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TaSe4(Se)2 crystallizes in the orthorhombic Cmmm space group. The structure is zero-dimensional and consists of four selenium molecules and two TaSe4 clusters. In each TaSe4 cluster, Ta4+ is bonded in a distorted rectangular see-saw-like geometry to four equivalent Se+0.67- atoms. All Ta–Se bond lengths are 2.47 Å. Se+0.67- is bonded in a single-bond geometry to one Ta4+ atom.
Ta12Co3Pt3Se32 crystallizes in the monoclinic Cm space group. The structure is two-dimensional and consists of two Ta12Co3Pt3Se32 sheets oriented in the (1, 0, 0) direction. there are twelve inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded in a 6-coordinate geometry to two equivalent Pt+0.67- and six Se2- atoms. Both Ta–Pt bond lengths are 3.05 Å. There are a spread of Ta–Se bond distances ranging from 2.56–2.80 Å. In the second Ta5+ site, Ta5+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share a cornercorner with one TaSe6 octahedra, edges with two equivalent TaSe6 pentagonal pyramids, and edges with two equivalent CoSe5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 50°. There are a spread of Ta–Se bond distances ranging from 2.54–2.64 Å. In the third Ta5+ site, Ta5+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share a cornercorner with one TaSe6 octahedra, edges with two equivalent TaSe6 pentagonal pyramids, and edges with two equivalent CoSe5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 51°. There are a spread of Ta–Se bond distances ranging from 2.53–2.65 Å. In the fourth Ta5+ site, Ta5+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share a cornercorner with one TaSe6 octahedra, edges with two equivalent TaSe6 pentagonal pyramids, and edges with two equivalent CoSe5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 50°. There are a spread of Ta–Se bond distances ranging from 2.54–2.65 Å. In the fifth Ta5+ site, Ta5+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are five shorter (2.62 Å) and one longer (2.64 Å) Ta–Se bond lengths. In the sixth Ta5+ site, Ta5+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of Ta–Se bond distances ranging from 2.61–2.63 Å. In the seventh Ta5+ site, Ta5+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are a spread of Ta–Se bond distances ranging from 2.60–2.62 Å. In the eighth Ta5+ site, Ta5+ is bonded in a 6-coordinate geometry to six Se2- atoms. There are five shorter (2.62 Å) and one longer (2.64 Å) Ta–Se bond lengths. In the ninth Ta5+ site, Ta5+ is bonded in a 6-coordinate geometry to two equivalent Pt+0.67- and six Se2- atoms. Both Ta–Pt bond lengths are 2.99 Å. There are a spread of Ta–Se bond distances ranging from 2.58–2.68 Å. In the tenth Ta5+ site, Ta5+ is bonded to six Se2- atoms to form TaSe6 octahedra that share a cornercorner with one TaSe6 pentagonal pyramid, edges with four TaSe6 octahedra, and edges with two equivalent CoSe5 trigonal bipyramids. There are a spread of Ta–Se bond distances ranging from 2.53–2.70 Å. In the eleventh Ta5+ site, Ta5+ is bonded to six Se2- atoms to form TaSe6 octahedra that share a cornercorner with one TaSe6 pentagonal pyramid, edges with two equivalent TaSe6 octahedra, and edges with two equivalent CoSe5 trigonal bipyramids. There are a spread of Ta–Se bond distances ranging from 2.53–2.71 Å. In the twelfth Ta5+ site, Ta5+ is bonded to six Se2- atoms to form TaSe6 octahedra that share a cornercorner with one TaSe6 pentagonal pyramid, edges with four TaSe6 octahedra, and edges with two equivalent CoSe5 trigonal bipyramids. There are a spread of Ta–Se bond distances ranging from 2.53–2.70 Å. There are three inequivalent Co2+ sites. In the first Co2+ site, Co2+ is bonded to five Se2- atoms to form CoSe5 trigonal bipyramids that share edges with two equivalent TaSe6 octahedra, edges with two equivalent TaSe6 pentagonal pyramids, and edges with two equivalent CoSe5 trigonal bipyramids. There are a spread of Co–Se bond distances ranging from 2.39–2.43 Å. In the second Co2+ site, Co2+ is bonded to five Se2- atoms to form CoSe5 trigonal bipyramids that share edges with two equivalent TaSe6 octahedra, edges with two equivalent TaSe6 pentagonal pyramids, and edges with two equivalent CoSe5 trigonal bipyramids. There are a spread of Co–Se bond distances ranging from 2.39–2.43 Å. In the third Co2+ site, Co2+ is bonded to five Se2- atoms to form CoSe5 trigonal bipyramids that share edges with two equivalent TaSe6 octahedra, edges with two equivalent TaSe6 pentagonal pyramids, and edges with two equivalent CoSe5 trigonal bipyramids. There are a spread of Co–Se bond distances ranging from 2.38–2.43 Å. There are three inequivalent Pt+0.67- sites. In the first Pt+0.67- site, Pt+0.67- is bonded in a square co-planar geometry to four Se2- atoms. All Pt–Se bond lengths are 2.48 Å. In the second Pt+0.67- site, Pt+0.67- is bonded in a square co-planar geometry to four Se2- atoms. There are two shorter (2.47 Å) and two longer (2.48 Å) Pt–Se bond lengths. In the third Pt+0.67- site, Pt+0.67- is bonded in a 9-coordinate geometry to four Ta5+ and five Se2- atoms. There are two shorter (2.50 Å) and three longer (2.57 Å) Pt–Se bond lengths. There are thirty-two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta5+ atoms. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta5+ atoms. In the third Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta5+ atoms. In the fourth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta5+ atoms. In the fifth Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ta5+ and one Co2+ atom. In the sixth Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ta5+ and one Co2+ atom. In the seventh Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ta5+ and one Pt+0.67- atom. In the eighth Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ta5+ and one Co2+ atom. In the ninth Se2- site, Se2- is bonded in a 4-coordinate geometry to two Ta5+ and two equivalent Pt+0.67- atoms. In the tenth Se2- site, Se2- is bonded in a 4-coordinate geometry to two Ta5+ and two equivalent Co2+ atoms. In the eleventh Se2- site, Se2- is bonded in a 4-coordinate geometry to two Ta5+ and two equivalent Co2+ atoms. In the twelfth Se2- site, Se2- is bonded in a 4-coordinate geometry to two Ta5+ and two equivalent Co2+ atoms. In the thirteenth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta5+ atoms. In the fourteenth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta5+ atoms. In the fifteenth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta5+ atoms. In the sixteenth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta5+ atoms. In the seventeenth Se2- site, Se2- is bonded in a distorted T-shaped geometry to one Ta5+ and two equivalent Co2+ atoms. In the eighteenth Se2- site, Se2- is bonded in a distorted T-shaped geometry to one Ta5+ and two equivalent Co2+ atoms. In the nineteenth Se2- site, Se2- is bonded in a 3-coordinate geometry to one Ta5+ and two equivalent Pt+0.67- atoms. In the twentieth Se2- site, Se2- is bonded in a distorted T-shaped geometry to one Ta5+ and two equivalent Co2+ atoms. In the twenty-first Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta5+ atoms. In the twenty-second Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta5+ atoms. In the twenty-third Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta5+ atoms. In the twenty-fourth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta5+ atoms. In the twenty-fifth Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ta5+ and one Pt+0.67- atom. In the twenty-sixth Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ta5+ and one Pt+0.67- atom. In the twenty-seventh Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ta5+ and one Pt+0.67- atom. In the twenty-eighth Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ta5+ and one Pt+0.67- atom. In the twenty-ninth Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ta5+ and one Pt+0.67- atom. In the thirtieth Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ta5+ and one Pt+0.67- atom. In the thirty-first Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ta5+ and one Pt+0.67- atom. In the thirty-second Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ta5+ and one Pt+0.67- atom.
CsTaSe3 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded to twelve Se2- atoms to form CsSe12 cuboctahedra that share corners with six CsSe12 cuboctahedra, corners with six TaSe6 octahedra, faces with eight CsSe12 cuboctahedra, and faces with six TaSe6 octahedra. The corner-sharing octahedra tilt angles range from 13–21°. There are a spread of Cs–Se bond distances ranging from 3.85–3.92 Å. In the second Cs1+ site, Cs1+ is bonded to twelve Se2- atoms to form CsSe12 cuboctahedra that share corners with six CsSe12 cuboctahedra, corners with six TaSe6 octahedra, faces with eight CsSe12 cuboctahedra, and faces with six TaSe6 octahedra. The corner-sharing octahedra tilt angles range from 11–22°. There are a spread of Cs–Se bond distances ranging from 3.85–3.93 Å. In the third Cs1+ site, Cs1+ is bonded to twelve Se2- atoms to form CsSe12 cuboctahedra that share corners with six CsSe12 cuboctahedra, corners with six TaSe6 octahedra, faces with eight CsSe12 cuboctahedra, and faces with six TaSe6 octahedra. The corner-sharing octahedra tilt angles range from 11–21°. There are a spread of Cs–Se bond distances ranging from 3.84–3.94 Å. In the fourth Cs1+ site, Cs1+ is bonded to twelve Se2- atoms to form CsSe12 cuboctahedra that share corners with six CsSe12 cuboctahedra, corners with six TaSe6 octahedra, faces with eight CsSe12 cuboctahedra, and faces with six TaSe6 octahedra. The corner-sharing octahedra tilt angles range from 12–21°. There are a spread of Cs–Se bond distances ranging from 3.85–3.94 Å. There are four inequivalent Ta5+ sites. In the first Ta5+ site, Ta5+ is bonded to six Se2- atoms to form TaSe6 octahedra that share corners with six CsSe12 cuboctahedra, faces with six CsSe12 cuboctahedra, and faces with two equivalent TaSe6 octahedra. There are a spread of Ta–Se bond distances ranging from 2.47–2.79 Å. In the second Ta5+ site, Ta5+ is bonded to six Se2- atoms to form TaSe6 octahedra that share corners with six CsSe12 cuboctahedra, faces with six CsSe12 cuboctahedra, and faces with two equivalent TaSe6 octahedra. There are a spread of Ta–Se bond distances ranging from 2.47–2.77 Å. In the third Ta5+ site, Ta5+ is bonded to six Se2- atoms to form TaSe6 octahedra that share corners with six CsSe12 cuboctahedra, faces with six CsSe12 cuboctahedra, and faces with two equivalent TaSe6 octahedra. There are a spread of Ta–Se bond distances ranging from 2.47–2.79 Å. In the fourth Ta5+ site, Ta5+ is bonded to six Se2- atoms to form TaSe6 octahedra that share corners with six CsSe12 cuboctahedra, faces with six CsSe12 cuboctahedra, and faces with two equivalent TaSe6 octahedra. There are a spread of Ta–Se bond distances ranging from 2.47–2.79 Å. There are twelve inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 6-coordinate geometry to four Cs1+ and two Ta5+ atoms. In the second Se2- site, Se2- is bonded in a 6-coordinate geometry to four Cs1+ and two Ta5+ atoms. In the third Se2- site, Se2- is bonded in a 6-coordinate geometry to four Cs1+ and two Ta5+ atoms. In the fourth Se2- site, Se2- is bonded in a 6-coordinate geometry to four Cs1+ and two Ta5+ atoms. In the fifth Se2- site, Se2- is bonded in a 6-coordinate geometry to four Cs1+ and two Ta5+ atoms. In the sixth Se2- site, Se2- is bonded in a 6-coordinate geometry to four Cs1+ and two Ta5+ atoms. In the seventh Se2- site, Se2- is bonded in a 6-coordinate geometry to four Cs1+ and two Ta5+ atoms. In the eighth Se2- site, Se2- is bonded in a 6-coordinate geometry to four Cs1+ and two Ta5+ atoms. In the ninth Se2- site, Se2- is bonded in a 6-coordinate geometry to four Cs1+ and two Ta5+ atoms. In the tenth Se2- site, Se2- is bonded in a 6-coordinate geometry to four Cs1+ and two Ta5+ atoms. In the eleventh Se2- site, Se2- is bonded in a 6-coordinate geometry to four Cs1+ and two Ta5+ atoms. In the twelfth Se2- site, Se2- is bonded in a 6-coordinate geometry to four Cs1+ and two Ta5+ atoms.
Ti5Ta24Se48 crystallizes in the trigonal R-3 space group. The structure is three-dimensional. there are three inequivalent Ti4+ sites. In the first Ti4+ site, Ti4+ is bonded to six Se2- atoms to form TiSe6 octahedra that share corners with twelve TaSe6 pentagonal pyramids and a faceface with one TaSe6 pentagonal pyramid. There are three shorter (2.52 Å) and three longer (2.68 Å) Ti–Se bond lengths. In the second Ti4+ site, Ti4+ is bonded in a distorted trigonal non-coplanar geometry to three equivalent Se2- atoms. All Ti–Se bond lengths are 2.46 Å. In the third Ti4+ site, Ti4+ is bonded to six equivalent Se2- atoms to form TiSe6 octahedra that share corners with twelve TaSe6 pentagonal pyramids and faces with two equivalent TaSe6 pentagonal pyramids. All Ti–Se bond lengths are 2.57 Å. There are six inequivalent Ta+3.17+ sites. In the first Ta+3.17+ site, Ta+3.17+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share a cornercorner with one TiSe6 octahedra, corners with two equivalent TaSe6 octahedra, and edges with four TaSe6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 47–50°. There are a spread of Ta–Se bond distances ranging from 2.62–2.67 Å. In the second Ta+3.17+ site, Ta+3.17+ is bonded to six Se2- atoms to form corner-sharing TaSe6 octahedra. There are three shorter (2.51 Å) and three longer (2.76 Å) Ta–Se bond lengths. In the third Ta+3.17+ site, Ta+3.17+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share a cornercorner with one TaSe6 octahedra, corners with three TiSe6 octahedra, and edges with five TaSe6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 46–50°. There are a spread of Ta–Se bond distances ranging from 2.58–2.66 Å. In the fourth Ta+3.17+ site, Ta+3.17+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share a cornercorner with one TaSe6 octahedra, corners with two TiSe6 octahedra, and edges with five TaSe6 pentagonal pyramids. The corner-sharing octahedra tilt angles range from 44–47°. There are a spread of Ta–Se bond distances ranging from 2.61–2.70 Å. In the fifth Ta+3.17+ site, Ta+3.17+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share edges with six TaSe6 pentagonal pyramids and faces with two TiSe6 octahedra. There are three shorter (2.62 Å) and three longer (2.63 Å) Ta–Se bond lengths. In the sixth Ta+3.17+ site, Ta+3.17+ is bonded in a trigonal planar geometry to three equivalent Se2- atoms. All Ta–Se bond lengths are 2.45 Å. There are eight inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to one Ti4+ and three Ta+3.17+ atoms to form a mixture of distorted edge, face, and corner-sharing SeTa3Ti trigonal pyramids. In the second Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to one Ti4+ and three Ta+3.17+ atoms. In the third Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta+3.17+ atoms. In the fourth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta+3.17+ atoms. In the fifth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta+3.17+ atoms. In the sixth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta+3.17+ atoms. In the seventh Se2- site, Se2- is bonded to one Ti4+ and three Ta+3.17+ atoms to form a mixture of distorted edge, face, and corner-sharing SeTa3Ti trigonal pyramids. In the eighth Se2- site, Se2- is bonded in a 3-coordinate geometry to one Ti4+ and two Ta+3.17+ atoms.
Ta3VSe6 is Ilmenite-like structured and crystallizes in the monoclinic C2 space group. The structure is three-dimensional. there are four inequivalent Ta3+ sites. In the first Ta3+ site, Ta3+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share corners with six equivalent VSe6 octahedra and edges with six equivalent TaSe6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 46°. There are two shorter (2.60 Å) and four longer (2.61 Å) Ta–Se bond lengths. In the second Ta3+ site, Ta3+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share corners with six equivalent VSe6 octahedra and edges with six equivalent TaSe6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 46°. There are two shorter (2.60 Å) and four longer (2.61 Å) Ta–Se bond lengths. In the third Ta3+ site, Ta3+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share corners with three equivalent VSe6 octahedra, edges with six TaSe6 pentagonal pyramids, and a faceface with one VSe6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are three shorter (2.61 Å) and three longer (2.63 Å) Ta–Se bond lengths. In the fourth Ta3+ site, Ta3+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share corners with three equivalent VSe6 octahedra, edges with six TaSe6 pentagonal pyramids, and a faceface with one VSe6 octahedra. The corner-sharing octahedra tilt angles range from 46–47°. There are three shorter (2.61 Å) and three longer (2.63 Å) Ta–Se bond lengths. V3+ is bonded to six Se2- atoms to form VSe6 octahedra that share corners with twelve TaSe6 pentagonal pyramids and faces with two TaSe6 pentagonal pyramids. There are four shorter (2.52 Å) and two longer (2.53 Å) V–Se bond lengths. There are six inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three Ta3+ and one V3+ atom to form a mixture of distorted face, edge, and corner-sharing SeTa3V trigonal pyramids. In the second Se2- site, Se2- is bonded to three Ta3+ and one V3+ atom to form a mixture of distorted face, edge, and corner-sharing SeTa3V trigonal pyramids. In the third Se2- site, Se2- is bonded to three Ta3+ and one V3+ atom to form a mixture of distorted face, edge, and corner-sharing SeTa3V trigonal pyramids. In the fourth Se2- site, Se2- is bonded to three Ta3+ and one V3+ atom to form a mixture of distorted face, edge, and corner-sharing SeTa3V trigonal pyramids. In the fifth Se2- site, Se2- is bonded to three Ta3+ and one V3+ atom to form a mixture of distorted face, edge, and corner-sharing SeTa3V trigonal pyramids. In the sixth Se2- site, Se2- is bonded to three Ta3+ and one V3+ atom to form a mixture of distorted face, edge, and corner-sharing SeTa3V trigonal pyramids.
Co2Ta4PdSe12 crystallizes in the monoclinic C2/m space group. The structure is two-dimensional and consists of one Co2Ta4PdSe12 sheet oriented in the (2, 0, -1) direction. there are two inequivalent Ta+4.50+ sites. In the first Ta+4.50+ site, Ta+4.50+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share a cornercorner with one TaSe6 octahedra, edges with two equivalent TaSe6 pentagonal pyramids, and edges with two equivalent CoSe5 trigonal bipyramids. The corner-sharing octahedral tilt angles are 52°. There are a spread of Ta–Se bond distances ranging from 2.53–2.64 Å. In the second Ta+4.50+ site, Ta+4.50+ is bonded to six Se2- atoms to form TaSe6 octahedra that share a cornercorner with one TaSe6 pentagonal pyramid, edges with four equivalent TaSe6 octahedra, and edges with two equivalent CoSe5 trigonal bipyramids. There are a spread of Ta–Se bond distances ranging from 2.55–2.72 Å. Co2+ is bonded to five Se2- atoms to form CoSe5 trigonal bipyramids that share edges with two equivalent TaSe6 octahedra, edges with two equivalent TaSe6 pentagonal pyramids, and edges with two equivalent CoSe5 trigonal bipyramids. There are three shorter (2.39 Å) and two longer (2.42 Å) Co–Se bond lengths. Pd2+ is bonded in a square co-planar geometry to four Se2- atoms. There are two shorter (2.47 Å) and two longer (2.49 Å) Pd–Se bond lengths. There are six inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ta+4.50+ and one Pd2+ atom. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ta+4.50+ and one Co2+ atom. In the third Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Ta+4.50+ atoms. In the fourth Se2- site, Se2- is bonded in a distorted T-shaped geometry to one Ta+4.50+ and two equivalent Co2+ atoms. In the fifth Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ta+4.50+ and one Pd2+ atom. In the sixth Se2- site, Se2- is bonded in a 4-coordinate geometry to two Ta+4.50+ and two equivalent Co2+ atoms.
TaSe2 is trigonal omega-like structured and crystallizes in the triclinic P-1 space group. The structure is two-dimensional and consists of one TaSe2 sheet oriented in the (1, 1, 1) direction. there are seven inequivalent Ta4+ sites. In the first Ta4+ site, Ta4+ is bonded to six Se2- atoms to form edge-sharing TaSe6 octahedra. All Ta–Se bond lengths are 2.66 Å. In the second Ta4+ site, Ta4+ is bonded to six Se2- atoms to form edge-sharing TaSe6 octahedra. There are a spread of Ta–Se bond distances ranging from 2.56–2.73 Å. In the third Ta4+ site, Ta4+ is bonded to six Se2- atoms to form edge-sharing TaSe6 octahedra. There are a spread of Ta–Se bond distances ranging from 2.56–2.73 Å. In the fourth Ta4+ site, Ta4+ is bonded to six Se2- atoms to form edge-sharing TaSe6 octahedra. There are a spread of Ta–Se bond distances ranging from 2.56–2.73 Å. In the fifth Ta4+ site, Ta4+ is bonded to six Se2- atoms to form edge-sharing TaSe6 octahedra. There are a spread of Ta–Se bond distances ranging from 2.48–2.77 Å. In the sixth Ta4+ site, Ta4+ is bonded to six Se2- atoms to form edge-sharing TaSe6 octahedra. There are a spread of Ta–Se bond distances ranging from 2.48–2.76 Å. In the seventh Ta4+ site, Ta4+ is bonded to six Se2- atoms to form edge-sharing TaSe6 octahedra. There are a spread of Ta–Se bond distances ranging from 2.48–2.76 Å. There are thirteen inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta4+ atoms. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta4+ atoms. In the third Se2- site, Se2- is bonded in a distorted T-shaped geometry to three Ta4+ atoms. In the fourth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta4+ atoms. In the fifth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta4+ atoms. In the sixth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta4+ atoms. In the seventh Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta4+ atoms. In the eighth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta4+ atoms. In the ninth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta4+ atoms. In the tenth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta4+ atoms. In the eleventh Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta4+ atoms. In the twelfth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta4+ atoms. In the thirteenth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta4+ atoms.
Ta4MoSe10 is Molybdenite-derived structured and crystallizes in the monoclinic Cm space group. The structure is two-dimensional and consists of one Ta4MoSe10 sheet oriented in the (2, 0, 1) direction. there are four inequivalent Ta+4.50+ sites. In the first Ta+4.50+ site, Ta+4.50+ is bonded to six Se2- atoms to form distorted edge-sharing TaSe6 pentagonal pyramids. There are four shorter (2.61 Å) and two longer (2.63 Å) Ta–Se bond lengths. In the second Ta+4.50+ site, Ta+4.50+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share edges with two equivalent MoSe6 pentagonal pyramids and edges with four TaSe6 pentagonal pyramids. There are four shorter (2.59 Å) and two longer (2.64 Å) Ta–Se bond lengths. In the third Ta+4.50+ site, Ta+4.50+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share edges with two equivalent MoSe6 pentagonal pyramids and edges with four TaSe6 pentagonal pyramids. There are a spread of Ta–Se bond distances ranging from 2.54–2.63 Å. In the fourth Ta+4.50+ site, Ta+4.50+ is bonded to six Se2- atoms to form distorted edge-sharing TaSe6 pentagonal pyramids. There are two shorter (2.61 Å) and four longer (2.62 Å) Ta–Se bond lengths. Mo2+ is bonded to six Se2- atoms to form distorted MoSe6 pentagonal pyramids that share edges with two equivalent MoSe6 pentagonal pyramids and edges with four TaSe6 pentagonal pyramids. There are two shorter (2.58 Å) and four longer (2.59 Å) Mo–Se bond lengths. There are nine inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to one Ta+4.50+ and two equivalent Mo2+ atoms. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta+4.50+ atoms. In the third Se2- site, Se2- is bonded in a distorted T-shaped geometry to three Ta+4.50+ atoms. In the fourth Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ta+4.50+ and one Mo2+ atom. In the fifth Se2- site, Se2- is bonded in a distorted T-shaped geometry to three Ta+4.50+ atoms. In the sixth Se2- site, Se2- is bonded in a 3-coordinate geometry to three Ta+4.50+ atoms. In the seventh Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ta+4.50+ and one Mo2+ atom. In the eighth Se2- site, Se2- is bonded in a distorted T-shaped geometry to three Ta+4.50+ atoms. In the ninth Se2- site, Se2- is bonded in a distorted T-shaped geometry to three Ta+4.50+ atoms.
Ta4CrSe8 crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. there are two inequivalent Ta+3.50+ sites. In the first Ta+3.50+ site, Ta+3.50+ is bonded to six equivalent Se2- atoms to form distorted TaSe6 pentagonal pyramids that share edges with six equivalent TaSe6 pentagonal pyramids and faces with two equivalent CrSe6 octahedra. All Ta–Se bond lengths are 2.60 Å. In the second Ta+3.50+ site, Ta+3.50+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share corners with four equivalent CrSe6 octahedra and edges with six TaSe6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 47°. There are two shorter (2.58 Å) and four longer (2.63 Å) Ta–Se bond lengths. Cr2+ is bonded to six equivalent Se2- atoms to form CrSe6 octahedra that share corners with twelve equivalent TaSe6 pentagonal pyramids and faces with two equivalent TaSe6 pentagonal pyramids. All Cr–Se bond lengths are 2.48 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Ta+3.50+ atoms. In the second Se2- site, Se2- is bonded to three Ta+3.50+ and one Cr2+ atom to form a mixture of distorted face, edge, and corner-sharing SeTa3Cr trigonal pyramids.
Ta3CrSe6 is Ilmenite-like structured and crystallizes in the hexagonal P6_322 space group. The structure is three-dimensional. there are two inequivalent Ta3+ sites. In the first Ta3+ site, Ta3+ is bonded to six equivalent Se2- atoms to form distorted TaSe6 pentagonal pyramids that share corners with six equivalent CrSe6 octahedra and edges with six equivalent TaSe6 pentagonal pyramids. The corner-sharing octahedral tilt angles are 47°. All Ta–Se bond lengths are 2.61 Å. In the second Ta3+ site, Ta3+ is bonded to six equivalent Se2- atoms to form distorted TaSe6 pentagonal pyramids that share corners with three equivalent CrSe6 octahedra, edges with six TaSe6 pentagonal pyramids, and a faceface with one CrSe6 octahedra. The corner-sharing octahedral tilt angles are 47°. There are three shorter (2.60 Å) and three longer (2.64 Å) Ta–Se bond lengths. Cr3+ is bonded to six equivalent Se2- atoms to form CrSe6 octahedra that share corners with twelve TaSe6 pentagonal pyramids and faces with two equivalent TaSe6 pentagonal pyramids. All Cr–Se bond lengths are 2.55 Å. Se2- is bonded to three Ta3+ and one Cr3+ atom to form a mixture of distorted face, edge, and corner-sharing SeTa3Cr trigonal pyramids.
NiTa8Se8 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are eight inequivalent Ta sites. In the first Ta site, Ta is bonded in a 5-coordinate geometry to one Ni and four Se atoms. The Ta–Ni bond length is 2.86 Å. There are a spread of Ta–Se bond distances ranging from 2.64–2.73 Å. In the second Ta site, Ta is bonded in a 4-coordinate geometry to one Ni and four Se atoms. The Ta–Ni bond length is 2.91 Å. There are a spread of Ta–Se bond distances ranging from 2.64–2.83 Å. In the third Ta site, Ta is bonded to six Se atoms to form distorted TaSe6 octahedra that share corners with two equivalent TaNi2Se3 trigonal bipyramids, edges with two equivalent TaSe6 octahedra, edges with two equivalent TaSe5 trigonal bipyramids, and a faceface with one TaNi2Se3 trigonal bipyramid. There are a spread of Ta–Se bond distances ranging from 2.61–2.79 Å. In the fourth Ta site, Ta is bonded in a 4-coordinate geometry to one Ni and five Se atoms. The Ta–Ni bond length is 2.92 Å. There are a spread of Ta–Se bond distances ranging from 2.60–3.14 Å. In the fifth Ta site, Ta is bonded to two equivalent Ni and three Se atoms to form distorted TaNi2Se3 trigonal bipyramids that share corners with two equivalent TaSe6 octahedra, corners with two equivalent TaNi2Se3 trigonal bipyramids, edges with three TaNi2Se3 trigonal bipyramids, and a faceface with one TaSe6 octahedra. The corner-sharing octahedral tilt angles are 49°. Both Ta–Ni bond lengths are 2.51 Å. There are one shorter (2.61 Å) and two longer (2.68 Å) Ta–Se bond lengths. In the sixth Ta site, Ta is bonded in a 5-coordinate geometry to two equivalent Ni and three Se atoms. Both Ta–Ni bond lengths are 2.54 Å. There are one shorter (2.58 Å) and two longer (2.68 Å) Ta–Se bond lengths. In the seventh Ta site, Ta is bonded to five Se atoms to form distorted TaSe5 trigonal bipyramids that share edges with two equivalent TaSe6 octahedra and edges with two equivalent TaSe5 trigonal bipyramids. There are a spread of Ta–Se bond distances ranging from 2.60–2.64 Å. In the eighth Ta site, Ta is bonded to two equivalent Ni and three Se atoms to form a mixture of distorted corner and edge-sharing TaNi2Se3 trigonal bipyramids. Both Ta–Ni bond lengths are 2.51 Å. There are one shorter (2.61 Å) and two longer (2.70 Å) Ta–Se bond lengths. Ni is bonded in a 9-coordinate geometry to nine Ta atoms. There are eight inequivalent Se sites. In the first Se site, Se is bonded in a 4-coordinate geometry to four Ta atoms. In the second Se site, Se is bonded in a 4-coordinate geometry to four Ta atoms. In the third Se site, Se is bonded in a 4-coordinate geometry to four Ta atoms. In the fourth Se site, Se is bonded in a distorted pentagonal planar geometry to five Ta atoms. In the fifth Se site, Se is bonded in a pentagonal planar geometry to five Ta atoms. In the sixth Se site, Se is bonded in a 3-coordinate geometry to three Ta atoms. In the seventh Se site, Se is bonded in a 5-coordinate geometry to five Ta atoms. In the eighth Se site, Se is bonded in a distorted T-shaped geometry to three Ta atoms.
CoTa8Se8 crystallizes in the orthorhombic Pnma space group. The structure is three-dimensional. there are eight inequivalent Ta sites. In the first Ta site, Ta is bonded in a 5-coordinate geometry to two equivalent Co and three Se atoms. Both Ta–Co bond lengths are 2.48 Å. There are one shorter (2.62 Å) and two longer (2.72 Å) Ta–Se bond lengths. In the second Ta site, Ta is bonded in a 5-coordinate geometry to two equivalent Co and three Se atoms. Both Ta–Co bond lengths are 2.53 Å. There are one shorter (2.59 Å) and two longer (2.68 Å) Ta–Se bond lengths. In the third Ta site, Ta is bonded to two equivalent Co and three Se atoms to form distorted TaCo2Se3 trigonal bipyramids that share corners with two equivalent TaSe6 octahedra, edges with two equivalent TaCo2Se3 trigonal bipyramids, and a faceface with one TaSe6 octahedra. The corner-sharing octahedral tilt angles are 49°. Both Ta–Co bond lengths are 2.48 Å. There are one shorter (2.63 Å) and two longer (2.69 Å) Ta–Se bond lengths. In the fourth Ta site, Ta is bonded in a 5-coordinate geometry to one Co and four Se atoms. The Ta–Co bond length is 2.86 Å. There are a spread of Ta–Se bond distances ranging from 2.64–2.74 Å. In the fifth Ta site, Ta is bonded in a 4-coordinate geometry to one Co and five Se atoms. The Ta–Co bond length is 2.95 Å. There are a spread of Ta–Se bond distances ranging from 2.59–3.10 Å. In the sixth Ta site, Ta is bonded in a 4-coordinate geometry to one Co and four Se atoms. The Ta–Co bond length is 2.94 Å. There are a spread of Ta–Se bond distances ranging from 2.64–2.81 Å. In the seventh Ta site, Ta is bonded to five Se atoms to form distorted TaSe5 trigonal bipyramids that share edges with two equivalent TaSe6 octahedra and edges with two equivalent TaSe5 trigonal bipyramids. There are a spread of Ta–Se bond distances ranging from 2.59–2.64 Å. In the eighth Ta site, Ta is bonded to six Se atoms to form distorted TaSe6 octahedra that share corners with two equivalent TaCo2Se3 trigonal bipyramids, edges with two equivalent TaSe6 octahedra, edges with two equivalent TaSe5 trigonal bipyramids, and a faceface with one TaCo2Se3 trigonal bipyramid. There are a spread of Ta–Se bond distances ranging from 2.60–2.80 Å. Co is bonded in a 9-coordinate geometry to nine Ta atoms. There are eight inequivalent Se sites. In the first Se site, Se is bonded in a pentagonal planar geometry to five Ta atoms. In the second Se site, Se is bonded in a distorted pentagonal planar geometry to five Ta atoms. In the third Se site, Se is bonded in a distorted T-shaped geometry to three Ta atoms. In the fourth Se site, Se is bonded in a 3-coordinate geometry to three Ta atoms. In the fifth Se site, Se is bonded in a 4-coordinate geometry to four Ta atoms. In the sixth Se site, Se is bonded in a 5-coordinate geometry to five Ta atoms. In the seventh Se site, Se is bonded in a 4-coordinate geometry to four Ta atoms. In the eighth Se site, Se is bonded in a 4-coordinate geometry to four Ta atoms.
TaReCuSe4TaSe2ReSe2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one ReSe2 sheet oriented in the (0, 0, 1) direction; one TaReCuSe4 sheet oriented in the (0, 0, 1) direction; and one TaSe2 sheet oriented in the (0, 0, 1) direction. In the ReSe2 sheet, Re3+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing ReSe6 pentagonal pyramids. All Re–Se bond lengths are 2.54 Å. Se2- is bonded in a distorted T-shaped geometry to three equivalent Re3+ atoms. In the TaReCuSe4 sheet, Ta+4.50+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share corners with six equivalent CuSe6 octahedra, edges with six equivalent TaSe6 pentagonal pyramids, and a faceface with one CuSe6 octahedra. The corner-sharing octahedral tilt angles are 45°. There are three shorter (2.60 Å) and three longer (2.63 Å) Ta–Se bond lengths. Re3+ is bonded to six Se2- atoms to form distorted ReSe6 pentagonal pyramids that share corners with six equivalent CuSe6 octahedra, edges with six equivalent ReSe6 pentagonal pyramids, and a faceface with one CuSe6 octahedra. The corner-sharing octahedral tilt angles are 44°. There are three shorter (2.51 Å) and three longer (2.66 Å) Re–Se bond lengths. Cu1+ is bonded to six Se2- atoms to form CuSe6 octahedra that share corners with six equivalent TaSe6 pentagonal pyramids, corners with six equivalent ReSe6 pentagonal pyramids, edges with six equivalent CuSe6 octahedra, a faceface with one TaSe6 pentagonal pyramid, and a faceface with one ReSe6 pentagonal pyramid. There are three shorter (2.55 Å) and three longer (2.67 Å) Cu–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Ta+4.50+ and three equivalent Cu1+ atoms to form distorted SeTa3Cu3 pentagonal pyramids that share corners with three equivalent SeCu3Re3 pentagonal pyramids and edges with nine SeTa3Cu3 pentagonal pyramids. In the second Se2- site, Se2- is bonded to three equivalent Re3+ and three equivalent Cu1+ atoms to form a mixture of distorted corner and edge-sharing SeCu3Re3 pentagonal pyramids. In the third Se2- site, Se2- is bonded in a distorted T-shaped geometry to three equivalent Re3+ atoms. In the fourth Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Ta+4.50+ atoms. In the TaSe2 sheet, Ta+4.50+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing TaSe6 pentagonal pyramids. All Ta–Se bond lengths are 2.61 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent Ta+4.50+ atoms.
TaReMnSe4TaSe2ReSe2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one ReSe2 sheet oriented in the (0, 0, 1) direction; one TaReMnSe4 sheet oriented in the (0, 0, 1) direction; and one TaSe2 sheet oriented in the (0, 0, 1) direction. In the ReSe2 sheet, Re3+ is bonded to six Se2- atoms to form distorted edge-sharing ReSe6 pentagonal pyramids. All Re–Se bond lengths are 2.54 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a distorted T-shaped geometry to three equivalent Re3+ atoms. In the second Se2- site, Se2- is bonded in a distorted T-shaped geometry to three equivalent Re3+ atoms. In the TaReMnSe4 sheet, Ta4+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share corners with six equivalent MnSe6 octahedra, edges with six equivalent TaSe6 pentagonal pyramids, and a faceface with one MnSe6 octahedra. The corner-sharing octahedral tilt angles are 45°. There are three shorter (2.61 Å) and three longer (2.64 Å) Ta–Se bond lengths. Re3+ is bonded to six Se2- atoms to form distorted ReSe6 pentagonal pyramids that share corners with six equivalent MnSe6 octahedra, edges with six equivalent ReSe6 pentagonal pyramids, and a faceface with one MnSe6 octahedra. The corner-sharing octahedral tilt angles are 45°. There are three shorter (2.51 Å) and three longer (2.65 Å) Re–Se bond lengths. Mn2+ is bonded to six Se2- atoms to form MnSe6 octahedra that share corners with six equivalent TaSe6 pentagonal pyramids, corners with six equivalent ReSe6 pentagonal pyramids, edges with six equivalent MnSe6 octahedra, a faceface with one TaSe6 pentagonal pyramid, and a faceface with one ReSe6 pentagonal pyramid. There are three shorter (2.56 Å) and three longer (2.64 Å) Mn–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Ta4+ and three equivalent Mn2+ atoms to form distorted edge-sharing SeTa3Mn3 pentagonal pyramids. In the second Se2- site, Se2- is bonded in a 6-coordinate geometry to three equivalent Re3+ and three equivalent Mn2+ atoms. In the third Se2- site, Se2- is bonded in a distorted T-shaped geometry to three equivalent Re3+ atoms. In the fourth Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Ta4+ atoms. In the TaSe2 sheet, Ta4+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing TaSe6 pentagonal pyramids. All Ta–Se bond lengths are 2.61 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent Ta4+ atoms.
TaReFeSe4TaSe2ReSe2 crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one ReSe2 sheet oriented in the (0, 0, 1) direction; one TaReFeSe4 sheet oriented in the (0, 0, 1) direction; and one TaSe2 sheet oriented in the (0, 0, 1) direction. In the ReSe2 sheet, Re3+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing ReSe6 pentagonal pyramids. All Re–Se bond lengths are 2.54 Å. Se2- is bonded in a distorted T-shaped geometry to three equivalent Re3+ atoms. In the TaReFeSe4 sheet, Ta4+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share corners with six equivalent FeSe6 octahedra, edges with six equivalent TaSe6 pentagonal pyramids, and a faceface with one FeSe6 octahedra. The corner-sharing octahedral tilt angles are 45°. There are three shorter (2.61 Å) and three longer (2.63 Å) Ta–Se bond lengths. Re3+ is bonded to six Se2- atoms to form distorted ReSe6 pentagonal pyramids that share corners with six equivalent FeSe6 octahedra, edges with six equivalent ReSe6 pentagonal pyramids, and a faceface with one FeSe6 octahedra. The corner-sharing octahedral tilt angles are 45°. There are three shorter (2.51 Å) and three longer (2.65 Å) Re–Se bond lengths. Fe2+ is bonded to six Se2- atoms to form FeSe6 octahedra that share corners with six equivalent TaSe6 pentagonal pyramids, corners with six equivalent ReSe6 pentagonal pyramids, edges with six equivalent FeSe6 octahedra, a faceface with one TaSe6 pentagonal pyramid, and a faceface with one ReSe6 pentagonal pyramid. There are three shorter (2.55 Å) and three longer (2.57 Å) Fe–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded to three equivalent Re3+ and three equivalent Fe2+ atoms to form distorted SeFe3Re3 pentagonal pyramids that share corners with three equivalent SeTa3Fe3 pentagonal pyramids and edges with nine SeFe3Re3 pentagonal pyramids. In the second Se2- site, Se2- is bonded to three equivalent Ta4+ and three equivalent Fe2+ atoms to form a mixture of distorted corner and edge-sharing SeTa3Fe3 pentagonal pyramids. In the third Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Ta4+ atoms. In the fourth Se2- site, Se2- is bonded in a distorted T-shaped geometry to three equivalent Re3+ atoms. In the TaSe2 sheet, Ta4+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing TaSe6 pentagonal pyramids. All Ta–Se bond lengths are 2.61 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent Ta4+ atoms.
TaReCoSe4TaSe2ReSe2 crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one ReSe2 sheet oriented in the (0, 0, 1) direction; one TaReCoSe4 sheet oriented in the (0, 0, 1) direction; and one TaSe2 sheet oriented in the (0, 0, 1) direction. In the ReSe2 sheet, Re3+ is bonded to six Se2- atoms to form distorted edge-sharing ReSe6 pentagonal pyramids. All Re–Se bond lengths are 2.54 Å. There are two inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Re3+ atoms. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Re3+ atoms. In the TaReCoSe4 sheet, Ta4+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share corners with six equivalent CoSe6 octahedra, edges with six equivalent TaSe6 pentagonal pyramids, and a faceface with one CoSe6 octahedra. The corner-sharing octahedral tilt angles are 46°. There are three shorter (2.61 Å) and three longer (2.63 Å) Ta–Se bond lengths. Re3+ is bonded to six Se2- atoms to form distorted ReSe6 pentagonal pyramids that share corners with six equivalent CoSe6 octahedra, edges with six equivalent ReSe6 pentagonal pyramids, and a faceface with one CoSe6 octahedra. The corner-sharing octahedral tilt angles are 48°. There are three shorter (2.52 Å) and three longer (2.59 Å) Re–Se bond lengths. Co2+ is bonded to six Se2- atoms to form CoSe6 octahedra that share corners with six equivalent TaSe6 pentagonal pyramids, corners with six equivalent ReSe6 pentagonal pyramids, edges with six equivalent CoSe6 octahedra, a faceface with one TaSe6 pentagonal pyramid, and a faceface with one ReSe6 pentagonal pyramid. There are three shorter (2.37 Å) and three longer (2.49 Å) Co–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 6-coordinate geometry to three equivalent Re3+ and three equivalent Co2+ atoms. In the second Se2- site, Se2- is bonded to three equivalent Ta4+ and three equivalent Co2+ atoms to form distorted edge-sharing SeTa3Co3 pentagonal pyramids. In the third Se2- site, Se2- is bonded in a 3-coordinate geometry to three equivalent Ta4+ atoms. In the fourth Se2- site, Se2- is bonded in a distorted T-shaped geometry to three equivalent Re3+ atoms. In the TaSe2 sheet, Ta4+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing TaSe6 pentagonal pyramids. All Ta–Se bond lengths are 2.61 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent Ta4+ atoms.
Ta2Pd3Se8 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. Ta5+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share corners with two equivalent PdSe5 square pyramids, edges with two equivalent TaSe6 pentagonal pyramids, and edges with two equivalent PdSe5 square pyramids. There are a spread of Ta–Se bond distances ranging from 2.57–2.65 Å. There are two inequivalent Pd2+ sites. In the first Pd2+ site, Pd2+ is bonded to five Se2- atoms to form PdSe5 square pyramids that share corners with two equivalent TaSe6 pentagonal pyramids, edges with two equivalent TaSe6 pentagonal pyramids, and edges with two equivalent PdSe5 square pyramids. There are four shorter (2.50 Å) and one longer (2.70 Å) Pd–Se bond lengths. In the second Pd2+ site, Pd2+ is bonded in a square co-planar geometry to four Se2- atoms. All Pd–Se bond lengths are 2.47 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to one Ta5+ and two equivalent Pd2+ atoms. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to one Ta5+ and two equivalent Pd2+ atoms. In the third Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ta5+ and two Pd2+ atoms. In the fourth Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ta5+ and one Pd2+ atom.
Ta2Pt3Se8 crystallizes in the orthorhombic Pbam space group. The structure is three-dimensional. Ta5+ is bonded to six Se2- atoms to form distorted TaSe6 pentagonal pyramids that share corners with two equivalent PtSe5 square pyramids, edges with two equivalent TaSe6 pentagonal pyramids, and edges with two equivalent PtSe5 square pyramids. There are a spread of Ta–Se bond distances ranging from 2.59–2.66 Å. There are two inequivalent Pt2+ sites. In the first Pt2+ site, Pt2+ is bonded to five Se2- atoms to form PtSe5 square pyramids that share corners with two equivalent TaSe6 pentagonal pyramids, edges with two equivalent TaSe6 pentagonal pyramids, and edges with two equivalent PtSe5 square pyramids. There are four shorter (2.50 Å) and one longer (2.68 Å) Pt–Se bond lengths. In the second Pt2+ site, Pt2+ is bonded in a square co-planar geometry to four Se2- atoms. All Pt–Se bond lengths are 2.47 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a 3-coordinate geometry to one Ta5+ and two equivalent Pt2+ atoms. In the second Se2- site, Se2- is bonded in a 3-coordinate geometry to one Ta5+ and two equivalent Pt2+ atoms. In the third Se2- site, Se2- is bonded in a distorted rectangular see-saw-like geometry to two equivalent Ta5+ and two Pt2+ atoms. In the fourth Se2- site, Se2- is bonded in a 3-coordinate geometry to two equivalent Ta5+ and one Pt2+ atom.