Materials Data on HfZr2UC4 by Materials Project

Abstract

UHfZr2C4 is alpha Po-derived structured and crystallizes in the trigonal R3m space group. The structure is three-dimensional. U4+ is bonded to six C4- atoms to form UC6 octahedra that share corners with three equivalent HfC6 octahedra, corners with three equivalent ZrC6 octahedra, edges with three equivalent HfC6 octahedra, edges with three equivalent ZrC6 octahedra, and edges with six equivalent UC6 octahedra. The corner-sharing octahedra tilt angles range from 0–1°. There are three shorter (2.41 Å) and three longer (2.42 Å) U–C bond lengths. Hf4+ is bonded to six C4- atoms to form HfC6 octahedra that share corners with three equivalent UC6 octahedra, corners with three equivalent ZrC6 octahedra, edges with three equivalent UC6 octahedra, edges with three equivalent ZrC6 octahedra, and edges with six equivalent HfC6 octahedra. The corner-sharing octahedra tilt angles range from 0–3°. There are three shorter (2.31 Å) and three longer (2.41 Å) Hf–C bond lengths. There are two inequivalent Zr4+ sites. In the first Zr4+ site, Zr4+ is bonded to six C4- atoms to form ZrC6 octahedra that share corners with three equivalent UC6 octahedra, corners with three equivalent ZrC6 octahedra, edges with three equivalent UC6 octahedra, and edges with nine ZrC6 octahedra. The corner-sharing octahedral tilt angles are 1°. There are three shorter (2.34 Å) and three longer (2.43 Å) Zr–C bond lengths. In the second Zr4+ site, Zr4+ is bonded to six C4- atoms to form ZrC6 octahedra that share corners with three equivalent HfC6 octahedra, corners with three equivalent ZrC6 octahedra, edges with three equivalent HfC6 octahedra, and edges with nine ZrC6 octahedra. The corner-sharing octahedra tilt angles range from 1–3°. There are three shorter (2.37 Å) and three longer (2.39 Å) Zr–C bond lengths. There are four inequivalent C4- sites. In the first C4- site, C4- is bonded to six Zr4+ atoms to form CZr6 octahedra that share corners with six CHf3Zr3 octahedra and edges with twelve CZr6 octahedra. The corner-sharing octahedra tilt angles range from 1–3°. In the second C4- site, C4- is bonded to three equivalent Hf4+ and three equivalent Zr4+ atoms to form a mixture of edge and corner-sharing CHf3Zr3 octahedra. The corner-sharing octahedra tilt angles range from 1–4°. In the third C4- site, C4- is bonded to three equivalent U4+ and three equivalent Hf4+ atoms to form a mixture of edge and corner-sharing CHf3U3 octahedra. The corner-sharing octahedra tilt angles range from 0–4°. In the fourth C4- site, C4- is bonded to three equivalent U4+ and three equivalent Zr4+ atoms to form a mixture of edge and corner-sharing CZr3U3 octahedra. The corner-sharing octahedra tilt angles range from 0–3°.