Materials Data on Hf2SiAs3 by Materials Project

Abstract

Hf2SiAs3 crystallizes in the tetragonal P-4m2 space group. The structure is three-dimensional. Hf4+ is bonded in a 9-coordinate geometry to two equivalent Si4- and seven As+1.33- atoms. Both Hf–Si bond lengths are 2.84 Å. There are a spread of Hf–As bond distances ranging from 2.77–2.88 Å. Si4- is bonded to four equivalent Hf4+ and four equivalent As+1.33- atoms to form distorted SiHf4As4 hexagonal bipyramids that share corners with four equivalent SiHf4As4 hexagonal bipyramids, edges with four equivalent AsHf4Si4 hexagonal bipyramids, and faces with four equivalent SiHf4As4 hexagonal bipyramids. All Si–As bond lengths are 2.59 Å. There are two inequivalent As+1.33- sites. In the first As+1.33- site, As+1.33- is bonded in a 5-coordinate geometry to five equivalent Hf4+ atoms. In the second As+1.33- site, As+1.33- is bonded to four equivalent Hf4+ and four equivalent Si4- atoms to form distorted AsHf4Si4 hexagonal bipyramids that share corners with four equivalent AsHf4Si4 hexagonal bipyramids, edges with four equivalent SiHf4As4 hexagonal bipyramids, and faces with four equivalent AsHf4Si4 hexagonal bipyramids.