title: High structural complexity of potassium uranyl borates derived from high-temperature/high-pressure reactions.
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.
authors.affiliation: Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, 511 Kehua Street, 510640 Guangzhou, People's Republic of China.
authors.forename: Shijun
authors.initials: S
authors.lastname: Wu
authors.forename: Shuao
authors.initials: S
authors.lastname: Wang
authors.forename: Matthew
authors.initials: M
authors.lastname: Polinski
authors.forename: Oliver
authors.initials: O
authors.lastname: Beermann
authors.forename: Philip
authors.initials: P
authors.lastname: Kegler
authors.forename: Thomas
authors.initials: T
authors.lastname: Malcherek
authors.forename: Astrid
authors.initials: A
authors.lastname: Holzheid
authors.forename: Wulf
authors.initials: W
authors.lastname: Depmeier
authors.forename: Dirk
authors.initials: D
authors.lastname: Bosbach
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Albrecht-Schmitt
authors.forename: Evgeny V
authors.initials: EV
authors.lastname: Alekseev