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DOE OSTI2022

Simulation of ENSO Teleconnections to Precipitation Extremes over the United States in the High-Resolution Version of E3SM

Abstract We evaluate the simulated teleconnection of El Niño–Southern Oscillation (ENSO) to winter season precipitation extremes over the United States in a long (98 years) 1950 control high-resolution version (HR; 25-km nominal atmosphere model horizontal resolution) of the U.S. Department of Energy’s (DOE) Energy Exascale Earth System Model version 1 (E3SMv1). The model bias and spatial pattern of ENSO teleconnections to mean and extreme precipitation in HR overall are similar to the low-resolution model’s (LR; 110 km) historical simulation (four-member ensemble, 1925–59). However, over the southeastern United States (SE-U.S.), HR produces stronger El Niño–associated extremes, reducing LR’s model bias. Both LR and HR produce weaker than observed increase in storm track activity during El Niño events there, but HR improves the ENSO-associated variability of moisture transport over SE-U.S. During El Niño, stronger vertical velocities in HR produce stronger large-scale precipitation, causing larger latent heating of the troposphere that pulls in more moisture from the Gulf of Mexico into the SE-U.S. This positive feedback also contributes to the stronger mean and extreme precipitation response in HR. Over the Pacific Northwest, LR’s bias of stronger than observed La Niña associated extremes is amplified in HR. Both models simulate stronger than observed moisture transport from the Pacific Ocean into the region during La Niña years. The amplified HR bias there is due to stronger orographically driven vertical updrafts that create stronger large-scale precipitation, despite weaker La Niña–induced storm track activity. Significance Statement New high-resolution Earth system models (ESMs) solve mathematical equations of fluid flow at much smaller spatial scales than prevalent ESMs, and thus are prohibitively expensive to compute. However, they can be useful for simulating accurate details of regional climate extremes that are driven by naturally occurring climate oscillations like El Niño–Southern Oscillation (ENSO). Here, we evaluate the simulation of ENSO-driven precipitation extremes over the United States in the high-resolution version of the U.S. Department of Energy’s new Energy Exascale Earth System Model version 1. We find that the high-resolution model improves upon its low-resolution counterpart over the southeastern United States by producing a better transport of moisture into the region from the Gulf of Mexico during El Niño. Over the U.S. Pacific Northwest, the high-resolution model simulates the atmospheric flow in more detail over the complex mountainous terrain. However, it also brings in more moisture from the Pacific Ocean just like the low-resolution model. This causes it to produce precipitation extremes during La Niña years there that are stronger than that observed in the real world.

54 ENVIRONMENTAL SCIENCES↗

DOE OSTI2020

Materials Data on U2Se3 by Materials Project

U2Se3 is Stibnite structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent U3+ sites. In the first U3+ site, U3+ is bonded to seven Se2- atoms to form a mixture of distorted corner and edge-sharing USe7 pentagonal bipyramids. There are a spread of U–Se bond distances ranging from 2.88–2.92 Å. In the second U3+ site, U3+ is bonded in a 7-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.95–3.46 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to five U3+ atoms to form a mixture of distorted corner and edge-sharing SeU5 trigonal bipyramids. In the second Se2- site, Se2- is bonded to five U3+ atoms to form a mixture of distorted corner and edge-sharing SeU5 square pyramids. In the third Se2- site, Se2- is bonded in a 4-coordinate geometry to five U3+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on USe2 by Materials Project

USe2 is Cotunnite structured and crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. U4+ is bonded in a 9-coordinate geometry to nine Se2- atoms. There are a spread of U–Se bond distances ranging from 2.86–3.22 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to four equivalent U4+ atoms to form a mixture of distorted edge and corner-sharing SeU4 tetrahedra. In the second Se2- site, Se2- is bonded in a 5-coordinate geometry to five equivalent U4+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on U3Se4 by Materials Project

U3Se4 crystallizes in the cubic I-43d space group. The structure is three-dimensional. U is bonded to eight equivalent Se atoms to form a mixture of distorted corner, edge, and face-sharing USe8 hexagonal bipyramids. There are four shorter (2.94 Å) and four longer (3.07 Å) U–Se bond lengths. Se is bonded to six equivalent U atoms to form a mixture of distorted corner, edge, and face-sharing SeU6 octahedra. The corner-sharing octahedra tilt angles range from 17–50°.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on USe by Materials Project

USe is Halite, Rock Salt structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. U is bonded to six equivalent Se atoms to form a mixture of edge and corner-sharing USe6 octahedra. The corner-sharing octahedral tilt angles are 0°. All U–Se bond lengths are 2.87 Å. Se is bonded to six equivalent U atoms to form a mixture of edge and corner-sharing SeU6 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on U3Se5 by Materials Project

U3Se5 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are two inequivalent U+3.33+ sites. In the first U+3.33+ site, U+3.33+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.93–3.13 Å. In the second U+3.33+ site, U+3.33+ is bonded to seven Se2- atoms to form distorted edge-sharing USe7 pentagonal bipyramids. There are a spread of U–Se bond distances ranging from 2.78–2.96 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to four U+3.33+ atoms to form distorted SeU4 trigonal pyramids that share corners with six SeU5 square pyramids, corners with two equivalent SeU5 trigonal bipyramids, corners with six equivalent SeU4 trigonal pyramids, edges with three SeU5 square pyramids, edges with two equivalent SeU5 trigonal bipyramids, and an edgeedge with one SeU4 trigonal pyramid. In the second Se2- site, Se2- is bonded to five U+3.33+ atoms to form distorted SeU5 trigonal bipyramids that share corners with six SeU5 square pyramids, corners with four equivalent SeU5 trigonal bipyramids, corners with four equivalent SeU4 trigonal pyramids, edges with six SeU5 square pyramids, and edges with four equivalent SeU4 trigonal pyramids. In the third Se2- site, Se2- is bonded to five U+3.33+ atoms to form SeU5 square pyramids that share corners with four equivalent SeU5 square pyramids, corners with five equivalent SeU5 trigonal bipyramids, corners with eight equivalent SeU4 trigonal pyramids, edges with three SeU5 square pyramids, edges with two equivalent SeU5 trigonal bipyramids, edges with two equivalent SeU4 trigonal pyramids, and a faceface with one SeU5 square pyramid. In the fourth Se2- site, Se2- is bonded to five U+3.33+ atoms to form distorted SeU5 square pyramids that share corners with eight SeU5 square pyramids, a cornercorner with one SeU5 trigonal bipyramid, corners with four equivalent SeU4 trigonal pyramids, an edgeedge with one SeU5 square pyramid, edges with four equivalent SeU5 trigonal bipyramids, edges with four equivalent SeU4 trigonal pyramids, and a faceface with one SeU5 square pyramid.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on U11Se20 by Materials Project

U11Se20 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are twenty-two inequivalent U+3.64+ sites. In the first U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.90–2.97 Å. In the second U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.88–3.21 Å. In the third U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.87–3.16 Å. In the fourth U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.88–3.17 Å. In the fifth U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.88–3.24 Å. In the sixth U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.88–3.18 Å. In the seventh U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.88–3.20 Å. In the eighth U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.88–3.19 Å. In the ninth U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.88–3.16 Å. In the tenth U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.90–2.99 Å. In the eleventh U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.90–3.00 Å. In the twelfth U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.90–2.97 Å. In the thirteenth U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.87–3.16 Å. In the fourteenth U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.88–3.19 Å. In the fifteenth U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.88–3.23 Å. In the sixteenth U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.88–3.20 Å. In the seventeenth U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.87–3.17 Å. In the eighteenth U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.88–3.19 Å. In the nineteenth U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.88–3.25 Å. In the twentieth U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.88–3.18 Å. In the twenty-first U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.90–3.00 Å. In the twenty-second U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.90–2.99 Å. There are forty inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to four U+3.64+ atoms to form SeU4 tetrahedra that share a cornercorner with one SeU5 trigonal bipyramid, corners with four SeU4 trigonal pyramids, edges with two equivalent SeU4 tetrahedra, an edgeedge with one SeU5 trigonal bipyramid, and an edgeedge with one SeU4 trigonal pyramid. In the second Se2- site, Se2- is bonded to four U+3.64+ atoms to form SeU4 tetrahedra that share corners with three SeU5 trigonal bipyramids, corners with four SeU4 trigonal pyramids, edges with two equivalent SeU4 tetrahedra, and an edgeedge with one SeU4 trigonal pyramid. In the third Se2- site, Se2- is bonded to four U+3.64+ atoms to form SeU4 tetrahedra that share corners with four SeU5 trigonal bipyramids, corners with four SeU4 trigonal pyramids, edges with two equivalent SeU4 tetrahedra, an edgeedge with one SeU5 trigonal bipyramid, and an edgeedge with one SeU4 trigonal pyramid. In the fourth Se2- site, Se2- is bonded in a 5-coordinate geometry to five U+3.64+ atoms. In the fifth Se2- site, Se2- is bonded to five U+3.64+ atoms to form distorted SeU5 trigonal bipyramids that share corners with four SeU4 tetrahedra, corners with four SeU4 trigonal pyramids, an edgeedge with one SeU4 tetrahedra, and edges with three SeU5 trigonal bipyramids. In the sixth Se2- site, Se2- is bonded to five U+3.64+ atoms to form distorted SeU5 trigonal bipyramids that share corners with four SeU4 tetrahedra, corners with two equivalent SeU5 trigonal bipyramids, corners with four SeU4 trigonal pyramids, an edgeedge with one SeU4 tetrahedra, and edges with two equivalent SeU5 trigonal bipyramids. In the seventh Se2- site, Se2- is bonded in a 5-coordinate geometry to five U+3.64+ atoms. In the eighth Se2- site, Se2- is bonded in a 5-coordinate geometry to five U+3.64+ atoms. In the ninth Se2- site, Se2- is bonded in a 5-coordinate geometry to five U+3.64+ atoms. In the tenth Se2- site, Se2- is bonded to five U+3.64+ atoms to form distorted SeU5 trigonal bipyramids that share corners with four SeU4 tetrahedra, corners with two equivalent SeU5 trigonal bipyramids, corners with four SeU4 trigonal pyramids, an edgeedge with one SeU4 tetrahedra, and an edgeedge with one SeU5 trigonal bipyramid. In the eleventh Se2- site, Se2- is bonded in a 5-coordinate geometry to five U+3.64+ atoms. In the twelfth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to four U+3.64+ atoms. In the thirteenth Se2- site, Se2- is bonded to four U+3.64+ atoms to form distorted SeU4 trigonal pyramids that share corners with four SeU4 tetrahedra, corners with two SeU5 trigonal bipyramids, a cornercorner with one SeU4 trigonal pyramid, an edgeedge with one SeU4 tetrahedra, and edges with two SeU4 trigonal pyramids. In the fourteenth Se2- site, Se2- is bonded to four U+3.64+ atoms to form distorted SeU4 trigonal pyramids that share corners with four SeU4 tetrahedra, corners with two equivalent SeU5 trigonal bipyramids, a cornercorner with one SeU4 trigonal pyramid, an edgeedge with one SeU4 tetrahedra, and edges with two SeU4 trigonal pyramids. In the fifteenth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to four U+3.64+ atoms. In the sixteenth Se2- site, Se2- is bonded to four U+3.64+ atoms to form distorted SeU4 trigonal pyramids that share corners with four SeU4 tetrahedra, corners with four SeU5 trigonal bipyramids, a cornercorner with one SeU4 trigonal pyramid, an edgeedge with one SeU4 tetrahedra, and edges with two SeU4 trigonal pyramids. In the seventeenth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to four U+3.64+ atoms. In the eighteenth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to four U+3.64+ atoms. In the nineteenth Se2- site, Se2- is bonded to four U+3.64+ atoms to form distorted SeU4 trigonal pyramids that share corners with four SeU4 tetrahedra, corners with four SeU5 trigonal bipyramids, a cornercorner with one SeU4 trigonal pyramid, an edgeedge with one SeU4 tetrahedra, and edges with two SeU4 trigonal pyramids. In the twentieth Se2- site, Se2- is bonded to four U+3.64+ atoms to form SeU4 tetrahedra that share corners with four SeU5 trigonal bipyramids, corners with four SeU4 trigonal pyramids, edges with two equivalent SeU4 tetrahedra, an edgeedge with one SeU5 trigonal bipyramid, and an edgeedge with one SeU4 trigonal pyramid. In the twenty-first Se2- site, Se2- is bonded to four U+3.64+ atoms to form SeU4 tetrahedra that share corners with three SeU5 trigonal bipyramids, corners with four SeU4 trigonal pyramids, edges with two equivalent SeU4 tetrahedra, and an edgeedge with one SeU4 trigonal pyramid. In the twenty-second Se2- site, Se2- is bonded to four U+3.64+ atoms to form SeU4 tetrahedra that share a cornercorner with one SeU5 trigonal bipyramid, corners with four SeU4 trigonal pyramids, edges with two equivalent SeU4 tetrahedra, an edgeedge with one SeU5 trigonal bipyramid, and an edgeedge with one SeU4 trigonal pyramid. In the twenty-third Se2- site, Se2- is bonded to four U+3.64+ atoms to form SeU4 tetrahedra that share corners with four SeU5 trigonal bipyramids, corners with four SeU4 trigonal pyramids, edges with two equivalent SeU4 tetrahedra, an edgeedge with one SeU5 trigonal bipyramid, and an edgeedge with one SeU4 trigonal pyramid. In the twenty-fourth Se2- site, Se2- is bonded in a 5-coordinate geometry to five U+3.64+ atoms. In the twenty-fifth Se2- site, Se2- is bonded in a 5-coordinate geometry to five U+3.64+ atoms. In the twenty-sixth Se2- site, Se2- is bonded in a 5-coordinate geometry to five U+3.64+ atoms. In the twenty-seventh Se2- site, Se2- is bonded to five U+3.64+ atoms to form distorted SeU5 trigonal bipyramids that share corners with four SeU4 tetrahedra, corners with two equivalent SeU5 trigonal bipyramids, corners with four SeU4 trigonal pyramids, an edgeedge with one SeU4 tetrahedra, and edges with two equivalent SeU5 trigonal bipyramids. In the twenty-eighth Se2- site, Se2- is bonded to five U+3.64+ atoms to form distorted SeU5 trigonal bipyramids that share corners with four SeU4 tetrahedra, corners with two equivalent SeU5 trigonal bipyramids, corners with four SeU4 trigonal pyramids, an edgeedge with one SeU4 tetrahedra, and an edgeedge with one SeU5 trigonal bipyramid. In the twenty-ninth Se2- site, Se2- is bonded to five U+3.64+ atoms to form distorted SeU5 trigonal bipyramids that share corners with four SeU4 tetrahedra, corners with four SeU4 trigonal pyramids, an edgeedge with one SeU4 tetrahedra, and edges with three SeU5 trigonal bipyramids. In the thirtieth Se2- site, Se2- is bonded in a 5-coordinate geometry to five U+3.64+ atoms. In the thirty-first Se2- site, Se2- is bonded in a 5-coordinate geometry to five U+3.64+ atoms. In the thirty-second Se2- site, Se2- is bonded to four U+3.64+ atoms to form distorted SeU4 trigonal pyramids that share corners with four SeU4 tetrahedra, corners with four SeU5 trigonal bipyramids, a cornercorner with one SeU4 trigonal pyramid, an edgeedge with one SeU4 tetrahedra, and edges with two SeU4 trigonal pyramids. In the thirty-third Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to four U+3.64+ atoms. In the thirty-fourth Se2- site, Se2- is bonded to four U+3.64+ atoms to form distorted SeU4 trigonal pyramids that share corners with four SeU4 tetrahedra, corners with two equivalent SeU5 trigonal bipyramids, a cornercorner with one SeU4 trigonal pyramid, an edgeedge with one SeU4 tetrahedra, and edges with two SeU4 trigonal pyramids. In the thirty-fifth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to four U+3.64+ atoms. In the thirty-sixth Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to four U+3.64+ atoms. In the thirty-seventh Se2- site, Se2- is bonded to four U+3.64+ atoms to form distorted SeU4 trigonal pyramids that share corners with four SeU4 tetrahedra, corners with four SeU5 trigonal bipyramids, a cornercorner with one SeU4 trigonal pyramid, an edgeedge with one SeU4 tetrahedra, and edges with two SeU4 trigonal pyramids. In the thirty-eighth Se2-

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on USe3 by Materials Project

USe3 crystallizes in the monoclinic P2_1/m space group. The structure is two-dimensional and consists of one USe3 sheet oriented in the (0, 0, 1) direction. U6+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.89–2.96 Å. There are three inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 2-coordinate geometry to two equivalent U6+ and one Se2- atom. The Se–Se bond length is 2.38 Å. In the second Se2- site, Se2- is bonded to four equivalent U6+ atoms to form a mixture of distorted edge and corner-sharing SeU4 trigonal pyramids. In the third Se2- site, Se2- is bonded in a 2-coordinate geometry to two equivalent U6+ and one Se2- atom.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on U11Se20 by Materials Project

U11Se20 crystallizes in the tetragonal P4 space group. The structure is three-dimensional. there are five inequivalent U+3.64+ sites. In the first U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.89–3.18 Å. In the second U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are a spread of U–Se bond distances ranging from 2.89–3.16 Å. In the third U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are four shorter (2.92 Å) and four longer (2.97 Å) U–Se bond lengths. In the fourth U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are four shorter (2.92 Å) and four longer (2.99 Å) U–Se bond lengths. In the fifth U+3.64+ site, U+3.64+ is bonded in a 8-coordinate geometry to eight Se2- atoms. There are four shorter (2.92 Å) and four longer (2.98 Å) U–Se bond lengths. There are six inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to four U+3.64+ atoms to form distorted SeU4 trigonal pyramids that share corners with four SeU4 tetrahedra, corners with seven SeU5 trigonal bipyramids, a cornercorner with one SeU4 trigonal pyramid, an edgeedge with one SeU4 tetrahedra, an edgeedge with one SeU5 trigonal bipyramid, and edges with two equivalent SeU4 trigonal pyramids. In the second Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to four U+3.64+ atoms. In the third Se2- site, Se2- is bonded to five U+3.64+ atoms to form distorted SeU5 trigonal bipyramids that share corners with four SeU4 tetrahedra, corners with four equivalent SeU5 trigonal bipyramids, corners with two equivalent SeU4 trigonal pyramids, an edgeedge with one SeU4 tetrahedra, edges with five SeU5 trigonal bipyramids, an edgeedge with one SeU4 trigonal pyramid, and faces with two equivalent SeU5 trigonal bipyramids. In the fourth Se2- site, Se2- is bonded to five U+3.64+ atoms to form distorted SeU5 trigonal bipyramids that share corners with four SeU4 tetrahedra, corners with four equivalent SeU5 trigonal bipyramids, corners with five equivalent SeU4 trigonal pyramids, an edgeedge with one SeU4 tetrahedra, edges with five SeU5 trigonal bipyramids, and faces with two equivalent SeU5 trigonal bipyramids. In the fifth Se2- site, Se2- is bonded to four U+3.64+ atoms to form SeU4 tetrahedra that share corners with eight SeU5 trigonal bipyramids, corners with two equivalent SeU4 trigonal pyramids, edges with two equivalent SeU4 tetrahedra, edges with two equivalent SeU5 trigonal bipyramids, and edges with two equivalent SeU4 trigonal pyramids. In the sixth Se2- site, Se2- is bonded to four U+3.64+ atoms to form SeU4 tetrahedra that share corners with eight SeU5 trigonal bipyramids, corners with six equivalent SeU4 trigonal pyramids, edges with two equivalent SeU4 tetrahedra, and edges with two equivalent SeU5 trigonal bipyramids.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on U3Se5 by Materials Project

U3Se5 crystallizes in the tetragonal I4/mcm space group. The structure is three-dimensional. there are two inequivalent U+3.33+ sites. In the first U+3.33+ site, U+3.33+ is bonded in a 10-coordinate geometry to ten Se2- atoms. There are a spread of U–Se bond distances ranging from 2.91–3.30 Å. In the second U+3.33+ site, U+3.33+ is bonded in a 10-coordinate geometry to eight equivalent Se2- atoms. All U–Se bond lengths are 2.98 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to four equivalent U+3.33+ atoms to form distorted edge-sharing SeU4 tetrahedra. In the second Se2- site, Se2- is bonded in a 6-coordinate geometry to six U+3.33+ atoms.

36 MATERIALS SCIENCE↗