Space Group P2 Research Articles

A comparative study of the high-pressure structural stability of zirconolite materials for nuclear waste immobilisation

We present a comparative study of the high-pressure behaviours of the nuclear waste immobilisation materials zirconolite-2M, −4M, –3O, and −3T. The materials are studied under high-pressure conditions using synchrotron powder X-ray diffraction. For zirconolite-2M we also performed density-functional theory calculations. A new triclinic crystal structure (space group P1¯), instead of the previously assigned monoclinic structure (space group C2/c) is proposed for zirconolite-2M. We named the triclinic structure as zirconolite-2TR. We also found that zirconolite-2TR undergoes a phase transition at 14.7 GPa to a monoclinic structure described by space group C2/c, which is different than the high-pressure structure previously proposed in the literature. These results are discussed in comparison with previous studies on zirconolite-2M and the related compound calzirtite. For the other three zirconolite structures (4M, 3O, and 3T) this is the first high-pressure study, and we find no evidence for pressure induced phase transitions in any of them. The linear compressibility of the studied compounds, as well as a room-temperature pressure–volume equation of state, are also presented and discussed.

Theoretical prediction of hexagonal ternary phase Mo2Ga2C and its evolution to layered carbide Mo2C

The stable structure of Mo2Ga2C was determined by using a combination of crystal structure searching technique and first-principles calculations. Mo2Ga2C crystallizes a hexagonal layered structure of space group P63/ m m c (No. 194), which is the typical structure of conventional M n+1AX n phases. The dynamical and mechanical stability of the predicted structure is confirmed by the phonon dispersion and elastic constants, respectively. The structural stability of Mo2Ga2C is investigated by analyzing the stability of chemical bonds under tensile and shear deformations. Layered structural stability of Mo2Ga2C is determined by the strength of covalent Mo–Ga bond under tensile and shear strains. The stress–strain relationships of Mo2Ga2C are evaluated and compared with Mo2GaC. Two-dimensional layered Mo2C can be obtained by the selective removal of Ga atoms from Mo2Ga2C. Theoretical prediction of monolayer Mo2C is metallic, and has potential application as anode and thermoelectric material.

Synthesis of spiro-pyrrolizidine: Crystal structure and anticancer activity

A novel spiro-pyrrolizidine[2′-{[3,5-bis(benzyloxy)phenyl]carbonyl}-1′-(4-ethoxyphenyl)-1,1′,2,2′,5′,6′,7′7’a-octahydrospiro[indole-3,3′-pyrrolizine]-2-one (compound1) was synthesized via 1,3-dipolar cycloaddition of by refluxing 1-(3,5-bis(benzyloxy)phenyl)-3-(4-ethoxyphenyl)prop-2-en-1-one with isatin and L-proline. The structure was successfully elucidated by determination of single-crystal structures. The spiro-pyrrolizidine (1) crystallized in the triclinic centrosymmetric space group P1. The compound1 exhibits significant anticancer activity on MDA-MB 231 and HCT-116 cell lines with an IC50 values of 61.07± 0.98 µM and 62.5±70 µM respectively.

Ni2Mo3N: crystal structure, thermal properties, and catalytic activity for ammonia decomposition

Abstract Ni2Mo3N was synthesized by ammonolysis of NiMoO4, prepared by a sol-gel-based modified Pechini route. X-ray powder diffraction measurements confirmed that Ni2Mo3N crystallizes in a filled β-Mn type (cubic space group P4132) with a lattice parameter of a = 6.6338 Å. Group theoretical methods were applied to elucidate the relation between the crystal structure of Ni2Mo3N and that of the rock salt type. The high-temperature behavior was investigated in-situ by X-ray diffraction measurements in flowing ammonia gas at temperatures up to 875 °C. Ni2Mo3N exhibits significant catalytical activity for ammonia decomposition, which is critically discussed in comparison to literature.

Synthesis, crystal structure, and spectroscopic characterization of a new non-centrosymmetric compound, 1-(2-chloroquinolin-3-yl)-N-(4-fluorobenzyl)methanimine

In this work, we report the synthesis and characterization of a new condensed aromatic heterocycle (1-(2-chloroquinolin-3-yl)-N-(4-fluorobenzyl)methanimine) useful in various fields, mainly in medicinal and therapeutic chemistry, with interesting biological properties. Characterization of the title compound was carried out by 1H, 13C, 19F nuclear magnetic resonance and X-ray diffraction techniques. The crystal structure reveals that title compound crystallizes in the monoclinic system and crystal data for C17H12ClFN2: monoclinic, space group P21 (no. 4), a = 7.2253(10) Å, b = 5.7720(10) Å, c = 17.105(2) Å, β = 95.338(10)°, V = 710.26(18) Å3, Z = 2, T = 298(2) K, μ(MoKα) = 0.274 mm-1, Dcalc = 1.397 g/cm3, 5010 reflections measured (4.784° ≤ 2Θ ≤ 54.324°), 3160 unique (Rint = 0.0501, Rsigma = 0.0506) which were used in all calculations. The final R1 was 0.0339 (I > 2σ(I)) and wR2 was 0.0907 (all data). The obtained molecular structure has an antiparallel arrangement of the molecular unit leading to a one-dimensional framework.

Synthesis of 2-amino-5-methylpyridinium tetrachloridocadmate(II) (C6H9N2)2[CdCl4]: Structure, DFT-calculated descriptors and molecular docking study

In this research paper, (C6H9N2)2[CdCl4], was effectively synthesized using the slow solvent evaporation procedure. Single crystal X-ray diffraction (scXRD) analysis revealed that the compound crystallizes in the triclinic system, specifically in the space group P1¯. Powder XRD (PXRD) of the bulk material showed some minor impurities. The atomic arrangement of the title structure comprises discrete tetrahedral groups [CdCl4]2− linked to the organic entities through weak N(C)H…Cl hydrogen bonds. Solid-state contacts were further studied through Hirshfeld surface analyses, complemented by 2D fingerprint plots. Computational results, obtained using the B3LYP tool with 6-311++G(d,p) + LANL2DZ mixed basis set, demonstrated consistent geometrical, vibrational, and electronic features to the experimental data. Non-covalent interactions were explored in depth using Atoms-In-Molecule (AIM) and Reduced Density Gradient (RDG) analyses. Thermogravimetry (TG) and Differential Scanning Calorimetry (DSC) analyses showed melting at 378 K and decomposition at around 540 K. Furthermore, the inhibition activity of the examined compound was explored in-silico through molecular docking studies targeting the inducible Nitric Oxide Synthase (iNOS) enzymes.

Crystal structure, hydrogen bonding interactions, Hirshfeld surfaces, energy frameworks, and DFT calculation of Diethyl 3-(4-substitutedbenzoyl)indolizine-1,2-dicarboxylates

The diethyl 3-(4-substitutedbenzoyl)indolizine-1,2-dicarboxylates have been synthesized by reacting the electron-deficient diethyl but-2-ynedioate with 1-(2-(4-substitutedphenyl)-2-oxoethyl)pyridin-1-ium bromide, the intermediates obtained from the reaction of pyridine and 4-substituted phenacyl bromides. The synthesized compounds were investigated by FT-IR, NMR (1H and 13C), LC-MS, and elemental analysis spectroscopic methods along with PXRD. The molecular structures were determined using the single crystal X-ray diffraction technique which revealed that 5a and 5c crystallize in triclinic space group P1¯. The crystal structures of 5a and 5c preferred the C-H···O hydrogen-bonded dimeric ring motifs, resembling those observed in the earlier reported 5b. Furthermore, various computational analyzes such as Hirshfeld surface, Energy framework, and MEP analysis predicted the interaction site and inter-molecular interactions in these molecules. The FMOs analysis was carried out to obtain global reactivity parameters for the synthesized compounds (5a-c). The NCI and QTAIM studies revealed the nature as well as qualitative and quantitative description of intra and inter-molecular hydrogen bonding interactions present in these molecules and their crystal packing.

Dinuclear cadmium(II) complexes with distorted octahedral/monocapped trigonal prism coordination geometries: synthesis, crystal structure, DFT/TD-DFT calculation and photocatalytic degradation of methylene blue

Two Cd(II) complexes [Cd2(L1)2(dca)(NO3)] (1) and [Cd2(L2)2(SCN)(NO3)] (2) (HL1 = 2-methoxy-6-[(2-phenylamino-ethylimino)-methyl]-phenol; and HL2 = 2-[(2-ethylamino-ethylimino)-methyl]-6-methoxy-phenol), have been synthesized and characterized by single crystal structure analysis, IR and mass spectroscopic studies. Both the complexes 1 and 2 possess a triclinic crystal system with space group P1¯. In complex 1, geometry around one metal centre is distorted octahedral and other centre is distorted monocapped trigonal prism, whereas in complex 2, both the metal centres possess distorted octahedral geometries. Strong NH⋅⋅⋅O and weak aromatic CH⋅⋅∙O hydrogen bonding interactions in 1 and strong NH⋅⋅⋅O and NH⋅⋅⋅S hydrogen bonding in 2 results 1D and 2D supramolecular structures, respectively. Experimentally determined electronic spectral data have been compared with the calculated data obtained by DFT and TD-DFT calculation. Photocatalytic abilities of 1 and 2 have been examined by using spectroscopic technique and found that in presence of UV light both the complexes catalytically decomposed methylene blue by 54.0 % and 50.3 %, respectively.

Synthesis, crystal structure, DFT calculation, Hirshfeld suface analysis and antitumor activity of 4-(tert-butyl)-5-(1H-1,2,4-triazole-1-yl)thiazole derivatives containing benzoxazinone

Seven novel 4-(tert-butyl)-5-(1H-1,2,4-triazole-1-yl)thiazole derivatives containing benzoxazinone (B1-B7) were obtained by cyclization of 4-(tert-butyl)-5-(1H-1,2,4-triazol-1-yl)-N-(2-hydroxy-benzyl)thiazol-2-amine. The chemical structures of the target compounds were confirmed by 1H NMR and 13C NMR. The single crystal X-ray diffraction revealed that B1 crystallizes in a triclinic system with the space group P1¯. Hirshfeld surfaces and two dimensional (2D) fingerprint plots were employed to quantitatively characterize the influence of intermolecular interactions within the crystal lattice of B1. And the molecular electrostatic potential (MEP) surface was calculated employing Becke-3-Lee Yang Parr (B3LYP)/6-311++G (d,p) theoretical approach. Meanwhile, the Frontier-molecular orbitals of B1 and B2 were calculated using density functional theory (DFT) B3LYP technique with the def2-SVP basis set in the ground state. Preliminary biological tests revealed that the title compounds had certain antitumor activities against three cell lines MCF-7, Hela and A549, and compound B2 presented the most potent antitumor efficacy against A549.

Structure of a novel form of phosphopantetheine adenylyltransferase from Klebsiella pneumoniae at 2.59Å resolution.

Phosphopantetheine adenylyltransferase (EC. 2.7.7.3, PPAT) catalyzes the penultimate step of the multistep reaction in the coenzyme A (CoA) biosynthesis pathway. In this step, an adenylyl group from adenosine triphosphate (ATP) is transferred to 4'-phosphopantetheine (PNS) yielding 3'-dephospho-coenzyme A (dpCoA) and pyrophosphate (PPi). PPAT from strain C3 of Klebsiella pneumoniae (KpPPAT) was cloned, expressed and purified. It was crystallized using 0.1M HEPES buffer and PEG10000 at pH 7.5. The crystals belonged to tetragonal space group P41212 with cell dimensions of a = b = 72.82Å and c = 200.37Å. The structure was determined using the molecular replacement method and refined to values of 0.208 and 0.255 for Rcryst and Rfree factors, respectively. The structure determination showed the presence of three crystallographically independent molecules A, B and C in the asymmetric unit. The molecules A and B are observed in the form of a dimer in the asymmetric unit while molecule C belongs to the second dimer whose partner is related by crystallographic twofold symmetry. The polypeptide chain of KpPPAT folds into a β/α structure. The conformations of the side chains of several residues in the substrate binding site in KpPPAT are significantly different from those reported in other PPATs. As a result, the modes of binding of substrates, phosphopantetheine (PNS) and adenosine triphosphate (ATP) differ considerably. The binding studies using fluorescence spectroscopy indicated a KD value of 3.45 × 10-4M for ATP which is significantly lower than the corresponding values reported for PPAT from other species.

Testibiopalladite, PdSbTe: A Valid Mineral and Sb-Analogue of Michenerite

Abstract Testibiopalladite was reported from two unnamed deposits in China by Anonymous (1974) to be ideally PdSbTe. The description of the mineral included an indexed X-ray powder diffraction pattern, space group determination, electron probe micro-analyses, reflectance, and micro-indentation hardness measurements. This description was published without prior submission to the IMA, which was the norm at the time before China became a member. It is unknown as to why the Commission for New Minerals and Mineral Names (CMNMN) did not examine and vote on the mineral as had been done for all other Chinese mineral descriptions published at the time. It is surprising because the chairman of the CMNMN at the time had reviewed the mineral (Fleischer et al. 1976) and concluded it was a valid species, i.e., the Sb analogue of michenerite (PdBiTe). Further, the same article included a description of “hexastibiopanickelite” which was voted on and rejected by the CMNMN in 1976. From 1981 to 2021 there were many papers published reporting testibiopalladite from several deposits in different countries (e.g., Hudson et al. 1978, Chen et al., 1993, Stepanets et al. 2019, 2020), as well as a single-crystal structure analysis of synthetic PdSbTe which confirmed the assigned space group (Foecker & Jeitschko 2001). The published data (e.g., Barkov et al. 2002, Liang et al. 2019, 2023) suggest that testibiopalladite is a valid mineral species, ideally PdSbTe, and is the Sb analogue of michenerite, PdBiTe, both crystallizing in space group P213. Both the name testibiopalladite and the mineral, ideally PdSbTe, were approved by the Commission of New Minerals, Nomenclature and Classification of the International Mineralogical Association (CNMNC-IMA), Nomenclature Voting Proposal 23-H. Liang et al. (2019, 2023) studied samples from the type locality (Yangliuping deposit, PRC) that are to be considered as a neotype.

Canted antiferromagnetism in Y2 –xCaxFeTaO7 –δ solid solutions with a pyrochlore-like structure

The existence of Y2 – xCaxFeTaO7-δ solid solutions (x = = 0 – 0.075) with a pyrochlore-like layered structure was established. The appearance of the magnetic properties characteristic for canted antiferromagnets was observed as a result of structure distortions (space group R3¯ ® space group P3121) associated with a change of composition. Y2 – xCaxFeTaO7 –δ exhibits ferromagnetic properties already at 300 K.

Proposed crystal structure of carbadox, C11H10N4O4

A model for the crystal structure of carbadox has been generated and refined using synchrotron X-ray powder diffraction data and optimized using density functional theory techniques. Carbadox crystallizes in space group P21 (#4) with a = 13.8155(3), b = 21.4662(1), c = 16.3297(3) Å, β = 110.0931(7)°, V = 4548.10(3) Å3, and Z = 16. The crystal structure is characterized by approximately parallel stacking of the eight independent carbadox molecules parallel to the bc-plane. There are two different molecular configurations of the eight carbadox molecules; five are in the lower-energy configuration and three are in a ~10% higher-energy configuration. This arrangement likely achieves the lowest-energy crystalline packing via hydrogen bonding. Hydrogen bonds link the molecules both within and between the planes. Each of the amino groups forms a N–H⋯O hydrogen bond to an oxygen atom of the 1,4-dioxidoquinoxaline ring system of another molecule. The result is four pairs of hydrogen-bonded molecules, which form rings with graph set R2,2(14). Variation in specimen preparation can affect the preferred orientation of particles considerably. The powder pattern has been submitted to ICDD for inclusion in the Powder Diffraction File™ (PDF®).

A new non-centrosymmetric material (C5H9N3)[ZnBr4]·H2O : Molecular structure, characterization, optical properties and biological activities

The use of 2,3-diaminopyridine as an aromatic organic molecule in the synthesis of a new hybrid halogenometallate compound by the slow evaporation method afforded an unexpected non-centrosymmetric structure type. The obtained material with the formula (C5H9N3)[ZnBr4]·H2O (1) crystallizes in the triclinic space group P1. The compound was characterized by UV–visible measurements, differential thermal analysis (TG-DTA), single crystal X-ray diffraction and nonlinear optical activity. The structure consists of isolated tetrahedral [ZnBr4]2− anions, 2-amino-3-ammoniopyridinium [C5H9N3]2+ cations and water molecules, which are connected via NH…O/Br and OH…Br hydrogen bonds leading to the formation and strengthening of a three-dimensional supramolecular assembly. The optical band gap and Urbach energy were obtained through Tauc's equation. The direct and indirect band gap values are found to be 3.23 and 3.55 eV, respectively. The bioassay results showed that the compound exhibits modest antibacterial and antifungal activities.

DyIrSn and the Lu3Co2In4-type stannides Sm3Rh2Sn4 and RE 3Ir2Sn4 (RE = Y, Sm, Gd–Tm, Lu)

Abstract The Lu3Co2In4-type stannides RE 3Ir2Sn4 (RE = Y, Sm, Gd–Tm, Lu) were synthesized from the elements by arc-melting and subsequent annealing sequences in sealed silica ampoules. For a more comprehensive phase analytical study, the isotypic stannide Sm3Rh2Sn4 and the ZrNiAl-type stannides DyIrSn and LT-YIrSn were also obtained. The polycrystalline samples were characterized through their X-ray powder patterns. The structures of DyIrSn and Gd3Ir2.63(2)Sn3.37(2) (ZrNiAl type, space group P6‾2m), Sm3Ir2.52(2)Sn3.48(1), Gd3Ir2.49(1)Sn3.51(1) and Tm3Ir2.20(3)Sn3.80(3) (Lu3Co2In4 type, space group P6‾) were refined from single-crystal X-ray diffractometer data, revealing residual Ir/Sn disorder in the low-symmetry variants. The RE 3Ir2Sn4 stannides are derived from the equiatomic stannides REIrSn (≍RE 3Rh3Sn3) by partial Ir/Sn substitution. The symmetry reduction from space group P6‾2m to P6‾ is forced by the Ir/Sn ordering within the RE 6 trigonal prisms. The new Sn2 position shows the rare motif of a trigonal planar tin coordination with 289 pm Sn2–Sn1 distances (data for Gd3Ir2.49(1)Sn3.51(1)). 119Sn Mössbauer spectra confirm the two crystallographically independent tin sites in Tm3Ir2Sn4 and the structural disorder in Gd3Ir2Sn4.

Synthesis of novel supramolecular selenomolybdate as anticancer agents: An experimental and DFT computational analysis

A novel organic–inorganic material based on three-dimensional (3D) Strandberg-type polyoxoselenomolybdate, (C6H14N2)2[Se2Mo5O21]·2·6H2O (I, where C6H14N2 = DABCO cation) was successfully synthesized by solution process and characterized by scanning electron microscopy (SEM), infrared (FT-IR) and ultraviolet (UV–vis) spectroscopies, thermogravimetric analysis (TGA), cyclic voltammetry (CV) measurement. The electronic and electrochemical behavior of the compound was further evaluated as a function of pH and time via UV–vis spectroscopy and CV. Single crystal X-Ray diffraction (XRD) technique was used for complete structure elucidation. The title compound crystallizes in the non-centrosymmetric orthorhombic space group P212121, thus resulting in non-linear optical properties. The supramolecular framework exhibits a periodic arrangement of Strandberg clusters anions [Se2Mo5O21]4– connected to each other with water molecules and dabconium cations, through a network of hydrogen bonds and van der Waals interactions. The occurrence of intermolecular interactions, ensuring the cohesion between different entities, was assessed by density functional theory (DFT) calculations and Hirshfeld surface analysis. DFT calculations with different functionals have been used to better understand several properties like as RDG, QTAIMs, ELF, MEP and NLO.A good agreement was indeed found between the experimental and computational results. Furthermore, the (C6H14N2)2[Se2Mo5O21]·2·6H2O compound was tested for its biological activity. This selenomolybdate displayed a significant inhibitory effect on the growth of human ovarian cancer cells A2780, with an IC50 value of 4.05 ± 0.55 μM, being thus the first Strandberg-type polyoxometalate to show a significant anticancer activity.

Study on the anti-cancer activity of α-phenethylamine ferrocenecarboxylic acid co-crystals.

Ferrocene derivatives show a wide range of pharmacological activities in the medical field, especially in the anti-tumor field, and can be used as candidate drugs or lead compounds for the treatment of tumors and other diseases. And α-phenethylamine is an important intermediate for the preparation of fine chemical products. (R)-(+)-1-Phenethylamine ferrocenecarboxylic acid/(S)-(-)-1-phenethylamine ferrocenecarboxylic acid were prepared, named compounds 1 and 2, respectively. Single crystal X-ray diffraction showed that compounds 1 and 2 crystallized in the orthorhombic system space group P21 21 21 , and the crystal structures of compounds 1 and 2 exhibited mirror symmetry. The inhibitory effect of two compounds on SW480, MDA-MB-231, and H1299 cells was tested by MTT colorimetry. The IC50 values of the compounds against cancer cells were also calculated. The anti-cancer effect was more pronounced for compounds in the S-configuration. Compound 2 made the wild-type cancer cells undergo apoptosis, thus preventing cancer; it also had the function of helping the cell gene repair defects.

Preparation and photoluminescence study of rare-earth-free red emitting La3Ga5SiO14:Mn4+ phosphors

Given the growing interest in eco-friendly lighting solutions, the use of high-quality phosphors has become integral to the advancement of all-solid white light-emitting diodes (WLEDs). One novel phosphor, La3Ga5SiO[Formula: see text]:Mn[Formula: see text] (LGS), has been successfully synthesized via a high-temperature solid-state reaction. The crystal structure of LGS is classified as belonging to the trigonal phase, with a space group P321. The excitation spectrum exhibits a wide peak within the wavelength range of 280–440 nm. It emits a highly intense red light, with a peak emission occurring at 715 nm within the spectral range of 670–740 nm is attributed to the transition of Mn[Formula: see text] from 4A2g to 4T2g. LGS:Mn[Formula: see text] demonstrates a favorable quantum efficiency of 16% when doped with a concentration of 0.25 mol% Mn. The decay curve of LGS:Mn[Formula: see text] exhibits a pattern of decreasing lifetime as the dopant concentration increases. Additionally, the LGS:Mn[Formula: see text] products demonstrate a CIE chromaticity of (0.688, 0.2644), which is located within the deep red light region. All the aforementioned findings support the potential application of LGS:Mn[Formula: see text] specimens in WLEDs, thereby contributing to the progress of environmentally friendly and energy-efficient lighting.

Two trinuclear cluster metal–organic frameworks: syntheses, structures, highly fluorescent sensing and magnetic properties

Two new metal–organic frameworks [Zn3(TCPB)2(H2O)2]·3DMF·2H2O (1) and [Mn1.5(TCPB)(DMF)(H2O)]·DMF(2)(H3TCPB = 1,3,5-tri(4-carboxyphenoxy)benzene), have been successfully constructed by solvothermal methods and structurally characterized by single crystal X-ray diffraction, elemental analyses, IR spectra, Raman spectra, 1H NMR spectra, powder X-ray diffraction and thermogravimetric analyses. Single-crystal X-ray diffraction analyses reveal that complex 1 crystallizes in the trigonal space group P3¯ 1c and possesses a 2D network, whereas complex 2 crystallizes in the triclinic space group P1¯ and also possesses a 2D network. TOPOS analyses reveal that both complexes 1 and 2 have a (3,6)-connected network topology with the Schläfli symbol of (43·612) (43)2 for 1 and {43}2{46·66·83} for 2. Notably, further investigation indicates that complex 1 can be employed as a bi-functional fluorescent sensor for highly sensitive and selective detection of ferric ions (Fe3+) and 2,4,6-trinitrophenol (TNP), with the detection limit of 0.11 μM for Fe3+ and 0.14 μM for TNP. Furthermore, the possible fluorescence quenching mechanisms are explained as: (a) photo-induced electron transfer (PET) caused by the HOMO-LUMO energy gap through DFT and (b) fluorescence resonance energy transfer (FRET). Besides, the magnetic property measurement indicated that complex 2 shows antiferromagnetic interactions between trinuclear {Mn3(COO)6} SBUs.

The local state of hydrogen atoms and proton transfer in the crystal structure of natural berborite, Be2(BO3)(OH)‧H2O: Low-temperature single crystal X-ray analysis, IR and 1H NMR spectroscopy, and crystal chemistry and structural complexity of beryllium borates

Beryllium borates are mostly water-free, with the natural mineral berborite, Be2(BO3)(OH)‧H2O, being the only known exception. A sample of berborite from the Vevja quarry, Tvedalen, Larvik, Norway was studied by single-crystal X-ray diffraction, variable temperature 1H nuclear magnetic resonance (NMR), and infrared (IR) spectroscopy. The crystal structure is the trigonal 1T-polytype with space group P321 and is based on electroneutral [BeØ2(BΔO3)]-layers formed by BeO3Ø-tetrahedra and BΔO3-triangles. Due to statistical occupancy of the Ø-ligand by hydroxyl groups (50%) and water molecules (50%), berborite-1T and its related polytypes are characterized by complex systems of hydrogen bonds. Accurate analysis shows that in the structure of berborite there are two independent systems of hydrogen bonds involving mobile protons. Lowering of temperature results in the complete stabilization of protons at the critical “freezing-point” of 243 K. The crystal chemistry and complexity of layered beryllium borates are discussed. Despite the broad structural diversity of these compounds, their crystal structures are classified as simple (20–100 bits per unit cell) or intermediately complex (100–500 bits per unit cell). The complexity of berborite polytypes increases in accordance with the quantity of layers from 29.038 (1T) to 78.077 (2H), which is in good agreement with the negative contribution of complexity to the configurational entropy.