Materials Data on Nb39C34 by Materials Project
Nb29C28(Nb3C2)2(Nb2C)2 crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one Nb29C28 sheet oriented in the (0, 0, 1) direction; two Nb2C sheets oriented in the (0, 0, 1) direction; and two Nb3C2 sheets oriented in the (0, 0, 1) direction. In the Nb29C28 sheet, there are thirteen inequivalent Nb+3.49+ sites. In the first Nb+3.49+ site, Nb+3.49+ is bonded in a distorted T-shaped geometry to three equivalent C4- atoms. All Nb–C bond lengths are 2.18 Å. In the second Nb+3.49+ site, Nb+3.49+ is bonded to six C4- atoms to form a mixture of edge and corner-sharing NbC6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are three shorter (2.23 Å) and three longer (2.27 Å) Nb–C bond lengths. In the third Nb+3.49+ site, Nb+3.49+ is bonded to six C4- atoms to form a mixture of edge and corner-sharing NbC6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.26 Å) and three longer (2.27 Å) Nb–C bond lengths. In the fourth Nb+3.49+ site, Nb+3.49+ is bonded to six C4- atoms to form a mixture of edge and corner-sharing NbC6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. All Nb–C bond lengths are 2.25 Å. In the fifth Nb+3.49+ site, Nb+3.49+ is bonded to six C4- atoms to form a mixture of edge and corner-sharing NbC6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.23 Å) and three longer (2.26 Å) Nb–C bond lengths. In the sixth Nb+3.49+ site, Nb+3.49+ is bonded to six C4- atoms to form a mixture of edge and corner-sharing NbC6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.24 Å) and three longer (2.25 Å) Nb–C bond lengths. In the seventh Nb+3.49+ site, Nb+3.49+ is bonded to six C4- atoms to form a mixture of edge and corner-sharing NbC6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.24 Å) and three longer (2.25 Å) Nb–C bond lengths. In the eighth Nb+3.49+ site, Nb+3.49+ is bonded to six C4- atoms to form a mixture of edge and corner-sharing NbC6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.24 Å) and three longer (2.25 Å) Nb–C bond lengths. In the ninth Nb+3.49+ site, Nb+3.49+ is bonded to six C4- atoms to form a mixture of edge and corner-sharing NbC6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.24 Å) and three longer (2.25 Å) Nb–C bond lengths. In the tenth Nb+3.49+ site, Nb+3.49+ is bonded to six C4- atoms to form a mixture of edge and corner-sharing NbC6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.24 Å) and three longer (2.25 Å) Nb–C bond lengths. In the eleventh Nb+3.49+ site, Nb+3.49+ is bonded to six C4- atoms to form a mixture of edge and corner-sharing NbC6 octahedra. The corner-sharing octahedral tilt angles are 0°. There are three shorter (2.24 Å) and three longer (2.25 Å) Nb–C bond lengths. In the twelfth Nb+3.49+ site, Nb+3.49+ is bonded to six C4- atoms to form a mixture of edge and corner-sharing NbC6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Nb–C bond lengths are 2.24 Å. In the thirteenth Nb+3.49+ site, Nb+3.49+ is bonded to six equivalent C4- atoms to form a mixture of edge and corner-sharing NbC6 octahedra. The corner-sharing octahedral tilt angles are 0°. All Nb–C bond lengths are 2.25 Å. There are twelve inequivalent C4- sites. In the first C4- site, C4- is bonded to six Nb+3.49+ atoms to form a mixture of edge and corner-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 1°. In the second C4- site, C4- is bonded to six Nb+3.49+ atoms to form a mixture of edge and corner-sharing CNb6 octahedra. The corner-sharing octahedra tilt angles range from 1–2°. In the third C4- site, C4- is bonded to six Nb+3.49+ atoms to form a mixture of edge and corner-sharing CNb6 octahedra. The corner-sharing octahedra tilt angles range from 0–2°. In the fourth C4- site, C4- is bonded to six Nb+3.49+ atoms to form a mixture of edge and corner-sharing CNb6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the fifth C4- site, C4- is bonded to six Nb+3.49+ atoms to form a mixture of edge and corner-sharing CNb6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. In the sixth C4- site, C4- is bonded to six Nb+3.49+ atoms to form a mixture of edge and corner-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the seventh C4- site, C4- is bonded to six Nb+3.49+ atoms to form a mixture of edge and corner-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the eighth C4- site, C4- is bonded to six Nb+3.49+ atoms to form a mixture of edge and corner-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the ninth C4- site, C4- is bonded to six Nb+3.49+ atoms to form a mixture of edge and corner-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the tenth C4- site, C4- is bonded to six Nb+3.49+ atoms to form a mixture of edge and corner-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the eleventh C4- site, C4- is bonded to six Nb+3.49+ atoms to form a mixture of edge and corner-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the twelfth C4- site, C4- is bonded to six Nb+3.49+ atoms to form a mixture of edge and corner-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 0°. In each Nb2C sheet, there are two inequivalent Nb+3.49+ sites. In the first Nb+3.49+ site, Nb+3.49+ is bonded in a distorted T-shaped geometry to three equivalent C4- atoms. All Nb–C bond lengths are 2.22 Å. In the second Nb+3.49+ site, Nb+3.49+ is bonded in a distorted T-shaped geometry to three equivalent C4- atoms. All Nb–C bond lengths are 2.23 Å. C4- is bonded to six Nb+3.49+ atoms to form edge-sharing CNb6 octahedra. In each Nb3C2 sheet, there are three inequivalent Nb+3.49+ sites. In the first Nb+3.49+ site, Nb+3.49+ is bonded in a distorted T-shaped geometry to three equivalent C4- atoms. All Nb–C bond lengths are 2.17 Å. In the second Nb+3.49+ site, Nb+3.49+ is bonded to six C4- atoms to form edge-sharing NbC6 octahedra. All Nb–C bond lengths are 2.29 Å. In the third Nb+3.49+ site, Nb+3.49+ is bonded in a distorted T-shaped geometry to three equivalent C4- atoms. All Nb–C bond lengths are 2.17 Å. There are two inequivalent C4- sites. In the first C4- site, C4- is bonded to six Nb+3.49+ atoms to form a mixture of edge and corner-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 0°. In the second C4- site, C4- is bonded to six Nb+3.49+ atoms to form a mixture of edge and corner-sharing CNb6 octahedra. The corner-sharing octahedral tilt angles are 0°.