Crystal structures and comparisons of huntite aluminum borates RE Al3(BO3)4 (RE = Tb, Dy and Ho)

Saehwa Chong; Brian J Riley; Zayne J Nelson; Samuel N Perry

doi:10.1107/S2056989020001802

Crystal structures and comparisons of huntite aluminum borates RE Al₃(BO₃)₄ (RE = Tb, Dy and Ho)

Acta Crystallogr E Crystallogr Commun. 2020 Feb 14;76(Pt 3):339-343. doi: 10.1107/S2056989020001802. eCollection 2020 Mar 1.

Authors

Saehwa Chong¹, Brian J Riley¹, Zayne J Nelson¹, Samuel N Perry²

Affiliations

¹ Pacific Northwest National Laboratory, Richland, WA 99354, USA.
² Department of Civil and Environmental Engineering and Earth Sciences, University of Notre Dame, Notre Dame, IN 46556, USA.

Abstract

Three huntite-type aluminoborates of stoichiometry REAl₃(BO₃)₄ (RE = Tb, Dy and Ho), namely, terbium/dysprosium/holmium trialuminium tetrakis(borate), were synthesized by slow cooling within a K₂Mo₃O₁₀ flux with spontaneous crystallization. The crystal structures were determined using single-crystal X-ray diffraction (SC-XRD) data. The synthesized borates are isostructural to the huntite [CaMg₃(CO₃)₄] structure and crystallized within the trigonal R32 space group. The structural parameters were compared to literature data of other huntite REAl₃(BO₃)₄ crystals within the R32 space group. All three borates fit well into the trends calculated from the literature data. The unit-cell parameters and volumes increase linearly with larger RE cations whereas the densities decrease. All of the crystals studied were refined as inversion twins.

Keywords: huntite borate; lanthanide aluminum borate; single-crystal XRD.

Grants and funding

This work was funded by US Department of Energy Office of Nuclear Energy grant .