Crystal structure of BaMnB2O5 containing structurally isolated manganese oxide sheets

Maschmeyer, E.M.; Sanjeewa, L.D.; Ranmohotti, K.G.S.

doi:10.1107/S2056989016013074

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Volume 72| Part 9| September 2016| Pages 1315-1320

https://doi.org/10.1107/S2056989016013074

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Crystal structure of BaMnB₂O₅ containing structurally isolated manganese oxide sheets

Elizabeth M. Maschmeyer,^a Liurukara D. Sanjeewa ^b and Kulugammana G. S. Ranmohotti ^a ^*

^aDivision of Chemistry and Biological Sciences, Governors State University, 1 University Parkway, University Park, IL 60484-0975, USA, and ^bDepartment of Chemistry, Clemson University, Clemson, SC 29634-0973, USA
^*Correspondence e-mail: kranmohotti@govst.edu

Edited by M. Weil, Vienna University of Technology, Austria (Received 24 June 2016; accepted 12 August 2016; online 19 August 2016)

In an attempt to search for mixed alkaline-earth and transition metal pyroborates, the title compound, barium manganese(II) pyroborate, has been synthesized by employing a flux method. The structure of BaMnB₂O₅ is composed of MnO₅ square pyramids that form Mn₂O₈ dimers by edge-sharing and of pyroborate units ([B₂O₅]⁴⁻) that are composed of two corner-sharing trigonal–planar BO₃ units. These building blocks share corners to form _∞²[MnB₂O₅]²⁻ layers extending parallel to (100). The Ba²⁺ cations reside in the gap between two manganese pyroborate slabs with a coordination number of nine. The title compound forms an interesting spiral framework propagating along the 2₁ screw axis. The structure is characterized by two alternating layers, which is relatively rare among known transition-metal-based pyroborate compounds.

Keywords: crystal structure; pyroborates; interplanar angle; layered framework; bond-valence-sum calculations.

CCDC reference: 1499124

1. Chemical context

Numerous borates with various crystal structures and compositions have been widely investigated over the last few decades (Heller et al., 1986 ). Pyroborates containing the (B₂O₅)⁴⁻ anion were first structurally characterized in 1950 (Berger, 1950 ). Pyroborates can be divided into two subclasses such as alkaline-earth-based pyroborates with general formula A₂B₂O₅ (A = alkaline earth metal) and transition-metal-based pyroborates with general formula MM′B₂O₅. If M = M′, the pyroborate is considered to be homo-metallic, otherwise it is hetero-metallic.

Alkaline-earth-based pyroborates adopt different structure types. During the investigation of the BaO/B₂O₃ system, Hubner revealed Ba₂B₂O₅ crystallizing in space group P2/m (Hubner, 1969 ). The other alkaline-earth-based A₂B₂O₅ pyroborates (A = Mg, Ca, Sr) have been synthesized by high-temperature solid-state reactions. Mg₂B₂O₅ (Guo et al., 1995b ) crystallizes in space group P2₁/c. Ca₂B₂O₅ (Lin et al., 1999a ) and Sr₂B₂O₅ (Lin et al., 1999b ) are isotypic and crystallize in the same space group type as Mg₂B₂O₅ but have a different structure from the latter. Additionally, there exists a triclinic magnesium pyroborate (P $[\overline{1}]$ ; Guo et al., 1995a ). The existence of mixed alkaline-earth-based pyroborates (AA′B₂O₅) has been proven by the study of naturally occurring minerals. The crystal structures of two polymorphs of CaMgB₂O₅, kurchatovite and clinokurchatovite, have been originally determined in space group types Pc2₁b (Yakubovich et al., 1976 ) and P2₁/c (Simonov et al., 1980 ). However, the crystal structures of both minerals have been re-examined and refined in different space group types (Callegari et al., 2003 ). Based on these models, kurchatovite crystallizes in space group type Pbca whilst clinokurchatovite crystallizes in space group type P2₁/c.

Investigations of transition-metal-based homo-metallic pyroborates, M₂B₂O₅ have led to four compounds, namely Mn₂B₂O₅ (Sarrat et al., 2005 ), Co₂B₂O₅ (Rowsell et al., 2003 ), Cd₂B₂O₅ (Weil, 2003 ), and Fe₂B₂O₅ (Neumair & Huppertz, 2009 ). These phases crystallize isotypically with the triclinic form of Mg₂B₂O₅ (Guo et al., 1995a). Efforts have been made to isolate transition-metal-based hetero-metallic phases, MM′B₂O₅. This has resulted in the synthesis of MnCoB₂O₅ and MnMgB₂O₅ (Utzolino & Bluhm, 1996 ), and Ni_1.5Zn_0.5B₂O₅ and Co_1.5Zn_0.5B₂O₅ (Busche & Bluhm, 1995 ). These structures are also isotypic with the triclinic form of Mg₂B₂O₅.

Investigations of the BaO/CuO/B₂O₃ phase diagram has resulted in the isolation of a non-centrosymmetric pyroborate, BaCuB₂O₅ (Smith & Keszler, 1997 ) with a unique structure type in space group type C2. As part of an effort to isolate new mixed alkaline earth and transition metal pyroborates, we have investigated the BaO/MnO/B₂O₃ phase diagram. In this study, we have grown single crystals of BaMnB₂O₅ and analyzed its crystal structure.

2. Structural commentary

The crystal structure of BaMnB₂O₅ defines a new structure type that can be described as being composed of manganese pyroborate slabs with composition _∞²[MnB₂O₅]²⁻ that extend parallel to (100). Fig. 1a shows a perspective drawing of the BaMnB₂O₅ structure with the quasi-two-dimensional lattice characterized by [MnB₂O₅]²⁻ slabs. The barium cations reside between the parallel slabs and maintain the interslab connectivity through coordination to nine oxygen atoms (Fig. 2c).

Figure 1
(a) Perspective view of the structure of BaMnB₂O₅ viewed along the c axis. The wavy and dotted line (left) indicates the zigzag arrays of Ba atoms. Only one Ba atom with bonds is drawn for clarity, demonstrating the function of Ba—O bonds with regard to holding neighboring [MnB₂O₅]²⁻ slabs. (b) Polyhedral representation showing the ²_∞[MnB₂O₅]²⁻ spiral framework centered around the 2₁ screw axis of the unit cell. (c) Polyhedral representation showing the arrangement of isolated pyroborate units viewed approximately along the [101] direction.

Figure 2
(a) Partial structure showing Mn₂O₈ dimers (polyhedral drawing). The apical oxygen, O3, in each MnO₅ square pyramid points in opposite directions. (b) Corner-sharing BO₃ groups forming a pyroborate unit. The BO₃ units within the pyroborate group are linked through a common O atom, O5. (c) The barium cation resides in a BaO₉ environment. Anisotropic displacement parameters are drawn at 95% probability.

Two non-equivalent boron atoms are present in the structure; both are surrounded by three oxygen atoms to form almost regular trigonal–planar units. As depicted in Fig. 2b, the isolated [B₂O₅]⁴⁻ pyroborate groups are composed of two corner-sharing trigonal–planar BO₃ units. In the reported pyroborate structures (Thompson et al., 1991 ), the terminal BO₂ planes pivot about the torsion angles to afford deviations from coplanarity that can range from 0 to 76.8° where the B—O—B angle ranges from 112 to 180°. In BaMnB₂O₅, the pyroborate groups show closely related geometric features as previously noted (Thompson et al., 1991), exhibiting a B—O—B angle of 125.1 (5)° whilst the dihedral angle between the two BO₃ units within the pyroborate group is 48.62 (8)°. The asymmetry of the bond lengths in the B₂O₅ group is indicated by slightly varied bond lengths of terminal and bridging B—O bonds. The bridging B—O bond lengths are slightly longer [B1—O5: 1.423 (7); B2—O5: 1.432 (7) Å] than the terminal B—O bond lengths [range 1.332 (8)–1.384 (7) Å]. Notwithstanding, the average B—O bond length (1.380 Å) in the title compound is very close to the corresponding average B—O bond length in BO₃ groups in previously reported borates (1.370 Å; Zobetz, 1982 ). Fig. 1c shows the arrangement of isolated pyroborate units, appearing as two parallel pseudo-one-dimensional chains spiraling around the 2₁ axis.

There is one crystallographically independent Mn atom which is coordinated by five oxygen atoms to form a square pyramid with four longer equatorial Mn—O bonds and one short apical Mn—O bond. Fig. 2a shows two Mn1O₅ square pyramids sharing a common edge, O2—O2(−x + 1, −y, −z), to form an Mn₂O₈ unit. As shown in Fig. 3a, Mn atoms are connected to each other via oxygen atoms with a Mn1⋯Mn1 separation of 3.317 (2) Å and an Mn1—O2—Mn1 angle of 101.23 (16)°. The neighboring Mn₂O₈ dimers share vertices through oxygen atom O3. The oxygen atom O1 in the Mn₂O₈ dimer is only corner-shared by the pyroborate group. The only unshared oxygen, O4, of the pyroborate group is pointing into the free space towards the neighboring slabs to form a bond with the barium atom. As shown in Fig. 3b, with respect to the pyroborate group, the B2O₃ unit shares two corners with neighboring MnO₅ square pyramids through O1 and O2 while the B1O₃ unit corner-shares a common oxygen atom, O3, with two other MnO₅ square pyramids. This arrangement facilitates the observed curvature which is necessary for the spiral framework found in the extended lattice (Fig. 1b). The unique arrangement of B₂O₅ groups around the 2₁ screw axis provides an essential element allowing the spiral chain to propagate along the b axis. It is well known that the interplanar angle of the B₂O₅ group is primarily dictated by packing effects and the nature of the associated cations in the given structure (Thompson et al., 1991). In addition to that, as previously noted, the greater deviations from coplanarity are observed in the arrangement of the B₂O₅ groups due to variation of the sizes of alkali metals in alkali metal Nb and Ta oxide pyroborates (Akella & Keszler, 1995 ). Accordingly, the inter-planar angle of the B₂O₅ group is likely to be determined by the associate coordination environment of the barium cations in the title compound. It should be noted that the connectivity of the Mn₂O₈ and B₂O₅ structure units would result in a `dangling' framework unless it can be tightly held together by external bonds. The Ba²⁺ cations, in this case, reside in the spiral framework arranging in zigzag fashion to support and maintain the distance between neighboring [MnB₂O₅]²⁻ slabs. Coincidentally, this wavy arrangement is critical for the spiral chain to propagate along the b axis. The flexible [MnB₂O₅]²⁻ framework revolves around Ba²⁺ cations, suggesting a template-like behavior.

Figure 3
(a) The Mn1O₅ square pyramids (ball and stick drawing) share a common edge, O2—O2, forming an Mn₂O₈ unit. (b) The B2O₃ unit (polyhedral drawing), shares two corners with neighboring MnO₅ square pyramids (ball and stick drawing) through O1 and O2. The only unshared oxygen, O4, of the pyroborate group forms a bond with a Ba atom.

The MnO₅ units adopt bond lengths normally observed in the Mn^II borates. The Mn²⁺—O bond lengths range from 2.082 (4) to 2.151 (4) Å, comparable with 2.10 Å, the sum of the Shannon crystal radii (Shannon, 1976 ) for a five coordinated Mn²⁺ (0.89 Å) and two-coordinated O²⁻ (1.21 Å). The bond-valence-sum (BVS) calculations (Brese & O'Keeffe, 1991 ) for BaMnB₂O₅ give a valence unit (v.u.) of 2.03 for the Mn²⁺ cation. Based on parameters for B³⁺—O, bond-valence sums of 2.95 for B1³⁺ and 2.95 for B2³⁺ were calculated. The Ba—O bond lengths are quite diverse, ranging from 2.707 (4) to 2.958 (4) Å. The average Ba—O bond length, 2.83 Å, however matches closely with 2.82 Å, the sum of the Shannon crystal radii for a nine coordinated Ba²⁺ (1.61 Å) and two-coordinated O²⁻ (1.21 Å). The BVS calculation for Ba²⁺ results in 2.08 v.u.

One of the interesting features of the title compound is that the structure can be alternatively viewed as a `porous' framework as shown in Fig. 4a. The B₂O₅ units together with interconnected Mn₂O₈ dimers extend along the b axis in a standing wave fashion, creating oval shape windows which also arrange in a zigzag fashion along the same direction. It is intriguing to notice that the two B₂O₅ groups along with the two Mn₂O₈ dimers and two MnO₅ square pyramids create an empty cage (Fig. 4c,d). The polyhedral and ball-and-stick drawing (Fig. 4b) clearly shows the three-dimensional framework bearing large cavities. This unusual structural arrangement is conceivably attributed to the limitation of the size of the pyroborate unit that simultaneously tends to interconnect with barium cations and neighboring Mn₂O₈ dimers in a corner-shared fashion (Fig. 3b). As shown in Fig. 5a, the layered nature of the title compound is characterized by parallel [MnB₂O₅]²⁻ slabs outlined by a dotted rectangle viewed along [010]. Fig. 5b shows the ball-and-stick drawing of a portion of the layered manganese oxide network. Each Mn₂O₈ dimer shares vertices with four other MnO₅ square pyramids through oxygen atoms to form these sheets. Within the extended Mn—O sheet, the MnO₅ square pyramids which share edges are separated from each other by 3.317 (2) Å (Mn1⋯Mn1 distance) whereas those which share corners are separated by 3.435 (1) Å. The distance between the Mn atoms of the adjacent sheets is 8.287 (2) Å. Given the description of the local configuration of the manganese oxide polyhedra, their connectivity along the sheet, and the structural isolation of neighboring Mn—O sheets from each other, one would suspect that the title compound offers opportunities for the study of spin exchange in a confined Mn—O lattice. In theory, a periodic array of well-defined transition metal oxide lattices could provide a useful model for experimental and theoretical developments of magnetic and electronic interactions in transition metal oxides because of their simplified structures (Snyder et al., 2001 ).

Figure 4
(a) Extended structure of BaMnB₂O₅ viewed approximately along the [101] direction. The connectivity of the barium atoms is not shown for clarity. (b) Partial structure of [MnB₂O₅]²⁻ slab viewed along [100] where the polyhedral drawing represents MnO₅ square pyramids and B₂O₅ units are represented by ball-and-stick drawing. (c) Edge-sharing and corner-sharing MnO₅ units corner-share with B₂O₅ pyroborate groups (polyhedral drawing) to create a cage. (d) Stick drawing of one cage with empty space in the middle.

Figure 5
(a) Layered BaMnB₂O₅ shown by polyhedral and ball-and-stick drawing viewed along the [010] direction. (b) Ball-and-stick drawing of a portion of the manganese oxide network formed by interconnected Mn₂O₈ dimers by corner sharing.

The structure of BaMnB₂O₅ is somewhat related to that of triclinic M₂B₂O₅ (M = Mn, Sarrat et al., 2005; Fe, Neumair & Huppertz, 2009; Co, Rowsell et al., 2003) phases. The structures of M₂B₂O₅ (M = Mn, Fe, Co) phases are based on structurally isolated [M₄O₁₈] tetramers, composed of four octahedra linked by three shared edges, connected through sharing four O—O edges, into ribbons extending along (001) while the boron atoms hold the ribbons together forming B₂O₅ groups. These extended ribbons are parallel to each other and therefore these M₂B₂O₅ phases have a quasi-one-dimensional structure in contrast to the two-dimensional Mn—O lattice in the title compound. Magnetic properties have been widely studied for Co₂B₂O₅ (Kawano et al., 2010 ), Fe₂B₂O₅ (Kawano et al., 2009 ), and Mn₂B₂O₅ (Fernandes et al., 2003 ) to understand the low-dimensional interactions derived from the ribbon-like substructures in these compounds. The spin configuration based on the electron-density distribution has been proposed (Sarrat et al., 2005) for Mn₂B₂O₅ in which the distance between manganese atoms of adjacent ribbons are 4.526–6.272 Å and electron-density distributions were indicated in the regions between the ribbons. According to their model, all coplanar ribbons of Mn₂B₂O₅ are ferromagnetic; their antiferromagnetic behavior is derived from antiparallel magnetic orientations between adjacent ribbons. In the title compound, the distance between manganese atoms within the sheets and adjacent sheets are 3.317 (2)–3.435 (1) Å and 8.287 (2) Å, respectively. It is important to note that the Ba²⁺ cations reside in the gap between the two Mn—O sheets. This, together with the greater separation between manganese atoms of adjacent sheets, leads us to believe that magnetic interactions that occur between Mn—O sheets can be extremely weak and the dominant magnetic exchange should be between Mn²⁺ ions within the Mn—O sheet. Judging from the interesting magnetic properties reported for M₂B₂O₅ (M = Mn, Fe, Co) compounds, we expect interesting magnetic phenomena from a systematic investigation of the magnetic susceptibility of BaMnB₂O₅.

3. Synthesis and crystallization

Light pink crystals of BaMnB₂O₅ were grown by employing a CsCl/RbCl flux in a fused silica ampoule under vacuum. MnO (2.74 mmol, 99.999+%, Alfa), BaO (1.37 mmol, 99.99+%, Aldrich) and B₂O₃ (1.37 mmol, 99.98+%, Aldrich) were mixed and ground with the flux (1:3 by weight) in a nitrogen-blanketed drybox. The resulting mixture was heated to 818 K at 1 K min⁻¹, isothermed for two days, heated to 1023 K at 1 K min⁻¹, isothermed for four days, then slowly cooled to 673 K at 0.1 K min⁻¹ followed by furnace-cooling to room temperature. Prismatic crystals of BaMnB₂O₅ were retrieved upon washing off the solidified melt with deionized water.

4. Refinement

Crystal data, data collection and structure refinement details are summarized in Table 1. The final Fourier difference synthesis showed the maximum residual electron density in the difference Fourier map, 0.82 e Å⁻³, located at 1.19 Å from Ba1 and the minimum, −0.98 e⁻ Å⁻³, at 0.92 Å from Ba1.

Table 1
Experimental details

Crystal data
Chemical formula	BaMnB₂O₅
M_r	293.90
Crystal system, space group	Monoclinic, P2₁/c
Temperature (K)	300
a, b, c (Å)	8.2868 (17), 8.6570 (17), 6.5263 (13)
β (°)	92.87 (3)
V (Å³)	467.60 (16)
Z	4
Radiation type	Mo Kα
μ (mm⁻¹)	10.99
Crystal size (mm)	0.17 × 0.05 × 0.02

Data collection
Diffractometer	Rigaku AFC8S
Absorption correction	Multi-scan (REQAB; Rigaku, 1998 )
T_min, T_max	0.518, 0.808
No. of measured, independent and observed [I > 2σ(I)] reflections	3807, 830, 777
R_int	0.052
(sin θ/λ)_max (Å⁻¹)	0.598

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.025, 0.056, 1.10
No. of reflections	830
No. of parameters	83
Δρ_max, Δρ_min (e Å⁻³)	0.82, −0.98
Computer programs: CrystalClear (Rigaku, 2006 ), SHELXT (Sheldrick, 2015a ), SHELXL2014 (Sheldrick, 2015b ), DIAMOND (Brandenburg, 1999 ) and publCIF (Westrip, 2010 ).

Supporting information

CCDC reference: 1499124

Crystal structure: contains datablock I. DOI: https://doi.org/10.1107/S2056989016013074/wm5306sup1.cif

Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S2056989016013074/wm5306Isup2.hkl

checkCIF report

Computing details top

Data collection: CrystalClear (Rigaku, 2006); cell refinement: CrystalClear (Rigaku, 2006); data reduction: CrystalClear (Rigaku, 2006); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2014 (Sheldrick, 2015b); molecular graphics: DIAMOND (Brandenburg, 1999); software used to prepare material for publication: publCIF (Westrip, 2010).

Barium manganese(II) pyroborate top

Crystal data top

BaMnB₂O₅	F(000) = 524
M_r = 293.90	D_x = 4.175 Mg m⁻³
Monoclinic, P2₁/c	Mo Kα radiation, λ = 0.71073 Å
a = 8.2868 (17) Å	Cell parameters from 3139 reflections
b = 8.6570 (17) Å	θ = 3.1–29.6°
c = 6.5263 (13) Å	µ = 10.99 mm⁻¹
β = 92.87 (3)°	T = 300 K
V = 467.60 (16) Å³	Prismatic, pink
Z = 4	0.17 × 0.05 × 0.02 mm

Data collection top

Rigaku AFC8S diffractometer	777 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.052
ω scans	θ_max = 25.2°, θ_min = 3.4°
Absorption correction: multi-scan (REQAB; Rigaku, 1998)	h = −9→9
T_min = 0.518, T_max = 0.808	k = −10→10
3807 measured reflections	l = −7→7
830 independent reflections	1 standard reflections every 1 reflections

Refinement top

Refinement on F²	0 restraints
Least-squares matrix: full	w = 1/[σ²(F_o²) + (0.0315P)²] where P = (F_o² + 2F_c²)/3
R[F² > 2σ(F²)] = 0.025	(Δ/σ)_max = 0.005
wR(F²) = 0.056	Δρ_max = 0.82 e Å⁻³
S = 1.10	Δρ_min = −0.98 e Å⁻³
830 reflections	Extinction correction: SHELXL2014 (Sheldrick, 2015b), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
83 parameters	Extinction coefficient: 0.0061 (7)

Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å²) top

	x	y	z	U_iso*/U_eq
Ba1	0.14891 (4)	0.07969 (4)	0.22488 (5)	0.00932 (16)
Mn1	0.53148 (10)	0.18805 (10)	0.02929 (12)	0.0087 (2)
B1	0.1784 (8)	−0.2828 (7)	0.1447 (10)	0.0100 (13)
B2	0.2960 (8)	0.4492 (7)	0.1980 (10)	0.0115 (13)
O1	0.3314 (5)	0.3308 (4)	0.0723 (6)	0.0133 (9)
O2	0.3587 (5)	0.0300 (4)	−0.1080 (6)	0.0126 (9)
O3	0.3228 (5)	−0.2185 (4)	0.2184 (6)	0.0106 (8)
O4	0.0457 (5)	−0.2018 (4)	0.0939 (6)	0.0110 (8)
O5	−0.1725 (5)	0.0536 (4)	0.3763 (6)	0.0109 (8)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Ba1	0.0103 (2)	0.0088 (2)	0.0088 (2)	0.00002 (12)	−0.00031 (13)	−0.00026 (13)
Mn1	0.0094 (5)	0.0080 (4)	0.0086 (5)	0.0000 (3)	−0.0006 (3)	−0.0001 (3)
B1	0.006 (3)	0.013 (3)	0.011 (3)	−0.002 (3)	0.000 (2)	0.002 (3)
B2	0.010 (3)	0.011 (3)	0.014 (3)	0.005 (3)	0.000 (3)	−0.003 (3)
O1	0.012 (2)	0.015 (2)	0.013 (2)	0.0056 (17)	−0.0030 (17)	−0.0054 (17)
O2	0.017 (2)	0.0073 (18)	0.012 (2)	−0.0008 (16)	−0.0055 (17)	−0.0004 (16)
O3	0.0108 (19)	0.0109 (19)	0.010 (2)	−0.0023 (16)	−0.0002 (16)	0.0011 (16)
O4	0.012 (2)	0.009 (2)	0.012 (2)	0.0033 (16)	0.0004 (16)	−0.0018 (16)
O5	0.013 (2)	0.0075 (19)	0.012 (2)	0.0010 (16)	−0.0036 (16)	0.0006 (16)

Geometric parameters (Å, º) top

Ba1—O4	2.707 (4)	Mn1—O1	2.098 (4)
Ba1—O1ⁱ	2.772 (4)	Mn1—O2	2.144 (4)
Ba1—O4ⁱⁱ	2.777 (4)	Mn1—O2^v	2.147 (4)
Ba1—O4ⁱⁱⁱ	2.787 (4)	Mn1—O3^vi	2.151 (4)
Ba1—O5^iv	2.845 (4)	B1—O4	1.332 (8)
Ba1—O1	2.855 (4)	B1—O3	1.384 (7)
Ba1—O2	2.882 (4)	B1—O5^vii	1.423 (7)
Ba1—O5	2.896 (4)	B2—O1	1.354 (7)
Ba1—O3	2.958 (4)	B2—O2ⁱ	1.357 (8)
Mn1—O3^v	2.082 (4)	B2—O5ⁱⁱⁱ	1.432 (7)

O4—Ba1—O1ⁱ	131.36 (11)	O1—Mn1—O2^v	144.52 (16)
O4—Ba1—O4ⁱⁱ	86.77 (11)	O2—Mn1—O2^v	78.77 (16)
O1ⁱ—Ba1—O4ⁱⁱ	141.16 (11)	O3^v—Mn1—O3^vi	102.81 (15)
O4—Ba1—O4ⁱⁱⁱ	124.37 (5)	O1—Mn1—O3^vi	95.36 (15)
O1ⁱ—Ba1—O4ⁱⁱⁱ	76.50 (12)	O2—Mn1—O3^vi	153.85 (15)
O4ⁱⁱ—Ba1—O4ⁱⁱⁱ	74.51 (8)	O2^v—Mn1—O3^vi	86.12 (14)
O4—Ba1—O5^iv	85.98 (11)	O1—B2—O2ⁱ	125.6 (5)
O1ⁱ—Ba1—O5^iv	49.87 (11)	O1—B2—O5ⁱⁱⁱ	116.5 (5)
O4ⁱⁱ—Ba1—O5^iv	148.29 (11)	O2ⁱ—B2—O5ⁱⁱⁱ	117.8 (5)
O4ⁱⁱⁱ—Ba1—O5^iv	84.37 (11)	B2—O1—Mn1	136.3 (4)
O4—Ba1—O1	137.70 (12)	B2—O1—Ba1^viii	99.1 (3)
O1ⁱ—Ba1—O1	78.21 (9)	Mn1—O1—Ba1^viii	117.24 (16)
O4ⁱⁱ—Ba1—O1	75.33 (12)	B2—O1—Ba1	103.3 (3)
O4ⁱⁱⁱ—Ba1—O1	87.65 (11)	Mn1—O1—Ba1	91.97 (13)
O5^iv—Ba1—O1	127.91 (11)	Ba1^viii—O1—Ba1	102.80 (13)
O4—Ba1—O2	79.67 (11)	B2^viii—O2—Mn1	121.5 (4)
O1ⁱ—Ba1—O2	109.48 (11)	B2^viii—O2—Mn1^v	118.6 (4)
O4ⁱⁱ—Ba1—O2	80.88 (11)	Mn1—O2—Mn1^v	101.23 (16)
O4ⁱⁱⁱ—Ba1—O2	143.59 (11)	B2^viii—O2—Ba1	117.8 (4)
O5^iv—Ba1—O2	127.79 (11)	Mn1—O2—Ba1	90.29 (13)
O1—Ba1—O2	60.05 (11)	Mn1^v—O2—Ba1	102.44 (14)
O4—Ba1—O5	75.88 (11)	B1—O3—Mn1^v	107.8 (4)
O1ⁱ—Ba1—O5	102.48 (11)	B1—O3—Mn1^ix	123.9 (3)
O4ⁱⁱ—Ba1—O5	77.04 (12)	Mn1^v—O3—Mn1^ix	108.48 (17)
O4ⁱⁱⁱ—Ba1—O5	49.20 (11)	B1—O3—Ba1	86.7 (3)
O5^iv—Ba1—O5	71.25 (13)	Mn1^v—O3—Ba1	101.68 (14)
O1—Ba1—O5	133.67 (10)	Mn1^ix—O3—Ba1	124.92 (15)
O2—Ba1—O5	147.72 (11)	B1—O4—Ba1	98.7 (3)
O4—Ba1—O3	49.93 (11)	B1—O4—Ba1ⁱⁱ	145.9 (4)
O1ⁱ—Ba1—O3	90.55 (11)	Ba1—O4—Ba1ⁱⁱ	93.23 (11)
O4ⁱⁱ—Ba1—O3	125.91 (11)	B1—O4—Ba1^vii	91.4 (3)
O4ⁱⁱⁱ—Ba1—O3	153.01 (10)	Ba1—O4—Ba1^vii	131.11 (15)
O5^iv—Ba1—O3	69.38 (11)	Ba1ⁱⁱ—O4—Ba1^vii	104.46 (13)
O1—Ba1—O3	113.11 (11)	B1ⁱⁱⁱ—O5—B2^vii	125.1 (5)
O2—Ba1—O3	63.01 (10)	B1ⁱⁱⁱ—O5—Ba1^iv	119.5 (3)
O5—Ba1—O3	113.20 (11)	B2^vii—O5—Ba1^iv	93.9 (3)
O3^v—Mn1—O1	121.48 (15)	B1ⁱⁱⁱ—O5—Ba1	85.3 (3)
O3^v—Mn1—O2	99.07 (15)	B2^vii—O5—Ba1	126.0 (3)
O1—Mn1—O2	85.17 (16)	Ba1^iv—O5—Ba1	108.75 (13)
O3^v—Mn1—O2^v	92.39 (15)

Symmetry codes: (i) x, −y+1/2, z+1/2; (ii) −x, −y, −z; (iii) −x, y+1/2, −z+1/2; (iv) −x, −y, −z+1; (v) −x+1, −y, −z; (vi) −x+1, y+1/2, −z+1/2; (vii) −x, y−1/2, −z+1/2; (viii) x, −y+1/2, z−1/2; (ix) −x+1, y−1/2, −z+1/2.

Acknowledgements

The Division of Science at Governors State University is gratefully acknowledged for the continuous support. Special thanks are due to Dr Julien P. A. Makongo for his X-ray crystallography expertise.

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