Materials Data on Hf2As by Materials Project
Hf2As crystallizes in the orthorhombic Pnnm space group. The structure is three-dimensional. there are six inequivalent Hf sites. In the first Hf site, Hf is bonded in a 4-coordinate geometry to four As atoms. There are two shorter (2.73 Å) and two longer (2.82 Å) Hf–As bond lengths. In the second Hf site, Hf is bonded in a 5-coordinate geometry to five As atoms. There are a spread of Hf–As bond distances ranging from 2.72–3.09 Å. In the third Hf site, Hf is bonded in a 3-coordinate geometry to three As atoms. There are two shorter (2.73 Å) and one longer (2.80 Å) Hf–As bond lengths. In the fourth Hf site, Hf is bonded in a distorted T-shaped geometry to three As atoms. There are one shorter (2.78 Å) and two longer (2.88 Å) Hf–As bond lengths. In the fifth Hf site, Hf is bonded to five As atoms to form distorted edge-sharing HfAs5 trigonal bipyramids. There are a spread of Hf–As bond distances ranging from 2.70–2.75 Å. In the sixth Hf site, Hf is bonded in a 4-coordinate geometry to four As atoms. There are a spread of Hf–As bond distances ranging from 2.69–3.04 Å. There are three inequivalent As sites. In the first As site, As is bonded to seven Hf atoms to form distorted edge-sharing AsHf7 pentagonal bipyramids. In the second As site, As is bonded in a 8-coordinate geometry to eight Hf atoms. In the third As site, As is bonded in a 9-coordinate geometry to nine Hf atoms.