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HfB12 crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. Hf is bonded in a 1-coordinate geometry to twenty-four equivalent B atoms. All Hf–B bond lengths are 2.74 Å. B is bonded in a 7-coordinate geometry to two equivalent Hf and five equivalent B atoms. There is one shorter (1.68 Å) and four longer (1.77 Å) B–B bond length.
HfNbB4 is hexagonal omega structure-derived structured and crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Hf4+ is bonded to twelve equivalent B+1.50- atoms to form HfB12 cuboctahedra that share edges with four equivalent NbB12 cuboctahedra, edges with eight equivalent HfB12 cuboctahedra, faces with two equivalent HfB12 cuboctahedra, and faces with six equivalent NbB12 cuboctahedra. All Hf–B bond lengths are 2.48 Å. Nb2+ is bonded to twelve equivalent B+1.50- atoms to form NbB12 cuboctahedra that share edges with four equivalent HfB12 cuboctahedra, edges with eight equivalent NbB12 cuboctahedra, faces with two equivalent NbB12 cuboctahedra, and faces with six equivalent HfB12 cuboctahedra. There are eight shorter (2.48 Å) and four longer (2.49 Å) Nb–B bond lengths. B+1.50- is bonded in a 9-coordinate geometry to three equivalent Hf4+, three equivalent Nb2+, and three equivalent B+1.50- atoms. There is one shorter (1.80 Å) and two longer (1.81 Å) B–B bond length.
ZrB2(HfB2) is hexagonal omega structure-derived structured and crystallizes in the orthorhombic Pmmm space group. The structure is three-dimensional. Hf4+ is bonded to twelve B+1.50- atoms to form HfB12 cuboctahedra that share edges with four equivalent HfB12 cuboctahedra, edges with eight equivalent ZrB12 cuboctahedra, faces with four equivalent HfB12 cuboctahedra, and faces with four equivalent ZrB12 cuboctahedra. All Hf–B bond lengths are 2.53 Å. Zr2+ is bonded to twelve B+1.50- atoms to form ZrB12 cuboctahedra that share edges with four equivalent ZrB12 cuboctahedra, edges with eight equivalent HfB12 cuboctahedra, faces with four equivalent HfB12 cuboctahedra, and faces with four equivalent ZrB12 cuboctahedra. All Zr–B bond lengths are 2.54 Å. There are two inequivalent B+1.50- sites. In the first B+1.50- site, B+1.50- is bonded in a 9-coordinate geometry to two equivalent Hf4+, four equivalent Zr2+, and three B+1.50- atoms. There is two shorter (1.83 Å) and one longer (1.84 Å) B–B bond length. In the second B+1.50- site, B+1.50- is bonded in a 9-coordinate geometry to four equivalent Hf4+, two equivalent Zr2+, and three B+1.50- atoms. The B–B bond length is 1.81 Å.
HfNbB4 is hexagonal omega structure-derived structured and crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Hf4+ is bonded to twelve equivalent B+1.50- atoms to form HfB12 cuboctahedra that share edges with twelve equivalent NbB12 cuboctahedra, faces with two equivalent NbB12 cuboctahedra, and faces with six equivalent HfB12 cuboctahedra. All Hf–B bond lengths are 2.50 Å. Nb2+ is bonded to twelve equivalent B+1.50- atoms to form NbB12 cuboctahedra that share edges with twelve equivalent HfB12 cuboctahedra, faces with two equivalent HfB12 cuboctahedra, and faces with six equivalent NbB12 cuboctahedra. All Nb–B bond lengths are 2.47 Å. B+1.50- is bonded in a 9-coordinate geometry to three equivalent Hf4+, three equivalent Nb2+, and three equivalent B+1.50- atoms. All B–B bond lengths are 1.81 Å.
HfTaB4 is hexagonal omega structure-derived structured and crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Hf is bonded to twelve equivalent B atoms to form HfB12 cuboctahedra that share edges with twelve equivalent TaB12 cuboctahedra, faces with two equivalent TaB12 cuboctahedra, and faces with six equivalent HfB12 cuboctahedra. All Hf–B bond lengths are 2.51 Å. Ta is bonded to twelve equivalent B atoms to form TaB12 cuboctahedra that share edges with twelve equivalent HfB12 cuboctahedra, faces with two equivalent HfB12 cuboctahedra, and faces with six equivalent TaB12 cuboctahedra. All Ta–B bond lengths are 2.45 Å. B is bonded in a 9-coordinate geometry to three equivalent Hf, three equivalent Ta, and three equivalent B atoms. All B–B bond lengths are 1.80 Å.
HfTiB4 is hexagonal omega structure-derived structured and crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Hf4+ is bonded to twelve equivalent B+1.50- atoms to form HfB12 cuboctahedra that share edges with twelve equivalent TiB12 cuboctahedra, faces with two equivalent TiB12 cuboctahedra, and faces with six equivalent HfB12 cuboctahedra. All Hf–B bond lengths are 2.51 Å. Ti2+ is bonded to twelve equivalent B+1.50- atoms to form TiB12 cuboctahedra that share edges with twelve equivalent HfB12 cuboctahedra, faces with two equivalent HfB12 cuboctahedra, and faces with six equivalent TiB12 cuboctahedra. All Ti–B bond lengths are 2.39 Å. B+1.50- is bonded in a 9-coordinate geometry to three equivalent Hf4+, three equivalent Ti2+, and three equivalent B+1.50- atoms. All B–B bond lengths are 1.79 Å.
HfB2 is hexagonal omega structure structured and crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Hf is bonded to twelve equivalent B atoms to form a mixture of edge and face-sharing HfB12 cuboctahedra. All Hf–B bond lengths are 2.52 Å. B is bonded in a 9-coordinate geometry to six equivalent Hf and three equivalent B atoms. All B–B bond lengths are 1.82 Å.
Hf(Nb2B3)4 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Hf4+ is bonded to twelve B2- atoms to form a mixture of edge and face-sharing HfB12 cuboctahedra. There are eight shorter (2.48 Å) and four longer (2.53 Å) Hf–B bond lengths. There are four inequivalent Nb+2.50+ sites. In the first Nb+2.50+ site, Nb+2.50+ is bonded in a 7-coordinate geometry to seven B2- atoms. There are a spread of Nb–B bond distances ranging from 2.40–2.58 Å. In the second Nb+2.50+ site, Nb+2.50+ is bonded in a 7-coordinate geometry to seven B2- atoms. There are a spread of Nb–B bond distances ranging from 2.39–2.59 Å. In the third Nb+2.50+ site, Nb+2.50+ is bonded in a 7-coordinate geometry to seven B2- atoms. There are a spread of Nb–B bond distances ranging from 2.39–2.58 Å. In the fourth Nb+2.50+ site, Nb+2.50+ is bonded to twelve B2- atoms to form a mixture of edge and face-sharing NbB12 cuboctahedra. There are eight shorter (2.48 Å) and four longer (2.51 Å) Nb–B bond lengths. There are six inequivalent B2- sites. In the first B2- site, B2- is bonded in a 9-coordinate geometry to six Nb+2.50+ and three B2- atoms. There is one shorter (1.82 Å) and two longer (1.85 Å) B–B bond length. In the second B2- site, B2- is bonded in a 9-coordinate geometry to six Nb+2.50+ and three B2- atoms. Both B–B bond lengths are 1.85 Å. In the third B2- site, B2- is bonded in a 9-coordinate geometry to four equivalent Hf4+, two equivalent Nb+2.50+, and three B2- atoms. There is one shorter (1.84 Å) and two longer (1.85 Å) B–B bond length. In the fourth B2- site, B2- is bonded in a 9-coordinate geometry to seven Nb+2.50+ and two equivalent B2- atoms. In the fifth B2- site, B2- is bonded in a 9-coordinate geometry to seven Nb+2.50+ and two equivalent B2- atoms. In the sixth B2- site, B2- is bonded in a 9-coordinate geometry to two equivalent Hf4+, five Nb+2.50+, and two equivalent B2- atoms.