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At least 505 records · Page 28

Materials Data on Cd3Si2Pb3O10 by Materials Project

Cd3Pb3Si2O10 crystallizes in the trigonal P3m1 space group. The structure is three-dimensional. Cd2+ is bonded to six O2- atoms to form distorted CdO6 octahedra that share corners with two equivalent CdO6 octahedra, corners with four SiO4 tetrahedra, and faces with two equivalent CdO6 octahedra. The corner-sharing octahedral tilt angles are 79°. There are a spread of Cd–O bond distances ranging from 2.37–2.62 Å. Pb2+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Pb–O bond distances ranging from 2.48–2.63 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with six equivalent CdO6 octahedra. The corner-sharing octahedra tilt angles range from 49–63°. There is three shorter (1.66 Å) and one longer (1.69 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with six equivalent CdO6 octahedra. The corner-sharing octahedral tilt angles are 51°. There is one shorter (1.63 Å) and three longer (1.67 Å) Si–O bond length. There are six inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Cd2+, two equivalent Pb2+, and one Si4+ atom. In the second O2- site, O2- is bonded to three equivalent Cd2+ and three equivalent Pb2+ atoms to form OCd3Pb3 octahedra that share corners with three equivalent OCd3Si tetrahedra and faces with two equivalent OCd3Pb3 octahedra. In the third O2- site, O2- is bonded to three equivalent Cd2+ and one Si4+ atom to form distorted corner-sharing OCd3Si tetrahedra. The corner-sharing octahedra tilt angles range from 8–64°. In the fourth O2- site, O2- is bonded to three equivalent Cd2+ and three equivalent Pb2+ atoms to form OCd3Pb3 octahedra that share corners with three equivalent OCd3Si tetrahedra and faces with two equivalent OCd3Pb3 octahedra. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to three equivalent Pb2+ and one Si4+ atom. In the sixth O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent Cd2+, one Pb2+, and one Si4+ atom.

36 MATERIALS SCIENCE↗

Synthesis, Crystal and Electronic Structure of Layered AM Sb Compounds ( A = Rb, Cs; M = Zn, Cd): Synthesis, Crystal and Electronic Structure of Layered AM Sb Compounds ( A = Rb, Cs; M = Zn, Cd)

Synthesis, crystal structure, thermal stability, and electronic band structure of four new metal antimonides AMSb (A = Rb, Cs; M = Zn, Cd) are reported. CsZnSb and RbZnSb crystallize in the hexagonal ZrBeSi structure type, in a P6 3 /mmc space group (no. 194, Z = 2) and unit cell dimensions of a = 4.5588(2)/4.5466(4) Å and c = 11.9246(6)/11.0999(10) Å. CsCdSb and RbCdSb crystallize in the tetragonal PbFCl structure type in a P4/nmm space group (no. 129; Z = 2) and unit cell parameters of a = 4.8884(5)/4.8227(3) Å and c = 8.8897(9)/8.5492(7) Å. All four compounds are air- and water-sensitive and are shown through DSC measurements to decompose between 975 K and 1060 K. Analysis of the calculated electronic band structure shows that the Zn-containing antimonides are topologically trivial narrow bandgap semiconductors, whereas Cd-containing compounds exhibit a band inversion along Γ-Z direction.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗

The solution structures of higher-order human telomere G-quadruplex multimers

Human telomeres contain the repeat DNA sequence 5'-d(TTAGGG), with duplex regions that are several kilobases long terminating in a 3' single-stranded overhang. The structure of the single-stranded overhang is not known with certainty, with disparate models proposed in the literature. We report here the results of an integrated structural biology approach that combines small-angle X-ray scattering, circular dichroism (CD), analytical ultracentrifugation, size-exclusion column chromatography and molecular dynamics simulations that provide the most detailed characterization to date of the structure of the telomeric overhang. We find that the single-stranded sequences 5'-d(TTAGGG)n, with n = 8, 12 and 16, fold into multimeric structures containing the maximal number (2, 3 and 4, respectively) of contiguous G4 units with no long gaps between units. The G4 units are a mixture of hybrid-1 and hybrid-2 conformers. In the multimeric structures, G4 units interact, at least transiently, at the interfaces between units to produce distinctive CD signatures. Global fitting of our hydrodynamic and scattering data to a worm-like chain (WLC) model indicates that these multimeric G4 structures are semi-flexible, with a persistence length of ~34 Å. Investigations of its flexibility using MD simulations reveal stacking, unstacking, and coiling movements, which yield unique sites for drug targeting.

59 BASIC BIOLOGICAL SCIENCES↗

Materials Data on RbCdC3(SN)3 by Materials Project

RbCdC3(NS)3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Rb1+ is bonded in a 8-coordinate geometry to three N3- and five S2- atoms. There are a spread of Rb–N bond distances ranging from 3.02–3.36 Å. There are a spread of Rb–S bond distances ranging from 3.56–3.78 Å. There are two inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded in an octahedral geometry to four N3- and two equivalent S2- atoms. There are two shorter (2.32 Å) and two longer (2.35 Å) Cd–N bond lengths. Both Cd–S bond lengths are 2.78 Å. In the second Cd2+ site, Cd2+ is bonded in an octahedral geometry to two equivalent N3- and four S2- atoms. Both Cd–N bond lengths are 2.33 Å. There are two shorter (2.75 Å) and two longer (2.80 Å) Cd–S bond lengths. There are three inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a distorted linear geometry to one N3- and one S2- atom. The C–N bond length is 1.19 Å. The C–S bond length is 1.63 Å. In the second C4+ site, C4+ is bonded in a distorted linear geometry to one N3- and one S2- atom. The C–N bond length is 1.19 Å. The C–S bond length is 1.63 Å. In the third C4+ site, C4+ is bonded in a distorted linear geometry to one N3- and one S2- atom. The C–N bond length is 1.18 Å. The C–S bond length is 1.64 Å. There are three inequivalent N3- sites. In the first N3- site, N3- is bonded in a 3-coordinate geometry to one Rb1+, one Cd2+, and one C4+ atom. In the second N3- site, N3- is bonded in a distorted bent 150 degrees geometry to one Rb1+, one Cd2+, and one C4+ atom. In the third N3- site, N3- is bonded in a 2-coordinate geometry to one Rb1+, one Cd2+, and one C4+ atom. There are three inequivalent S2- sites. In the first S2- site, S2- is bonded in a 2-coordinate geometry to two equivalent Rb1+, one Cd2+, and one C4+ atom. In the second S2- site, S2- is bonded in a 2-coordinate geometry to one Rb1+, one Cd2+, and one C4+ atom. In the third S2- site, S2- is bonded in a 4-coordinate geometry to two equivalent Rb1+, one Cd2+, and one C4+ atom.

36 MATERIALS SCIENCE↗

Materials Data on YMg14CdO16 by Materials Project

Mg14YCdO16 is alpha Po-derived structured and crystallizes in the orthorhombic Pmmm space group. The structure is three-dimensional. there are seven inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent YO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.10–2.20 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent CdO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 1.99–2.25 Å. In the third Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent YO6 octahedra, edges with two equivalent CdO6 octahedra, and edges with eight MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are a spread of Mg–O bond distances ranging from 2.12–2.31 Å. In the fourth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Mg–O bond distances ranging from 2.19–2.24 Å. In the fifth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent YO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are a spread of Mg–O bond distances ranging from 2.07–2.30 Å. In the sixth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, edges with two equivalent CdO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are a spread of Mg–O bond distances ranging from 2.14–2.24 Å. In the seventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six equivalent MgO6 octahedra, an edgeedge with one YO6 octahedra, an edgeedge with one CdO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–6°. There are a spread of Mg–O bond distances ranging from 2.11–2.28 Å. Y is bonded to six O atoms to form YO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with two equivalent YO6 octahedra, corners with two equivalent CdO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Y–O bond distances ranging from 2.16–2.28 Å. Cd is bonded to six O atoms to form CdO6 octahedra that share corners with two equivalent MgO6 octahedra, corners with two equivalent YO6 octahedra, corners with two equivalent CdO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Cd–O bond distances ranging from 2.20–2.38 Å. There are ten inequivalent O sites. In the first O site, O is bonded to five Mg and one Y atom to form OYMg5 octahedra that share corners with six OYMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the second O site, O is bonded to five Mg and one Cd atom to form OMg5Cd octahedra that share corners with six OYMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. In the third O site, O is bonded to five Mg and one Cd atom to form OMg5Cd octahedra that share corners with six OYMg5 octahedra and edges with twelve OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. There are two shorter (2.16 Å) and two longer (2.20 Å) O–Mg bond lengths. In the fourth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra and edges with twelve OYMg5 octahedra. The corner-sharing octahedra tilt angles range from 2–6°. In the fifth O site, O is bonded to four Mg and two equivalent Y atoms to form OY2Mg4 octahedra that share corners with six OY2Mg4 octahedra and edges with twelve OYMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the sixth O site, O is bonded to four Mg and two equivalent Cd atoms to form OMg4Cd2 octahedra that share corners with six OY2Mg4 octahedra and edges with twelve OMg5Cd octahedra. The corner-sharing octahedral tilt angles are 0°. In the seventh O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OY2Mg4 octahedra and edges with twelve OYMg5 octahedra. The corner-sharing octahedral tilt angles are 0°. In the eighth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OMg4Cd2 octahedra and edges with twelve OMg5Cd octahedra. The corner-sharing octahedral tilt angles are 0°. In the ninth O site, O is bonded to four Mg, one Y, and one Cd atom to form OYMg4Cd octahedra that share corners with six OYMg4Cd octahedra and edges with twelve OYMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–8°. In the tenth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OYMg4Cd octahedra and edges with twelve OYMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–6°.

36 MATERIALS SCIENCE↗

Materials Data on HfMg30CdO32 by Materials Project

Mg30HfCdO32 is Molybdenum Carbide MAX Phase-derived structured and crystallizes in the tetragonal P4/mmm space group. The structure is three-dimensional. there are eight inequivalent Mg sites. In the first Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent CdO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 1.94–2.25 Å. In the second Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with two equivalent HfO6 octahedra, corners with four MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are a spread of Mg–O bond distances ranging from 2.11–2.20 Å. In the third Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are four shorter (2.12 Å) and two longer (2.21 Å) Mg–O bond lengths. In the fourth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.15 Å) and four longer (2.16 Å) Mg–O bond lengths. In the fifth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one HfO6 octahedra, an edgeedge with one CdO6 octahedra, and edges with ten MgO6 octahedra. The corner-sharing octahedra tilt angles range from 4–13°. There are a spread of Mg–O bond distances ranging from 2.10–2.25 Å. In the sixth Mg site, Mg is bonded to six O atoms to form a mixture of edge and corner-sharing MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–4°. There are a spread of Mg–O bond distances ranging from 2.15–2.19 Å. In the seventh Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one CdO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 1–11°. There are a spread of Mg–O bond distances ranging from 2.14–2.20 Å. In the eighth Mg site, Mg is bonded to six O atoms to form MgO6 octahedra that share corners with six MgO6 octahedra, an edgeedge with one HfO6 octahedra, and edges with eleven MgO6 octahedra. The corner-sharing octahedra tilt angles range from 3–5°. There are a spread of Mg–O bond distances ranging from 2.10–2.22 Å. Hf is bonded to six O atoms to form HfO6 octahedra that share corners with two equivalent CdO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.00 Å) and four longer (2.12 Å) Hf–O bond lengths. Cd is bonded to six O atoms to form CdO6 octahedra that share corners with two equivalent HfO6 octahedra, corners with four equivalent MgO6 octahedra, and edges with twelve MgO6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.36 Å) and four longer (2.38 Å) Cd–O bond lengths. There are eleven inequivalent O sites. In the first O site, O is bonded to five Mg and one Cd atom to form OMg5Cd octahedra that share corners with six OHfMg5 octahedra and edges with twelve OMg5Cd octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the second O site, O is bonded to five Mg and one Hf atom to form OHfMg5 octahedra that share corners with six OMg5Cd octahedra and edges with twelve OHfMg5 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the third O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–6°. In the fourth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. Both O–Mg bond lengths are 2.19 Å. In the fifth O site, O is bonded to five Mg and one Cd atom to form a mixture of edge and corner-sharing OMg5Cd octahedra. The corner-sharing octahedra tilt angles range from 0–6°. There are a spread of O–Mg bond distances ranging from 1.94–2.19 Å. In the sixth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. There are two shorter (2.10 Å) and two longer (2.19 Å) O–Mg bond lengths. In the seventh O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six equivalent OMg6 octahedra and edges with twelve OMg5Cd octahedra. The corner-sharing octahedra tilt angles range from 1–6°. In the eighth O site, O is bonded to four equivalent Mg, one Hf, and one Cd atom to form OHfMg4Cd octahedra that share corners with six OHfMg4Cd octahedra and edges with twelve OMg5Cd octahedra. The corner-sharing octahedra tilt angles range from 0–10°. In the ninth O site, O is bonded to six Mg atoms to form OMg6 octahedra that share corners with six OHfMg4Cd octahedra and edges with twelve OMg5Cd octahedra. The corner-sharing octahedra tilt angles range from 0–10°. In the tenth O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. In the eleventh O site, O is bonded to six Mg atoms to form a mixture of edge and corner-sharing OMg6 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. The O–Mg bond length is 2.16 Å.

36 MATERIALS SCIENCE↗

The Specific Carbohydrate Diet and Diet Modification as Induction Therapy for Pediatric Crohn’s Disease: A Randomized Diet Controlled Trial

Background: Crohn’s disease (CD) is a chronic inflammatory intestinal disorder associated with intestinal dysbiosis. Diet modulates the intestinal microbiome and therefore has a therapeutic potential. The aim of this study is to determine the potential efficacy of three versions of the specific carbohydrate diet (SCD) in active Crohn’s Disease. Methods: 18 patients with mild/moderate CD (PCDAI 15–45) aged 7 to 18 years were enrolled. Patients were randomized to either SCD, modified SCD(MSCD) or whole foods (WF) diet. Patients were evaluated at baseline, 2, 4, 8 and 12 weeks. PCDAI, inflammatory labs and multi-omics evaluations were assessed. Results: Mean age was 14.3 ± 2.9 years. At week 12, all participants (n = 10) who completed the study achieved clinical remission. The C-reactive protein decreased from 1.3 ± 0.7 at enrollment to 0.9 ± 0.5 at 12 weeks in the SCD group. In the MSCD group, the CRP decreased from 1.6 ± 1.1 at enrollment to 0.7 ± 0.1 at 12 weeks. In the WF group, the CRP decreased from 3.9 ± 4.3 at enrollment to 1.6 ± 1.3 at 12 weeks. In addition, the microbiome composition shifted in all patients across the study period. While the nature of the changes was largely patient specific, the predicted metabolic mode of the organisms increasing and decreasing in activity was consistent across patients. Conclusions: This study emphasizes the impact of diet in CD. Each diet had a positive effect on symptoms and inflammatory burden; the more exclusionary diets were associated with a better resolution of inflammation.

60 APPLIED LIFE SCIENCES↗

Assessment of Clonal Expansion Using CarcSeq Measurement of Lung Cancer Driver Mutations and Correlation With Mouse Strain- and Sex-Related Incidence of Spontaneous Lung Neoplasia

Quantification of variation in levels of spontaneously occurring cancer driver mutations (CDMs) was developed to assess clonal expansion and predict future risk of neoplasm development. Specifically, an error-corrected next-generation sequencing method, CarcSeq, and a mouse CarcSeq panel (analogous to human and rat panels) were developed and used to quantify low-frequency mutations in a panel of amplicons enriched in hotspot CDMs. Mutations in a subset of panel amplicons, Braf, Egfr, Kras, Stk11, and Tp53, were related to incidence of lung neoplasms at 2 years. This was achieved by correlating median absolute deviation (MAD) from the overall median mutant fraction (MF) measured in the lung DNA of 16-week-old male and female, B6C3F1 and CD-1 mice (10 mice/sex/strain) with percentages of spontaneous alveolar/bronchioloalveolar adenomas and carcinomas reported in bioassay control groups. A total of 1586 mouse lung mutants with MFs > x 10-4 were recovered. The ratio of nonsynonymous to synonymous mutations was used to assess the proportion of recovered mutations conferring a positive selective advantage. The greatest ratio was observed in what is considered the most lung tumor-sensitive model examined, male B6C3F1 mice. Of the recurrent, nonsynonymous mouse mutations recovered, 55.5% have been reported in human tumors, with many located in or around the mouse equivalent of human cancer hotspot codons. MAD for the same subset of amplicons measured in normal human lung DNA samples showed a correlation of moderate strength and borderline significance with age (a cancer risk factor), as well as age-related cumulative lung cancer risk, suggesting MAD may inform species extrapolation.

Toxicology↗

Test summary for advanced H2 cycle NI-CD cell

To improve operational tolerances and mass, the H2 gas recombination design provisions of the Ni-H2 system were incorporated into the sealed Ni-Cd system. Produced is a cell design capable of operating on the H2 cycle versus the normal O2 cycle. Three test cells have now completed approximately 4,330 LEO (90 minute) cycles at 20 percent depth of discharge (DOD). Performance remains stable although one cell exhibited a temporary pressure anomaly.

Miller, Lee↗

Materials Data on Tl2(CdSb)3 by Materials Project

Tl2(CdSb)3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded to four Sb+2.67- atoms to form a mixture of distorted edge and corner-sharing CdSb4 tetrahedra. There are a spread of Cd–Sb bond distances ranging from 2.89–3.23 Å. In the second Cd2+ site, Cd2+ is bonded to two equivalent Tl1+ and four Sb+2.67- atoms to form a mixture of distorted edge and corner-sharing CdTl2Sb4 tetrahedra. Both Cd–Tl bond lengths are 3.36 Å. There are a spread of Cd–Sb bond distances ranging from 2.91–3.00 Å. In the third Cd2+ site, Cd2+ is bonded to four Sb+2.67- atoms to form corner-sharing CdSb4 tetrahedra. There are a spread of Cd–Sb bond distances ranging from 2.91–3.02 Å. There are two inequivalent Tl1+ sites. In the first Tl1+ site, Tl1+ is bonded in a 6-coordinate geometry to two equivalent Cd2+, two equivalent Tl1+, and two equivalent Sb+2.67- atoms. Both Tl–Tl bond lengths are 3.73 Å. Both Tl–Sb bond lengths are 3.51 Å. In the second Tl1+ site, Tl1+ is bonded in a 3-coordinate geometry to three Sb+2.67- atoms. There are two shorter (3.43 Å) and one longer (3.51 Å) Tl–Sb bond lengths. There are three inequivalent Sb+2.67- sites. In the first Sb+2.67- site, Sb+2.67- is bonded in a 4-coordinate geometry to four Cd2+ and three Tl1+ atoms. In the second Sb+2.67- site, Sb+2.67- is bonded in a 7-coordinate geometry to five Cd2+ and two equivalent Tl1+ atoms. In the third Sb+2.67- site, Sb+2.67- is bonded in a 4-coordinate geometry to three Cd2+ and one Sb+2.67- atom. The Sb–Sb bond length is 2.87 Å.

36 MATERIALS SCIENCE↗

Materials Data on Cd4SF6 by Materials Project

Cd4SF6 crystallizes in the tetragonal P4_2/nmc space group. The structure is three-dimensional. Cd2+ is bonded to one S2- and six F1- atoms to form a mixture of distorted edge and corner-sharing CdSF6 pentagonal bipyramids. The Cd–S bond length is 2.48 Å. There are a spread of Cd–F bond distances ranging from 2.31–2.64 Å. S2- is bonded to four equivalent Cd2+ atoms to form SCd4 tetrahedra that share corners with eight equivalent FCd4 tetrahedra. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a 4-coordinate geometry to four equivalent Cd2+ atoms. In the second F1- site, F1- is bonded to four equivalent Cd2+ atoms to form FCd4 tetrahedra that share corners with four equivalent SCd4 tetrahedra and edges with two equivalent FCd4 tetrahedra.

36 MATERIALS SCIENCE↗

Materials Data on Li2MgCd by Materials Project

Li2MgCd crystallizes in the cubic F-43m space group. The structure is three-dimensional. there are two inequivalent Li sites. In the first Li site, Li is bonded in a 4-coordinate geometry to four equivalent Mg atoms. All Li–Mg bond lengths are 2.95 Å. In the second Li site, Li is bonded to four equivalent Cd atoms to form distorted corner-sharing LiCd4 tetrahedra. All Li–Cd bond lengths are 2.95 Å. Mg is bonded in a body-centered cubic geometry to four equivalent Li and four equivalent Cd atoms. All Mg–Cd bond lengths are 2.95 Å. Cd is bonded in a body-centered cubic geometry to four equivalent Li and four equivalent Mg atoms.

36 MATERIALS SCIENCE↗

Materials Data on CdTe(Pb3O5)2 by Materials Project

Pb6CdTeO10 crystallizes in the orthorhombic C222_1 space group. The structure is three-dimensional. Cd2+ is bonded to six O2- atoms to form distorted CdO6 pentagonal pyramids that share edges with two equivalent PbO6 octahedra and edges with two equivalent TeO6 octahedra. There are a spread of Cd–O bond distances ranging from 2.27–2.51 Å. There are four inequivalent Pb2+ sites. In the first Pb2+ site, Pb2+ is bonded in a 2-coordinate geometry to five O2- atoms. There are a spread of Pb–O bond distances ranging from 2.27–2.97 Å. In the second Pb2+ site, Pb2+ is bonded in a 4-coordinate geometry to four O2- atoms. There are two shorter (2.23 Å) and two longer (2.55 Å) Pb–O bond lengths. In the third Pb2+ site, Pb2+ is bonded in a 5-coordinate geometry to five O2- atoms. There are a spread of Pb–O bond distances ranging from 2.26–2.91 Å. In the fourth Pb2+ site, Pb2+ is bonded to six O2- atoms to form distorted PbO6 octahedra that share an edgeedge with one TeO6 octahedra and edges with two equivalent CdO6 pentagonal pyramids. There are a spread of Pb–O bond distances ranging from 2.47–2.74 Å. Te6+ is bonded to six O2- atoms to form TeO6 octahedra that share an edgeedge with one PbO6 octahedra and edges with two equivalent CdO6 pentagonal pyramids. There is four shorter (1.97 Å) and two longer (2.01 Å) Te–O bond length. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to one Cd2+, three Pb2+, and one Te6+ atom. In the second O2- site, O2- is bonded to one Cd2+ and three Pb2+ atoms to form distorted corner-sharing OCdPb3 tetrahedra. In the third O2- site, O2- is bonded in a 4-coordinate geometry to three Pb2+ and one Te6+ atom. In the fourth O2- site, O2- is bonded in a 4-coordinate geometry to one Cd2+, two Pb2+, and one Te6+ atom. In the fifth O2- site, O2- is bonded to four Pb2+ atoms to form distorted corner-sharing OPb4 tetrahedra.

36 MATERIALS SCIENCE↗

Materials Data on NaAlCdF6 by Materials Project

NaCdAlF6 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Na1+ is bonded to six F1- atoms to form distorted NaF6 octahedra that share corners with two equivalent CdF7 hexagonal pyramids, corners with five equivalent AlF6 octahedra, edges with two equivalent CdF7 hexagonal pyramids, and edges with two equivalent NaF6 octahedra. The corner-sharing octahedra tilt angles range from 53–55°. There are a spread of Na–F bond distances ranging from 2.32–2.56 Å. Cd2+ is bonded to seven F1- atoms to form distorted CdF7 hexagonal pyramids that share corners with two equivalent NaF6 octahedra, corners with two equivalent AlF6 octahedra, edges with four equivalent CdF7 hexagonal pyramids, an edgeedge with one AlF6 octahedra, and edges with two equivalent NaF6 octahedra. The corner-sharing octahedra tilt angles range from 51–53°. There are a spread of Cd–F bond distances ranging from 2.29–2.35 Å. Al3+ is bonded to six F1- atoms to form AlF6 octahedra that share corners with two equivalent CdF7 hexagonal pyramids, corners with two equivalent AlF6 octahedra, corners with five equivalent NaF6 octahedra, and an edgeedge with one CdF7 hexagonal pyramid. The corner-sharing octahedra tilt angles range from 4–55°. There are a spread of Al–F bond distances ranging from 1.78–1.85 Å. There are six inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted trigonal planar geometry to two equivalent Cd2+ and one Al3+ atom. In the second F1- site, F1- is bonded to one Na1+ and three equivalent Cd2+ atoms to form a mixture of edge and corner-sharing FNaCd3 tetrahedra. In the third F1- site, F1- is bonded in a distorted trigonal planar geometry to two equivalent Na1+ and one Al3+ atom. In the fourth F1- site, F1- is bonded in a distorted trigonal planar geometry to one Na1+, one Cd2+, and one Al3+ atom. In the fifth F1- site, F1- is bonded in a 4-coordinate geometry to two equivalent Na1+, one Cd2+, and one Al3+ atom. In the sixth F1- site, F1- is bonded in a linear geometry to two equivalent Al3+ atoms.

36 MATERIALS SCIENCE↗

Molecular Coatings Improve the Selectivity and Durability of CO 2 Reduction Chalcogenide Photocathodes

The quest for solar-driven conversion of carbon dioxide to chemicals and fuels hinges upon the identification of an efficient, durable, and selective photocathode. Chalcogenide p-type semiconductors exemplified by chalcopyrite Cu(In,Ga)Se 2 (CIGS) have been effectively deployed as photocathodes. However, selectivity toward CO 2 reduction and durability of the commonly used CdS adlayer remain primary challenges. Here, we demonstrate that for the wide band gap CuGa 3 Se 5 chalcopyrite absorber these challenges are well addressed by an organic coating generated in situ from an N,N'-(1,4-phenylene)bispyridinium ditriflate salt in the electrolyte. The molecular additive provides a 30-fold increase in selectivity toward CO2R products compared to the unmodified system and lowers Cd corrosion at least 10-fold. This dual functionality highlights the promise of hybrid solid-state-molecular photocathodes for enabling durable and efficient solar fuel systems.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

Impact of dopant-induced optoelectronic tails on open-circuit voltage in arsenic-doped Cd(Se)Te solar cells

Fluctuations refer to inhomogeneity in the distribution of donors and acceptors at the nanometer scale and occur in many compound solar cell materials such as Cu(In,Ga)Se 2 , Cu 2 ZnSn(S,Se) 4 , and CdSe x Te 1-x . In this work, numerical simulations show that these fluctuations produce not only electrostatic potential variation, but also, local changes in the carrier density and effective bandgap. For a CdSe x Te 1-x absorber doped with arsenic, simulations and cathodoluminescence data within single grains demonstrate how donor and acceptor densities—consistent with capacitance-voltage and secondary-ion mass-spectrometry data—produce tails in photoluminescence, quantum efficiency, and absorption measurements. Using multiple theoretical approaches, we demonstrate that the fluctuations can hinder expected performance gains from increased carrier density, and we describe the significant open-circuit voltage deficit observed in the CdSe x Te 1-x :As solar technology. Our results demonstrate that it is critical to characterize and reduce carrier compensation to realize a higher efficiency.

14 SOLAR ENERGY↗

Harnessing interpretable and unsupervised machine learning to address big data from modern X-ray diffraction

The information content of crystalline materials becomes astronomical when collective electronic behavior and their fluctuations are taken into account. In the past decade, improvements in source brightness and detector technology at modern X-ray facilities have allowed a dramatically increased fraction of this information to be captured. Now, the primary challenge is to understand and discover scientific principles from big datasets when a comprehensive analysis is beyond human reach. We report the development of an unsupervised machine learning approach, X-ray diffraction (XRD) temperature clustering (X-TEC), that can automatically extract charge density wave order parameters and detect intraunit cell ordering and its fluctuations from a series of high-volume X-ray diffraction measurements taken at multiple temperatures. We benchmark X-TEC with diffraction data on a quasi-skutterudite family of materials, (Ca x Sr 1–x ) 3 Rh 4 Sn 13 , where a quantum critical point is observed as a function of Ca concentration. We apply X-TEC to XRD data on the pyrochlore metal, Cd 2 Re 2 O 7 , to investigate its two much-debated structural phase transitions and uncover the Goldstone mode accompanying them. We demonstrate how unprecedented atomic-scale knowledge can be gained when human researchers connect the X-TEC results to physical principles. Specifically, we extract from the X-TEC–revealed selection rules that the Cd and Re displacements are approximately equal in amplitude but out of phase. This discovery reveals a previously unknown involvement of 5d 2 Re, supporting the idea of an electronic origin to the structural order. Our approach can radically transform XRD experiments by allowing in operando data analysis and enabling researchers to refine experiments by discovering interesting regions of phase space on the fly.

36 MATERIALS SCIENCE↗

Abundance of 17 trace elements in carbonaceous chondrites.

Seventeen trace elements (Ag, Au, Bi, Br, Cd, Cs, Ge, In, Ir, Rb, Re, Sb, Se, Te, Tl, U, and Zn) were measured by neutron activation analysis in eight C1 samples (1 Alais, 3 Ivuna, 4 Orgueil and in three C2 samples (one each of Mighei, Murchison, Murray). The results show far less scatter than earlier literature data. The standard deviation of a single measurement from the mean of eight C1 samples lies between 2 and 14%, except for the following four elements: Au, Ag, Rb, and Br. The first two probably reflect contamination and sample heterogeneity, the last two, analytical error. Apparently C1 chondrites have a far more uniform composition than some authors have claimed.

Kraehenbuehl, U.↗