High structural complexity of potassium uranyl borates derived from high-temperature/high-pressure reactions

Shijun Wu; Shuao Wang; Matthew Polinski; Oliver Beermann; Philip Kegler; Thomas Malcherek; Astrid Holzheid; Wulf Depmeier; Dirk Bosbach; Thomas E Albrecht-Schmitt; Evgeny V Alekseev

doi:10.1021/ic400016z

High structural complexity of potassium uranyl borates derived from high-temperature/high-pressure reactions

Inorg Chem. 2013 May 6;52(9):5110-8. doi: 10.1021/ic400016z. Epub 2013 Apr 8.

Authors

Shijun Wu¹, Shuao Wang, Matthew Polinski, Oliver Beermann, Philip Kegler, Thomas Malcherek, Astrid Holzheid, Wulf Depmeier, Dirk Bosbach, Thomas E Albrecht-Schmitt, Evgeny V Alekseev

Affiliation

¹ Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, 510640 Guangzhou, People's Republic of China.

PMID: 23566253
DOI: 10.1021/ic400016z

Abstract

Three new potassium uranyl borates, K12[(UO2)19(UO4)(B2O5)2(BO3)6(BO2OH)O10] ·nH2O (TPKBUO-1), K4[(UO2)5(BO3)2O4]·H2O (TPKBUO-2), and K15[(UO2)18(BO3)7O15] (TPKBUO-3), were synthesized under high-temperature/high-pressure conditions. In all three compounds, the U/B ratio exceeds 1. Boron exhibits BO3 coordination only, which is different from other uranyl borates prepared at room temperature or under mild hydrothermal conditions. A rare uranium(VI) tetraoxide core UO4O2, which is coordinated by two BO3 groups, is observed in the structure of TPKBUO-1. Both structures of TPKBUO-1 and TPKBUO-3 contain three different coordination environments of uranium, namely, UO4O2, UO2O4, and UO2O5 and UO2O4, UO2O5, and UO2O6 bipyramids in TPKBUO-1 and TPKBUO-3, respectively.