Dipraseodymium(III) pyroborate molybdate(VI), Pr2(B2O5)(MoO4)

Held, P.; Becker, P.

doi:10.1107/S1600536808010386

inorganic compounds

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Volume 64| Part 6| June 2008| Page i28

doi:10.1107/S1600536808010386

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Dipraseodymium(III) pyroborate molybdate(VI), Pr₂(B₂O₅)(MoO₄)

Peter Held ^a ^* and Petra Becker ^a

^aInstitut für Kristallographie, Universität zu Köln, Zülpicher Strasse 49b, D-50674 Köln, Germany
^*Correspondence e-mail: peter.held@uni-koeln.de

(Received 1 April 2008; accepted 15 April 2008; online 3 May 2008)

Single crystals of triclinic Pr₂(B₂O₅)(MoO₄) were prepared from an incongruently melting flux in the system Pr₂O₃–MoO₃–B₂O₃ in a platinum crucible in an atmosphere of air. In the crystal structure, distorted edge-sharing [PrO₈] square antiprisms form a three-dimensional framework. These are further linked by isolated [MoO₄] tetrahedra and isolated pyroborate groups [B₂O₅], the latter consisting of two independent trigonal [BO₃] groups sharing one O atom. The [MoO₄] tetrahedra and the [B₂O₅] groups are arranged in alternating layers parallel to the ab plane.

Related literature

A rough investigation of the ternary systems RE₂O₃—B₂O₃—MoO₃ (RE = rare earth element) has been reported by Lysanova et al. (1983 ) and Dzhurinskii & Lysanova (1998 ). X-ray powder diffraction data of RE₂(B₂O₅)(MoO₄) compounds with RE = Pr, Nd, Sm, Eu, Gd and Tb were reported by Lysanova et al. (1983). Geometric parameters of [BO₃] groups were reviewed by Zobetz (1982 ).

Experimental

Crystal data

Pr₂(B₂O₅)(MoO₄)
M_r = 543.38
Triclinic, $[P \overline 1]$
a = 5.2806 (5) Å
b = 7.0278 (5) Å
c = 10.5824 (9) Å
α = 74.557 (6)°
β = 76.307 (7)°
γ = 73.065 (6)°
V = 356.69 (5) Å³
Z = 2
Mo Kα radiation
μ = 15.20 mm⁻¹
T = 291 (2) K
0.20 × 0.15 × 0.12 mm

Data collection

Enraf–Nonius CAD-4 diffractometer
Absorption correction: ψ scan (MolEN; Fair, 1990 ) T_min = 0.296, T_max = 0.999 (expected range = 0.048–0.161)
4733 measured reflections
2155 independent reflections
1983 reflections with I > 2σ(I)
R_int = 0.019
3 standard reflections every 100 reflections intensity decay: 1.7%

Refinement

R[F² > 2σ(F²)] = 0.031
wR(F²) = 0.082
S = 1.13
2155 reflections
127 parameters
Δρ_max = 2.55 e Å⁻³
Δρ_min = −1.73 e Å⁻³

Table 1
Selected bond lengths (Å)

Pr1—O4	2.370 (3)
Pr1—O3ⁱ	2.430 (3)
Pr1—O1ⁱ	2.450 (3)
Pr1—O5ⁱⁱ	2.461 (3)
Pr1—O7	2.480 (3)
Pr1—O2	2.529 (3)
Pr1—O2ⁱⁱⁱ	2.557 (3)
Pr1—O6^iv	2.610 (3)
Pr2—O8	2.364 (3)
Pr2—O8^v	2.375 (3)
Pr2—O4^vi	2.456 (3)
Pr2—O3	2.506 (3)
Pr2—O1	2.513 (3)
Pr2—O3^vii	2.585 (3)
Pr2—O1^viii	2.585 (3)
Pr2—O6^ix	2.645 (4)
Mo—O5	1.748 (3)
Mo—O7	1.748 (3)
Mo—O6	1.782 (4)
Mo—O2^x	1.803 (3)
B1—O8	1.345 (6)
B1—O4	1.370 (6)
B1—O9	1.387 (6)
B2—O9^xi	1.373 (6)
B2—O1^xi	1.378 (6)
B2—O3	1.384 (6)
Symmetry codes: (i) x, y+1, z; (ii) -x+1, -y+1, -z-1; (iii) -x+1, -y, -z-1; (iv) x, y-1, z; (v) -x, -y-1, -z; (vi) -x+1, -y-1, -z; (vii) -x, -y-2, -z; (viii) -x+1, -y-2, -z; (ix) -x, -y, -z; (x) -x, -y+1, -z-1; (xi) x-1, y, z.

Data collection: MACH3 (Enraf–Nonius, 1993 ); cell refinement: MACH3; data reduction: MolEN (Fair, 1990); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ATOMS (Dowty, 2002 ); software used to prepare material for publication: publCIF (Westrip, 2008 ).

Supporting information

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536808010386/wm2175sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536808010386/wm2175Isup2.hkl

checkCIF report

Comment top

The existence of several compounds in the systems RE₂O₃— B₂O₃—MoO₃ (RE = rare earth element) has been studied by Lysanova et al. (1983) by means of X-ray powder diffraction data and was partly corroborated by Dzhurinskii & Lysanova (1998). Among these pseudo-ternary compounds, rare earth pyroborate molybdates of the type RE₂(B₂O₅)(MoO₄) were reported for RE = Pr - Tb (excluding Pm) (Lysanova et al., 1983), all with incongruent melting behaviour. However, no structural information about these compounds has been given so far. In the course of our investigations of the systems RE₂O₃—B₂O₃—MO₃ (M = Mo, W) we grew single crystals of the Pr-compound Pr₂(B₂O₅)(MoO₄), (I), as a representative of the rare earth pyroborate molybdate series.

In the crystal structure of (I) the two symmetrically non-equivalent Pr atoms show a distinct eightfold coordination by oxygen atoms, both with a slightly distorted square antiprismatic coordination polyhedron, and with Pr—O bond lengths ranging from 2.370 (3) Å to 2.610 (3) Å for Pr1, and from 2.364 (3) Å to 2.645 (4) Å for Pr2 (Fig. 2). The [PrO₈] polyhedra are connected via common edges, where Pr2 is connected to six neighbouring [PrO₈] polyhedra with Pr—Pr distances ranging from 3.9237 (5) Å to 4.1242 (5) Å, while Pr1 is connected to only four [PrO₈] polyhedra with Pr—Pr distances between 3.9702 (6) Å and 4.1583 (6) Å. From the different connection schemes of the two Pr atoms a three-dimensional framework of [PrO₈] polyhedra with interstitial voids results (Fig. 1). In these voids nearly undistorted and isolated [MoO₄] tetrahedra, that are arranged in layers parallel to the ab plane are positioned (Fig. 1).

The two crystallographically different B atoms are threefold coordinated by O atoms. The two [BO₃] groups are linked by a common oxygen ligand O9 (see Fig. 2), thus forming isolated pyroborate groups [B₂O₅]. The pyroborate groups are bent with an angle (B1— O9— B2) of 125.1 (4)°, while the individual [BO₃] groups show no unusual distortions (Zobetz, 1982). The oxygen ligands of the pyroborate group (apart from the bridging oxygen O9, see Fig. 2) each belong either to two different [PrO₈] polyhedra (being simultaneously ligands of B1) or to three different [PrO₈] polyhedra (being simultaneously ligands of B2). All [B₂O₅] groups are arranged in double layers that extend parallel to the ab-plane and alternate with layers of [MoO₄] tetrahedra (see Fig. 1).

Related literature top

A rough investigation of the ternary systems RE₂O₃—B₂O₃—MoO₃ (RE = rare earth element) has been reported by Lysanova et al. (1983) and Dzhurinskii & Lysanova (1998). X-ray powder diffraction data of RE₂(B₂O₅)(MoO₄) compounds with RE = Pr, Nd, Sm, Eu, Gd and Tb are given by Lysanova et al. (1983). Geometric parameters of [BO₃] groups were reviewed by Zobetz (1982).

Experimental top

Single crystals of (I) were obtained by growth from the melt. A homogenized powder mixture of Pr₄O₁₁ (99.9%, Alfa Aesar), B₂O₃ (99.98%, Alfa Aesar) and MoO₃ (99.95%, Alfa Aesar) in a molar ratio of 1: 3.33: 7 was heated in a covered platinum crucible in air atmosphere to 1423 K and subsequently cooled at a rate of 3 K h^-1 to 1173 K. Transparent, light-green prismatic single crystals of the title compound were separated mechanically from the fine-grained praseodymium borate molybdate matrix.

Computing details top

Data collection: MACH3 (Enraf–Nonius, 1993); cell refinement: MACH3 (Enraf–Nonius, 1993); data reduction: MolEN (Fair, 1990); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ATOMS (Dowty, 2002); software used to prepare material for publication: publCIF (Westrip, 2008).

Figures top

Fig. 1. : View of the structure of (I) approximately along the a-axis, emphasizing coordination surroundings of the cations. Pr atoms are shown as large red spheres, Mo atoms as smaller orange spheres, and B atoms as small green spheres. O atoms are indicated by the corners of the coordination polyhedra and are not drawn.

Fig. 2. : Fraction of the structure of (I) with atomic labelling scheme in a projection approximately along the a-axis. The atoms are drawn as displacement ellipsoids at the 50% probability level. [Symmetry codes: (i) x, y + 1, z; (ii) -x + 1, -y + 1, -z - 1; (iii) -x + 1, -y, (iv) x, y - 1, z; -z - 1; (x) -x, -y, -z; (xii) x + 1, y, z; (xiii) x + 1, y + 1, z; (xiv) -x + 1, -y - 1, -z; (xv) x + 1, y - 1, z.]

Dipraseodymium(III) pyroborate molybdate(VI) top

Crystal data top

Pr₂(B₂O₅)(MoO₄)	Z = 2
M_r = 543.38	F(000) = 484
Triclinic, P1	D_x = 5.059 Mg m⁻³
a = 5.2806 (5) Å	Mo Kα radiation, λ = 0.71073 Å
b = 7.0278 (5) Å	Cell parameters from 25 reflections
c = 10.5824 (9) Å	θ = 20.8–24.2°
α = 74.557 (6)°	µ = 15.20 mm⁻¹
β = 76.307 (7)°	T = 291 K
γ = 73.065 (6)°	Prism, light green
V = 356.69 (5) Å³	0.20 × 0.15 × 0.12 mm

Data collection top

Enraf–Nonius CAD-4 diffractometer	1983 reflections with I > 2σ(I)
Radiation source: fine-focus sealed tube	R_int = 0.019
Graphite monochromator	θ_max = 30.4°, θ_min = 3.1°
ω/2θ scans	h = −7→7
Absorption correction: ψ scan (MolEN; Fair, 1990)	k = −10→10
T_min = 0.296, T_max = 0.999	l = −15→15
4733 measured reflections	3 standard reflections every 100 reflections
2155 independent reflections	intensity decay: 1.7%

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.031	w = 1/[σ²(F_o²) + (0.0533P)² + 1.1726P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.082	(Δ/σ)_max < 0.001
S = 1.13	Δρ_max = 2.55 e Å⁻³
2155 reflections	Δρ_min = −1.73 e Å⁻³
127 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0319 (13)

Crystal data top

Pr₂(B₂O₅)(MoO₄)	γ = 73.065 (6)°
M_r = 543.38	V = 356.69 (5) Å³
Triclinic, P1	Z = 2
a = 5.2806 (5) Å	Mo Kα radiation
b = 7.0278 (5) Å	µ = 15.20 mm⁻¹
c = 10.5824 (9) Å	T = 291 K
α = 74.557 (6)°	0.20 × 0.15 × 0.12 mm
β = 76.307 (7)°

Data collection top

Enraf–Nonius CAD-4 diffractometer	1983 reflections with I > 2σ(I)
Absorption correction: ψ scan (MolEN; Fair, 1990)	R_int = 0.019
T_min = 0.296, T_max = 0.999	3 standard reflections every 100 reflections
4733 measured reflections	intensity decay: 1.7%
2155 independent reflections

Refinement top

R[F² > 2σ(F²)] = 0.031	127 parameters
wR(F²) = 0.082	0 restraints
S = 1.13	Δρ_max = 2.55 e Å⁻³
2155 reflections	Δρ_min = −1.73 e Å⁻³

Special details top

Experimental. A suitable single-crystal was carefully selected under a polarizing microscope and mounted in a glass capillary.

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

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

	x	y	z	U_iso*/U_eq
Pr1	0.37016 (5)	0.07689 (4)	−0.31461 (2)	0.00706 (11)
Pr2	0.15410 (5)	−0.79427 (4)	0.04666 (2)	0.00693 (11)
Mo	0.03514 (8)	0.70782 (6)	−0.41958 (4)	0.00758 (12)
O7	0.1449 (8)	0.4427 (5)	−0.3778 (4)	0.0144 (7)
O5	0.2335 (7)	0.7903 (6)	−0.5706 (3)	0.0152 (7)
O6	0.0805 (7)	0.8248 (6)	−0.2991 (4)	0.0141 (7)
O2	0.3079 (7)	0.1829 (5)	−0.5554 (3)	0.0111 (6)
B1	0.4573 (10)	−0.4118 (7)	−0.1373 (5)	0.0077 (8)
O4	0.4775 (7)	−0.2184 (5)	−0.1465 (3)	0.0114 (6)
O8	0.2350 (7)	−0.4758 (5)	−0.0732 (3)	0.0114 (6)
O9	0.6870 (7)	−0.5435 (5)	−0.1886 (4)	0.0121 (7)
B2	−0.2634 (10)	−0.7520 (8)	−0.1570 (5)	0.0091 (8)
O1	0.5437 (7)	−0.8575 (5)	−0.1392 (3)	0.0094 (6)
O3	−0.0094 (7)	−0.8664 (5)	−0.1355 (3)	0.0086 (6)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Pr1	0.00931 (15)	0.00715 (15)	0.00456 (15)	−0.00225 (10)	−0.00160 (10)	−0.00032 (10)
Pr2	0.00839 (16)	0.00662 (15)	0.00584 (15)	−0.00215 (10)	−0.00193 (10)	−0.00046 (9)
Mo	0.0094 (2)	0.0072 (2)	0.00587 (19)	−0.00159 (14)	−0.00209 (14)	−0.00082 (13)
O7	0.0190 (18)	0.0082 (15)	0.0112 (15)	−0.0002 (12)	−0.0023 (14)	0.0025 (12)
O5	0.0167 (17)	0.0188 (17)	0.0100 (15)	−0.0069 (14)	0.0023 (13)	−0.0039 (13)
O6	0.0165 (17)	0.0179 (17)	0.0109 (15)	−0.0060 (13)	−0.0036 (13)	−0.0052 (13)
O2	0.0110 (15)	0.0136 (16)	0.0096 (15)	−0.0016 (12)	−0.0034 (12)	−0.0038 (12)
B1	0.011 (2)	0.008 (2)	0.0034 (19)	−0.0022 (16)	−0.0003 (16)	−0.0011 (15)
O4	0.0159 (16)	0.0096 (15)	0.0101 (15)	−0.0046 (12)	−0.0044 (13)	−0.0008 (11)
O8	0.0093 (15)	0.0086 (14)	0.0130 (16)	−0.0015 (11)	0.0004 (13)	0.0005 (12)
O9	0.0120 (16)	0.0075 (15)	0.0142 (17)	−0.0020 (12)	0.0011 (13)	−0.0012 (12)
B2	0.009 (2)	0.009 (2)	0.008	−0.0028 (16)	−0.0004 (17)	−0.0010 (16)
O1	0.0099 (15)	0.0107 (15)	0.0088 (14)	−0.0036 (12)	−0.0030 (12)	−0.0017 (11)
O3	0.0076 (14)	0.0106 (15)	0.0071 (14)	−0.0025 (11)	0.0007 (11)	−0.0024 (11)

Geometric parameters (Å, º) top

Pr1—O4	2.370 (3)	Pr2—O1^ix	2.585 (3)
Pr1—O3ⁱ	2.430 (3)	Pr2—O6^x	2.645 (4)
Pr1—O1ⁱ	2.450 (3)	Pr2—B2^viii	3.021 (5)
Pr1—O5ⁱⁱ	2.461 (3)	Pr2—Pr2^vii	3.9237 (6)
Pr1—O7	2.480 (3)	Pr2—Pr1^vi	3.9702 (5)
Pr1—O2	2.529 (3)	Pr2—Pr1^iv	3.9893 (5)
Pr1—O2ⁱⁱⁱ	2.557 (3)	Mo—O5	1.748 (3)
Pr1—O6^iv	2.610 (3)	Mo—O7	1.748 (3)
Pr1—Mo^v	3.6714 (6)	Mo—O6	1.782 (4)
Pr1—Pr2^vi	3.9702 (5)	Mo—O2^v	1.803 (3)
Pr1—Pr2ⁱ	3.9893 (5)	Mo—Pr1^v	3.6714 (6)
Pr1—Pr2^vii	4.0171 (5)	B1—O8	1.345 (6)
Pr2—O8	2.364 (3)	B1—O4	1.370 (6)
Pr2—O8^vii	2.375 (3)	B1—O9	1.387 (6)
Pr2—O4^vi	2.456 (3)	B2—O9^xi	1.373 (6)
Pr2—O3	2.506 (3)	B2—O1^xi	1.378 (6)
Pr2—O1	2.513 (3)	B2—O3	1.384 (6)
Pr2—O3^viii	2.585 (3)	B2—Pr2^viii	3.021 (5)

O4—Pr1—O3ⁱ	77.59 (12)	O4^vi—Pr2—O1^ix	64.22 (10)
O4—Pr1—O1ⁱ	67.58 (11)	O3—Pr2—O1^ix	102.94 (11)
O3ⁱ—Pr1—O1ⁱ	73.79 (11)	O1—Pr2—O1^ix	75.10 (12)
O4—Pr1—O5ⁱⁱ	112.06 (12)	O3^viii—Pr2—O1^ix	54.11 (11)
O3ⁱ—Pr1—O5ⁱⁱ	139.81 (11)	O8—Pr2—O6^x	117.87 (11)
O1ⁱ—Pr1—O5ⁱⁱ	74.69 (11)	O8^vii—Pr2—O6^x	68.69 (12)
O4—Pr1—O7	149.37 (12)	O4^vi—Pr2—O6^x	79.69 (11)
O3ⁱ—Pr1—O7	75.46 (11)	O3—Pr2—O6^x	126.73 (10)
O1ⁱ—Pr1—O7	90.93 (12)	O1—Pr2—O6^x	154.52 (11)
O5ⁱⁱ—Pr1—O7	80.77 (12)	O3^viii—Pr2—O6^x	69.74 (10)
O4—Pr1—O2	141.05 (11)	O1^ix—Pr2—O6^x	82.67 (11)
O3ⁱ—Pr1—O2	121.14 (11)	O8—Pr2—Pr2^vii	34.21 (8)
O1ⁱ—Pr1—O2	146.59 (11)	O8^vii—Pr2—Pr2^vii	34.03 (8)
O5ⁱⁱ—Pr1—O2	76.77 (11)	O4^vi—Pr2—Pr2^vii	97.53 (8)
O7—Pr1—O2	67.53 (11)	O3—Pr2—Pr2^vii	93.69 (8)
O4—Pr1—O2ⁱⁱⁱ	76.63 (11)	O1—Pr2—Pr2^vii	103.65 (8)
O3ⁱ—Pr1—O2ⁱⁱⁱ	145.67 (11)	O3^viii—Pr2—Pr2^vii	140.80 (7)
O1ⁱ—Pr1—O2ⁱⁱⁱ	115.72 (11)	O1^ix—Pr2—Pr2^vii	161.72 (7)
O5ⁱⁱ—Pr1—O2ⁱⁱⁱ	71.93 (11)	O6^x—Pr2—Pr2^vii	93.54 (8)
O7—Pr1—O2ⁱⁱⁱ	133.79 (11)	B2^viii—Pr2—Pr2^vii	166.65 (10)
O2—Pr1—O2ⁱⁱⁱ	70.32 (12)	O8—Pr2—Pr1^vi	113.11 (9)
O4—Pr1—O6^iv	69.35 (11)	O8^vii—Pr2—Pr1^vi	125.58 (9)
O3ⁱ—Pr1—O6^iv	72.69 (11)	O4^vi—Pr2—Pr1^vi	33.96 (8)
O1ⁱ—Pr1—O6^iv	129.69 (11)	O3—Pr2—Pr1^vi	139.70 (8)
O5ⁱⁱ—Pr1—O6^iv	147.48 (12)	O1—Pr2—Pr1^vi	90.73 (8)
O7—Pr1—O6^iv	115.17 (12)	O3^viii—Pr2—Pr1^vi	79.17 (7)
O2—Pr1—O6^iv	83.51 (11)	O1^ix—Pr2—Pr1^vi	36.78 (7)
O2ⁱⁱⁱ—Pr1—O6^iv	77.21 (11)	O6^x—Pr2—Pr1^vi	63.84 (8)
O4—Pr1—Pr2^vi	35.36 (8)	B2^viii—Pr2—Pr1^vi	57.28 (10)
O3ⁱ—Pr1—Pr2^vi	89.53 (8)	Pr2^vii—Pr2—Pr1^vi	126.063 (11)
O1ⁱ—Pr1—Pr2^vi	39.18 (8)	O8—Pr2—Pr1^iv	82.46 (9)
O5ⁱⁱ—Pr1—Pr2^vi	81.40 (9)	O8^vii—Pr2—Pr1^iv	115.15 (9)
O7—Pr1—Pr2^vi	129.95 (9)	O4^vi—Pr2—Pr1^iv	115.41 (8)
O2—Pr1—Pr2^vi	149.14 (8)	O3—Pr2—Pr1^iv	35.45 (7)
O2ⁱⁱⁱ—Pr1—Pr2^vi	82.37 (8)	O1—Pr2—Pr1^iv	35.98 (7)
O6^iv—Pr1—Pr2^vi	104.66 (8)	O3^viii—Pr2—Pr1^iv	88.62 (7)
Mo^v—Pr1—Pr2^vi	173.822 (12)	O1^ix—Pr2—Pr1^iv	89.26 (7)
O4—Pr1—Pr2ⁱ	68.51 (8)	O6^x—Pr2—Pr1^iv	157.63 (7)
O3ⁱ—Pr1—Pr2ⁱ	36.74 (8)	B2^viii—Pr2—Pr1^iv	87.02 (10)
O1ⁱ—Pr1—Pr2ⁱ	37.06 (8)	Pr2^vii—Pr2—Pr1^iv	100.262 (11)
O5ⁱⁱ—Pr1—Pr2ⁱ	108.19 (8)	Pr1^vi—Pr2—Pr1^iv	118.956 (9)
O7—Pr1—Pr2ⁱ	81.16 (8)	O5—Mo—O7	107.10 (17)
O2—Pr1—Pr2ⁱ	147.30 (8)	O5—Mo—O6	107.70 (16)
O2ⁱⁱⁱ—Pr1—Pr2ⁱ	142.36 (8)	O7—Mo—O6	111.77 (17)
O6^iv—Pr1—Pr2ⁱ	102.41 (8)	O5—Mo—O2^v	105.62 (17)
Mo^v—Pr1—Pr2ⁱ	124.637 (12)	O7—Mo—O2^v	118.20 (16)
Pr2^vi—Pr1—Pr2ⁱ	61.044 (9)	O6—Mo—O2^v	105.89 (16)
O4—Pr1—Pr2^vii	53.61 (8)	Pr1ⁱ—O6—Pr2^x	99.70 (12)
O3ⁱ—Pr1—Pr2^vii	38.13 (7)	Mo^v—O2—Pr1	114.85 (15)
O1ⁱ—Pr1—Pr2^vii	91.90 (8)	Mo^v—O2—Pr1ⁱⁱⁱ	122.00 (16)
O5ⁱⁱ—Pr1—Pr2^vii	164.08 (9)	Pr1—O2—Pr1ⁱⁱⁱ	109.68 (12)
O7—Pr1—Pr2^vii	108.49 (8)	O8—B1—O4	122.1 (4)
O2—Pr1—Pr2^vii	118.48 (8)	O8—B1—O9	121.5 (4)
O2ⁱⁱⁱ—Pr1—Pr2^vii	107.57 (8)	O4—B1—O9	116.2 (4)
O6^iv—Pr1—Pr2^vii	40.47 (8)	B1—O4—Pr1	129.0 (3)
Mo^v—Pr1—Pr2^vii	97.798 (12)	B1—O4—Pr2^vi	113.9 (3)
Pr2^vi—Pr1—Pr2^vii	82.769 (10)	Pr1—O4—Pr2^vi	110.68 (12)
Pr2ⁱ—Pr1—Pr2^vii	62.010 (9)	B1—O8—Pr2	134.1 (3)
O8—Pr2—O8^vii	68.24 (13)	B1—O8—Pr2^vii	113.4 (3)
O8—Pr2—O4^vi	79.16 (11)	Pr2—O8—Pr2^vii	111.76 (13)
O8^vii—Pr2—O4^vi	113.81 (11)	B2^xii—O9—B1	125.1 (4)
O8—Pr2—O3	95.79 (11)	O9^xi—B2—O1^xi	123.8 (4)
O8^vii—Pr2—O3	90.33 (12)	O9^xi—B2—O3	119.3 (4)
O4^vi—Pr2—O3	150.59 (11)	O1^xi—B2—O3	116.8 (4)
O8—Pr2—O1	72.10 (11)	Pr1^iv—O1—Pr2	106.97 (12)
O8^vii—Pr2—O1	134.09 (11)	B2^xii—O1—Pr2^ix	94.4 (3)
O4^vi—Pr2—O1	79.52 (11)	Pr1^iv—O1—Pr2^ix	104.05 (12)
O3—Pr2—O1	71.43 (11)	Pr2—O1—Pr2^ix	104.90 (12)
O8—Pr2—O3^viii	167.27 (12)	B2—O3—Pr1^iv	123.2 (3)
O8^vii—Pr2—O3^viii	108.01 (11)	B2—O3—Pr2	114.9 (3)
O4^vi—Pr2—O3^viii	113.02 (11)	Pr1^iv—O3—Pr2	107.81 (12)
O3—Pr2—O3^viii	71.81 (12)	B2—O3—Pr2^viii	94.2 (3)
O1—Pr2—O3^viii	105.54 (10)	Pr1^iv—O3—Pr2^viii	106.39 (12)
O8—Pr2—O1^ix	134.34 (11)	Pr2—O3—Pr2^viii	108.19 (12)
O8^vii—Pr2—O1^ix	150.80 (11)

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

Experimental details

Crystal data
Chemical formula	Pr₂(B₂O₅)(MoO₄)
M_r	543.38
Crystal system, space group	Triclinic, P1
Temperature (K)	291
a, b, c (Å)	5.2806 (5), 7.0278 (5), 10.5824 (9)
α, β, γ (°)	74.557 (6), 76.307 (7), 73.065 (6)
V (Å³)	356.69 (5)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	15.20
Crystal size (mm)	0.20 × 0.15 × 0.12

Data collection
Diffractometer	Enraf–Nonius CAD-4 diffractometer
Absorption correction	ψ scan (MolEN; Fair, 1990)
T_min, T_max	0.296, 0.999
No. of measured, independent and observed [I > 2σ(I)] reflections	4733, 2155, 1983
R_int	0.019
(sin θ/λ)_max (Å⁻¹)	0.712

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.031, 0.082, 1.13
No. of reflections	2155
No. of parameters	127
Δρ_max, Δρ_min (e Å⁻³)	2.55, −1.73

Computer programs: MACH3 (Enraf–Nonius, 1993), MolEN (Fair, 1990), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), ATOMS (Dowty, 2002), publCIF (Westrip, 2008).

Selected bond lengths (Å) top

Pr1—O4	2.370 (3)	Pr2—O3^vii	2.585 (3)
Pr1—O3ⁱ	2.430 (3)	Pr2—O1^viii	2.585 (3)
Pr1—O1ⁱ	2.450 (3)	Pr2—O6^ix	2.645 (4)
Pr1—O5ⁱⁱ	2.461 (3)	Mo—O5	1.748 (3)
Pr1—O7	2.480 (3)	Mo—O7	1.748 (3)
Pr1—O2	2.529 (3)	Mo—O6	1.782 (4)
Pr1—O2ⁱⁱⁱ	2.557 (3)	Mo—O2^x	1.803 (3)
Pr1—O6^iv	2.610 (3)	B1—O8	1.345 (6)
Pr2—O8	2.364 (3)	B1—O4	1.370 (6)
Pr2—O8^v	2.375 (3)	B1—O9	1.387 (6)
Pr2—O4^vi	2.456 (3)	B2—O9^xi	1.373 (6)
Pr2—O3	2.506 (3)	B2—O1^xi	1.378 (6)
Pr2—O1	2.513 (3)	B2—O3	1.384 (6)

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

Acknowledgements

This work was supported by the Deutsche Forschungsgemeinschaft (DFG) under project BE 2147/6–1.

References

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