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Research development of new borophosphates prepared by hydrothermal method
Abstract
Borophosphates as a new type of potential functional materials have attracted much attention of scientists in the last few years. Other than conventional solid state reaction method, hydrothermal method have been proved to be efficient in synthesizing such kind of compounds with variety of structures. The typical structure features in consideration of different partial anionic structures of transition metal and main group metal borophosphates synthesized by hydrothermal methods have been reviewed in detail in this paper. The new prospects of borophosphate researches, such as synthesis with organic molecule templates or with early transition metals and potential applications have also been discussed.
Motivation:
A suite of MBPO5 (borophosphates-BPO):Eu3+ (M = Ca, Sr, Ba) red emitting phosphors were synthesized and their luminescent properties were studied by excitation and emission spectra.
Results:
The energy gap of CBPO, SBPO and BBPO are 5.481, 5.498 and 5.604 eV, respectively. While, these samples showed similar total and partial densities of states. The x-ray powder diffraction (XRD) patterns indicated that the samples were simple MPBO5 phase. According to the absorption spectra, the band gap energies of CBPO:Eu3+, SBPO: Eu3+ and BBPO:Eu3+ were calculated to be 5.499, 5.516 and 5.659 eV, respectively. The spectra of all three MBPO5:Eu3+ samples were similar with main excitation and emission peaks at 394 nm and 594 nm, respectively. The concentration quenching did not appear with the increase of the concentration of Eu3+. The charge compensator can improve the emission intensity. The average decay time of CBPO:0.05Eu3+, SBPO:0.05Eu3+ and BBPO:0.05Eu3+ was 3.29, 2.54, and 3.15 ms, respectively. The above results suggested that this phosphor was qualified as red phosphor, which could be used as a near UV-based white LED.
Nano-sized red emitting phosphors of SrBPO5:Sm3+ were synthesized by a combustion synthesis method at ignition temperatures of 650°C using urea as a fuel and H3BO3 as a flux. The phase structure, morphology and luminescence properties of the samples were investigated. The results show that the prepared phosphor powder samples are a pure phase of SrBPO5, which trigonal system, space group for P3121. The phosphor powder with the particle size of 200 nm is well-dispersive. The main emission peaks were located at 558, 596 and 645 nm under the excitation of 404 nm, corresponding to 4G5/2→6H5/2, 4G5/2→6H7/2 and 4G5/2→6H9/2 transitions, respectively. Furthermore, when the optimal doping content of Sm3+ is 10% in mole, and the content of H3BO3 used as raw material and fluxes is 0.8% in mole, the SrBPO5:Sm3+ phosphors exhibit an optimum luminescent intensity. The SrBPO5:Sm3+ phosphors are promising as red-emitting phosphors by near-UV excitation for white light emitting diodes.
A series of KSrBP2O8: RE(RE=Eu2+, Tb3+, Eu3+) phosphors were prepared through high-temperature solid-state reaction. The phosphors were characterized by X-ray diffraction (XRD) and fluorescence spectrophotometer (PL). XRD patterns revealed that the samples KSrBP2O8 maintained single phase after doping rare earth ions. The PL results showed that KSrBP2O8: Eu2+ could emit the blue light with the broad band of Eu2+ peaking at about 450 nm. The emission color of KSrBP2O8: Eu2+ could be changed from blue to blue-white with the increase of doped Eu2+. In addition, KSrBP2O8: Tb3+ and KSrBP2O8: Eu3+ could emit green light and red light excited by near-UV light with the optimal concentration values of 0.04% Tb3+ and 0.08% Eu3+, respectively.
A novel cobalt borophosphate, (NH4)2(C4H12N2)[Co2B4P6O24(OH)2]·H2O with the mixed cations has been synthesized under mild hydrothermal conditions. Its crystal structure was determined by the single-crystal X-ray diffraction (tetragonal, I41/a (no. 88), a=14.207(3)Å, c=24.956(6)Å, V=5037.09(2)Å3, Z=8). The crystal structure consists of a new type of three-dimensional borophosphatic anionic partial framework, which is built from the condensation of the fundamental building unit (FBU) [B2P3O14(OH)]. The CoO6 octahedra are enchased in such borophosphate network to form a complex open framework with a three-dimensional intersecting channel system, the voids of which are occupied by ammonium, dipronated piperazine ions and water molecules, respectively. The magnetic measurement of the title compound has also been investigated.
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NaCd (H2O)(2)[BP2O8]center dot 0.8H(2)O and NaZn (H2O)(2) [BP(2)O(8)center dot H2O have been synthesized under room temperature and ambient pressure. The two borophosphates were characterized by powder X-ray diffraction. Their morphology were observed by SEM. The formation procedure of NaZn(H2O)(2)[BP2O8]center dot H2O was studied by in situ powder X-ray diffraction.
A novel chromium borophosphate with anionic clusters has been synthesized using boric acid as flux. X-ray diffraction analysis on a single crystal reveals that its structure comprises of crown-shaped 6-membered ring clusters [NaCr(8)B(4)P(12)O(60)H(8)](15-), which are built from [Cr(4)O(18)] groups, [BP(2)O(10)] anions and PO(4) tetrahedra with Na(+) cations encapsulated in the clusters. Magnetic investigation showed strong antiferromagnetic interactions between Cr(3+)-Cr(3+) dimers at low temperature.
BHO9P2RbV, monoclinic, P12(1)/cl (No. 14), a = 9.3789(5) Angstrom, b = 8.3296(4) Angstrom, c = 9.6701(3) Angstrom, beta = 102.0781(8)degrees, V = 738.7 Angstrom(3), Z = 4, R-gt(F) = 0.100, wR(ref)(F-2) = 0.111, T = 293 K.
AlBH3NaO10p2, monoclinic, C12/c1 (No. 15), a = 10.497(2) Å, b = 7.993(2) Å, c = 9.077(2) Å, β= 117.26(3)°, V= 677.0 Å3, Z = 4, Rgt(F) = 0.049, wR(F2) = 0.077, T= 293 K.
BH4NO8P2Zn, monoclinic, C12/c1 (No. 15), a = 12.848(3) Å, b = 12.896(3) Å, c = 8.519(1) Å, β = 91.024(3)°, V =1411.2 ̊3, Z = 8, Rgt(F) = 0.040, wRref(F2) = 0.073, T = 293 K.
BCsFeHO9P2, monoclinic, P121/c1 (No. 14), a = 9.351(2) Å, b = 8.631(4) Å, c = 9.763(2) Å, β = 102.58(2)°, V= 769.0 Å3, Z = 4, Rgt(F) = 0.024, wR(F2) = 0.083, T= 293 K.
BGaH 3NaO10P2, monoclinic, C12/c1 (No. 15), a = 10.408(3) Å, b = 8.094(2) Å, c = 9.099(2) Å, b = 116.64(2)°, V = 685.2 Å 3 , Z = 4, R gt (F) = 0.025, wR ref (F 2) = 0.068, T = 293 K. Source of material NaGa[BP 2O7(OH)3] was synthesized under mild hydrothermal conditions. The reaction was carried out with mixtures of Ga metal (0.139 g) dissolved in 1ml of HCl (18%) with Na 2 HPO 4 ·12H 2 O (1.075 g) and Na 2 B 4 O 7 ·10H 2 O (0.4767 g) (molar ratio of Ga:P:B = 2:3:6) in aqueous solution. The mixture was sealed in glass tubes (after adding 1 ml H 2O to achieve a degree of filling of 30%) with subsequent heating at 408 K for 60 days. The starting materials are all of analytical grade. Discussion With the increasing interest in microporous materials, synthesis of compounds like borophosphates with open framework struc-ture have drawn much attention during the past few years and show a rich crystal chemistry [1]. Systems including a p-block metal have not been widely explored up to now besides one Al compound [2] reported only recently. The structure of the title compound is isotypic to the Fe [3] and Al analogues [2] and is characterized by isolated GaO 4 (OH) 2 octahedra sharing common O-corners with phosphate and common O (OH) -corners with hydrogenborate groups from the oligomeric units [B 2 P 2 O 7 (OH) 3 ] 4– . The condensation of the borophosphate oligo-mers with Ga-coordination octahedra via common corners results in an overall three-dimensional framework which contains ellip-tical channels running along the [001] direction. The cross section of the channels is defined by eight-membered octahedral/tetrahe-dral rings (four Ga coordination octahedra, two phosphate-and two borate-groups). Sodium ions are distributed within the open channels. The Ga—O bond distances are 1.925 and 1.965 Å, while the Ga—OH value is increased to 1.995 Å. The bond dis-tances P—O and B—O in the oligomeric borophosphate groups correspond to respective values in the Fe-and Al-analogues [2,3].
BLiO11P2Zn, hexagonal, P61 (No. 169), a = 9.469(2) Å, c = 15.667(2) Å, V= 1216.6 Å3, Z = 6, Rgt(F) = 0.031, wRref(F2) = 0.086, T = 293 K.
BH5InNO9P2, triclinic, P (1) over bar (No. 2), a = 5.2980(4) Angstrom, b = 8.4880(4) Angstrom, c = 8.3901(5) Angstrom, alpha = 93.077(5)degrees, beta = 93,331(6)degrees, gamma = 80.634(5)degrees, V = 371.3 Angstrom(3), Z = 2, R-gt(F) = 0.038, wR(ref)(F-2) = 0.091, T = 293 K.
BGaH3KO10P2, monoclinic, C12/c1 (No. 15), a = 10.863(1) Angstrom, b = 8.1623(7) Angstrom, c = 9.305(1), beta = 116.587(4)degrees, V = 737.8 Angstrom(3), Z = 4, R-gt(F) = 0.020, wR(ref)(F-2) 0.053, T = 295 K.
AlBH5NO9P2, monoclinic, P12 1/c1 (No. 14), a = 9.234(2) Å, b = 8.370(1) Å, c = 9.413(2) Å, β= 103.670(7)°, V = 706.9 Å3, Z = 4, Rgt(F) = 0.038, wRref(F2); = 0.089, T = 295 K.
BHInKO9P2, triclinic, P (1) over bar (No. 2), a = 5.2638(4) Angstrom, b = 8.4791(5) Angstrom, c = 8.1469(9) Angstrom, a = 91.741(7)degrees, beta = 93.061(7)degrees, gamma = 79.823(5)degrees, V = 357.3 Angstrom(3) Z = 2, R-gt(F) = 0.052, wR(ref)(F-2) = 0.113, T = 293 K.
BGaH5NO9P2, monoclinic, P12(1)/c1 (No. 14), a = 9.281(2) Angstrom, b = 8.292(2) Angstrom, c = 9.564(2) Angstrom, beta = 102.65(3)degrees, V = 718.2 Angstrom(3), Z = 4, R-gt(F) 0.061, wR(ref)(F-2) 0.142, T = 293 K.
AlBHKO9P2, monoclinic, P12(1)/c1 (No. 14), a = 9.255(4) Angstrom, b = 8.190(1) Angstrom, c = 9.323(1) Angstrom, beta = 102.89(3)degrees, V = 688.9 Angstrom(3), Z = 4, R(P) = 0.113, R(I) = 0.059, T = 295 K.
BHInO9P2Rb, triclinic, P (1) over bar (No. 2), a = 5.3157(5) Angstrom, b = 8.3209(8) Angstrom, c = 8.4840(7) Angstrom, a = 87.35(1)degrees, beta = 80.23(1)degrees, gamma = 86.78(1)degrees, V = 369.0 Angstrom(3), Z = 2, R-gt(F) = 0.042, wR(ref)(F-2) = 0.086, T = 295 K.
B4H12In4Na4O40P8, monoclinic, C12/c1 (No. 15), a = 10.368(2) Angstrom, b = 8.520(l) Angstrom, c = 9.415(2) Angstrom, beta = 115.951(5)degrees, V = 747.8 Angstrom(3), Z = 1, R-gt(F) = 0.076, wR(ref)(F-2) = 0.202, T = 293 K.
A novel borophosphate, Zn 3(C 6H 14N 2) 3[B 6P 12O 39(OH) 12] · (C 6H 14N 2)[HPO 4] has been synthesised under mild hydrothermal conditions at T = 165°C. The chiral crystal structure was determined by single crystal X-ray diffraction data (trigonal, R3 (no. 146), Z = 3, a = 2089.55(4) pm, c = 1237.03(4) pm, V = 4677.5(2) · 10 6 pm 3, R 1 = 0.066, wR 2 = 0.164 for 5100 observed reflections). The title compound can be considered as an ordered composite of the two different and neutral structures which fit into each other: An open framework of composition Zn 3(C 6H 14N 2) 3[B 6P 12O 39(OH) 12] and columns of composition (C 6H 14N 2)[HPO 4]. The framework structure is formed by mixed octahedral-tetrahedral secondary building units, in a three-dimensional arrangement reflecting a hierarchical derivative of the NbO structure type. The underlying NbO topology is illustrated with the help of Periodic Nodal Surfaces. The composite nature of the compound is resolved in the spatial segregation of two frameworks with a separating surface.
Two open-framework ammonium−iron borophosphates, black colored (NH4)0.4FeII0.55FeIII0.5(H2O)2[BP2O8]·0.6H2O (1a) (pale gray colored 1b with a powder X-ray diffraction pattern indicating an isotype relationship was also observed) and pale pink colored NH4FeIII[BP2O8(OH)] (2), were synthesized under mild hydrothermal conditions at 180 °C. Their crystal structures were determined by single-crystal X-ray investigations (hexagonal, P65 (no. 170), a = 9.483(4) Å, c = 15.697(5) Å, V = 1222.5(8) Å3, and Z = 6 for 1a and monoclinic P21/c (no. 14), a = 9.370(1) Å, b = 8.309(2) Å, c = 9.680(1) Å, β = 102.05(1)°, V = 737.0(2) Å3, and Z = 4 for 2, respectively). The crystal structure of 1a is characterized by corner-sharing PO4 and BO4 tetrahedra, leading to infinite helical {[BP2O8]3-} ribbons, which are connected by FeII/IIIO4(H2O)2 coordination octahedra. An additional trigonal bipyramidal FeII/IIIO2(H2O)3 coordination polyhedron shares common corners and edges with three FeII/IIIO4(H2O)2 coordination octahedra, leading to tetrameric units. Helical channels, running along [001], are statistically occupied by H2O molecules and NH4+ ions. The structure of 2 is characterized by an infinite {[BP2O8(OH)]4-} chain, which is further connected by FeIIIO4(H2O)2 coordination octahedra leading to one-dimensional channels which are occupied by NH4+ ions. The magnetic properties of both compounds are presented. For compound 1a (and 1b), the mixed-valence state of iron was confirmed. The susceptibility of compound 2 reveals a stronger magnetic interaction and an antiferromagnetic ordering at 17 K.
The so far unknown compounds Zn3BPO7 and Mg3BPO7 both occur in two forms. The transition of the high-temperature form into the low-temperature form is very sluggish for Zn3BPO7, but prompt for Mg3BPO7. Therefore, the growing of larger crystals is restricted to β-Zn3BPO7. β-Mg3BPO7 cannot be quenched to room temperature. The crystal data are given for β-Zn3BPO7 with the hexagonal space group P[unk]m2 or P[unk]2m and for the orthorhombic α-phases of both compounds with the probable space group Imm2.
The first example of a molecular cluster of the metal–borophosphate class of compounds has been prepared.
CsV3(H2O)2[B2P 4O16(OH)4] was prepared under mild hydrothermal conditions (T = 165 °C) from mixtures of CsOH(aq), VCl3, H3BO3, and H3PO4 (molar ratio 1:1:1:2). The crystal structure was determined by X-ray single crystal methods (monoclinic; space group C2/m, No. 12): a = 958.82(15) pm, b = 1840.8(4) pm, c = 503.49(3) pm; β= 110.675(4)°; Z = 2. The anionic partial structure contains oligomeric units [BP2O8(OH)2]5-, which are built up by a central BO2(OH)2 tetrahedron and two PO4 tetrahedra sharing common corners. VIII is octahedrally coordinated by oxygen of adjacent phosphate tetrahedra and OH groups of borate tetrahedra as well as oxygen of phosphate tetrahedra and H2O molecules, respectively (coordination octahedra VO4(OH)2 and VO4(H2O)2). The oxidation state +3 for vanadium was confirmed by measurements of the magnetic susceptibility. The trimeric borophosphate groups are connected via vanadium centres to form layers with octahedratetrahedra ring systems, which are likewise linked via VIII-coordination octahedra. Overall, a three-dimensional framework constructed from VO4(OH)2 and VO4(H2O)2 octahedra as well as BO2(OH)2 and PO4 tetrahedra results. The structure contains channels running along [001], which are occupied by Cs+ in a distorted octahedral coordination (CsO4(H2O)2).
The hydrothermal reaction of NaVO3, BPO4, ethylenediamine, CuCl2 . 2H(2)O, and water yields the open-framework material [H3NCH2CH2NH3](2)[(VO)(5)(H2O){O3POB(O)(2)OPO3}(2)]. 1.5H(2)O, VOBOPO-1. The framework, constructed from binuclear {V2O10}, mononuclear {VO(H2O)O-4}, and {O3POB(O)(2)OPO3}(7-) building blocks, provides channels occupied by the (H3NCH2CH2NH3)(2+) cations and water molcules of crystallization.
Hydrothermal synthesis provides new vanadium borophosphates. BP2O10 trimers and V2O8 dimers are connected by common oxygen atoms to give a building unit of composition (VO)2BP2O10. Four-, five-, and six-rings are formed by further connection of these units; the first case is shown schematically. The ring size of the anion is determined by the size of the specific cation used in the synthesis.
C 2 H 10 N 2 )[BPO 4 F 2 ] — Strukturbeziehungen zwischen [BPO 4 F 2 ] 2— und [Si 2 O 6 ] 4—
Colourless crystals of (C 2 H 10 N 2 )[BPO 4 F 2 ] were prepared from mixture of ethylendiamine, H 3 BO 3 , BF 3 · C 2 H 5 NH 2 , H 3 PO 4 and HCl under mild hydrothermal conditions (220 °C). The crystal structure was determined by single crystal methods (triclinic, P 1¯ (no. 2), a = 451.85(5) pm, b = 710.20(8) pm, c = 1210.2(2) pm, α = 86.08(1)°, β = 88.52(2)°, γ = 71.74(1)°, Z = 2) and contains infinite tetrahedral zweier‐single‐chains {[BPO 4 F 2 ] 2— } which are isoelectronic (48e — ) with the polyanions {[Si 2 O 6 ] 4— } of the pyroxene family.
CsV3(H2O)2[B2P4O16(OH)4] wurde unter milden hydrothermalen Bedingungen (T = 165 °C) aus Mischungen von CsOH(aq), VCl3, H3BO3 und H3PO4 (molares Verhältnis 1 : 1 : 1 : 2) dargestellt. Die Kristallstruktur (monoklin; Raumgruppe C2/m, Nr. 12) wurde mit Röntgen-Einkristallmethoden bestimmt: a = 958,82(15) pm, b = 1840,8(4) pm, c = 503,49(3) pm; β = 110,675(4)°; Z = 2. Die Anionenteilstruktur enthält oligomere Einheiten [BP2O8(OH)2]5–, die durch Eckenverknüpfung eines zentralen BO2(OH)2-Tetraeders mit zwei PO4-Tetraedern gebildet werden. VIII ist oktaedrisch von Sauerstoff benachbarter Phosphat-Tetraeder und OH-Gruppen der Borat-Tetraeder bzw. von Sauerstoff der Phosphat-Tetraeder und H2O-Molekülen umgeben (Koordinationsoktaeder VO4(OH)2 bzw. VO4(H2O)2). Die Oxidationsstufe +3 für Vanadium wurde durch Messungen der magnetischen Suszeptibilität bestätigt. Die trimeren Borophosphat-Gruppen werden über die Vanadium-Zentren so weiterverknüpft, daß Schichten mit Oktaeder-Tetraeder-Ringstrukturen gebildet werden, die ihrerseits untereinander über VIII-Koordinationsoktaeder verbunden sind. Insgesamt resultiert ein komplexer dreidimensionaler Strukturverband aus VO4(OH)2- und VO4(H2O)2-Oktaedern sowie BO2(OH)2- und PO4-Tetraedern, der von parallel [001] verlaufenden Kanälen durchzogen wird, in denen sich Cs⁺ in verzerrt oktaedrischer Koordination befindet (CsO4(H2O)2).
The first layered vanadium borophosphate has been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, infrared and Raman spectroscopy, and magnetic measurements. The structure contains a novel borophosphate secondary building unit, [B2P5O10], that is connected to V2O8 dimers and VO5 square pyramids to form a layer structure. Disordered imidazolium cations and water molecules form a complex network of hydrogen bonds and fill the space between the layers.
Together with the MI ions, the tetrahedral ribbons of the title compounds form double helices, the central channels of which are filled with water helices (see picture). Coordination octahedra MIIO4(H2O)2 link the spiral ribbons, which run parallel to one another. Partial dehydration of the title compounds leads to microporous phases with channeled structure and is reversible in the sense of a topochemical reaction.
The open framework zinco-cobalto-borophosphate, NH4[(Zn1−xCox)BP2O8] (0⩽x⩽0.14), has been synthesized as pale blue powder under hydrothermal conditions. The crystal structure was determined at 293 K from single-crystal X-ray diffraction data (triclinic (no. 2), NH4[(Zn0.88Co0.12)BP2O8]: a=7.4319(11) Å, b=7.5997(5) Å, c=7.8402(2) Å, α=118.9940(9)°, β=101.6597(9)°, γ=103.4308(14)°, V=350.01 Å3, Z=2). The structure is characterized by channels of eight-membered rings of tetrahedra running along [1 0 1] and [1 1 0] directions, respectively. The title compound is an isotype of the zinco-borophosphates A[ZnBP2O8] (A=NH4+, Rb+, Cs+) which exhibit a gismondine-type framework topology.
A novel borophosphate-hydrate, (Ni3-xMgx)[B3P3O12(OH)(6)] . 16H(2)O (x approximate to 1.5), has been prepared by hydrothermal synthesis (T = 170 degreesC) from a mixture of NiCl2 . 6H(2)O, Mg(OH)(2), B2O3 and H3PO4. The crystal structure was determined at 293 K from single-crystal X-ray diffraction data (trigonal, R(3) over barc (no.167), a = 14.957(10) Angstrom, c = 13.812(6) Angstrom, V = 2676(2) Angstrom (3), Z = 6, R-1 = 0.0276, wR(2) = 0.0714 for 779 observed reflections with I > 2 sigma (I)). The crystal structure contains unbranched six-membered rings [B3P3O12(OH)(6)](6-) of alternating corner linked borate and phosphate tetrahedra, which are stacked along [001] and connected via (MO2)-O-II(OH)(2)(H2O)(2) coordination polyhedra. Hydrogen bonding between the tetrahedral six-membered rings and (MO2)-O-II(OK)(2)(H2O)(2) octahedra leads to a further cross-linking. With respect to the arrangement of isolated six-membered tetrahedral rings the crystal structure of this borophosphate-hydrate is closely related to the cyclo-hexasilicate dioptase, Cu-6[Si6O18] . 6 H2O.
Two novel borophosphatcs, MII(C4H12N2)-[B2P 3O12(OH)] (MII = Co, Zn), exhibiting open frameworks, have been synthesized by hydrothermal reactions (T = 165°C). The crystal structures of the isotypic compounds have been determined both at 293 K (orthorhombic, Ima2 (no. 46), Z = 4; MII = Co: a = 12.4635(4) Å b = 9.4021(4) Å, c = 11.4513(5) Å, V = 1341.90 Å3, R1 = 0.0202, wR2 = 0.0452, 2225 observed reflections with I > 2σ(I); MII = Zn: a = 12.4110(9) Å, b = 9.4550(5) Å, c = 11.4592(4) Å, V = 1344.69 Å3, R1 = 0.0621, wR2 = 0.0926, 1497 observed reflections with I > 2σ(I)). Distorted CoO6-octahedra and ZnO5-square-pyramids, respectively, share common oxygen-corners with BO4-, PO4- and (HO)PO3-tetrahedra. The tetrahedral groups are linked via common corners to form infinite loop-branched borophosphate chains ∝1[B2P3O12(OH) 4-]. The open framework of MII-coordination polyhedra and tetrahedral borophosphate chains contains a three-dimensional system of interconnected structural channels running along [100], [001] and [001], respectively, which are occupied by di-protonated piperazinium ions.
Tetrahedral framework structures with topologies that show close relationships to the feldspar group or to gismondine are formed by the zincoborophosphates A[ZnBP2O8] (see picture). The compounds are readily accessible under mild hydrothermal conditions (Tmax=170°C) and are thermally remarkably stable (for example, 940°C for A=Cs). Metalloborophosphates are a new class of compounds, which are expected to provide access to zeolite-like microporous systems.
Crystals of NaZn(H2O)2[BP2O8].H2O were grown under mild hydrothermal conditions at 170 degrees C. The crystal structure (solved by X-ray single-crystal methods: hexagonal, P6(1)22 (no. 178), a = 946.2(2), c= 1583.5(1) pm, V= 1227.8(4).10(6) pm3, Z = 6) exhibits a chiral octahedral-tetrahedral framework related to the CZP topology and contains helical ribbons of corner-linked borate and phosphate tetrahedra. Investigation of the thermal behavior up to 180 degrees C shows a (reversible) dehydration process; this leads to the microporous compound Na[ZnBP2O8].H2O, which has the CZP topology. The crystal structure of Na[ZnBP2O8].H2O was determined by X-ray powder diffraction by using a combination of simulated annealing, lattice-energy minimization, and Rietveld refinement procedures (hexagonal, P6(1)22 (no. 178), a = 954.04(2), c = 1477.80(3) pm, V= 164.88(5).10(6) pm3, Z = 6). The essential structural difference caused by the dehydration concerns the coordination of Zn2- changing from octahedral to tetrahedral arrangement.
The first example of a dimer of corner sharing BO3 and PO4 units, BPO64-, occurs in the title compound. The structure is built of layers of such dimers separated by double layers of isolated PO4 tetrahedra. The cobalt atoms are 6-, 5-, and 4-coordinated by the oxygen.