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Ba crystallizes in the hexagonal P6/mmm space group. The structure is three-dimensional. Ba is bonded to five equivalent Ba atoms to form a mixture of edge and corner-sharing BaBa5 trigonal bipyramids. There are two shorter (4.07 Å) and three longer (4.27 Å) Ba–Ba bond lengths.
Ba is Tungsten structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. Ba is bonded in a distorted body-centered cubic geometry to eight equivalent Ba atoms. There are a spread of Ba–Ba bond distances ranging from 4.35–4.42 Å.
Ba is Magnesium structured and crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. Ba is bonded to twelve equivalent Ba atoms to form a mixture of face, edge, and corner-sharing BaBa12 cuboctahedra. There are a spread of Ba–Ba bond distances ranging from 4.36–4.57 Å.
By a combination of x-ray diffraction, structural chemistry, and DFT calculations, the presence and location of anionic hydrogen in the two new, layered lanthanide oxyhydrides, Ba 3 Ln 2 O 5 H 2 (Ln = Yb, Lu) is inferred. Single crystals of the compounds have been synthesized from a molten barium flux with the addition of small amounts of BaH 2 . These phases crystallize in space group I4/mmm (#139, Z = 2) with lattice parameters a = 4.3336(2) Å and c = 22.7197(6) Å, and a = 4.3291(1) Å and c = 22.597(1) Å, respectively. The Ba 3 Ln 2 O 5 H 2 phases comprise two different structural moieties: a perovskite double layer of stoichiometry Ba 2 Ln 2 O 5 H – formed by corner-connected LnO 5 tetragonal bi-pyramids with a terminating hydrogen anion, and a puckered rocksalt-type (BaH) + layer that is stretched along the c-axis. DFT calculations were used to arrive at hydrogen positions that minimize energy and are consistent with structural chemistry principles. Furthermore, the calculations show that the valence band edge is dominated by oxygen 2p orbitals with hydrogen 1s states admixed. The conduction band is formed by barium 5d-orbitals and Lu (Yb) 5d-orbitals. These are characteristics of materials with anionic H – . These new phases are isostructural with the Ba 3 Ln 2 O 5 Cl 2 (Ln = Gd–Lu) family of compounds with the chlorine atom in the same apical position as the hydrogen atom. Finally, steric effects limit the size of the lanthanide ion for Ba 3 Ln 2 O 5 H 2 .
As the simplest example of geometrical frustration, the two-dimensional triangular lattice antiferromagnet exhibits the mismatch between the lattice geometry and spin-exchange interaction, which has been the subject of intensive studies due to its exotic quantum phenomena. In this work, we performed detailed studies of the magnetic structures and spin wave excitations by neutron powder diffraction and inelastic neutron scattering measurements on the triple-perovskite oxides Ba 3 MNb 2 O 9 (M = Co, Ni, and Mn) with triangular-lattice geometry. The interplay between the frustrated interaction and easy-plane/axis anisotropy gives rise to two magnetic phase transition temperatures for Ba 3 CoNb 2 O 9 (Ba 3 MnNb 2 O 9 ) and only one for Ba 3 NiNb 2 O 9 . The linear spin-wave theory +1/S calculations indicate that both spatial dimensionality and the spin size have a significant impact on the strength of quantum fluctuations, which lead to their different magnetic ground states and exotic physical properties. Moreover, the effects of the thermal fluctuations are presented for Ba 3 NiNb 2 O 9 .
Five novel Zintl phase solid solutions in the Ba 1–x Sr x Zn 2–y Cd y Sb 2 (0 ≤ x ≤ 0.13(1); 0 ≤ y ≤ 0.32(2)) system were successfully synthesized by the molten Pb metal-flux method, and the powder X-ray diffraction and single-crystal X-ray diffraction analyses proved that all five title compounds adopted the BaCu 2 S 2 -type phase having the orthorhombic Pnma space group (Z = 4, Pearson code oP20) with five crystallographically independent atomic sites. The previously studied BaCu 2 S 2 -type antimonides demonstrated a limited tolerance for doping in contrast to the CaAl 2 Si 2 -type antimonides. To understand the relatively narrower phase width and limited dopability of the title BaCu 2 S 2 -type phase than the CaAl 2 Si 2 -type phase in the overall Ba 1–x Sr x Zn 2–y Cd y Sb 2 system, the radius ratio of cations and anionic elements r + /r – for two structure types were thoroughly investigated. For the first time, the r + /r – ratio was identified as a critical factor for the phase selectivity: (1) r + /r – > 1 favored the BaCu 2 S 2 -type phase, and (2) r + /r – < 1 favored the CaAl 2 Si 2 -type phase. Further, we also revealed the structural transformation mechanism from the more widely observed CaAl 2 Si 2 -type phase to the title BaCu 2 S 2 -type phase as the relatively larger cationic elements were introduced to the system. A series of DFT calculations using the three hypothetical models indicated that a resonance peak near EF in the density of states curves was descended from the relatively flat band structure at several special symmetry points rationalizing the enhanced Seebeck coefficients of Ba 0.94(1) Sr 0.06 Zn 1.86(3) Cd 0.14 Sb 2 and Ba 0.96(1) Sr 0.04 Zn 1.68(2) Cd 0.32 Sb 2 . Electron localization function analysis rationalized the correlation between the polarity change of anionic Zn/Cd–Sb bonds and the charge carrier mobility on the anionic frameworks. Temperature-dependent thermoelectric properties were studied for the four title compounds, and the results proved that the Sr and Cd doping in the title Ba 1–x Sr x Zn 2–y Cd y Sb 2 system successfully enhanced the ZT values through the increased Seebeck coefficients and the reduced total thermal conductivities.
ABO 3 oxides with the perovskite-related structures are attracting significant interest due to their promising physical and chemical properties for many applications requiring tunable chemistry, including fuel cells, catalysis, and electrochemical water splitting. Here we report on the crystal structure of the entire family of perovskite oxides with ABO 3 stoichiometry, where A and B are Ba, Sr, Mn, Ce. Given the vast size of this chemically complex material system, exploration for stable perovskite-related structures with respect to its constituent elements and annealing temperature is performed by combinatorial pulsed laser deposition and spatially-resolved characterization of composition and structure. As a result of this high-throughput experimental study, we identify hexagonal perovskite-related polytypic transformation as a function of composition in the Ba 1-x Sr x MnO 3 oxides after annealing at different temperatures. Furthermore, a hexagonal perovskite-related polytype is observed in a narrow composition-temperature range of the Ba 1-x Sr x MnO 3 oxides. In contrast, a tetragonally-distorted perovskite is observed across a wider range of compositions and annealing temperatures in the Sr 1-x Ce x MnO 3 oxides. This structure stability is further enhanced along the Ba 1-x Sr x MnO 3 - Sr 1-x Ce x MnO 3 pseudo-binary tie-line at x=0.25 by increasing Ba-incorporation and annealing temperature. These results indicate that the BaCe x Mn 1-x O 3 - Sr 1-x Ce x MnO 3 pseudo-binary oxide alloys (solid solutions) with tetragonal perovskite structure and broad composition-temperature range of stability are promising candidates for thermochemical water splitting applications.
In this work, a new clathrate solid solution Ba 8 Cu 16 – x Au x P 30 ( x = 4, 8, 12) was synthesized by a high-temperature solid-state annealing method. The crystal structures of Ba 8 Cu 16 – x Au x P 30 were determined by single crystal x-ray diffraction. This clathrate solid solution crystallizes in the orthorhombic superstructure of clathrate-I type with 23 crystallographically independent framework sites, eight of them are occupied by Au/Cu and 15 are exclusively occupied by P atoms. The distribution of Au and Cu atoms over these eight framework sites is not random with a clear preference for Au to occupy the largest (Au/Cu)P 4 tetrahedra in the framework. The thermal stability and thermoelectric properties of the Ba 8 Cu 16 – x Au x P 30 solid solution were evaluated. Low thermal conductivity was achieved for Ba 8 Cu 16 – x Au x P 30 due to the combination of the host–guest crystal structure with rattling Ba atoms with the presence of heavy Au atoms and substitutional Cu/Au disorder in the clathrate framework.
We report that the recently discovered cuprate superconductor Ba 2 CuO 3+δ exhibits a high T c ≃73 K at δ ≃ 0.2. The polycrystal grown under high pressure has a structure similar to La 2 CuO 4 but with dramatically different lattice parameters due to the CuO 6 octahedron compression. The crystal field in the compressed Ba 2 CuO 4 leads to an inverted Cu 3d e g complex with the d x 2 -y 2 orbital sitting below the d 3z 2 - r 2 and an electronic structure highly unusual compared to the conventional cuprates. We construct a two-orbital Hubbard model for the Cu d 9 state at hole doping x = 2δ and study the orbital-dependent strong correlation and superconductivity. For the undoped case at x = 0 , we found that strong correlation drives an orbital-polarized Mott-insulating state with the spin-1/2 moment of the localized d 3z 2 - r 2 orbital. In contrast to the single-band cuprates where superconductivity is suppressed in the overdoped regime, hole doping the two-orbital Mott insulator leads to orbital-dependent correlations and the robust spin and orbital exchange interactions produce a high-T c antiphase d-wave superconductor even in the heavily doped regime at x = 0.4 . We conjecture that Ba 2 CuO 3+δ realizes mixtures of such heavily hole-doped superconducting Ba 2 CuO 4 and disordered Ba 2 CuO 3 chains in a single-layer or predominately separated bilayer structure. Our findings suggest that unconventional cuprates with liberated orbitals as doped two-band Mott insulators can be a direction for realizing high-T c superconductivity with enhanced transition temperature T c .
The perovskite ruthenates (A RuO 3 , A=Ca, Ba, or Sr) exhibit unique properties owing to a subtle interplay of crystal structure and electronic-spin degrees of freedom. Here, in this study, we demonstrate an intriguing continuous tuning of crystal symmetry from orthorhombic to tetragonal (no octahedral rotations) phases in epitaxial SrRuO 3 achieved via Ba substitution (Sr 1-x Ba x RuO 3 with 0 ≤ x ≤ 0.7 ). An initial Ba substitution to SrRuO 3 not only changes the ferromagnetic properties, but also tunes the perpendicular magnetic anisotropy via flattening the Ru–O–Ru bond angle (to 180°), resulting in the maximum Curie temperature and an extinction of RuO 6 rotational distortions at x≈0.20. For x ≤ 0.2, the reduction of RuO 6 octahedral rotational distortion dominantly enhances the ferromagnetism in the system, though competing with the effect of the RuO 6 tetragonal distortion. Further increasing Ba substitution (x > 0.2) gradually enhances the tetragonal-type distortion, resulting in the tuning of Ru-4d orbital occupancy and suppression of ferromagnetism. Our results demonstrate that isovalent substitution of the A-site cations significantly and controllably impacts both electronic and magnetic properties of perovskite oxides.
We reinvestigated the neutron multiplicity yields of Ba-Mo, Ce-Zr, Te-Pd, and Nd-Sr from the spontaneous fission of 252 Cf by (i) using both γ -γ -γ -γ and γ -γ -γ coincidence data, (ii) using up to date level scheme structures, and (iii) crosschecking analogous energy transitions in multiple isotopes, we have achieved higher precision than previous analyses. Particular attention was given to the Ba-Mo pairs where our results clearly confirm that the Ba-Mo yield data have a second hot fission mode where 8–10, and now 11 neutron evaporation channels are observed. These are the first observations of the 11 neutron channel. These 8–11 neutron channels are observed for the first time in the Ce-Zr pairs, but are not observed in other fission pairs. The measured intensities of the second mode in Ba-Mo and Ce-Zr pairs are ~1.5(4)% and ~1.0(3)%, respectively. These high neutron number evaporation modes can be an indication of hyperdeformation and/or octupole deformation in 143-145 Ba and in 146,148 Ce at scission to give rise to such high neutron multiplicities.
Here, we report the structure and properties of ( Ca , Ba ) x La 2 – x CuIrO 6 . The rock-salt double perovskite structure goes through a P 1 ¯ to P 2 1 / n phase transition with increasing Ba content but not with Ca content. In both cases, the Ir ion is oxidized from 4 + to 5 + with increasing substitution. Transport and magnetic properties measurements reveal that all compositions are insulating with hysteretic spin-freezing magnetic behavior. Seebeck coefficient measurements reveal a large thermopower change from + 176 μ V /K in La 2 CuIrO 6 to – 223 μ V /K with increasing Ba content in Ba x La 2 – x CuIrO 6 . This behavior is modeled well by the Heikes formula for correlated hopping conduction. ( Ca , Ba ) x La 2 – x CuIrO 6 provides a model system for investigations of other systems with similar carrier sign tuning, with applications toward semiconductors and thermoelectric materials.
The novel Zintl phase dibarium zinc diphosphide (Ba 2 ZnP 2 ) was synthesized for the first time. This was accomplished using the Pb flux technique, which allowed for the growth of crystals of adequate size for structural determination via single-crystal X-ray diffraction methods. The Ba 2 ZnP 2 compound was determined to crystallize in a body-centered orthorhombic space group, Ibam (No. 72). Formally, this crystallographic arrangement belongs to the K 2 SiP 2 structure type. Therefore, the structure can be best described as infinite [ZnP 2 ] 4– polyanionic chains with divalent Ba 2+ cations located between the chains. All valence electrons are partitioned, which conforms to the Zintl–Klemm concept and suggests that Ba 2 ZnP 2 is a valence-precise composition. In conclusion, the electronic band structure of this new compound, computed with the aid of the TB–LMTO–ASA code, shows that Ba 2 ZnP 2 is an intrinsic semiconductor with a band gap of ca 0.6 eV.
Neutrinoless double beta decay (0𝜈𝛽𝛽) provides a way to probe physics beyond the Standard Model of particle physics. The upcoming nEXO experiment will search for 0𝜈𝛽𝛽 decay in 136 Xe with a projected half-life sensitivity exceeding 10 28 years at the 90% confidence level using a liquid xenon (LXe) Time Projection Chamber (TPC) filled with 5 tonnes of Xe enriched to ∼90% in the 𝛽𝛽-decaying isotope 136 Xe. In parallel, a potential future upgrade to nEXO is being investigated with the aim to further suppress radioactive backgrounds and to confirm 𝛽𝛽-decay events. This technique, known as Ba-tagging, comprises extracting and identifying the 𝛽𝛽-decay daughter 136 Ba ion. One tagging approach being pursued involves extracting a small volume of LXe in the vicinity of a potential 𝛽𝛽-decay using a capillary tube and facilitating a liquid-to-gas phase transition by heating the capillary exit. The Ba ion is then separated from the accompanying Xe gas using a radio-frequency (RF) carpet and RF funnel, conclusively identifying the ion as 136 Ba via laser-fluorescence spectroscopy and mass spectrometry. Simultaneously, an accelerator-driven Ba ion source is being developed to validate and optimize this technique. The motivation for the project, the development of the different aspects, along with the current status and results, are discussed here.
Hydrostatic effects on the superconducting transition temperature of the Y-Ba-Cu-O compound system, resistively, up to 19 kbar are investigated. It is found that pressure has little effect on the superconducting state of Y-Ba-Cu-O, in marked contrast to the behavior of the K2NiF4-phase La-Ba-Cu-O and La-Sr-Cu-O systems. It is suggested that this effect may be due to chemical pressure associated with the smaller Y atoms already present in Y-Ba-Cu-O. X-ray powder-diffraction studies show that the high-temperature superconductivity in Y-Ba-Cu-O can only be attributed to one or more phases with structures different from the cubic perovskite or tetragonal layered ones.
Ba(MgBi)2 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Ba is bonded to six equivalent Bi atoms to form BaBi6 octahedra that share corners with twelve equivalent MgBi4 tetrahedra, edges with six equivalent BaBi6 octahedra, and edges with six equivalent MgBi4 tetrahedra. All Ba–Bi bond lengths are 3.60 Å. Mg is bonded to four equivalent Bi atoms to form MgBi4 tetrahedra that share corners with six equivalent BaBi6 octahedra, corners with six equivalent MgBi4 tetrahedra, edges with three equivalent BaBi6 octahedra, and edges with three equivalent MgBi4 tetrahedra. The corner-sharing octahedra tilt angles range from 19–52°. All Mg–Bi bond lengths are 3.00 Å. Bi is bonded to three equivalent Ba and four equivalent Mg atoms to form a mixture of distorted corner and edge-sharing BiBa3Mg4 pentagonal bipyramids.
BaMo6O10 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of Ba–O bond distances ranging from 2.81–3.37 Å. In the second Ba2+ site, Ba2+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of Ba–O bond distances ranging from 2.79–3.38 Å. In the third Ba2+ site, Ba2+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of Ba–O bond distances ranging from 2.79–3.40 Å. In the fourth Ba2+ site, Ba2+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of Ba–O bond distances ranging from 2.83–3.40 Å. There are twenty-four inequivalent Mo3+ sites. In the first Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 1.95–2.17 Å. In the second Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 2.00–2.21 Å. In the third Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 2.10–2.18 Å. In the fourth Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 1.96–2.18 Å. In the fifth Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 1.96–2.17 Å. In the sixth Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 2.09–2.16 Å. In the seventh Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 2.08–2.18 Å. In the eighth Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 1.95–2.16 Å. In the ninth Mo3+ site, Mo3+ is bonded to five O2- atoms to form corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 2.01–2.16 Å. In the tenth Mo3+ site, Mo3+ is bonded to five O2- atoms to form corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 1.92–2.10 Å. In the eleventh Mo3+ site, Mo3+ is bonded to five O2- atoms to form corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 1.93–2.12 Å. In the twelfth Mo3+ site, Mo3+ is bonded to five O2- atoms to form corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 1.92–2.14 Å. In the thirteenth Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 2.08–2.18 Å. In the fourteenth Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 2.07–2.18 Å. In the fifteenth Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 2.09–2.20 Å. In the sixteenth Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 2.07–2.20 Å. In the seventeenth Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 2.05–2.19 Å. In the eighteenth Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 2.09–2.22 Å. In the nineteenth Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 2.10–2.20 Å. In the twentieth Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 2.01–2.16 Å. In the twenty-first Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 2.10–2.19 Å. In the twenty-second Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 2.07–2.18 Å. In the twenty-third Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 2.07–2.16 Å. In the twenty-fourth Mo3+ site, Mo3+ is bonded to five O2- atoms to form a mixture of edge and corner-sharing MoO5 square pyramids. There are a spread of Mo–O bond distances ranging from 2.07–2.18 Å. There are forty inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted L-shaped geometry to two Ba2+ and two Mo3+ atoms. In the second O2- site, O2- is bonded in a 2-coordinate geometry to two Ba2+ and two Mo3+ atoms. In the third O2- site, O2- is bonded in a 2-coordinate geometry to two Ba2+ and two Mo3+ atoms. In the fourth O2- site, O2- is bonded in a distorted L-shaped geometry to two Ba2+ and two Mo3+ atoms. In the fifth O2- site, O2- is bonded in a distorted L-shaped geometry to two Ba2+ and two Mo3+ atoms. In the sixth O2- site, O2- is bonded in a 2-coordinate geometry to two Ba2+ and two Mo3+ atoms. In the seventh O2- site, O2- is bonded in a 2-coordinate geometry to two Ba2+ and two Mo3+ atoms. In the eighth O2- site, O2- is bonded in a 2-coordinate geometry to two Ba2+ and two Mo3+ atoms. In the ninth O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the tenth O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the eleventh O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the twelfth O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the thirteenth O2- site, O2- is bonded in a see-saw-like geometry to one Ba2+ and four Mo3+ atoms. In the fourteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ba2+ and four Mo3+ atoms. In the fifteenth O2- site, O2- is bonded in a rectangular see-saw-like geometry to one Ba2+ and four Mo3+ atoms. In the sixteenth O2- site, O2- is bonded in a see-saw-like geometry to one Ba2+ and four Mo3+ atoms. In the seventeenth O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the eighteenth O2- site, O2- is bonded in a distorted see-saw-like geometry to one Ba2+ and four Mo3+ atoms. In the nineteenth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ba2+ and four Mo3+ atoms. In the twentieth O2- site, O2- is bonded in a see-saw-like geometry to one Ba2+ and four Mo3+ atoms. In the twenty-first O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the twenty-second O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the twenty-third O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the twenty-fourth O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the twenty-fifth O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the twenty-sixth O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the twenty-seventh O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the twenty-eighth O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the twenty-ninth O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the thirtieth O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the thirty-first O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the thirty-second O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the thirty-third O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the thirty-fourth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ba2+ and three Mo3+ atoms. In the thirty-fifth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ba2+ and three Mo3+ atoms. In the thirty-sixth O2- site, O2- is bonded in a distorted trigonal pyramidal geometry to one Ba2+ and three Mo3+ atoms. In the thirty-seventh O2- site, O2- is bonded in a 4-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the thirty-eighth O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the thirty-ninth O2- site, O2- is bonded in a 3-coordinate geometry to one Ba2+ and three Mo3+ atoms. In the fortieth O2- site, O2- is bonded in a distorted rectangular see-saw-like geometry to one Ba2+ and four Mo3+ atoms.
Ba(OH)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Ba2+ sites. In the first Ba2+ site, Ba2+ is bonded in a 2-coordinate geometry to five H1+ and seven O2- atoms. There are a spread of Ba–H bond distances ranging from 2.68–2.91 Å. There are a spread of Ba–O bond distances ranging from 2.72–3.04 Å. In the second Ba2+ site, Ba2+ is bonded in a 3-coordinate geometry to three O2- atoms. There are a spread of Ba–O bond distances ranging from 2.64–2.71 Å. There are four inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to two equivalent Ba2+ and one O2- atom. The H–O bond length is 0.99 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to one Ba2+ and one O2- atom. The H–O bond length is 0.99 Å. In the third H1+ site, H1+ is bonded in a single-bond geometry to one Ba2+ and one O2- atom. The H–O bond length is 0.97 Å. In the fourth H1+ site, H1+ is bonded in a single-bond geometry to one Ba2+ and one O2- atom. The H–O bond length is 0.98 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a single-bond geometry to three Ba2+ and one H1+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to three Ba2+ and one H1+ atom. In the third O2- site, O2- is bonded in a single-bond geometry to two Ba2+ and one H1+ atom. In the fourth O2- site, O2- is bonded in a single-bond geometry to two equivalent Ba2+ and one H1+ atom.