•Ba6Al4B14O33 has a 3D network formed by AlO4 tetrahedra, BO3 triangles, [Al4O14]16−, [B6O14]10−, and [B6O13]8− groups.•IR spectrum confirms the presence of BO3 and BO4 groups.•UV-VIS diffuse reflectance spectrum shows a band gap of about 3.44 eV.•Solid-state fluorescence spectrum shows a broad emission band at about 527 nm.•Band structure calculations indicate that it is a direct band-gap insulator.A new barium aluminoborate, Ba6Al4B14O33, has been synthesized by the high-temperature solution reaction at 700 °C. The single-crystal XRD analysis showed that it crystallizes in a new structure type with space group P  1¯, a=7.0070(14) Å, b=13.880(3) Å, c =14.702(3) Å, α=86.48(3)°, β=88.99(3)°, γ=83.46(3)°, V=1417.8(5) Å3, and Z=2. The fundamental building blocks in this structure are AlO4 tetrahedra, BO3 triangles, [Al4O14]16− groups composed of two AlO4 tetrahedra and two AlO5 trigonal bipyramids, [B6O14]10− groups formed by one BO3 triangle bonded to one [B5O12]9− double ring, and [B6O13]8− groups consisting of one BO3 triangle linked to one [B5O11]7− double ring. They are held together via common O atoms to form a 3D network, with intersecting open channels accommodating Ba2+ cations. The existence of both BO3 and BO4 groups is confirmed by FT-IR spectrum and an optical band gap of 3.44 eV is obtained from UV–VIS diffuse reflectance spectrum. Solid-state fluorescence spectrum has also been studied exhibiting the maximum emission peak at around 527 nm. Band structure calculations by the density functional theory method indicate that it is a direct band-gap insulator.The fundamental building blocks in Ba6Al4B14O33 are AlO4 tetrahedra, BO3 triangles, [Al4O14]16− groups, [B6O14]10− groups, and [B6O13]8− groups. They are held together via common O atoms to form a 3D network, with intersecting open channels accommodating Ba2+ cations.

•LiMBO3 (M = Zn, Cd) crystals were synthesized by high-temperature solution reaction.•Their crystal structures have 3D character, with open channels occupied by Li+ cations.•IR spectra confirmed the presence of planar BO3 groups.•UV–vis diffuse reflectance spectra revealed band gaps of about 3.10 and 4.28 eV, respectively.•Band structure calculations indicated both to be direct band-gap insulators.Two alkaline and transition metal orthoborates, LiMBO3 (M = Zn, Cd), have been synthesized and their crystal structures determined by single-crystal XRD methods with the following crystal data: LiZnBO3, P  1¯(No.2), a = 5.0559 (15) Å, b = 6.097 (2) Å, c = 8.0359 (18) Å, α = 75.75 (2)°, β = 89.86 (2)°, γ = 89.79 (3) °, Z = 4; LiCdBO3, P21/c (No.14), a = 10.4159 (14) Å, b = 9.005 (2) Å, c = 10.756 (2) Å, β = 92.521 (13)°, Z = 16. The crystal structure of LiZnBO3 is composed of edge-sharing ZnO5 trigonal bipyramids which are bound together via ZnO4 tetrahedra and BO3 planar triangles to form a polyanionic framework. LiCdBO3 also features a 3D framework, but constructed by edge-sharing CdO5 trigonal bipyramids and BO3 triangles. Both structures afford open channels that are occupied by Li+ cations. IR spectra further confirm that these two compounds contain the planar triangular BO3 groups. UV–VIS diffuse reflectance spectra show band gaps of about 3.10 and 4.28 eV and solid-state fluorescence spectra demonstrate emission bands at around 542 and 412 nm for LiZnBO3 and LiCdBO3, respectively. Band structure calculations by the density functional theory method indicate that both compounds are direct band-gap insulators.

•Na2Cs2Sr(B9O15)2 has been synthesized and characterized.•It has a 3D network formed by the unprecedented [B9O19]11− groups.•IR spectrum confirms the presence of low symmetric BO3 and BO4 groups.•UV–VIS diffuse reflectance spectrum shows a band gap of about 3.26 eV.•Band structure calculations indicate that it is an indirect band-gap insulator.A new sodium cesium strontium borate, Na2Cs2Sr(B9O15)2, has been synthesized and its crystal structure determined by single-crystal XRD methods. The compound crystallizes in the space group P21/c (No. 14) with the following cell parameters: a = 8.4670(17) Å, b = 8.5220(17) Å, c = 17.206(3) Å, β = 92.60(3)°, V = 1240.2(4) Å3, Z = 2. It represents a new structure type in which three [B3O7]5− triborate groups are bridged by two common oxygen atoms to form a [B9O19]11− group that is further condensed into a 3D [B9O15]3-∞3 network, with the shorthand notation 9:∞3[3 × (3:2Δ + T)], where Δ and T represent BO3 triangles and BO4 tetrahedra, respectively. The 3D borate anionic network also affords intersecting open channels as well as pockets that accommodate Cs+, Sr2+, and Na+ cations. IR spectrum further confirms that this compound contains low symmetric BO3 and BO4 groups. UV–VIS diffuse reflectance spectrum shows a high degree of transparency under the visible light and a band gap of about 3.26 eV. Solid-state fluorescence spectrum demonstrates a broad emission band at around 494.8 nm. Band structure calculations by the density functional theory method indicate that it is an indirect band-gap insulator.Na2Cs2Sr(B9O15)2 represents a new structure type in which three [B3O7]5− triborate groups are bridged by two common oxygen atoms to form a [B9O19]11− group that is further condensed into a 3D [B9O15]3-∞3 network, with the intersecting open channels as well as pockets accommodating Cs+, Sr2+, and Na+ cations.

•Ba4K2Zn5(B3O6)3(B9O19) has been synthesized by high-temperature solution reaction.•It has a layered structure consisting of ZnO4 tetrahedra, [B3O6]3− rings, and [B9O19]11− groups.•The IR spectrum confirmed the presence of both BO3 and BO4 groups.•UV–vis diffuse reflectance spectrum revealed a band gap of about 3.18 eV.•Solid-state fluorescence spectrum shows a broad emission band at about 515.8 nm.A new barium potassium zincoborate, Ba4K2Zn5(B3O6)3(B9O19), has been synthesized by high-temperature solution reaction at 750 °C. Its crystal structure was established by single-crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P21/n (No. 14) with cell parameters of a = 7.1620(14) Å, b = 38.772(8) Å, c = 12.360(3) Å, β = 90.26(3)°, V = 3432.2(12) Å3, and Z   = 4. It has a new structure type that features two-dimensional [Zn5(B3O6)3(B9O19)]∞210− anionic layers composed of ZnO4 tetrahedra, [B3O6]3− rings with notation of 3[3Δ], and [B9O19]11− groups with notation of 3[2Δ + 1T] + 3Δ + 3[2Δ + 1T], where Δ and T represent BO3 triangles and BO4 tetrahedra, respectively. The zinc borate anionic layers stack along b-axis, with the intralayer open channels and interlayer void spaces filled by Ba2+, K+, or Ba2+/K+ cations to compensate the negative charges of the layers. Infrared spectrum was measured, which confirms the presence of both BO3 and BO4 groups. The optical properties were investigated in terms of diffuse reflectance and fluorescence spectra, which reveal an optical band gap of 3.18 eV as well as a broad emission band at around 515.8 nm upon laser excitation at 325 nm.

A new sodium strontium aluminoborate, NaSr7AlB18O36, has been synthesized by high-temperature solution reaction at 860 °C. Its crystal structure was established by single-crystal X-ray diffraction technique: the space group R\( {\bar{3}} \)c (No. 167), cell parameters a = 11.356(2) Å, c = 36.655(7) Å, V = 4093.7(12) Å3, and Z = 6. It is isostructural with Sr8MgB18O36 and the crystal structure consists of the cyclic B18O3618− building unit of corner-sharing twelve BO3 triangles and six BO4 tetrahedra. Each B18O3618− group is bonded to six octahedrally coordinated Al3+ centers via Al–O bonds to generate a 3D \( _{\infty }^{3} \)[Al(B18O36)]15− framework that has intersecting open channels occupied by Sr2+/Na+ cations. The IR spectrum has further confirmed that the compound contains low symmetric BO3 and BO4 groups; UV–Vis diffuse reflectance spectrum revealed an optical band gap of about 3.65 eV; while solid-state fluorescence spectrum exhibited a broad emission band with the emitted main peak localized at about 533.3 nm and shoulder at 420 nm upon excitation by laser of 325 nm.

Highlights•Ba4Na2Zn4(B3O6)2(B12O24) has been prepared by solid state reaction method.•It has a layered structure consisting of ZnO4 tetrahedra, [B3O6]3− rings, and [B12O24]12− groups.•The IR spectrum confirmed the presence of both BO3 and BO4 groups.•UV–vis diffuse reflectance spectrum revealed a band gap of about 3.13 eV.•Band structure calculations indicated that it is an indirect band material.A new barium sodium zincoborate, Ba4Na2Zn4(B3O6)2(B12O24), has been prepared by solid state reaction method below 750 °C. Single-crystal XRD analysis showed that it crystallizes in the triclinic space group P  1¯ with a = 7.0288(14) Å, b = 7.0687(14) Å, c = 17.501(4) Å, α = 91.92(3)°, β = 96.46(3)°, γ = 119.72(3)°, Z = 1. The crystal structure exhibits complicated porous anionic layers composed of ZnO4 tetrahedra, [B3O6]3− rings with notation of 3[3Δ], and [B12O24]12− groups built up from four BO4 tetrahedra and eight BO3 triangles with notation of 2 × {2 × (3[2Δ + 1T])}. The anionic layers stack along c-axis, with the intralayer open channels and interlayer void spaces occupied by Na+ or Ba2+ cations to balance charge. The IR spectrum further confirmed the presence of both BO3 and BO4 groups. UV–vis diffuse reflectance spectrum revealed a band gap of about 3.13 eV. Solid-state fluorescence spectrum exhibited a broad emission band at around 540 nm. Band structure calculations indicated that it is an indirect band material with the calculated band gap of about 4.278 eV.Ba4Na2Zn4(B3O6)2(B12O24) contains complicated porous anionic layers composed of ZnO4 tetrahedra, [B3O6]3− rings with notation of 3[3Δ], and [B12O24]12− groups built up from four BO4 tetrahedra and eight BO3 triangles with notation of 2 × {2 × (3[2Δ + 1T])}. The anionic layers stack along c-axis, with the intralayer open channels and interlayer void spaces occupied by Na+ or Ba2+ cations to balance charge.

A new barium aluminoborate, Ba8[(Al6IV)(Al2IV)(Al2V)B12IIIO41]∞, has been prepared by solid state reaction method below 770 °C, with adding Bi2O3 as a flux. Single-crystal XRD analysis showed that it crystallizes in the triclinic space group P1¯ with a = 9.2437(11) Å, b = 9.8100(12) Å, c = 11.0830(14) Å, α = 76.130(10)°, β = 73.550(9)°, γ = 77.990(10)°, Z = 1. The crystal structure contains Latin capital H letter shaped Al6O1920− groups built up from six corner-sharing AlO4 tetrahedra. The Al6O1920− groups, AlO4 tetrahedra, AlO5 trigonal bipyramids, and BO3 triangles are linked to form a two-dimensional [(Al6IV)(Al2IV)(AVl2)B12IIIO41]16−[(Al6IV)(Al2IV)(Al2V)B12IIIO41]16− layer by sharing O vertices. The layers are stacked along the c-axis, with the interlayer void spaces and intralayer open channels occupied by Ba2+ cations to balance charge. The IR spectrum further confirmed the presence of BO3 groups. UV–Vis diffuse reflectance spectrum showed a band gap of about 3.10 eV. Solid-state fluorescence spectrum exhibited a broad emission band at around 430 nm. Band structure calculations indicated that it is a direct band material with the calculated band gap (3.25 eV) close to the observed one.Graphical abstractThe crystal structure of Ba8[(Al6IV)(Al2IV)(Al2V)B12IIIO41]∞ is composed of Latin capital H letter shaped Al6O1920− groups, AlO4 tetrahedra, AlO5 trigonal bipyramids, and BO3 triangles that are linked to form a two-dimensional [(Al6IV)(Al2IV)(AVl2)B12IIIO41]16−[(Al6IV)(Al2IV)(Al2V)B12IIIO41]16− layer by sharing O vertices. The layers are stacked along the c-axis, with the interlayer void spaces and intralayer open channels occupied by Ba2+ cations to balance charge.Highlights► Ba8[(Al6IV)(Al2IV)(Al2V)B12IIIO41]∞ has been prepared by solid state reaction method. ► It has a layered structure consisting of Latin capital H letter shaped Al6O1920− groups, AlO4 tetrahedra, and AlO5 trigonal bipyramids bridged by BO3 triangles. ► The IR spectrum confirmed the presence of BO3 groups. Band structure calculations indicated that it is a direct band material with the calculated band gap (3.25 eV) close to the observed one (3.10 eV).

A novel quaternary borate, Na2.18K0.82SrB5O10, has been prepared by high-temperature solution reaction below 800 °C. Single-crystal XRD analyses showed that it crystallizes in the triclinic \( P\bar{1} \) group with a = 7.3900(15) Å, b = 7.6490(15) Å, c = 9.773(2) Å, α = 79.31(2)°, β = 70.85(2)°, γ = 62.09(1)°, Z = 2. The basic structural unit in Na2.18K0.82SrB5O10 is a double ring [B5O10]5− composed of one BO4 tetrahedron and four BO3 triangles. The [B5O10]5− groups are arranged around crystallographic centers of symmetry to form [B10O20]10− columns that are held together by Na+, K+/Na+, and Sr2+ cations via electrostatic interactions. The IR spectrum further confirmed the presence of both BO3 and BO4 groups. UV–vis diffuse reflectance spectrum showed a band gap of about 3.80 eV. Solid-state fluorescence spectrum exhibited the maximum emission peak at around 337.6 nm.

A novel non-centrosymmetric borate, BiCd3(AlO)3(BO3)4, has been prepared by solid state reaction methods below 750 °C. Single-crystal XRD analysis showed that it crystallizes in the hexagonal group P63 with a=10.3919(15) Å, c=5.7215(11) Å, Z=2. In its structure, AlO6 octahedra share edges to form 1D [AlO4]5−∞1 chains that are bridged by BO3 groups through sharing O atoms to form the 3D [AlBO4]2−∞3 framework. The 3D framework affords two kinds of channels that are occupied by Bi3+/Cd2+ atoms only or by Bi3+/Cd2+ atoms together with BO3 groups. The IR spectrum further confirmed the presence of BO3 groups. Second-harmonic-generation measurements displayed a response of about 0.5×KDP (KH2PO4). UV–vis diffuse reflectance spectrum showed a band gap of about 3.19 eV. Solid-state fluorescence spectrum exhibited the maximum emission peak at around 390.6 nm. Band structure calculations indicated that it is an indirect semiconductor.Graphical abstractBiCd3(AlO)3(BO3)4 has a 3D network formed by stitching 1D chains of edge-sharing AlO6 octahedra via BO3 groups. There are channels occupied by Bi3+/Cd2+ only or by Bi3+/Cd2+ with BO3 groups.

Two oxoborates, (Pb3O)2(BO3)2MO4 (M=Cr, Mo), have been prepared by solid-state reactions below 700 °C. Single-crystal XRD analyses showed that the Cr compound crystallizes in the orthorhombic group Pnma with a=6.4160(13) Å, b=11.635(2) Å, c=18.164(4) Å, Z=4 and the Mo analog in the group Cmcm with a=18.446(4) Å, b=6.3557(13) Å, c=11.657(2) Å, Z  =4. Both compounds are characterized by one-dimensional ∞1[Pb3O]4+ chains formed by corner-sharing OPb4 tetrahedra. BO3 and CrO4 (MoO4) groups are located around the chains to hold them together via Pb–O bonds. The IR spectra further confirmed the presence of BO3 groups in both structures and UV–vis diffuse reflectance spectra showed band gaps of about 1.8 and 2.9 eV for the Cr and Mo compounds, respectively. Band structure calculations indicated that (Pb3O)2(BO3)2MoO4 is a direct semiconductor with the calculated energy gap of about 2.4 eV.(Pb3O)2(BO3)2MO4 (M  =Cr, Mo) are characterized by 1D ∞1[Pb3O]4+ chains formed by corner-sharing OPb4 tetrahedra. BO3 and CrO4 (MoO4) groups are located around the chains to hold them together via Pb–O bonds.

Two alkali-metal zinc borates, α-LiZnBO3 and Li0.48Na0.52ZnBO3, have been prepared by solid-state reactions below 850 °C. Single-crystal XRD analyses showed that the former crystallizes in the C2/c group with a = 8.746(2) Å, b = 5.091(1) Å, c = 6.129(1) Å, β = 118.75(3)°, Z = 4 and the latter in the group P1¯ with a = 5.054(1) Å, b = 6.113(1) Å, c = 8.045(2) Å, α = 75.73(2)°, β = 89.87(3)°, γ = 89.86(3)°, Z = 4. The crystal structure of α-LiZnBO3 is composed of tetrahedral ZnO4 and triangular BO3 groups that are arranged into a three-dimensional (3D) network by sharing O vertices. Li0.48Na0.52ZnBO3 is also characterized by a 3D framework, but built up from corner-sharing ZnO4 tetratahedra, ZnO5 trigonal bipyramids, and BO3 triangles. Both structures afford open channels that are occupied by alkali-metal cations. The IR spectra further confirmed the presence of BO3 groups and UV-vis diffuse reflectance spectra showed band gaps of about 3.10 and 2.95 eV for the Li and Li/Na compounds, respectively. Band structure calculations indicated that both compounds are direct semiconductors with the calculated band gaps close to the observed ones.

A new calcium borate, CaB6O10, has been prepared by solid-state reactions at temperature below 750 °C. The single-crystal X-ray structural analysis showed that CaB6O10 crystallizes in the monoclinic space group P21/c with a = 9.799(1) Å, b = 8.705(1) Å, c = 9.067(1) Å, β = 116.65(1)°, Z = 4. It represents a new structure type in which two [B3O7]5− triborate groups are bridged by one oxygen atom to form a [B6O13]8− group that is further condensed into a 3D [B6O10]2−∞3 network, with the shorthand notation 6: ∞3[2 × (3:2Δ + T)]. The 3D [B6O10]2−∞3 network affords intersecting open channels running parallel to three crystallographically axis directions, where Ca2+ cations reside. The IR spectrum further confirms the presence of both BO3 and BO4 groups.

A new strontium borate, Sr2B16O26, has been prepared by solid-state reactions at temperature below 750 °C. The single-crystal X-ray structural analysis showed that Sr2B16O26 crystallizes in the monoclinic space group P21/c with a = 8.408(1) Å, b = 16.672(2) Å, c = 13.901(2) Å, β = 106.33(1)°, and Z = 4. Its crystal structure consists of a 3D network of the complex borate anion [B16O20O12/2]4−, formed by 12 BO3 triangles and 4 BO4 tetrahedra, which can be viewed as 3 linked [B3O3O4/2]− triborate groups bonded to 1 pentaborate [B5O6O4/2]− group and 2 BO3 triangles; this leads to a Fundamental Building Block (FBB) with the shorthand notation 16: ∞3[3 × (3:2Δ + T) + (5:4Δ + T) + 2Δ]. The 3D network affords intersecting open channels running parallel to the crystallographic a and c axes, where Sr2+ cations reside. The IR spectrum further confirms the presence of both BO3 and BO4 groups.The crystal structure of Sr2B16O26 consists of a 3D network of the complex borate anion [B16O32]16−, formed by 12 BO3 triangles and 4 BO4 tetrahedra, which can be viewed as three linked [B3O7]5− triborate groups bonded to one pentaborate [B5O10]5− group and two BO3 triangles; this leads to a Fundamental Building Block (FBB) with the shorthand notation 16: ∞3[3 × (3:2Δ + T) + (5:4Δ + T) + 2Δ].

A novel lithium molybdenyl iodate, LiMoO3(IO3), has been prepared by hydrothermal reactions at 170 °C. Its crystal structure has been determined from single-crystal X-ray data: space group P21, a = 5.4104(4) Å, b = 5.3158(3) Å, c = 9.0025(7) Å, β = 106.863(6)°, Z = 2. LiMoO3(IO3) is a new layered material containing [MoO3(IO3)]1−[MoO3(IO3)]1− anionic layers separated by Li+ cations. The anionic layer has an unprecedented configuration consisting of WO3-type sheets “capped” by IO3− groups. The iodate groups have their stereochemically active nonbonded electron pairs align along the b-axis, which creates the polarity in the structure. Second-harmonic-generation measurements on LiMoO3(IO3) display a response of about 4 × KH2PO4. DTA measurements demonstrate that LiMoO3(IO3) is stable up to at least 430 °C. UV–vis diffuse reflectance spectrum of this compound shows a high degree of transparency from 1.1 to 2.8 eV and a band gap of about 2.8 eV.

A novel ternary borate, trisodium zinc pentaborate, Na3ZnB5O10, has been prepared by solid-state reaction at temperature below 750 °C. The single-crystal X-ray structural analysis showed that Na3ZnB5O10 crystallizes in the monoclinic space group P21/n with a=6.6725(7) Å, b=18.1730(10) Å, c=7.8656(9) Å, β=114.604(6)°, Z=4. It represents a new structure type in which double ring [B5O10]5− building units are bridged by ZnO4 tetrahedra through common O atoms to form a two-dimensional ∞2[ZnB5O10]3--layer that affords one-dimensional channels running parallel to the [101] direction. Symmetry-center   related ∞2[ZnB5O10]3- layers are stacked along the b-axis, with the interlayer void spaces and intralayer open channels filled by Na+ cations to balance charge. The IR spectrum further confirms the presence of both BO3 and BO4 groups and UV–vis diffuse reflectance spectrum shows a band gap of about 3.2 eV.Na3ZnB5O10 represents a new structure type in which double ring [B5O10]5− building units are bridged by ZnO4 tetrahedra through common O atoms to form a two-dimensional ∞2[ZnB5O10]3- layer. Symmetry-center   related ∞2[ZnB5O10]3- layers are stacked along the b-axis, with the interlayer void spaces and intralayer open channels filled by Na+ cations.

Two ternary borates, Na3CaB5O10 and Na3MgB5O10, have been prepared by solid-state reactions at temperature below 750 °C. Single-crystal X-ray structural analyses showed that Na3CaB5O10 crystallizes in the triclinic space group P1¯ with a = 7.4403(6) Å, b = 9.7530(10) Å, c = 12.9289(9) Å, α = 90.972(7)°, β = 90.073(7)°, γ = 109.656(6)°, Z = 4 and Na3MgB5O10 in the orthorhombic group Pbca with a = 7.838(1) Å, b = 12.288(1) Å, c = 18.180(2) Å, Z = 8. Na3CaB5O10 has a superstructure, with the cell volume being two times of that reported previously. The crystal structure consists of discrete [B5O10]5− anions separated by six-coordinated Ca2+ as well as five-, six- and seven-coordinated Na+ cations. Na3MgB5O10 contains [B5O10]5− groups that are bridged by MgO4 tetrahedra through common O atoms to form 2D [MgB5O10]3−∞2 layers, with Na+ cations situated between and within the layers. The IR spectra further confirmed the presence of BO3 and BO4 groups in both compounds.Na3CaB5O10 has a superstructure, with the cell volume being two times of that reported previously. The crystal structure consists of discrete [B5O10]5− anions separated by six-coordinated Ca2+ as well as five-, six- and seven-coordinated Na+ cations. Na3MgB5O10 contains [B5O10]5− groups that are bridged by MgO4 tetrahedra through common O atoms to form 2D [MgB5O10]3−∞2 layers, with Na+ cations situated between and within the layers.

The low-temperature α-form and the high-temperature β-form of Zn3B2O6 have been prepared by solid-state reactions. The X-ray structural analysis showed that α-Zn3B2O6 crystallizes in a triclinic space group P1¯ with a = 6.302(2) Å, b = 8.248(1) Å, c = 10.020(1) Å, α = 89.85(1)°, β = 89.79(1)°, γ = 73.25(1)°, Z = 4 and β-Zn3B2O6 in a monoclinic group C2/c with a = 23.840(1) Å, b = 5.049(1) Å, c = 8.388(1) Å, β = 102.905(9)°, Z = 8. α-Zn3B2O6 represents a new structure type in which ZnO4 tetrahedra are connected to each other and also to BO3 triangles by common corners giving rise to a three-dimensional framework, while β-Zn3B2O6 is characterized by a three-dimensional network built from corner- and edge-sharing ZnO4 tetrahedra as well as corner-sharing ZnO4 tetrahedra and BO3 triangles. It is the difference in the orientation of the BO3 groups as well as the variation of the connection modes of ZnO4 groups that is responsible for the structural differences between α- and β-Zn3B2O6.

Two new hydrated borates, Zn8[(BO3)3O2(OH)3] and Pb[B5O8(OH)]·1.5H2O, have been prepared by hydrothermal reactions at 170 °C. Single-crystal X-ray structural analyses showed that Zn8[(BO3)3O2(OH)3] crystallizes in a non-centrosymmetric space group R32 with a=8.006(2) Å, c=17.751(2) Å, Z=3 and Pb[B5O8(OH)]·1.5H2O in a triclinic space group P1¯ with a=6.656(2) Å, b=6.714(2) Å, c=10.701(2) Å, α=99.07(2)°, β=93.67(2)°, γ=118.87(1)°, Z=2. Zn8[(BO3)3O2(OH)3] represents a new structure type in which Zn-centered tetrahedra are connected via common vertices leading to helical ribbons ∞1[Zn8O15(OH)3]17− that pack side by side and are further condensed through sharing oxygen atoms to form a three-dimensional ∞3[Zn8O11(OH)3]9− framework. The boron atoms are incorporated into the channels in the framework to complete the final structure. Pb[B5O8(OH)]·1.5H2O is a layered compound containing double ring [B5O8(OH)]2− building units that share exocyclic oxygen atoms to form a two-dimensional layer. Symmetry-center-related layers are stacked along the c-axis and held together by interlayer Pb2+ ions and water molecules via electrostatic and hydrogen bonding interactions. The IR spectra further confirmed the existence of both triangular BO3 and OH groups in Zn8[(BO3)3O2(OH)3], and BO3, BO4, OH groups as well as guest water molecules in Pb[B5O8(OH)]·1.5H2O.Zn8[(BO3)3O2(OH)3] represents a new structure type in which Zn-centered tetrahedra are connected via common vertices to form a three-dimensional framework. The boron atoms are incorporated into the channels in the framework to strengen the structure via B–O bonds. Pb[B5O8(OH)]·1.5H2O is a new layered material containing double ring [B5O8(OH)]2− building units that share exocyclic oxygen atoms to form a two-dimensional layer.

A novel ternary borate oxide, lead bismuth boron tetraoxide, PbBiBO4, has been prepared by solid-state reaction at temperature below 800 °C. The single-crystal X-ray structural analysis showed that PbBiBO4 crystallizes in the monoclinic space group P21/n with a=7.473(1)Å, b=7.517(1)Å, c=7.609(1)Å, β=91.48(1)β=91.48(1), Z=4Z=4. It represents a new structure type in which distorted BiO69− octahedra are connected to each other in corner- and edge-sharing manner to form two-dimensional ∞2[BiO4]5- layers that are bridged by B atoms of BO3 triangles giving rise to a three-dimensional ∞3[BiBO4]2- framework, with channels parallel to the [0 1 0] direction accommodating the pyramidally coordinated Pb2+ cations.PbBiBO4 represents a new structure type in which ∞2[BiO4]5- layers are bridged by B atoms of BO3 triangles to give rise to a three-dimensional framework. Channels parallel to the [0 1 0] direction accommodate Pb2+ cations.