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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on K3V by Materials Project

VK3 is alpha bismuth trifluoride structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. there are two inequivalent K sites. In the first K site, K is bonded to four equivalent K and four equivalent V atoms to form a mixture of distorted corner, edge, and face-sharing KK4V4 tetrahedra. All K–K bond lengths are 3.99 Å. All K–V bond lengths are 3.99 Å. In the second K site, K is bonded in a body-centered cubic geometry to eight equivalent K atoms. V is bonded in a body-centered cubic geometry to eight equivalent K atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K3V(SO5)2 by Materials Project

K3VO2(SO4)2 crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are three inequivalent K1+ sites. In the first K1+ site, K1+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of K–O bond distances ranging from 2.75–3.15 Å. In the second K1+ site, K1+ is bonded to seven O2- atoms to form KO7 pentagonal bipyramids that share corners with four SO4 tetrahedra and an edgeedge with one SO4 tetrahedra. There are a spread of K–O bond distances ranging from 2.73–3.02 Å. In the third K1+ site, K1+ is bonded in a 7-coordinate geometry to seven O2- atoms. There are a spread of K–O bond distances ranging from 2.88–3.01 Å. V5+ is bonded in a 4-coordinate geometry to six O2- atoms. There are a spread of V–O bond distances ranging from 1.66–2.54 Å. There are two inequivalent S6+ sites. In the first S6+ site, S6+ is bonded to four O2- atoms to form SO4 tetrahedra that share corners with two equivalent KO7 pentagonal bipyramids and an edgeedge with one KO7 pentagonal bipyramid. There are a spread of S–O bond distances ranging from 1.46–1.56 Å. In the second S6+ site, S6+ is bonded to four O2- atoms to form SO4 tetrahedra that share corners with two equivalent KO7 pentagonal bipyramids. There are a spread of S–O bond distances ranging from 1.46–1.57 Å. There are ten inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted water-like geometry to one K1+, one V5+, and one S6+ atom. In the second O2- site, O2- is bonded in a distorted single-bond geometry to two equivalent K1+, one V5+, and one S6+ atom. In the third O2- site, O2- is bonded in a 1-coordinate geometry to two K1+, one V5+, and one S6+ atom. In the fourth O2- site, O2- is bonded in a distorted water-like geometry to two K1+, one V5+, and one S6+ atom. In the fifth O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one S6+ atom. In the sixth O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one V5+ atom. In the seventh O2- site, O2- is bonded in a distorted single-bond geometry to three K1+ and one S6+ atom. In the eighth O2- site, O2- is bonded in a distorted single-bond geometry to two K1+ and one S6+ atom. In the ninth O2- site, O2- is bonded in a distorted single-bond geometry to three K1+ and one S6+ atom. In the tenth O2- site, O2- is bonded in a distorted single-bond geometry to three K1+ and one V5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K3V(PO4)2 by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on K3V3O8 by Materials Project

K3V(VO4)2 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. there are two inequivalent K1+ sites. In the first K1+ site, K1+ is bonded to twelve O2- atoms to form KO12 cuboctahedra that share edges with six equivalent KO12 cuboctahedra, edges with six equivalent VO4 tetrahedra, and faces with two equivalent VO6 octahedra. There are six shorter (3.06 Å) and six longer (3.34 Å) K–O bond lengths. In the second K1+ site, K1+ is bonded in a 1-coordinate geometry to ten O2- atoms. There are a spread of K–O bond distances ranging from 2.62–3.13 Å. There are two inequivalent V+4.33+ sites. In the first V+4.33+ site, V+4.33+ is bonded to six equivalent O2- atoms to form VO6 octahedra that share corners with six equivalent VO4 tetrahedra and faces with two equivalent KO12 cuboctahedra. All V–O bond lengths are 2.05 Å. In the second V+4.33+ site, V+4.33+ is bonded to four O2- atoms to form VO4 tetrahedra that share corners with three equivalent VO6 octahedra and edges with three equivalent KO12 cuboctahedra. The corner-sharing octahedral tilt angles are 16°. There is one shorter (1.68 Å) and three longer (1.77 Å) V–O bond length. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a 2-coordinate geometry to four K1+ and two V+4.33+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to four K1+ and one V+4.33+ atom.

36 MATERIALS SCIENCE↗
NASA NTRS1981

A four-hour orbital period of the X-ray burster 4U/MXB1636-53

The characterization of X-ray burst sources and other, non-bursting galactic bulge X-ray sources as low-mass close binary systems is generally accepted. The companion stars of the transient burst sources Aql X-1 and Cen X-4 are of spectral types G7-K3V and K3-7V, respectively. If these stars fill their Roche lobe, their orbital periods are in the range of 5-8 hr. X-ray observations offer evidence for a Cen X-4 orbital period of about 8 hr. An analysis of average optical properties yields values for the typical companion star masses and orbital periods of this class of low-mass X-ray binaries of about 0.6 solar masses and 6 hr, respectively.

Pedersen, H.↗