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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Fe2(CO)9 by Materials Project

Fe2(CO)9 crystallizes in the hexagonal P6_3/m space group. The structure is zero-dimensional and consists of six formaldehyde molecules and four Fe(CO)3 clusters. In each Fe(CO)3 cluster, Fe3+ is bonded in a 3-coordinate geometry to three equivalent C+1.33+ atoms. All Fe–C bond lengths are 1.82 Å. C+1.33+ is bonded in a distorted single-bond geometry to one Fe3+ and one O2- atom. The C–O bond length is 1.16 Å. O2- is bonded in a single-bond geometry to one C+1.33+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS1986

On the Bonding in Fe2(CO)9

The bonding in Fe2(CO)9 is analyzed using an self consistend field (SCF) wave function for a large basis set. There is no direct Fe-Fe metal-metal bond. The bridging CO's hold the two Fe(CO)3 fragments together by a sigma donation into the empty Fe-Fe d pi orbital and metal donation from the d pi* orbital into the CO 2pi* orbital. The bonding of the terminal CO is similar to that in Ni(CO)4 and the equatorial groups in Fe(CO)5.

Bauschlicher, Charles W., Jr.↗
NASA NTRS1986

On the bonding in Fe2(CO)9

The present paper is concerned with an analysis of the bonding in Fe2(CO)9, taking into account the results of self-consistent-field (SCF) calculations. The basis sets used are the same as those employed in the study of Fe(CO)5 conducted by Bauschlicher and Bagus (1985). The Fe basis set starts with the 14s9p5d primitive set optimized by Wachters (1970), which is contracted to 8s4p5d. An SCF wave function, consisting of only the core electrons, was determined, and then electrons were slowly added to the virtual orbitals with the lowest eigenvalues. The conducted calculations show no direct Fe-Fe bonding, but rather bonding resulting from the bridging CO's. The bonding is found to involve both the 5 sigma and 2 pi(asterisk) orbitals of the bridging CO's.

Bauschlicher, C. W., Jr.↗
DOE OSTI2024

Iron Carbonyl Complexes of [2.2.2]Hericene as a Rigid Tris(1,3-diene) Ligand

Hericene is an unusual hexaolefin consisting of three 1,3-diene units located on a rigid bicyclo [2.2.2]octane framework that restricts the geometrical relationships of metal atoms bonded to these olefinic units. In order to explore possible effects of this rigidity limiting metal–metal interaction in polynuclear derivatives possibly stabilizing coordinatively unsaturated species, the structures and energetics of the hericene iron carbonyl complexes (hericene)Fem(CO)n (m = 1, n = 3; m = 2, n = 6, 5; m = 3, n = 9, 8) have been investigated by density functional theory. The lowest-energy (hericene)Fem(CO)3m (m = 1, 2, 3) structures have the cavities of the hericene ligand filled with a single Fe(CO)3 moiety bonded to a 1,3-diolefin unit. Such species have been synthesized by the reaction of Fe2(CO)9 with hericene. For the (hericene)Fe2(CO)5 system, the lowest energy structures are singlet structures with an Fe(CO)3 unit bonded to a 1,3-diene unit in one hericene cavity and an Fe(CO)2 unit in another hericene cavity bonded to three C=C double bonds from two 1,3-diene units. Higher energy (hericene)Fe2(CO)5 structures include a structure in which a single hericene cavity contains a Fe2(CO)4(µ-CO) moiety with each iron atom bonded to a 1,3-diene unit. In addition, both singlet and triplet (hericene)Fe2(CO)5 structures are found in which an Fe(CO)3 moiety and an Fe(CO)2 moiety located in separate hericene cavities are each bonded to a 1,3-diene unit. The lowest-energy (hericene)Fe3(CO)8 structures have two hericene cavities containing Fe(CO)3 moieties fully bonded to 1,3-diene units and a third hericene cavity containing an Fe(CO)2 moiety fully bonded to a 1,3-diene unit.

Luo, Jinfeng↗
DOE OSTI2020

Materials Data on FeCoP by Materials Project

CoFeP crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. Fe2+ is bonded in a 5-coordinate geometry to five equivalent P3- atoms. There are a spread of Fe–P bond distances ranging from 2.24–2.58 Å. Co1+ is bonded to four equivalent P3- atoms to form a mixture of edge and corner-sharing CoP4 tetrahedra. There are a spread of Co–P bond distances ranging from 2.15–2.22 Å. P3- is bonded in a 9-coordinate geometry to five equivalent Fe2+ and four equivalent Co1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on FeCoAs by Materials Project

FeCoAs crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are six inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to five As3- atoms to form distorted FeAs5 trigonal bipyramids that share corners with three equivalent FeAs5 square pyramids, corners with two equivalent FeAs4 tetrahedra, corners with four CoAs4 tetrahedra, corners with two equivalent CoAs5 trigonal bipyramids, corners with five FeAs5 trigonal bipyramids, an edgeedge with one FeAs5 square pyramid, edges with six CoAs4 tetrahedra, an edgeedge with one CoAs5 trigonal bipyramid, and edges with four FeAs5 trigonal bipyramids. There are a spread of Fe–As bond distances ranging from 2.43–2.57 Å. In the second Fe2+ site, Fe2+ is bonded to five As3- atoms to form distorted FeAs5 trigonal bipyramids that share corners with three equivalent FeAs5 square pyramids, corners with two equivalent FeAs4 tetrahedra, corners with four CoAs4 tetrahedra, corners with two equivalent CoAs5 trigonal bipyramids, corners with five FeAs5 trigonal bipyramids, an edgeedge with one FeAs5 square pyramid, edges with six CoAs4 tetrahedra, an edgeedge with one CoAs5 trigonal bipyramid, and edges with four FeAs5 trigonal bipyramids. There are a spread of Fe–As bond distances ranging from 2.43–2.57 Å. In the third Fe2+ site, Fe2+ is bonded to five As3- atoms to form distorted FeAs5 square pyramids that share corners with six CoAs4 tetrahedra, corners with ten FeAs5 trigonal bipyramids, edges with two equivalent FeAs5 square pyramids, edges with six CoAs4 tetrahedra, and edges with four FeAs5 trigonal bipyramids. There are a spread of Fe–As bond distances ranging from 2.43–2.56 Å. In the fourth Fe2+ site, Fe2+ is bonded to five As3- atoms to form distorted FeAs5 trigonal bipyramids that share corners with two equivalent FeAs5 square pyramids, corners with six CoAs4 tetrahedra, corners with three equivalent CoAs5 trigonal bipyramids, corners with five FeAs5 trigonal bipyramids, an edgeedge with one FeAs5 square pyramid, edges with two equivalent FeAs4 tetrahedra, edges with four CoAs4 tetrahedra, an edgeedge with one CoAs5 trigonal bipyramid, and edges with four FeAs5 trigonal bipyramids. There are a spread of Fe–As bond distances ranging from 2.42–2.58 Å. In the fifth Fe2+ site, Fe2+ is bonded to five As3- atoms to form distorted FeAs5 trigonal bipyramids that share corners with two equivalent FeAs5 square pyramids, corners with six CoAs4 tetrahedra, corners with three equivalent CoAs5 trigonal bipyramids, corners with five FeAs5 trigonal bipyramids, an edgeedge with one FeAs5 square pyramid, edges with two equivalent FeAs4 tetrahedra, edges with four CoAs4 tetrahedra, an edgeedge with one CoAs5 trigonal bipyramid, and edges with four FeAs5 trigonal bipyramids. There are a spread of Fe–As bond distances ranging from 2.41–2.59 Å. In the sixth Fe2+ site, Fe2+ is bonded to four As3- atoms to form FeAs4 tetrahedra that share corners with two equivalent FeAs4 tetrahedra, corners with eight CoAs4 tetrahedra, corners with two equivalent CoAs5 trigonal bipyramids, corners with four FeAs5 trigonal bipyramids, edges with two CoAs4 tetrahedra, edges with two equivalent CoAs5 trigonal bipyramids, and edges with four FeAs5 trigonal bipyramids. There are a spread of Fe–As bond distances ranging from 2.27–2.36 Å. There are six inequivalent Co1+ sites. In the first Co1+ site, Co1+ is bonded to four As3- atoms to form CoAs4 tetrahedra that share a cornercorner with one FeAs4 tetrahedra, corners with nine CoAs4 tetrahedra, corners with two equivalent CoAs5 trigonal bipyramids, corners with four FeAs5 trigonal bipyramids, edges with two equivalent FeAs5 square pyramids, edges with two CoAs4 tetrahedra, and edges with four FeAs5 trigonal bipyramids. There are two shorter (2.27 Å) and two longer (2.36 Å) Co–As bond lengths. In the second Co1+ site, Co1+ is bonded to five As3- atoms to form distorted CoAs5 trigonal bipyramids that share corners with two equivalent FeAs4 tetrahedra, corners with four CoAs4 tetrahedra, corners with ten FeAs5 trigonal bipyramids, edges with two equivalent FeAs4 tetrahedra, edges with four CoAs4 tetrahedra, edges with two equivalent CoAs5 trigonal bipyramids, and edges with four FeAs5 trigonal bipyramids. There are a spread of Co–As bond distances ranging from 2.41–2.56 Å. In the third Co1+ site, Co1+ is bonded to four As3- atoms to form CoAs4 tetrahedra that share corners with two equivalent FeAs5 square pyramids, corners with ten CoAs4 tetrahedra, corners with four FeAs5 trigonal bipyramids, edges with two equivalent FeAs5 square pyramids, edges with two CoAs4 tetrahedra, and edges with four FeAs5 trigonal bipyramids. There are two shorter (2.27 Å) and two longer (2.37 Å) Co–As bond lengths. In the fourth Co1+ site, Co1+ is bonded to four As3- atoms to form CoAs4 tetrahedra that share corners with two equivalent FeAs5 square pyramids, corners with three equivalent FeAs4 tetrahedra, corners with seven CoAs4 tetrahedra, corners with four FeAs5 trigonal bipyramids, an edgeedge with one FeAs4 tetrahedra, an edgeedge with one CoAs4 tetrahedra, edges with two equivalent CoAs5 trigonal bipyramids, and edges with four FeAs5 trigonal bipyramids. There are a spread of Co–As bond distances ranging from 2.26–2.36 Å. In the fifth Co1+ site, Co1+ is bonded to four As3- atoms to form CoAs4 tetrahedra that share corners with two equivalent FeAs5 square pyramids, corners with three equivalent FeAs4 tetrahedra, corners with seven CoAs4 tetrahedra, corners with four FeAs5 trigonal bipyramids, an edgeedge with one FeAs4 tetrahedra, an edgeedge with one CoAs4 tetrahedra, edges with two equivalent CoAs5 trigonal bipyramids, and edges with four FeAs5 trigonal bipyramids. There are a spread of Co–As bond distances ranging from 2.26–2.36 Å. In the sixth Co1+ site, Co1+ is bonded to four As3- atoms to form CoAs4 tetrahedra that share a cornercorner with one FeAs4 tetrahedra, corners with nine CoAs4 tetrahedra, corners with two equivalent CoAs5 trigonal bipyramids, corners with four FeAs5 trigonal bipyramids, edges with two equivalent FeAs5 square pyramids, edges with two CoAs4 tetrahedra, and edges with four FeAs5 trigonal bipyramids. There are two shorter (2.27 Å) and two longer (2.36 Å) Co–As bond lengths. There are six inequivalent As3- sites. In the first As3- site, As3- is bonded in a 9-coordinate geometry to four Fe2+ and five Co1+ atoms. In the second As3- site, As3- is bonded in a 9-coordinate geometry to five Fe2+ and four Co1+ atoms. In the third As3- site, As3- is bonded in a 9-coordinate geometry to six Fe2+ and three Co1+ atoms. In the fourth As3- site, As3- is bonded in a 9-coordinate geometry to six Fe2+ and three Co1+ atoms. In the fifth As3- site, As3- is bonded in a 9-coordinate geometry to three Fe2+ and six Co1+ atoms. In the sixth As3- site, As3- is bonded in a 9-coordinate geometry to five Fe2+ and four Co1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Fe(BW)2 by Materials Project

Fe(WB)2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. W2+ is bonded in a distorted hexagonal planar geometry to six equivalent B3- atoms. There are two shorter (2.32 Å) and four longer (2.35 Å) W–B bond lengths. Fe2+ is bonded in a square co-planar geometry to four equivalent B3- atoms. All Fe–B bond lengths are 2.28 Å. B3- is bonded in a 9-coordinate geometry to six equivalent W2+, two equivalent Fe2+, and one B3- atom. The B–B bond length is 1.86 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Nb2FeB2 by Materials Project

Nb2FeB2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Nb2+ is bonded in a distorted hexagonal planar geometry to six equivalent B3- atoms. There are two shorter (2.39 Å) and four longer (2.43 Å) Nb–B bond lengths. Fe2+ is bonded in a square co-planar geometry to four equivalent B3- atoms. All Fe–B bond lengths are 2.31 Å. B3- is bonded in a 9-coordinate geometry to six equivalent Nb2+, two equivalent Fe2+, and one B3- atom. The B–B bond length is 1.87 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Fe(BW)2 by Materials Project

Fe(WB)2 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. W2+ is bonded in a 6-coordinate geometry to six equivalent B3- atoms. There are four shorter (2.35 Å) and two longer (2.52 Å) W–B bond lengths. Fe2+ is bonded in a square co-planar geometry to four equivalent B3- atoms. All Fe–B bond lengths are 2.08 Å. B3- is bonded in a 9-coordinate geometry to six equivalent W2+, two equivalent Fe2+, and one B3- atom. The B–B bond length is 1.88 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Fe(BMo)2 by Materials Project

Mo2FeB2 crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. Mo2+ is bonded in a distorted hexagonal planar geometry to six equivalent B3- atoms. There are two shorter (2.33 Å) and four longer (2.34 Å) Mo–B bond lengths. Fe2+ is bonded in a square co-planar geometry to four equivalent B3- atoms. All Fe–B bond lengths are 2.33 Å. B3- is bonded in a 9-coordinate geometry to six equivalent Mo2+, two equivalent Fe2+, and one B3- atom. The B–B bond length is 1.85 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on V11FeB8 by Materials Project

V11FeB8 crystallizes in the monoclinic P2/m space group. The structure is three-dimensional. there are six inequivalent V2+ sites. In the first V2+ site, V2+ is bonded in a distorted hexagonal planar geometry to six B3- atoms. There are a spread of V–B bond distances ranging from 2.25–2.28 Å. In the second V2+ site, V2+ is bonded in a distorted hexagonal planar geometry to six B3- atoms. There are four shorter (2.27 Å) and two longer (2.28 Å) V–B bond lengths. In the third V2+ site, V2+ is bonded in a 6-coordinate geometry to six B3- atoms. All V–B bond lengths are 2.26 Å. In the fourth V2+ site, V2+ is bonded in a distorted hexagonal planar geometry to six B3- atoms. There are a spread of V–B bond distances ranging from 2.27–2.29 Å. In the fifth V2+ site, V2+ is bonded in a square co-planar geometry to four B3- atoms. There are two shorter (2.31 Å) and two longer (2.32 Å) V–B bond lengths. In the sixth V2+ site, V2+ is bonded in a rectangular see-saw-like geometry to four B3- atoms. There are two shorter (2.30 Å) and two longer (2.32 Å) V–B bond lengths. Fe2+ is bonded in a distorted square co-planar geometry to four B3- atoms. There are two shorter (2.26 Å) and two longer (2.29 Å) Fe–B bond lengths. There are four inequivalent B3- sites. In the first B3- site, B3- is bonded in a 9-coordinate geometry to seven V2+, one Fe2+, and one B3- atom. The B–B bond length is 1.80 Å. In the second B3- site, B3- is bonded in a 9-coordinate geometry to eight V2+ and one B3- atom. In the third B3- site, B3- is bonded in a 9-coordinate geometry to seven V2+, one Fe2+, and one B3- atom. The B–B bond length is 1.80 Å. In the fourth B3- site, B3- is bonded in a 9-coordinate geometry to eight V2+ and one B3- atom. The B–B bond length is 1.79 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on FeH4 by Materials Project

FeH4 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. Fe2+ is bonded in a 9-coordinate geometry to eleven H+0.50- atoms. There are a spread of Fe–H bond distances ranging from 1.59–2.12 Å. There are three inequivalent H+0.50- sites. In the first H+0.50- site, H+0.50- is bonded in a distorted square co-planar geometry to four equivalent Fe2+ atoms. In the second H+0.50- site, H+0.50- is bonded in a distorted bent 120 degrees geometry to two equivalent Fe2+ atoms. In the third H+0.50- site, H+0.50- is bonded in a 1-coordinate geometry to three equivalent Fe2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Sr3FeCo(ClO2)2 by Materials Project

Sr3FeCo(O2Cl)2 crystallizes in the tetragonal I4mm space group. The structure is three-dimensional. there are three inequivalent Sr2+ sites. In the first Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to four equivalent O2- and five Cl1- atoms. All Sr–O bond lengths are 2.63 Å. There are four shorter (3.08 Å) and one longer (3.25 Å) Sr–Cl bond lengths. In the second Sr2+ site, Sr2+ is bonded in a 9-coordinate geometry to four equivalent O2- and five Cl1- atoms. All Sr–O bond lengths are 2.63 Å. There are four shorter (3.14 Å) and one longer (3.41 Å) Sr–Cl bond lengths. In the third Sr2+ site, Sr2+ is bonded in a body-centered cubic geometry to eight O2- atoms. There are four shorter (2.64 Å) and four longer (2.73 Å) Sr–O bond lengths. Fe2+ is bonded in a distorted rectangular see-saw-like geometry to four equivalent O2- and one Cl1- atom. All Fe–O bond lengths are 2.05 Å. The Fe–Cl bond length is 2.98 Å. Co2+ is bonded to four equivalent O2- and one Cl1- atom to form corner-sharing CoClO4 square pyramids. All Co–O bond lengths are 2.05 Å. The Co–Cl bond length is 2.66 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded to four Sr2+ and two equivalent Fe2+ atoms to form distorted OSr4Fe2 octahedra that share corners with eight OSr4Co2 octahedra, edges with three OSr4Co2 octahedra, and faces with four equivalent OSr4Fe2 octahedra. The corner-sharing octahedra tilt angles range from 2–65°. In the second O2- site, O2- is bonded to four Sr2+ and two equivalent Co2+ atoms to form a mixture of face, edge, and corner-sharing OSr4Co2 octahedra. The corner-sharing octahedra tilt angles range from 2–65°. There are two inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 6-coordinate geometry to five Sr2+ and one Fe2+ atom. In the second Cl1- site, Cl1- is bonded in a 6-coordinate geometry to five Sr2+ and one Co2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba2FeCoClF7 by Materials Project

Ba2FeCoF7Cl crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to three equivalent Cl1- and six F1- atoms. All Ba–Cl bond lengths are 3.40 Å. There are a spread of Ba–F bond distances ranging from 2.69–2.75 Å. In the second Ba2+ site, Ba2+ is bonded in a 12-coordinate geometry to twelve F1- atoms. There are a spread of Ba–F bond distances ranging from 2.77–3.23 Å. Fe2+ is bonded to one Cl1- and five F1- atoms to form distorted FeClF5 octahedra that share corners with four equivalent CoClF5 octahedra. The corner-sharing octahedra tilt angles range from 21–32°. The Fe–Cl bond length is 2.58 Å. There are four shorter (2.07 Å) and one longer (2.13 Å) Fe–F bond lengths. Co2+ is bonded to one Cl1- and five F1- atoms to form CoClF5 octahedra that share corners with four equivalent FeClF5 octahedra. The corner-sharing octahedra tilt angles range from 21–32°. The Co–Cl bond length is 2.54 Å. There are four shorter (2.04 Å) and one longer (2.07 Å) Co–F bond lengths. Cl1- is bonded in a 2-coordinate geometry to three equivalent Ba2+, one Fe2+, and one Co2+ atom. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted bent 150 degrees geometry to two equivalent Ba2+, one Fe2+, and one Co2+ atom. In the second F1- site, F1- is bonded in a distorted bent 150 degrees geometry to two equivalent Ba2+, one Fe2+, and one Co2+ atom. In the third F1- site, F1- is bonded in a 4-coordinate geometry to three Ba2+ and one Co2+ atom. In the fourth F1- site, F1- is bonded in a 4-coordinate geometry to three Ba2+ and one Fe2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2023

A conformational equilibrium in the nitrogenase MoFe protein with an α-V70I amino acid substitution illuminates the mechanism of H 2 formation

Study of α-V70I-substituted nitrogenase MoFe protein identified Fe6 of FeMo-cofactor (Fe 7 S 9 MoC-homocitrate) as a critical N 2 binding/reduction site. Freeze-trapping this enzyme during Ar turnover captured the key catalytic intermediate in high occupancy, denoted E 4 (4H), which has accumulated 4[e — /H + ] as two bridging hydrides, Fe2–H–Fe6 and Fe3–H–Fe7, and protons bound to two sulfurs. E 4 (4H) is poised to bind/reduce N 2 as driven by mechanistically-coupled H 2 reductive-elimination of the hydrides. This process must compete with ongoing hydride protonation (HP), which releases H 2 as the enzyme relaxes to state E 2 (2H), containing 2[e — /H + ] as a hydride and sulfur-bound proton; accumulation of E 4 (4H) in α-V70I is enhanced by HP suppression. EPR and 95 Mo ENDOR spectroscopies now show that resting-state α-V70I enzyme exists in two conformational states, both in solution and as crystallized, one with wild type (WT)-like FeMo-co and one with perturbed FeMo-co. These reflect two conformations of the Ile residue, as visualized in a reanalysis of the X-ray diffraction data of α-V70I and confirmed by computations. EPR measurements show delivery of 2[e — /H + ] to the E 0 state of the WT MoFe protein and to both α-V70I conformations generating E 2 (2H) that contains the Fe3–H–Fe7 bridging hydride; accumulation of another 2[e — /H + ] generates E 4 (4H) with Fe2–H–Fe6 as the second hydride. E 4 (4H) in WT enzyme and a minority α-V70I E 4 (4H) conformation as visualized by QM/MM computations relax to resting-state through two HP steps that reverse the formation process: HP of Fe2–H–Fe6 followed by slower HP of Fe3–H–Fe7, which leads to transient accumulation of E 2 (2H) containing Fe3–H–Fe7. In the dominant α-V70I E 4 (4H) conformation, HP of Fe2–H–Fe6 is passively suppressed by the positioning of the Ile sidechain; slow HP of Fe3–H–Fe7 occurs first and the resulting E 2 (2H) contains Fe2–H–Fe6. Importantly, it is this HP suppression in E 4 (4H) that enables α-V70I MoFe to accumulate E 4 (4H) in high occupancy. In addition, HP suppression in α-V70I E 4 (4H) kinetically unmasks hydride reductive-elimination without N 2 -binding, a process that is precluded in WT enzyme.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRSDate not supplied

Assessing Organic Preservation and the Implications for Potential Biosignatures in the Bastide Member of the Séítah Formation, Jezero Crater

Introduction: Olivine has the highest CO2 trapping potential of ultramafic minerals, due to its rapid rate of dissolution and high percentage of divalent cations/unpolymerized silicate tetrahedra [1]. It generates divalent carbonates from CO2 and sequesters CO2 into the mineral matrix of the target lithology. The co-occurrence of olivine and carbonate within abraded targets from the Bastide Member of the Séítah Formation (Fm) of the Jezero crater floor [2] suggests the carbonation of olivine occurred within the mineral matrix hosted in a subsurface system. Hydrothermal origins for the subsurface system are hypothesized from orbital data [3]. This is supported by the detection of hydration features within the rock as well as the carbonate features are solely detected within the abrasion patch but not the rock’s surface. Organic preservation potential of abrasion patches: We incorporated the SHERLOC/WATSON results acquired from the Dourbes, Garde, and Quartier abrasion patches in the Séítah Fm to investigate the organomineral associations, and determine the biosignature preservation potential of these rocks. Dourbes is dominated by olivine and has minor amounts of carbonate, hydrated Ca-sulfate, and amorphous or microcrystalline silicate. Fluorescence features (330-340 nm) are detected in discrete locales and could be consistent with double ring aromatic organic molecules; yet, these features do not appear to be associated with an identified mineral phase. Dark subhedral to euhedral olivine grains within the Garde abrasion patch often co-occur with carbonate-consistent spectral signatures in all analyzed scans. The availability of Fe2+ is a known influence on olivine dissolution rates [1] and SuperCam estimates of the olivine composition (Forsterite-60 average for Sols 202-234) may thereby provide a constraint on the carbonation extent. Carbonated olivine phenocrysts within the matrix may be due to aqueous alteration, as the carbonation of nodules is consistent with observations in other hydrothermal systems and within Martian meteorites (ALH84001) [4]. In comparison, the Quartier abrasion patch represents an extensively altered endmember within the Bastide Member of the Séítah Fm. It contains a fluorescence doublet at 305/325 nm that coexists with multiple species of Na-sulfate and Mg-sulfate, Mg-carbonates, olivine [5]. Aqueous alteration and implications for habitability: The identification of primary and secondary mineral phases observed in the Bastide Member suggests the release of cations from primary ultramafic minerals through aqueous alteration. Within Garde, the carbonate detected appears to be Mg-rich and likely formed from the in situ alteration of Mg-rich olivine within the region as carbonate has only been detected within the rock via in situ analysis. Carbonates derived from abiotic and biotic reactions preserve biosignatures (i.e. indices of habitability) on Earth. The detected carbonate phase found in association with fluorescent features within the rock matrix may also indicate potential organic compounds preserved in a putative hydrothermal system. Fluorescent features (~330 nm) are unique to Garde and Dourbes, though they are co-located to carbonate signatures solely within Garde, and between the light toned minerals. Identification of these fluorescent features may be consistent with 1-2 ring aromatic compounds. The limit of detection for Raman is multiple orders of magnitude greater than the limit of detection required for fluorescence [6]. Implications for provenance: Hydrothermal systems represent disequilibrium chemical conditions that are hypothesized to have supported the emergence of life and also preserve ancient carbon within precipitated carbonates [7]. Hydrothermal system associated carbonates are capable of preserving biosignatures up to an estimated ~3.77 – 4.28 Gya [8]. Thus, carbonated olivine found within the Séítah Fm may represent a high-potential biosignature preserving environment on Mars. The formation of carbonates by an aqueous alteration process, such as carbonation of olivine is also consistent with hypotheses for carbonate within the greater regional-olivine bearing unit [2,3], which contains Garde, Dourbes, and Quartier. Acknowledgments: This work was carried out at the Jet Propulsion Laboratory, The California Institute of Technology under a contract from NASA. References: [1] Wood et al., (2019) ES&T, 6, 10. [2] Stack, K. et al., (2020) Space Sci Rev, 216, 127. [3] Tarnas, J. et al., (2021) JGR: Planets, 126, 11. [4] Steele et al., (2007) Meteorit. Planet. Sci., 42, 9. [5] Murphy, A.E. et al., (2022) LPSC [6] Bhartia et al., (2021) Space Sci Rev, 217, 58. [7] Luther (2021) GRL, 48, e2021GL094869. [8] Dodd et al., (2017) Nature, 543, 60-64

E L Cardarelli↗
DOE OSTI2020

Materials Data on CsK2Fe3P4ClO14 by Materials Project

CsK2Fe3P4O14Cl crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Cs1+ is bonded in a 12-coordinate geometry to ten O2- and two equivalent Cl1- atoms. There are a spread of Cs–O bond distances ranging from 3.21–3.69 Å. Both Cs–Cl bond lengths are 3.88 Å. K1+ is bonded in a 9-coordinate geometry to eight O2- and one Cl1- atom. There are a spread of K–O bond distances ranging from 2.77–3.26 Å. The K–Cl bond length is 3.10 Å. There are two inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to five O2- atoms to form distorted FeO5 trigonal bipyramids that share corners with five PO4 tetrahedra and an edgeedge with one FeO5 trigonal bipyramid. There are a spread of Fe–O bond distances ranging from 2.02–2.39 Å. In the second Fe2+ site, Fe2+ is bonded to four O2- and two equivalent Cl1- atoms to form distorted FeCl2O4 octahedra that share corners with two equivalent FeCl2O4 octahedra and corners with four PO4 tetrahedra. The corner-sharing octahedral tilt angles are 0°. There are two shorter (2.07 Å) and two longer (2.21 Å) Fe–O bond lengths. Both Fe–Cl bond lengths are 2.70 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one FeCl2O4 octahedra, a cornercorner with one PO4 tetrahedra, and corners with two equivalent FeO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 22°. There are a spread of P–O bond distances ranging from 1.51–1.65 Å. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share a cornercorner with one FeCl2O4 octahedra, a cornercorner with one PO4 tetrahedra, and corners with three equivalent FeO5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 25°. There are a spread of P–O bond distances ranging from 1.50–1.65 Å. There are seven inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 120 degrees geometry to two equivalent Cs1+ and two P5+ atoms. In the second O2- site, O2- is bonded in a 4-coordinate geometry to two equivalent K1+, one Fe2+, and one P5+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent K1+, one Fe2+, and one P5+ atom. In the fourth O2- site, O2- is bonded in a 1-coordinate geometry to two equivalent K1+, one Fe2+, and one P5+ atom. In the fifth O2- site, O2- is bonded in a 2-coordinate geometry to one K1+, two equivalent Fe2+, and one P5+ atom. In the sixth O2- site, O2- is bonded in a 3-coordinate geometry to one Cs1+, one K1+, one Fe2+, and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two equivalent Cs1+, one Fe2+, and one P5+ atom. Cl1- is bonded in a distorted square co-planar geometry to two equivalent Cs1+, two equivalent K1+, and two equivalent Fe2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba9(FeSe4)4 by Materials Project

Ba9Fe4Se16 crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are ten inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.31–3.50 Å. In the second Ba2+ site, Ba2+ is bonded in a 8-coordinate geometry to eight Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.32–3.46 Å. In the third Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to seven Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.16–3.57 Å. In the fourth Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.29–3.91 Å. In the fifth Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to seven Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.17–3.75 Å. In the sixth Ba2+ site, Ba2+ is bonded in a 9-coordinate geometry to nine Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.26–3.90 Å. In the seventh Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to seven Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.13–3.70 Å. In the eighth Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to nine Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.12–3.97 Å. In the ninth Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to seven Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.13–3.72 Å. In the tenth Ba2+ site, Ba2+ is bonded in a 7-coordinate geometry to nine Se+1.62- atoms. There are a spread of Ba–Se bond distances ranging from 3.15–3.94 Å. There are four inequivalent Fe2+ sites. In the first Fe2+ site, Fe2+ is bonded to four Se+1.62- atoms to form edge-sharing FeSe4 tetrahedra. There are a spread of Fe–Se bond distances ranging from 2.38–2.41 Å. In the second Fe2+ site, Fe2+ is bonded to four Se+1.62- atoms to form edge-sharing FeSe4 tetrahedra. There are a spread of Fe–Se bond distances ranging from 2.39–2.42 Å. In the third Fe2+ site, Fe2+ is bonded to four Se+1.62- atoms to form edge-sharing FeSe4 tetrahedra. There are a spread of Fe–Se bond distances ranging from 2.38–2.41 Å. In the fourth Fe2+ site, Fe2+ is bonded to four Se+1.62- atoms to form edge-sharing FeSe4 tetrahedra. There are a spread of Fe–Se bond distances ranging from 2.38–2.41 Å. There are seventeen inequivalent Se+1.62- sites. In the first Se+1.62- site, Se+1.62- is bonded to five Ba2+ and one Fe2+ atom to form a mixture of distorted corner, edge, and face-sharing SeBa5Fe octahedra. The corner-sharing octahedra tilt angles range from 48–50°. In the second Se+1.62- site, Se+1.62- is bonded to five Ba2+ and one Fe2+ atom to form a mixture of distorted corner, edge, and face-sharing SeBa5Fe octahedra. The corner-sharing octahedra tilt angles range from 46–53°. In the third Se+1.62- site, Se+1.62- is bonded to five Ba2+ and one Fe2+ atom to form a mixture of distorted corner, edge, and face-sharing SeBa5Fe octahedra. The corner-sharing octahedra tilt angles range from 46–50°. In the fourth Se+1.62- site, Se+1.62- is bonded to five Ba2+ and one Fe2+ atom to form a mixture of distorted corner, edge, and face-sharing SeBa5Fe octahedra. The corner-sharing octahedra tilt angles range from 48–53°. In the fifth Se+1.62- site, Se+1.62- is bonded in a 6-coordinate geometry to five Ba2+ and one Fe2+ atom. In the sixth Se+1.62- site, Se+1.62- is bonded in a 6-coordinate geometry to five Ba2+ and one Fe2+ atom. In the seventh Se+1.62- site, Se+1.62- is bonded in a 6-coordinate geometry to five Ba2+ and one Fe2+ atom. In the eighth Se+1.62- site, Se+1.62- is bonded in a 6-coordinate geometry to five Ba2+ and one Fe2+ atom. In the ninth Se+1.62- site, Se+1.62- is bonded in a 5-coordinate geometry to four Ba2+, two equivalent Fe2+, and one Se+1.62- atom. The Se–Se bond length is 3.54 Å. In the tenth Se+1.62- site, Se+1.62- is bonded in a 5-coordinate geometry to three Ba2+ and two equivalent Fe2+ atoms. In the eleventh Se+1.62- site, Se+1.62- is bonded in a 5-coordinate geometry to four Ba2+, two equivalent Fe2+, and one Se+1.62- atom. The Se–Se bond length is 3.56 Å. In the twelfth Se+1.62- site, Se+1.62- is bonded in a 5-coordinate geometry to three Ba2+ and two equivalent Fe2+ atoms. In the thirteenth Se+1.62- site, Se+1.62- is bonded in a 4-coordinate geometry to four Ba2+ atoms. In the fourteenth Se+1.62- site, Se+1.62- is bonded in a 4-coordinate geometry to four Ba2+ atoms. In the fifteenth Se+1.62- site, Se+1.62- is bonded in a 4-coordinate geometry to five Ba2+ and three Se+1.62- atoms. There are one shorter (2.41 Å) and one longer (2.95 Å) Se–Se bond lengths. In the sixteenth Se+1.62- site, Se+1.62- is bonded in a square co-planar geometry to four Ba2+ atoms. In the seventeenth Se+1.62- site, Se+1.62- is bonded in a 4-coordinate geometry to five Ba2+ and three Se+1.62- atoms. The Se–Se bond length is 2.93 Å.

36 MATERIALS SCIENCE↗