonded in a 1-coordinate geometry to sixteen Fe and one C atom. There are a spread of Ho–Fe bond distances ranging from 2.99–3.35 Å. The Ho–C bond length is 2.82 Å. There are six inequivalent Fe sites. In the first Fe site, Fe is bonded to three Ho and nine Fe atoms to form distorted FeHo3Fe9 cuboctahedra that share corners with fourteen FeHo3Fe9 cuboctahedra, edges with three FeHo2Fe10 cuboctahedra, and faces with twelve FeHo3Fe9 cuboctahedra. There are a spread of Fe–Fe bond distances ranging from 2.36–2.74 Å. In the second Fe site, Fe is bonded in a single-bond geometry to two Ho, seven Fe, and one C atom. There are a spread of Fe–Fe bond distances ranging from 2.46–2.73 Å. The Fe–C bond length is 1.98 Å. In the third Fe site, Fe is bonded in a 2-coordinate geometry to two Ho and twelve Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.60–2.78 Å. In the fourth Fe site, Fe is bonded to two Ho and ten Fe atoms to form a mixture of distorted corner, edge, and face-sharing FeHo2Fe10 cuboctahedra. There are a spread of Fe–Fe bond distances ranging from 2.41–2.56 Å. In the fifth Fe site, Fe is bonded to four Ho and eight Fe atoms to form a mixture of distorted corner and face-sharing FeHo4Fe8 cuboctahedra. In the sixth Fe site, Fe is bonded in a water-like geometry to two equivalent Ho, four Fe, and two equivalent C atoms. Both Fe–C bond lengths are 2.02 Å. C is bonded in a 6-coordinate geometry to one Ho and six Fe atoms.

36 MATERIALS SCIENCE↗

Developing Accelerated Test Protocols and Tuning Microstructures of the Common Materials to Improve Robustness, Reliability, and Endurance of SOFC Cells

This work is built on our prior work where we found that phase transformation in praseodymium nickelates, e.g. Pr 2 NiO 4 (PNO) and (Pr 1-x Nd x ) 2 NiO 4 (PNNO), can be electrochemically driven, and is substantially faster when compared to thermal annealing studies. The first task aims at an attempt to further accelerate the phase transformation in the oxygen electrode by alternating the current input in the cells, which lead to the development of accelerated test protocols (ATPs). ATPs showed up to 60x faster phase transformation and up to 10x faster performance degradation in (Pr 0.50 Nd 0.50 ) 2 NiO 4 electrodes, when compared to long-term operation under constant current density. Furthermore, the phase stable Nd 2 NiO 4 and (La 0.6 Sr 0.4 )(Co 0.8 Fe 0.2 )O 3 (LSCF6482) electrodes were tested in full cells under ATPs, and showed up to 10x faster performance degradation within 1,100 hours in a comparison with long-term thermal annealing studies and electrochemical operation under constant current density. The second task aims at the quantification of the contributions of cell components to the total impedance of a solid oxide fuel cell (SOFC) using electrochemical impedance spectroscopy (EIS) and distribution of relaxation times (DRT). Specifically, the role of gas composition at both anode and cathode was systematically studied, aiming at deconvoluting, identifying and quantifying the contributions of different electrode processes. This was achieved by first tuning the partial pressure of H 2 at the anode and subsequently varying the partial pressure of O 2 at the cathode. The results suggest that, while DRT offers a viable way of deconvoluting different times distributions, additional attention is needed before assigning a peak to a specific electrode process due to the significant overlap of the contributions from the cathode and the anode. Density function theory studies show that both Pr-vacancies and O-defects play a key role on the activity and stability for nickelates towards oxygen reduction reaction. The resident O-interstitials and oxygen ions in the PrO layer form peroxide (O 2 2- ) nearby Pr vacancies. The O 2 2- limits oxygen-ion transport due to the required additional energy to break its O-O bond. We further calculated the formation and segregation energies for different Ln ions (La, Pr, Nd, Pm, Sm, Gd, Tb, Dy, and Ho) in PNO and CeO 2 (111) surfaces. In addition to Nd, Pm and La are suggested as potential dopants in PNO to enhance it stability without decomposition due to their more negative formation energies, lower diffusion energies, and positive separation energies.

01 COAL, LIGNITE, AND PEAT↗

Injection-seeded operation of a Q-switched Cr,Tm,Ho:YAG laser

Single-frequency Tm,Ho:YAG lasers operating near 2 microns are attractive sources for several applications including eye-safe laser radar (lidar) and pumping of AgGaSe2 parametric oscillators for efficient generation of longer wavelengths. As part of a program to develop a coherent lidar system using Tm,Ho:YAG lasers, a diode laser-pumped tunable CW single-longitudinal-mode (SLM) Cr:Tm:Ho:YAG laser and a flashlamp-pumped single-transverse-mode Q-switched Cr,Tm,Ho:YAG laser were developed. The CW laser was used to injection-seed the flashlamp-pumped laser, resulting in SLM Q-switched output. Operational characteristics of the CW and Q-switched lasers and injection-seeding results are reported.

Henderson, Sammy W.↗

Materials Data on NdHoFe14B by Materials Project

HoNdFe14B crystallizes in the tetragonal P4_2/mnm space group. The structure is three-dimensional. Ho is bonded in a 1-coordinate geometry to one Ho, two equivalent Nd, sixteen Fe, and one B atom. The Ho–Ho bond length is 3.59 Å. Both Ho–Nd bond lengths are 3.75 Å. There are a spread of Ho–Fe bond distances ranging from 3.01–3.35 Å. The Ho–B bond length is 2.86 Å. Nd is bonded in a 6-coordinate geometry to two equivalent Ho, sixteen Fe, and two equivalent B atoms. There are a spread of Nd–Fe bond distances ranging from 3.02–3.21 Å. Both Nd–B bond lengths are 3.26 Å. There are six inequivalent Fe sites. In the first Fe site, Fe is bonded in a distorted single-bond geometry to one Ho, one Nd, seven Fe, and one B atom. There are a spread of Fe–Fe bond distances ranging from 2.43–2.73 Å. The Fe–B bond length is 2.08 Å. In the second Fe site, Fe is bonded in a 2-coordinate geometry to one Ho, one Nd, and twelve Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.62–2.78 Å. In the third Fe site, Fe is bonded in a 12-coordinate geometry to two equivalent Ho, one Nd, and nine Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.37–2.50 Å. In the fourth Fe site, Fe is bonded in a distorted q6 geometry to one Ho, one Nd, and ten Fe atoms. There are a spread of Fe–Fe bond distances ranging from 2.45–2.53 Å. In the fifth Fe site, Fe is bonded in a distorted L-shaped geometry to two equivalent Nd, four Fe, and two equivalent B atoms. Both Fe–B bond lengths are 2.07 Å. In the sixth Fe site, Fe is bonded to two equivalent Ho, two equivalent Nd, and eight Fe atoms to form corner-sharing FeNd2Ho2Fe8 cuboctahedra. B is bonded in a 6-coordinate geometry to one Ho, two equivalent Nd, and six Fe atoms.

36 MATERIALS SCIENCE↗

Recent advances in polymeric facilitated transport membranes for carbon dioxide separation and hydrogen purification

Membrane and membrane process have been widely considered as one of the best candidates for mitigating CO 2 emissions from the combustion or utilization of fossil fuels. Various amine-containing polymers constitute an important class of membranes, where the highly selective CO 2 transport is achieved by the facilitated transport mechanism. In this review, the amine–CO 2 chemistry is discussed in conjunction with the mechanism of the reaction-mediated CO 2 transport. A wide variety of amine-containing polymers are discussed based on two synthesis motifs: (a) polyamines with amino groups covalently bound to the polymer backbone and (b) small molecule amines embedded in a polymer matrix. This review concludes with the remarks on the facilitated transport membranes for post-combustion carbon capture (CO 2 /N 2 ) and hydrogen purification (CO 2 /H 2 ).

42 ENGINEERING↗

Materials Data on Ho3(Ga2Cu)2 by Materials Project

Ho3(CuGa2)2 crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. there are six inequivalent Ho sites. In the first Ho site, Ho is bonded in a 12-coordinate geometry to three equivalent Cu and nine Ga atoms. All Ho–Cu bond lengths are 2.91 Å. There are a spread of Ho–Ga bond distances ranging from 3.00–3.35 Å. In the second Ho site, Ho is bonded in a 12-coordinate geometry to three equivalent Cu and nine Ga atoms. All Ho–Cu bond lengths are 2.91 Å. There are a spread of Ho–Ga bond distances ranging from 3.00–3.35 Å. In the third Ho site, Ho is bonded in a 12-coordinate geometry to six Cu and six Ga atoms. There are three shorter (2.94 Å) and three longer (3.12 Å) Ho–Cu bond lengths. There are three shorter (3.01 Å) and three longer (3.35 Å) Ho–Ga bond lengths. In the fourth Ho site, Ho is bonded in a 12-coordinate geometry to six Cu and six Ga atoms. There are three shorter (2.95 Å) and three longer (3.13 Å) Ho–Cu bond lengths. There are three shorter (3.00 Å) and three longer (3.36 Å) Ho–Ga bond lengths. In the fifth Ho site, Ho is bonded in a 12-coordinate geometry to three equivalent Cu and nine Ga atoms. All Ho–Cu bond lengths are 3.15 Å. There are a spread of Ho–Ga bond distances ranging from 2.97–3.33 Å. In the sixth Ho site, Ho is bonded in a 12-coordinate geometry to three equivalent Cu and nine Ga atoms. All Ho–Cu bond lengths are 3.16 Å. There are a spread of Ho–Ga bond distances ranging from 2.96–3.33 Å. There are four inequivalent Cu sites. In the first Cu site, Cu is bonded in a 10-coordinate geometry to six Ho and four Ga atoms. There are three shorter (2.51 Å) and one longer (3.17 Å) Cu–Ga bond lengths. In the second Cu site, Cu is bonded in a 10-coordinate geometry to six Ho and four Ga atoms. There are three shorter (2.52 Å) and one longer (3.17 Å) Cu–Ga bond lengths. In the third Cu site, Cu is bonded in a 9-coordinate geometry to six Ho, three equivalent Cu, and one Ga atom. All Cu–Cu bond lengths are 2.51 Å. The Cu–Ga bond length is 3.23 Å. In the fourth Cu site, Cu is bonded in a 9-coordinate geometry to six Ho, three equivalent Cu, and one Ga atom. The Cu–Ga bond length is 3.24 Å. There are eight inequivalent Ga sites. In the first Ga site, Ga is bonded in a 9-coordinate geometry to six Ho and three equivalent Cu atoms. In the second Ga site, Ga is bonded in a 9-coordinate geometry to six Ho and three equivalent Cu atoms. In the third Ga site, Ga is bonded in a 6-coordinate geometry to six Ho, one Cu, and three equivalent Ga atoms. All Ga–Ga bond lengths are 2.56 Å. In the fourth Ga site, Ga is bonded in a 9-coordinate geometry to six Ho and three equivalent Ga atoms. All Ga–Ga bond lengths are 2.56 Å. In the fifth Ga site, Ga is bonded in a 9-coordinate geometry to six Ho and three equivalent Ga atoms. All Ga–Ga bond lengths are 2.56 Å. In the sixth Ga site, Ga is bonded in a 10-coordinate geometry to six Ho, one Cu, and three equivalent Ga atoms. In the seventh Ga site, Ga is bonded in a 10-coordinate geometry to six Ho, one Cu, and three equivalent Ga atoms. In the eighth Ga site, Ga is bonded in a 10-coordinate geometry to six Ho, one Cu, and three equivalent Ga atoms.

36 MATERIALS SCIENCE↗

Materials Data on Ho2Zn17 by Materials Project

Ho2Zn17 crystallizes in the trigonal R-3m space group. The structure is three-dimensional. Ho is bonded in a 10-coordinate geometry to nineteen Zn atoms. There are a spread of Ho–Zn bond distances ranging from 3.10–3.45 Å. There are four inequivalent Zn sites. In the first Zn site, Zn is bonded to three equivalent Ho and nine Zn atoms to form distorted ZnHo3Zn9 cuboctahedra that share corners with twenty-three ZnHo2Zn10 cuboctahedra, edges with ten ZnHo2Zn10 cuboctahedra, and faces with twenty ZnHo3Zn9 cuboctahedra. There are a spread of Zn–Zn bond distances ranging from 2.54–2.86 Å. In the second Zn site, Zn is bonded in a 2-coordinate geometry to one Ho and thirteen Zn atoms. There are a spread of Zn–Zn bond distances ranging from 2.64–2.98 Å. In the third Zn site, Zn is bonded to two equivalent Ho and ten Zn atoms to form ZnHo2Zn10 cuboctahedra that share corners with twenty-two ZnHo2Zn10 cuboctahedra, edges with ten ZnHo2Zn10 cuboctahedra, and faces with eighteen ZnHo3Zn9 cuboctahedra. All Zn–Zn bond lengths are 2.59 Å. In the fourth Zn site, Zn is bonded to two equivalent Ho and ten Zn atoms to form distorted ZnHo2Zn10 cuboctahedra that share corners with twenty-four ZnHo2Zn10 cuboctahedra, edges with five ZnHo2Zn10 cuboctahedra, and faces with twenty-one ZnHo3Zn9 cuboctahedra. Both Zn–Zn bond lengths are 2.67 Å.

36 MATERIALS SCIENCE↗

Materials Data on Ho2P7Rh12 by Materials Project

Ho2Rh12P7 crystallizes in the trigonal P-3 space group. The structure is three-dimensional. Ho is bonded to six equivalent Rh and six equivalent P atoms to form distorted HoP6Rh6 cuboctahedra that share corners with twelve equivalent RhP4 tetrahedra, edges with three equivalent RhP4 tetrahedra, and faces with two equivalent HoP6Rh6 cuboctahedra. All Ho–Rh bond lengths are 3.03 Å. There are three shorter (3.01 Å) and three longer (3.02 Å) Ho–P bond lengths. There are two inequivalent Rh sites. In the first Rh site, Rh is bonded in a 2-coordinate geometry to two equivalent Ho and four equivalent P atoms. There are a spread of Rh–P bond distances ranging from 2.32–2.59 Å. In the second Rh site, Rh is bonded to four P atoms to form distorted RhP4 tetrahedra that share corners with four equivalent HoP6Rh6 cuboctahedra, corners with seven equivalent RhP4 tetrahedra, an edgeedge with one HoP6Rh6 cuboctahedra, and edges with two equivalent RhP4 tetrahedra. There are a spread of Rh–P bond distances ranging from 2.34–2.48 Å. There are two inequivalent P sites. In the first P site, P is bonded in a distorted octahedral geometry to six equivalent Rh atoms. In the second P site, P is bonded in a 9-coordinate geometry to two equivalent Ho and seven Rh atoms.

36 MATERIALS SCIENCE↗

Materials Data on BaP2(HO)4 by Materials Project

Ba(H2PO2)2 crystallizes in the orthorhombic Ccce space group. The structure is two-dimensional and consists of two Ba(H2PO2)2 sheets oriented in the (0, 1, 0) direction. Ba2+ is bonded in a 8-coordinate geometry to eight equivalent O2- atoms. There are four shorter (2.82 Å) and four longer (2.83 Å) Ba–O bond lengths. P1+ is bonded in a distorted tetrahedral geometry to two equivalent H1+ and two equivalent O2- atoms. Both P–H bond lengths are 1.42 Å. Both P–O bond lengths are 1.53 Å. H1+ is bonded in a single-bond geometry to one P1+ atom. O2- is bonded in a distorted single-bond geometry to two equivalent Ba2+ and one P1+ atom.

36 MATERIALS SCIENCE↗

Materials Data on Ho2Fe17H3 by Materials Project

Ho2Fe17H3 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Ho sites. In the first Ho site, Ho is bonded in a 3-coordinate geometry to eight Fe and three equivalent H atoms. There are two shorter (2.89 Å) and six longer (3.20 Å) Ho–Fe bond lengths. All Ho–H bond lengths are 2.50 Å. In the second Ho site, Ho is bonded in a trigonal planar geometry to three equivalent H atoms. All Ho–H bond lengths are 2.44 Å. There are four inequivalent Fe sites. In the first Fe site, Fe is bonded to two equivalent Ho and ten Fe atoms to form FeHo2Fe10 cuboctahedra that share corners with four equivalent FeHo2Fe10 cuboctahedra, corners with two equivalent HHo2Fe4 octahedra, faces with six equivalent FeHo2Fe10 cuboctahedra, and faces with four equivalent HHo2Fe4 octahedra. The corner-sharing octahedral tilt angles are 40°. There are a spread of Fe–Fe bond distances ranging from 2.43–2.61 Å. In the second Fe site, Fe is bonded in a single-bond geometry to four Fe and one H atom. Both Fe–Fe bond lengths are 2.73 Å. The Fe–H bond length is 1.82 Å. In the third Fe site, Fe is bonded in a 2-coordinate geometry to one Ho and thirteen Fe atoms. There are one shorter (2.38 Å) and three longer (2.66 Å) Fe–Fe bond lengths. In the fourth Fe site, Fe is bonded in a single-bond geometry to three Fe and one H atom. The Fe–H bond length is 1.90 Å. H is bonded to two Ho and four Fe atoms to form HHo2Fe4 octahedra that share corners with two equivalent FeHo2Fe10 cuboctahedra, corners with four equivalent HHo2Fe4 octahedra, and faces with four equivalent FeHo2Fe10 cuboctahedra. The corner-sharing octahedral tilt angles are 60°.

36 MATERIALS SCIENCE↗

Materials Data on Ho2Mn17C3 by Materials Project

Ho2Mn17C3 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are three inequivalent Ho sites. In the first Ho site, Ho is bonded in a distorted trigonal planar geometry to eight Mn and three equivalent C atoms. There are two shorter (3.00 Å) and six longer (3.23 Å) Ho–Mn bond lengths. All Ho–C bond lengths are 2.50 Å. In the second Ho site, Ho is bonded in a distorted trigonal planar geometry to eight Mn and three equivalent C atoms. There are two shorter (3.00 Å) and six longer (3.23 Å) Ho–Mn bond lengths. All Ho–C bond lengths are 2.50 Å. In the third Ho site, Ho is bonded in a trigonal planar geometry to three equivalent C atoms. All Ho–C bond lengths are 2.43 Å. There are four inequivalent Mn sites. In the first Mn site, Mn is bonded to two Ho and ten Mn atoms to form MnHo2Mn10 cuboctahedra that share corners with four equivalent MnHo2Mn10 cuboctahedra, corners with two equivalent CHo2Mn4 octahedra, faces with six equivalent MnHo2Mn10 cuboctahedra, and faces with four equivalent CHo2Mn4 octahedra. The corner-sharing octahedral tilt angles are 40°. There are a spread of Mn–Mn bond distances ranging from 2.44–2.63 Å. In the second Mn site, Mn is bonded in a single-bond geometry to four Mn and one C atom. Both Mn–Mn bond lengths are 2.66 Å. The Mn–C bond length is 1.88 Å. In the third Mn site, Mn is bonded in a 2-coordinate geometry to one Ho and thirteen Mn atoms. There are one shorter (2.32 Å) and three longer (2.64 Å) Mn–Mn bond lengths. In the fourth Mn site, Mn is bonded in a single-bond geometry to three Mn and one C atom. The Mn–C bond length is 1.90 Å. C is bonded to two Ho and four Mn atoms to form CHo2Mn4 octahedra that share corners with two equivalent MnHo2Mn10 cuboctahedra, corners with four equivalent CHo2Mn4 octahedra, and faces with four equivalent MnHo2Mn10 cuboctahedra. The corner-sharing octahedral tilt angles are 60°.

36 MATERIALS SCIENCE↗