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A polyanionic borate [Zn(H2O)6](NO3)2·[Zn{B3O3(OH)4}2(H2O)4]·2H2O (1) have been synthesized by a molten salt method in this work. Its crystal structure consists of [B3O3(OH)4]− cluster and NO3− anions. Zn2+ cations are covalently bonded to the polyanionic clusters and water molecules leading to a [Zn(H2O)6] octahedron and a [Zn{B3O3(OH)4}2(H2O)4] cluster, which are connected by hydrogen bonds (H-Bs) to form a fictitious 3D structure, in which the NO3− anion are filled in the void. Crystal data for 1 is as following: Monoclinic, P21/c, a = 11.2817(12)A, b = 6.5374(7)A, c = 17.668(2)A, α = 90.00°, β = 100.981(5)°, γ = 90.00°, Z = 2. Two isostructural compounds, [Co(H2O)6](NO3)2·[Co{B3O3(OH)4}2(H2O)4]·2H2O (2) and [Ni(H2O)6](NO3)2·[Ni{B3O3(OH)4}2(H2O)4]·2H2O (3) have been obtained by similar molten salt method, indicating the structure of 1 can be manipulated by replacement of Zn2+ with Co2+ or Ni2+. Structures of the borates have been further confirmed by element analysis, FTIR, PXRD, TG, and UV–vis diffusion reflectance spectra. The bandgap of the borates showed a tunable performance with a change of metallic ions. Furthermore, we studied that flame retardant property of 1 by mixing it with Acrylonitrile Butadiene Styrene (ABS). The cone calorimetry tests confirmed that ABS/1 composites with 15 wt% loading of 1 exhibited superior performance.

The general synthesis and control of the coordination environment of single-atom catalysts (SACs) remains a great challenge. Herein, a general host-guest cooperative protection strategy has been developed to construct SACs by introducing polypyrrole (PPy) into a bimetallic metal-organic framework. As an example, the introduction of Mg2+ in MgNi-MOF-74 extends the distance between adjacent Ni atoms; the PPy guests serve as N source to stabilize the isolated Ni atoms during pyrolysis. As a result, a series of single-atom Ni catalysts (named NiSA -Nx -C) with different N coordination numbers have been fabricated by controlling the pyrolysis temperature. Significantly, the NiSA -N2 -C catalyst, with the lowest N coordination number, achieves high CO Faradaic efficiency (98 %) and turnover frequency (1622 h-1 ), far superior to those of NiSA -N3 -C and NiSA -N4 -C, in electrocatalytic CO2 reduction. Theoretical calculations reveal that the low N coordination number of single-atom Ni sites in NiSA -N2 -C is favorable to the formation of COOH* intermediate and thus accounts for its superior activity.

In this work, different synthetic methods were used to prepare metal borates. One cadmium borate Cd3[B6O9(OH)2]2·2NO3·4H2O (1) and two nickel borate Ni0.8Mn0.2{B6O7(OH)3[O(CH2)2NH2]3} (2), [Ni(1-MI)6]·[B5O6(OH)4]2·2DMF (3, 1-MI = 1-methylimidazole, DMF = N,N-dimethylformamide) species were successfully prepared. The structures of these three compounds were confirmed via single crystal powder X-ray diffraction (SCPXRD), elemental analysis, FTIR, PXRD, and ICP studies. Compound 1 was prepared via molten salt synthesis, and compounds 2 and 3 were prepared via precursor synthesis, which is a synthetic method that uses a certain polyanionic cluster as a reagent. Compound 1 shows a novel three-dimensional (3D) structure, in which the [B6O11(OH)2] units acting as the basic polyanionic cluster form a two-dimensional (2D) anionic structure. In addition, the unexpected Cd3O14 clusters are connected with the 2D structures, leading to the 3D structure. The crystal structure of 2 is packed with very large neutral Ni0.8Mn0.2{B6O7(OH)3[O(CH2)2NH2]3} oxo-metal-boron clusters. The crystal structure of 3 consists of a [B5O6(OH)4]- cluster, a DMF molecule, and a [Ni(1-MI)6]2+ complex. In particular, 2 was successfully constructed using the same hexaborate cluster as its precursor. However, 3 only contains Ni2+ cations when a neutral NixMn1-x[B6O7(OH)6] cluster was used as an initial reagent, and it shows an ability to select a certain metal cation during the self-assembly process. Moreover, compounds 1, 2, and 3 exhibit different wide band gaps of 3.06 eV (1), 3.95 eV (2), and 4.24 eV (3).

Two templated borates [HDBU][B5O6(OH)4] and [HDBN][B5O6(OH)4] (denoted 1 and 2, DBU=1,8-diazabicyclo[5.4.0]undec-7-ene and DBN=1,5-diazabicyclo[4.3.0]non-5-ene) have been synthesized by solvent evaporation in this work. The crystal structure of 1 is reported and consists of superbase cations and [B5O6(OH)4]− anions. The [B5O6(OH)4]− anions are connected together by H-bonds to form a supramolecular framework in which the [HDBU]+ cations are located. Crystal data for 1 are as following: Triclinic, P-1(NO.2), a = 9.5380(7) A, b = 9.9420(8) A, c = 10.5633(7) A, α = 66.697(3)°, β = 66.457(3)°, γ = 87.720(4)°, Z = 2. Additionally, structures of the obtained templated borates have been further confirmed by Elemental Analysis, FTIR, PXRD, TG and DSC techniques.

Self-assembly reaction of Pb(NO3)2 with thiophene-2, 5-dicarboxylic acid (H2TDC) led to an acentric three-dimensional (3D) metal-organic framework under solvothermal conditions, namely, Pb(TDC) (1). The 3D framework of 1 is a pillared-layer structure with the I2O1 type which is composed of a 2D inorganic Pb–O–Pb substructural layer and two independent μ6-TDC2- anions pillars. This 3D framework shows a six-connected pcu topological net according to the topological analysis. Compound 1 crystallizes in an acentric space group and displays potential ferroelectric property which could be due to the swing of the thiophene rings. The remnant polarization (Pr), coercive field (Ec) and saturation spontaneous polarization (Ps) of 1 are ca. 0.034 μC cm−2, 15.7 kV cm−1 and 0.0997 μC cm−2, respectively. Among the H2TDC-based MOFs, the present compound is the first example which shows ferroelectric property. In addition, 1 also exhibits photoluminescent property which can be attributed to ligand-to-metal charge transfer.

Crystalline materials containing hybrid inorganic–organic metal borates (complexes with oxidoborate ligands) display a variety of novel framework building blocks. The structural aspects of these hybrid metallaoxidoborates containing Cd(II), Co(II), Cu(II), Ga(III), In(III), Mn(II), Ni(II) or Zn(II) metal centers are discussed in this review. The review describes synthetic approaches to these hybrid materials, their physical properties, their spectroscopic properties and their potential applications.

Two unusual organic templated borates, [Al(C 3 H 12 N 2 )(C 2 H 7 N)]·[B 5 O 10 ] ( 1 ) and [Zn(HCOO)(1,2-dap) 2 ]·[B 5 O 7 (OH) 4 ] ( 2 ) were synthesized under solvothermal conditions ([HCOO] − = formic ion; 1,2-dap = 1,2-diaminopropane). The obtained 1 and 2 borates were characterized by using elemental analysis, FTIR, PXRD, TG, and single-crystal X-ray diffraction. 1 crystallizes in the Pbca space group and shows a 3D anionic framework based on AlO 4 and B 5 O 10 clusters. Interestingly, there are two kinds of organic amines in the structure: one was 1, 2-dap, while the other was ethylamine from the in situ reaction of 1,2-dap. 2 crystallizes in the P -1 space group, and consists of a [Zn(HCOO)(1,2-dap) 2 ] + cation and [B 5 O 6 (OH) 4 ] − polyanion, the presence of [HCOO] − suggests the in situ decomposition of DMF (DMF = N, N-Dimethylformamide).

Our systematic exploration of chainlike borate in the hybrid templated borate systems has led to three new borates, namely, [GaTETA]·[B5O8(OH)2]·H2O, [InTETA]·[B5O8(OH)2]·1.5H2O, and [Cd(1,2-dap)]·[B6O11(OH)2]·H2O. The structures of the three borates were determined by single-crystal X-ray diffraction. [Cd(1,2-dap)]·[B6O11(OH)2]·H2O represents the first example of chainlike borate containing Cd2+ transition metal cations and [B6O11(OH)2] cluster. [GaTETA]·[B5O8(OH)2]·H2O is isostructural with [InTETA]·[B5O8(OH)2]·1.5H2O, whose structure features a one-dimensional (1D) polyatomic chain constructed of MO2N4 octahedron and [B5O8(OH)2] groups, such chains are further bridged by HBs resulting in a three-dimensional (3D) supermolecular network. Optical and luminescent property measurements have also been performed on the three compounds. Only fluorescence intensity of [GaTETA]·[B5O8(OH)2]·H2O decreased fiercely with temperature increase. Besides, the band gap of [GaTETA]·[B5O8(OH)2]·H2O and its isomer [InTETA]·[B5O8(OH)2]·1.5H2O and [Cd(1,2-dap)]·[B6O11(OH)2]·H2O are very distinct from each other, it may indicate that optical and luminescent property of hybrid borate can be manipulated by adjusting of polyatomic cluster and metallic ion.

A sodium-ammonia tetraborate Na1.33(NH4)0.67B4O5(OH)4·(H2O)2 (denoted 1) has been synthesized under mild solvothermal condition. The compound crystallizes in the chiral trigonal R32 (155) space group, with the following unit cell parameters: a = 11.172(3) A, b = 11.172(3) A, c = 21.282(10) A; V = 2300.4(14) A3; Z = 3. It has been characterized by single crystal X-ray analysis, element analysis, FTIR, PXRD, TG-DSC and Second-harmonic-generation response. Its structure contains [B4O5(OH)4]2− polyanions, which are further linked by a rare [Na4O18] cluster to form a 3-D framework.

A templated borate [Hdmpip][B5O6(OH)4] (dmpip = 1,4-dimethylpiperazine) has been synthesized and characterized by single crystal X-ray analysis, element analysis, IR spectroscopy, PXRD, TG-DSC, EPR, luminescence spectroscopy, and quantum chemistry analysis. The title compound contains the [B5O6(OH)4]− anions that are connected together by O–H···H H-bonds to form a 3-D network with 1-D tunnels, in which [Hdmpip]+ cations were located in. The luminescence spectra of [C9H14N]·[B5O6(OH)4] showed tunable luminescence emission by means of annealing treatment from 150 to 360 °C.

A new phosphor Sm(IO3)3·2H2O was synthesized under mild hydrothermal conditions. The structure was confirmed by single-crystal X-ray powder diffraction analysis. It crystallizes in the triclinic system with space group P (No.2), a = 7.1570A, b = 7.4306A, c = 10.6367A, α = 95.205°, β = 104.844°, γ = 109.958°. Some characterizations were performed such as Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), thermogravimetric and differential thermal analysis (TG-DTA), and luminescence spectroscopy. The overall structure of the title compound is two-dimensional. The adjacent iodate layers are further linked with each other by hydrogen bonds to form a three-dimensional supramolecular network. The luminescent properties of Sm(IO3)3·2H2O were studied, the exhibit tunable emission spectra by means of heating treatment.

The templated borate, [C9H14N]·[B5O6(OH)4], was synthesized under hydrothermal conditions. Single crystal X-ray diffraction techonology reveals that it crystallizes in the triclinic system, space group P (No. 2). The material was also characterized by element analysis, Fourier transform infrared spectroscopy (FTIR), powder X-ray diffraction (PXRD), thermogravimetric and differential thermal analysis (TG-DTA), and luminescence spectroscopy. The compound consisted of isolated pentaborate [B5O6(OH)4]– and N-butylpyridinium cations [C9H14N]+. The [B5O6(OH)4]– anions are connected together by hydrogen bonds to form a three-dimensional framework, in which [C9H14N]+ cations are located in. [C9H14N]·[B5O6(OH)4] exhibits tunable luminescence emission at 415–458 nm by means of heating treatment from 100 to 300 °C.

We report herein the preparation of a new zeotype borogermanate β -K 2 B 2 Ge 3 O 10 , and an unusual isostructural phenomenon is revealed for the first time in borogermanate family. β -K 2 B 2 Ge 3 O 10 crystallizes in the monoclinic system, space group C 2 , a = 15.884(4) A, b = 6.1758(9) A, c = 11.877 A, β = 131.237(6)°, V = 878.3(4) A 3 , Z = 4. β -K 2 B 2 Ge 3 O 10 with 8-M ring helical channels possesses the framework topology of the NAT. Its property related to its chiral space group are performed and discussed in this work.

A new hydrated borate compound, [NH3CH2CHCH3NH3]][B(8)O11(OH)(4)].H2O 1, has been synthesized in the presence of 1,2diaminopropane acting as a structure-directing agent under mild conditions. Its structure was determined by single crystal X-ray diffraction and further characterized FTIR, elemental analysis, powder X-ray diffraction and thermogravimetric analysis. Compound I crystallizes in the monoclinic system, space group P21/c (No. 14), a = 10.0787(7)angstrom, b = 8.8482(6) angstrom, c = 19.3097(4) angstrom, beta = 91.352(6)degrees, V = 1721.53(2)angstrom(3), and Z = 4. The structure consists of infinite open-branched borate chains constructed from [B3O6(OH)] units, onto which the [B5O7(OH)(3)] groups are grafted. It represents the first example of one-dimensional borate templated by an organic amine. The adjacent borate chains are further linked together by extensive hydrogen bonds to form a 3D supramolecular network. The diprotonated organic amines and guest water molecules are filled in the free space of the hydrogen-bonded network and interact with the inorganic framework by extensive hydrogen bonds. (C) 2007 Elsevier Inc. All rights reserved.

Ni(en)3·Hen·[B9O13(OH)4]·H2O was prepared under the cotemplating effect of [Ni(en)3](2+) and Hen(+). It was the first example of a cotemplated borate with an unusual chiral polyanionic chain, which was constructed from [B5O8(OH)2] and [B4O7(OH)2] clusters.

A zinc borate Zn(1,3-DAP)[B4O7] (1) was prepared. 1 possessed a rare chiral zeolitic framework based on a [B4O9] cluster. The combination of a [B4O9] cluster and Zn(1,3-DAP)O3 chain produced a helical ribbon motif and gave rise to a single-stranded helical channel.

In the title compound, [C6H10(NH3)2]2+·[B4O5(OH)4]2−·2.5H2O, the asymmetric unit contains one anion, two half-cations and 2.5 water molecules. Each cation is centrosymmetric. In the crystal structure, the anions are connected to each other via hydrogen bonding, forming a three-dimensional framework with rectangular channels, which are occupied by the templating organic amine cations and guest water molecules.

The title compound, {C2H10N2 2+·B5O8(OH)2−} n , has been hydrothermally synthesized. The structure consists of two-dimensional polymeric sheets constructed from [B5O8(OH)]2− pentaborate anions. Adjacent borate sheets are linked by O—H...O hydrogen bonds into a three-dimensional framework with channels running along one direction. The ethylenediammonium cations lie on centres of inversion within the channels, interacting with the framework through N—H...O hydrogen bonds.

A new conformer of indium germanate InGe(3)O(7.5)(en) (denoted as δ-type), constructed with the flexible unit of In(2)Ge(6)O(15)N(2) was successfully prepared through a solvothermal method. The crystal data for the δ-type InGe(3)O(7.5)(en) are listed as follows: triclinic, space group P-1 (No.2), a = 7.826(4) Å, b = 8.287(3) Å, c = 9.224(4) Å, α = 71.887(17)°, β = 85.343(18)°, γ = 63.734(12)°, V = 508.64 Å(3), Z = 2. Four relevant conformers of indium germanate are compared with each other. The conformational polymorphism in the germanate family is reported for the first time.

Five aluminoborates Al[B5O10]·H2dab·2H2O (1), [Al(B4O9)(BO)]·H2en (2), [Al(B4O9)(BO)]·H2dap (3), K2Al[B5O10]·4H2O (4), and (NH4)2Al[B5O10]·4H2O (5) have been synthesized under hydrothermal conditions and characterized by means of elemental analysis, IR, TG analysis, MAS NMR, UV−vis and fluorescence spectroscopy, powder X-ray diffraction, single-crystal X-ray diffraction, and NLO determination. The structure 1 comprises of AlO4 tetrahedra and B5O10 clusters and contains 12-, 11-, and 8-MR 3D-intersecting channels with a CrB4 topological net. Structures 2 and 3 are both constructed from the same AlB5O13 clusters and exhibit a six-connected framework with 41263 topology. Structures 4 and 5 are isomorphous and are composed of AlO4 tetrahedra and B5O10 clusters that possess odd 11-MR channels and 8-MR helical channels. Structures 2−5 crystallized in an acentric structure and presented good SHG properties. UV−vis spectral investigation indicates that they are wide-band-gap semiconductors. The electronic structu...

Five aluminoborates Al[B(5)O(10)] x H(2)dab x 2 H(2)O (1), [Al(B(4)O(9))(BO)] x H(2)en (2), [Al(B(4)O(9))(BO)] x H(2)dap (3), K(2)Al[B(5)O(10)] x 4 H(2)O (4), and (NH(4))(2)Al[B(5)O(10)] x 4 H(2)O (5) have been synthesized under hydrothermal conditions and characterized by means of elemental analysis, IR, TG analysis, MAS NMR, UV-vis and fluorescence spectroscopy, powder X-ray diffraction, single-crystal X-ray diffraction, and NLO determination. The structure 1 comprises of AlO(4) tetrahedra and B(5)O(10) clusters and contains 12-, 11-, and 8-MR 3D-intersecting channels with a CrB(4) topological net. Structures 2 and 3 are both constructed from the same AlB(5)O(13) clusters and exhibit a six-connected framework with 4(12)6(3) topology. Structures 4 and 5 are isomorphous and are composed of AlO(4) tetrahedra and B(5)O(10) clusters that possess odd 11-MR channels and 8-MR helical channels. Structures 2-5 crystallized in an acentric structure and presented good SHG properties. UV-vis spectral investigation indicates that they are wide-band-gap semiconductors. The electronic structure calculations for the compounds also have been performed.

A new borogermanate open-framework, FJ-18, with intersecting 12-/8-, 9-, and 9-ring channels in multidimensions was synthesized by using an organic diamine as structure-directing agent (SDA). X-ray diffraction showed that its structure is constructed by flexible connection of strictly alternate B(4)O(9) clusters (with fictitious tetrahedral geometry) and GeO(4) tetrahedra to form a zeotype framework with the CrB(4) topology. The topology and structural relations between FJ-18 and FJ-16, a known borogermanate based on the linkage of B(4)O(9) clusters and GeO(4) units, are described in detail. Different guest SDAs can, by means of their shape, size, and charge, directly influence the structure of the host framework, and the origin of these phenomena can be attributed to fundamental parameters such as host-guest symmetry and charge matching through H-bonding interactions, the concept of which has for the first time been extended to tetrahedral-triangular frameworks. This result is a part of our ongoing work aimed at making new large-pore materials constructed from B-O polyanions and Ge-O cluster units.

A new borogermanate open-framework, FJ-18, with intersecting 12-/8-, 9-, and 9-ring channels in multidimensions was synthesized by using an organic diamine as structure-directing agent (SDA). X-ray diffraction showed that its structure is constructed by flexible connection of strictly alternate B(4)O(9) clusters (with fictitious tetrahedral geometry) and GeO(4) tetrahedra to form a zeotype framework with the CrB(4) topology. The topology and structural relations between FJ-18 and FJ-16, a known borogermanate based on the linkage of B(4)O(9) clusters and GeO(4) units, are described in detail. Different guest SDAs can, by means of their shape, size, and charge, directly influence the structure of the host framework, and the origin of these phenomena can be attributed to fundamental parameters such as host-guest symmetry and charge matching through H-bonding interactions, the concept of which has for the first time been extended to tetrahedral-triangular frameworks. This result is a part of our ongoing work aimed at making new large-pore materials constructed from B-O polyanions and Ge-O cluster units.

Two new organically templated borates, [H(2)DAB][B(7)O(9)(OH)(5)](.)2H(2)O (1) and [H(2)DAB][B(7)O(10)(OH)(3)] (2), have been synthesized under mild conditions in the presence of DAB acting as structure-directing agent (DAB = 1,4-diaminobutane). The structures were determined by single crystal X-ray diffraction and further characterized by FTIR, elemental analysis, and thermogravimetric analysis. Both 1 and 2 crystallize in the same triclinic system, space group P (l) over bar (No. 2); 1: a = 8.238(4) angstrom, b = 8.348 (5) angstrom, c = 14.574(8) angstrom, a = 101.050(3)degrees, beta = 92.313(7)degrees, gamma = 112.694(5)degrees, V = 900.3(8) angstrom(3), Z = 2; 2: a = 8.8769(3) angstrom, b = 9.3204(2) angstrom, c = 10.2204(5) angstrom, alpha = 74.474(2)degrees, beta = 85.292(5)degrees, gamma = 72.730(2)degrees, V = 778.01(5) angstrom(3), Z = 2. The structure of 1 consists of [B(7)O(9)(OH)(5)](2-) groups, which represents the first example of organically templated heptaborate. The structure exhibits interesting hydrogen-bonded network formed by borate polyanion [B(14)O(20)(OH)(6)](4-), which can be regarded as being constructed from the dehydration of the FBBs in 1. The diprotonated organic amines are filled in the free space of the hydrogen-bonded network and interact with the inorganic framework by extensive hydrogen bonds.

A new iodate Er(IO3)3·2H2O was synthesized under mild hydrothermal conditions. The structure has been confirmed by single-crystal X-ray analysis. It crystallizes in the triclinic system with space group P-1 (No.2), a = 7.338(4) Å, b = 7.506(4) Å, c = 9.409(5) Å, α = 79.698(5)°, β = 85.245(4)°, γ = 71.934(4)°, V = 484.5(5) Å3, Z = 2. Some characterizations were performed such as Fourier transform infrared spectroscopy (FTIR), thermogravimetric–differential scanning calorimetry (TG-DSC) analysis, luminescence spectroscopy, and magnetic property measurements. The overall framework of Er(IO3)3·2H2O is based on one-dimensional chains. The adjacent chains are further linked with each other by hydrogen bonds to form a three-dimensional supramolecular network. The luminescent and magnetic properties of Er(IO3)3·2H2O were studied.

A series of new 3-D boratopolyoxovanadates {K2V12B18O54(OH)6(H2O)[K8(H2O)16]}·3H2O (1), {K10V12B18O54(OH)6(H2O)}·14H2O (2), {V12B18O54(OH)6(H2O)[K6(H2O)12]}·2(H2dien)·3H2O (3, dien = diethylenetriamine), {V6B20O44(OH)8(H2O)[K8(H2O)6]} (4), and {V6B20O44(OH)8(H2O)[K(H2O)]2}·2(H3dien)·6H2O (5) have been hydrothermally synthesized and structurally characterized. These compounds contain five types of [KxOy]n building units, namely, a dimeric [K2O16] unit for 5, a 1-D [K3O12]n chain for 3, a 3-D [K5O10]n sub-network for 1, a 3-D [K5O12]n sub-network for 2, and a 3-D [K4O7]n sub-network for 4. The 3-D frameworks of both 1 and 2 are built up from a different 3-D inorganic [KxOy]n sub-network and entrapped [V12B18O54(OH)6(H2O)]10− (denoted as [V12B18]) clusters, respectively. 3 contains [V12B18] clusters and 1-D [K3O12]n chains, which are interconnected to form a 3-D {V12B18O54(OH)6(H2O)[K6(H2O)12]}n architecture with 1-D tunnels filled with protonated H2dien2+ ions. The 3-D architecture of 4 is constructed by another rare 3-D inorganic [K4O7]n sub-network and entrapped [V6B20O44(OH)8(H2O)] (denoted as V6B20) clusters. Compounds 1, 2 and 4 represent rare examples of extended POVs with the 3-D inorganic [KxOy]n sub-networks. 5 contains [V6B20] clusters and dimeric [K2O16] units, which are interconnected to give a 3-D {B20V6O44(OH)8(H2O)[K(H2O)]2}n architecture with 1-D tunnels filled with protonated H3dien3+ ions. Although a few boratopolyoxovanadates contain the [V6B20] cluster, they display either a discrete [V6B20] cluster or a low-dimensional extended structure. Therefore, both 4 and 5 are rare examples of 3-D boratopolyoxovanadate architectures based on the [V6B20] clusters. The magnetic susceptibilities of both 4 and 5 show the antiferromagnetic interaction between VIV cations. Their spectroscopic properties were also investigated.

The title compound (GDUT-4) is the first templated borate compound shown to have ferroelectric properties. Its structure consists of a metal complex and isolated polyanion. The chiral structure of the compound was induced by guest-complex cations according to host-guest symmetry through hydrogen bonds (H-bonds). The origins of ferroelectricity in GDUT-4 was shown to be dependent on proton transfer through H-bonds.