Materials Data on TmAsO4 by Materials Project
TmAsO4 is Zircon-like structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. Tm3+ is bonded in a 8-coordinate geometry to eight O2- atoms. There are a spread of Tm–O bond distances ranging from 2.30–2.48 Å. As5+ is bonded in a tetrahedral geometry to four O2- atoms. There is three shorter (1.72 Å) and one longer (1.73 Å) As–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Tm3+ and one As5+ atom. In the second O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Tm3+ and one As5+ atom. In the third O2- site, O2- is bonded in a 3-coordinate geometry to two equivalent Tm3+ and one As5+ atom. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to two equivalent Tm3+ and one As5+ atom.