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Materials Data on Na2CO3 by Materials Project
Na2CO3 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a hexagonal planar geometry to six equivalent O2- atoms. All Na–O bond lengths are 2.65 Å. In the second Na1+ site, Na1+ is bonded to six equivalent O2- atoms to form face-sharing NaO6 octahedra. All Na–O bond lengths are 2.37 Å. C4+ is bonded in a trigonal planar geometry to three equivalent O2- atoms. All C–O bond lengths are 1.30 Å. O2- is bonded in a 5-coordinate geometry to four Na1+ and one C4+ atom.
Materials Data on Na2CO3 by Materials Project
Na2CO3 crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of Na–O bond distances ranging from 2.60–2.71 Å. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form face-sharing NaO6 octahedra. There are two shorter (2.35 Å) and four longer (2.37 Å) Na–O bond lengths. In the third Na1+ site, Na1+ is bonded to six O2- atoms to form face-sharing NaO6 octahedra. There are four shorter (2.33 Å) and two longer (2.45 Å) Na–O bond lengths. C4+ is bonded in a trigonal planar geometry to three O2- atoms. All C–O bond lengths are 1.30 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one C4+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one C4+ atom.
Materials Data on Na2CO3 by Materials Project
Na2CO3 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are twelve inequivalent Na1+ sites. In the first Na1+ site, Na1+ is bonded to six O2- atoms to form face-sharing NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.35–2.44 Å. In the second Na1+ site, Na1+ is bonded to six O2- atoms to form face-sharing NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.36–2.41 Å. In the third Na1+ site, Na1+ is bonded to six O2- atoms to form face-sharing NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.33–2.45 Å. In the fourth Na1+ site, Na1+ is bonded to six O2- atoms to form face-sharing NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.33–2.46 Å. In the fifth Na1+ site, Na1+ is bonded to six O2- atoms to form face-sharing NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.33–2.46 Å. In the sixth Na1+ site, Na1+ is bonded to six O2- atoms to form face-sharing NaO6 octahedra. There are a spread of Na–O bond distances ranging from 2.31–2.46 Å. In the seventh Na1+ site, Na1+ is bonded in a 4-coordinate geometry to nine O2- atoms. There are a spread of Na–O bond distances ranging from 2.43–3.07 Å. In the eighth Na1+ site, Na1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.45–3.01 Å. In the ninth Na1+ site, Na1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.40–2.96 Å. In the tenth Na1+ site, Na1+ is bonded in a 6-coordinate geometry to six O2- atoms. There are a spread of Na–O bond distances ranging from 2.39–2.63 Å. In the eleventh Na1+ site, Na1+ is bonded in a 4-coordinate geometry to nine O2- atoms. There are a spread of Na–O bond distances ranging from 2.43–3.04 Å. In the twelfth Na1+ site, Na1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Na–O bond distances ranging from 2.43–2.95 Å. There are six inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a trigonal planar geometry to three O2- atoms. All C–O bond lengths are 1.30 Å. In the second C4+ site, C4+ is bonded in a trigonal planar geometry to three O2- atoms. All C–O bond lengths are 1.30 Å. In the third C4+ site, C4+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.30 Å) and one longer (1.31 Å) C–O bond length. In the fourth C4+ site, C4+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.30 Å) and one longer (1.31 Å) C–O bond length. In the fifth C4+ site, C4+ is bonded in a trigonal planar geometry to three O2- atoms. All C–O bond lengths are 1.30 Å. In the sixth C4+ site, C4+ is bonded in a trigonal planar geometry to three O2- atoms. There is two shorter (1.30 Å) and one longer (1.31 Å) C–O bond length. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one C4+ atom. In the second O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one C4+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one C4+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one C4+ atom. In the fifth O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one C4+ atom. In the sixth O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one C4+ atom. In the seventh O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one C4+ atom. In the eighth O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one C4+ atom. In the ninth O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one C4+ atom. In the tenth O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one C4+ atom. In the eleventh O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one C4+ atom. In the twelfth O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one C4+ atom. In the thirteenth O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one C4+ atom. In the fourteenth O2- site, O2- is bonded in a 1-coordinate geometry to four Na1+ and one C4+ atom. In the fifteenth O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one C4+ atom. In the sixteenth O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one C4+ atom. In the seventeenth O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one C4+ atom. In the eighteenth O2- site, O2- is bonded in a 1-coordinate geometry to five Na1+ and one C4+ atom.
Plutonium Retention by Crystalline Silicotitanate under Hyperalkaline Conditions Relevant to Tank-Side Cesium-Removal at the Hanford Site
Crystalline silicotitanate (CST) is used in Hanford’s Tank-Side Cesium-Removal (TSCR) process to selectively remove Cs-137 from highly caustic, nitrate-rich tank supernatants. Recent testing with actual waste samples suggests that CST can also retain measurable plutonium (Pu), which could affect radiological classification and disposal pathways for spent CST. To quantify this behavior, Pu partitioning to CST was studied under Hanford-relevant conditions using batch-contact experiments in a representative simulant (2 M NaNO3, 0.7 M NaOH). Isotherm data were measured and distribution ratios calculated, with Cs+ uptake used as benchmark. Under low-carbonate conditions, Pu was retained strongly by CST in systems initially contacted with either PuO2 nanoparticles (Pu(IV)) or aqueous Pu(VI), with distribution ratios of ~2,200–3,700 mL/g, generally exceeding those for Cs+ (~400–1,000 mL/g). Increasing carbonate concentration strongly reduced PuO2 nanoparticle retention; at [Na2CO3] = 1 M, distribution ratios decreased by up to one order of magnitude to roughly 100–300 mL/g. Electron microscopy suggests that Pu retention involves a combination of mechanisms such as PuO2 NP aggregation induced by CST leachate components, and association with CST bead surfaces.