Na₈[Cr₄B₁₂P₈O₄₄(OH)₄][P₂O₇]⋅nH₂O: A 3D Borophosphate Framework with Spherical Cages

Abstract

A chromium borophosphate–phosphate (Na8[Cr4B12P8O44(OH)4][P2O7]⋅nH2O, 1), which has an unusual 3D framework structure, was synthesized under hydrothermal conditions. The framework consists of spherical cages composed of CrO6, PO4, BO4, and BO3 polyhedra. The cages are located at the vertices and the body center of the cubic cell and are interconnected through 12‐membered‐ring windows along the {111} direction. The actual framework structure is very complex, but the description can be simplified by using the 5‐connected fundamental building cluster [CrP5B3O24]11−. In addition, 1 represents the first borate‐rich borophosphate that contains a 3D borophosphate partial framework (${{{\hfill 3\atop \hfill \infty }}}$[B3P2O11(OH)]) in which the fundamental building unit is an oB dreier single ring (Δ4□:□<Δ2□>□). The cavities of the framework are filled with disengaged water molecules and Na+ counterions. The former can be reversibly desorbed and reabsorbed and the latter can be exchanged by Li+ ions, which results in significant shrinkages of the cell volume.

An open-framework borophosphate, LiCu2BP2O8(OH)2

“…The phosphorous atoms are allocated in regular tetrahedral environments with four types of oxygen atoms. Bond lengths and angles within the anionic partial structure are consistent with related borophosphates (Boy et al, 2001;Yang et al 2008),. Li + is coordinated by the oxygen functions groups of PO 4 groups.…”

“…For chiral structures and potential applications in catalysis of borophosphates with the general formula AM(H 2 O) 2 -[BP 2 O 8 ].yH 2 O (A = Li, Na, K, NH 4 + ; M = Mg, Mn, Fe, Co, Ni, Cu, Zn, Cd) (y = 0.5-1), see: Ewald et al (2007); Kniep et al (1997). For related structures, see: Boy & Kniep (2001); Yang et al (2008). 2143 3Symmetry codes:…”

Cd3[B2P4O14(OH)4]: A 3D Open‐Framework Cadmium Borophosphate with Unique Twisted 8‐Ring Channels

“…[18,19] The infinite alternation of such units by sharing edges leads to one-dimensional "zigzag" cadmium polyhedral chains, as shown in Figure 3. Although the MO 6 octahedral chains have been found in other transition metal borophosphates, [11,[20][21] compound 1 is the first example exhibiting edge-sharing cadmium-oxide chains in cadmium borophosphates. The interconnection of the PO 4 and PO 3 (OH) tetrahedra with the zigzag chains through sharing vertexes results in two-dimensional layers with the sequence …ABAB… (Figure 4).…”

“…[4,5] So far, a large number of metal borophosphates have been reported. Notable examples including Na 8 [7] with intersecting 8-, 12-, and 16-ring channels, Na 3 Cd 3 B(PO 4 6 ], [9] KMnBP 2 O 7 (OH) 2 , [10] and Cu 3 [15] Afterwards, only two cadmium borophosphates, Cd 3 BPO 7 [16] and Na 3 Cd 3 B(PO 4 ) 4 , [8] have been reported. Therefore, the synthesis of cadmium boro- …”

Synthesis, Crystal Structure, and Characterization of a New Metal Borophosphate: PbII4{Co2[B(OH)2P2O8](PO4)2}Cl

“…Introducing boron atoms with their three‐ or four‐coordination ability into the framework provide an opportunity to synthesize new open‐framework structures. Notable examples including the first metal borophosphate Na 8 [Cr 4 B 12 P 8 O 44 (OH) 4 ][P 2 O 7 ] · n H 2 O 4 featuring a spherical cage structure, Na 2 [VB 3 P 2 O 12 (OH)] · 2,92H 2 O 5 with intersecting 8‐, 12‐, and 16‐ring channels, and several borophosphates [NH 4 ] 4 [Mn 9 B 2 (OH) 2 (HPO 4 ) 4 (PO 4 ) 6 ] 6, (C 4 N 3 H 16 )(C 4 N 3 H 15 ) 0.5 [Fe 2 B 4 P 7 O 26 (OH) 4 ] 7, and SrFe[BP 2 O 8 (OH) 2 ] 8 with interesting magnetic properties have been reported. In most cases, metal borophosphates are prepared in the presence of organic amines or inorganic cations, which lead to negative charged frameworks constructed from metal centered polyhedra and various borophosphate partial structures.…”