Al₅B₁₂O₂₅(OH) and Ga₄InB₁₂O₂₅(OH) – two additional triel borates with the structure type M ₅B₁₂O₂₅(OH) (M = Ga, In)

Abstract

<jats:title>Abstract</jats:title><jats:p>The isotypic triel borates Al<jats:sub>5</jats:sub>B<jats:sub>12</jats:sub>O<jats:sub>25</jats:sub>(OH) and Ga<jats:sub>4</jats:sub>InB<jats:sub>12</jats:sub>O<jats:sub>25</jats:sub>(OH) were synthesized in a Walker-type multianvil apparatus under high-pressure/high-temperature conditions of 12.0 GPa/1400 °C and 12.3 GPa/1200 °C, respectively. The crystal structures of both compounds, determined by single-crystal X-ray diffraction, constitute new representatives of the structure type <jats:italic>M</jats:italic><jats:sub>5</jats:sub>B<jats:sub>12</jats:sub>O<jats:sub>25</jats:sub>(OH) (<jats:italic>M</jats:italic> = Ga, In) crystallizing in the space group <jats:italic>I</jats:italic>4<jats:sub>1</jats:sub>/<jats:italic>acd</jats:italic>. The presence of the hydroxyl groups was confirmed via single-crystal IR spectroscopy.</jats:p>

Crystal Structure of c‐M5B12O25(OH) (M=Al, Al/Ga, Ga/In) – Three Disordered Cubic Trielborates Synthesized under High‐Pressure Conditions

“…The values for the M 2 cations on the Wyckoff position 4 a are consequently too low (2.49 for Al2, 2.57 for Ga2, and 2.67 for In). For these cations forming isolated octahedra, an abnormal low BVS was observed already in the tetragonal phases M 5 B 12 O 25 (OH) ( M =Al, Ga, In, Ga/In) and Ti 5 B 12 O 26 being somehow characteristic for this structural arrangement [5b,11] . Consequently, the M 2−O distances (see Table 5) are rather high for octahedral bonds compared to values found in the literature [1,4,12] .…”

High-pressure synthesis and crystal structure of HP-Al2B3O7(OH)

“…Regarding the system Al-B-O-H, the literature research yields five compounds so far. Besides the well-known mineral Jeremejevite (Al 6 (BO 3 ) 5 (F,OH) 3 ) [1], our working group recently prepared the compound Al 5 B 12 O 25 (OH) which represents a new member of the high-pressure structure type M 5 B 12 O 25 (OH) (M = Al, Ga, In, Ga/In) [2,3]. Jianhua Lin et al who are working on hydrothermally synthesized zeolite-like borate structures, published the remaining three compounds in the system Al-B-O-H.…”

“…In this compound all Al atoms are octahedrally coordinated building up a porous structure with 10-and 18-membered ring windows. PKU-2 (Al 2 B 5 O 9 (OH) 3 •nH 2 O) is even more porous featuring 24-membered rings around channels of edge-sharing AlO 6 octahedra. PKU-6 (Al 2 B 3 O 7 (OH)designated as HAl 2 B 3 O 8 in reference [6]) was published in 2007 and shares the sum formula and point group with our title compound but shows a completely different structure.…”