AUTHOR=Ibragimova Olga , Vaquero Lia , Hussein Zain , Drozd Vadym , Chariton Stella , Prakapenka Vitali , Chuvashova Irina 

TITLE=The synthesis of novel lanthanum hydroxyborate at extreme conditions

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 11 - 2023

YEAR=2023

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2023.1259000

DOI=10.3389/fchem.2023.1259000

ISSN=2296-2646

ABSTRACT=The novel structure of lanthanum hydroxyborate La2B2O5(OH)2 was synthesized by the reaction of partially hydrolyzed lanthanum and boron oxide in a diamond anvil cell under high-pressure/hightemperature (HPHT) conditions of 30 GPa and 2400 K. The single-crystal X-ray structure determination of the lanthanum hydroxyborate revealed: 𝑃3 ̅ 𝑐1, a = 6.555(2) Å, c = 17.485(8) Å, Z = 6, R1 = 0.056. The three-dimensional structure consists of discrete planar BO3 groups and three crystallographically different La ions: one is surrounded by 9, one by 10, and one by 12 oxygen anions. The band gap was estimated using ab-initio calculations to be 4.64 eV at ambient pressure and 5.26 eV at 30 GPa. The current work describes the novel HPHT lanthanum hydroxyborate with potential application as a deep-ultraviolet birefringent material.