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LaH2 is Fluorite structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. La2+ is bonded in a body-centered cubic geometry to eight equivalent H1- atoms. All La–H bond lengths are 2.45 Å. H1- is bonded to four equivalent La2+ atoms to form a mixture of edge and corner-sharing HLa4 tetrahedra.
LaH3 is alpha bismuth trifluoride structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. La3+ is bonded to twelve H1- atoms to form a mixture of distorted edge, face, and corner-sharing LaH12 cuboctahedra. There are eight shorter (2.42 Å) and four longer (2.65 Å) La–H bond lengths. There are two inequivalent H1- sites. In the first H1- site, H1- is bonded to four equivalent La3+ atoms to form a mixture of edge and corner-sharing HLa4 tetrahedra. In the second H1- site, H1- is bonded in a square co-planar geometry to four equivalent La3+ atoms.
LaH3 is alpha bismuth trifluoride structured and crystallizes in the cubic Fm-3m space group. The structure is three-dimensional. La3+ is bonded in a distorted body-centered cubic geometry to fourteen H1- atoms. There are eight shorter (2.41 Å) and six longer (2.79 Å) La–H bond lengths. There are two inequivalent H1- sites. In the first H1- site, H1- is bonded to six equivalent La3+ atoms to form HLa6 octahedra that share corners with six equivalent HLa6 octahedra, corners with twenty-four equivalent HLa4 tetrahedra, edges with twelve equivalent HLa6 octahedra, and faces with eight equivalent HLa4 tetrahedra. The corner-sharing octahedral tilt angles are 0°. In the second H1- site, H1- is bonded to four equivalent La3+ atoms to form HLa4 tetrahedra that share corners with twelve equivalent HLa6 octahedra, corners with sixteen equivalent HLa4 tetrahedra, edges with six equivalent HLa4 tetrahedra, and faces with four equivalent HLa6 octahedra. The corner-sharing octahedral tilt angles are 55°.
La2H5 crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. La+2.50+ is bonded in a distorted body-centered cubic geometry to eleven H1- atoms. There are a spread of La–H bond distances ranging from 2.40–2.79 Å. There are two inequivalent H1- sites. In the first H1- site, H1- is bonded to four equivalent La+2.50+ atoms to form HLa4 tetrahedra that share corners with six equivalent HLa6 octahedra, corners with sixteen equivalent HLa4 tetrahedra, edges with six equivalent HLa4 tetrahedra, and faces with two equivalent HLa6 octahedra. The corner-sharing octahedra tilt angles range from 52–58°. In the second H1- site, H1- is bonded to six equivalent La+2.50+ atoms to form HLa6 octahedra that share corners with four equivalent HLa6 octahedra, corners with twenty-four equivalent HLa4 tetrahedra, edges with four equivalent HLa6 octahedra, and faces with eight equivalent HLa4 tetrahedra. The corner-sharing octahedral tilt angles are 2°.