α-Ba(2)P(2)O(7).

Single crystals of α-Ba(2)P(2)O(7), dibarium diphosphate, were obtained by solid-state reaction. The ortho-rhom-bic structure is isotypic with α-Sr(2)P(2)O(7) and is the second polymorph obtained for this composition. The structure is built from two different BaO(9) polyhedra (both with m symmetry), with Ba-O distances in the ranges 2.7585 (10)-3.0850 (6) and 2.5794 (13)-2.9313 (4) Å. These polyhedra are further linked by sharing corners along [010] and either edges or triangular faces perpendicularly to [010] to form the three-dimensional framework. This polyhedral linkage delimits large channels parallel to [010] where the P(2)O(7) diphosphate anions are located. These groups (symmetry m) are characterized by a P-O-P angle of 131.52 (9)° and an eclipsed conformation. They are connected to the BaO(9) polyhedra through edges and corners.

Related literature

Besides crystals of the title compound, crystals of the hexa­gonal polymorph σ-Ba2P2O7 were obtained (ElBelghitti et al. 1995 ▶). For isotypic structures, see: Hagman et al. (1968 ▶); Grenier & Masse (1977 ▶); Barbier & Echard (1998 ▶). For closely related structures, see: Elmarzouki et al. (1995 ▶). For polymorphism in Ba2P2O7, see: McCauley & Hummel (1968 ▶); Mehdi et al. (1977 ▶); Bian et al. (2004 ▶); Kokhanovskii (2004 ▶). For a review of the crystal chemistry of diphosphates, see: Durif (1995 ▶). For applications of alkaline earth diphosphates, see: Pang et al. (2009 ▶); Peng et al. (2010 ▶). For an independent refinement of the α-Ba2P2O7 structure based on data from a hydro­thermally grown crystal, see: Heyward et al. (2010 ▶).

Experimental

Crystal data

Ba2P2O7

M = 448.62

Orthorhombic,

a = 9.2875 (1) Å

b = 5.6139 (1) Å

c = 13.8064 (1) Å

V = 719.85 (2) Å3

Z = 4

Mo Kα radiation

μ = 11.31 mm−1

T = 296 K

0.26 × 0.14 × 0.14 mm

Data collection

Bruker APEXII CCD diffractometer

Absorption correction: multi-scan (SADABS; Bruker, 2008 ▶) T min = 0.155, T max = 0.205

18034 measured reflections

4304 independent reflections

3726 reflections with I > 2σ(I)

R int = 0.028

Refinement

R[F 2 > 2σ(F 2)] = 0.021

wR(F 2) = 0.046

S = 1.07

4304 reflections

62 parameters

Δρmax = 1.59 e Å−3

Δρmin = −1.99 e Å−3

Data collection: APEX2 (Bruker, 2008 ▶); cell refinement: SAINT (Bruker, 2008 ▶); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008 ▶); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008 ▶); molecular graphics: DIAMOND (Brandenburg, 1999 ▶) and ORTEP-3 for Windows (Farrugia, 1997 ▶); software used to prepare material for publication: SHELXTL (Sheldrick, 2008 ▶).

Crystal structure: contains datablocks I, global. DOI: 10.1107/S1600536810043539/wm2413sup1.cif

Structure factors: contains datablocks I. DOI: 10.1107/S1600536810043539/wm2413Isup2.hkl

Additional supplementary materials: crystallographic information; 3D view; checkCIF report

Ba2P2O7	F(000) = 792
Mr = 448.62	Dx = 4.139 Mg m−3
Orthorhombic, Pnma	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2n	Cell parameters from 7790 reflections
a = 9.2875 (1) Å	θ = 3.7–52.2°
b = 5.6139 (1) Å	µ = 11.31 mm−1
c = 13.8064 (1) Å	T = 296 K
V = 719.85 (2) Å3	Hexagonal prism, colourless
Z = 4	0.26 × 0.14 × 0.14 mm

Bruker APEXII CCD diffractometer	4304 independent reflections
Radiation source: fine-focus sealed tube	3726 reflections with I > 2σ(I)
graphite	Rint = 0.028
Detector resolution: 8.3333 pixels mm-1	θmax = 52.4°, θmin = 4.5°
ω and φ scans	h = −17→20
Absorption correction: multi-scan (SADABS; Bruker, 2008)	k = −12→10
Tmin = 0.155, Tmax = 0.205	l = −30→28
18034 measured reflections

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)] = 0.021	w = 1/[σ2(Fo2) + (0.0176P)2 + 0.4317P] where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.046	(Δ/σ)max = 0.004
S = 1.07	Δρmax = 1.59 e Å−3
4304 reflections	Δρmin = −1.99 e Å−3
62 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraints	Extinction coefficient: 0.0075 (2)

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.

Refinement. Refinement of F2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F2, conventional R-factors R are based on F, with F set to zero for negative F2. The threshold expression of F2 > σ(F2) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F2 are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

	x	y	z	Uiso*/Ueq
Ba1	0.159652 (9)	0.2500	0.744870 (6)	0.00801 (2)
Ba2	0.138138 (9)	0.2500	0.417071 (6)	0.00841 (2)
P1	−0.04603 (4)	−0.2500	0.81569 (3)	0.00724 (6)
P2	−0.28072 (4)	−0.2500	0.95778 (3)	0.00722 (6)
O1	−0.11642 (14)	−0.2500	0.92264 (9)	0.0129 (2)
O2	−0.09496 (10)	−0.0264 (2)	0.76295 (7)	0.01169 (13)
O3	−0.35537 (10)	−0.0271 (2)	0.91982 (6)	0.01215 (14)
O4	−0.27382 (15)	−0.2500	0.06760 (9)	0.0130 (2)
O5	0.11429 (14)	−0.2500	0.83242 (11)	0.0160 (3)

	U11	U22	U33	U12	U13	U23
Ba1	0.00795 (3)	0.00736 (4)	0.00873 (3)	0.000	−0.00047 (2)	0.000
Ba2	0.00856 (3)	0.00891 (4)	0.00776 (3)	0.000	0.00084 (2)	0.000
P1	0.00544 (11)	0.00757 (16)	0.00873 (13)	0.000	0.00010 (9)	0.000
P2	0.00839 (12)	0.00706 (16)	0.00622 (12)	0.000	0.00066 (9)	0.000
O1	0.0088 (4)	0.0198 (7)	0.0100 (4)	0.000	0.0012 (3)	0.000
O2	0.0126 (3)	0.0091 (4)	0.0133 (3)	0.0008 (3)	0.0005 (2)	0.0022 (3)
O3	0.0145 (3)	0.0101 (4)	0.0119 (3)	0.0029 (3)	0.0000 (2)	0.0022 (3)
O4	0.0161 (5)	0.0160 (6)	0.0069 (4)	0.000	0.0003 (3)	0.000
O5	0.0061 (3)	0.0243 (8)	0.0176 (5)	0.000	−0.0008 (3)	0.000

Ba1—O3i	2.7585 (10)	P1—O2xiii	1.5208 (11)
Ba1—O3ii	2.7585 (10)	P1—O2	1.5208 (11)
Ba1—O2ii	2.7591 (10)	P1—O1	1.6148 (13)
Ba1—O2i	2.7591 (10)	P1—Ba2iii	3.3255 (4)
Ba1—O4iii	2.7978 (13)	P2—O4xiv	1.5175 (13)
Ba1—O2	2.8392 (10)	P2—O3xiii	1.5236 (11)
Ba1—O2iv	2.8392 (10)	P2—O3	1.5236 (11)
Ba1—O5v	3.0850 (6)	P2—O1	1.6012 (14)
Ba1—O5	3.0850 (6)	P2—Ba2xv	3.3668 (4)
Ba2—O5vi	2.5794 (13)	P2—Ba2xvi	3.3812 (2)
Ba2—O3ii	2.7377 (10)	P2—Ba2xvii	3.3812 (2)
Ba2—O3i	2.7377 (10)	O2—Ba1xvi	2.7591 (10)
Ba2—O2iii	2.8133 (10)	O2—Ba2iii	2.8133 (10)
Ba2—O2vii	2.8133 (10)	O3—Ba2xvi	2.7377 (10)
Ba2—O3viii	2.9094 (10)	O3—Ba1xvi	2.7585 (10)
Ba2—O3ix	2.9094 (10)	O3—Ba2xv	2.9094 (10)
Ba2—O4x	2.9313 (4)	O4—P2xviii	1.5175 (13)
Ba2—O4xi	2.9313 (4)	O4—Ba1iii	2.7978 (13)
Ba2—P1iii	3.3255 (4)	O4—Ba2xix	2.9313 (4)
Ba2—P2viii	3.3668 (4)	O4—Ba2xx	2.9313 (4)
Ba2—P2xii	3.3812 (2)	O5—Ba2xxi	2.5794 (13)
P1—O5	1.5067 (13)	O5—Ba1xxii	3.0850 (6)
O3i—Ba1—O3ii	68.66 (5)	O3ii—Ba2—O3ix	76.39 (3)
O3i—Ba1—O2ii	109.06 (3)	O3i—Ba2—O3ix	104.688 (19)
O3ii—Ba1—O2ii	72.09 (3)	O2iii—Ba2—O3ix	94.29 (3)
O3i—Ba1—O2i	72.09 (3)	O2vii—Ba2—O3ix	71.99 (3)
O3ii—Ba1—O2i	109.06 (3)	O3viii—Ba2—O3ix	50.95 (4)
O2ii—Ba1—O2i	68.43 (4)	O5vi—Ba2—O4x	77.53 (3)
O3i—Ba1—O4iii	141.44 (2)	O3ii—Ba2—O4x	52.44 (3)
O3ii—Ba1—O4iii	141.44 (3)	O3i—Ba2—O4x	118.59 (3)
O2ii—Ba1—O4iii	73.93 (3)	O2iii—Ba2—O4x	122.07 (3)
O2i—Ba1—O4iii	73.93 (3)	O2vii—Ba2—O4x	71.11 (3)
O3i—Ba1—O2	73.87 (3)	O3viii—Ba2—O4x	131.51 (3)
O3ii—Ba1—O2	109.79 (3)	O3ix—Ba2—O4x	80.73 (3)
O2ii—Ba1—O2	177.035 (6)	O5vi—Ba2—O4xi	77.53 (3)
O2i—Ba1—O2	112.59 (4)	O3ii—Ba2—O4xi	118.59 (3)
O4iii—Ba1—O2	103.55 (3)	O3i—Ba2—O4xi	52.44 (3)
O3i—Ba1—O2iv	109.79 (3)	O2iii—Ba2—O4xi	71.11 (3)
O3ii—Ba1—O2iv	73.87 (3)	O2vii—Ba2—O4xi	122.07 (3)
O2ii—Ba1—O2iv	112.59 (4)	O3viii—Ba2—O4xi	80.73 (3)
O2i—Ba1—O2iv	177.035 (6)	O3ix—Ba2—O4xi	131.51 (3)
O4iii—Ba1—O2iv	103.55 (3)	O4x—Ba2—O4xi	146.51 (5)
O2—Ba1—O2iv	66.25 (4)	O5—P1—O2xiii	111.63 (5)
O3i—Ba1—O5v	146.01 (3)	O5—P1—O2	111.63 (5)
O3ii—Ba1—O5v	78.63 (3)	O2xiii—P1—O2	111.29 (8)
O2ii—Ba1—O5v	67.45 (3)	O5—P1—O1	105.06 (8)
O2i—Ba1—O5v	129.77 (3)	O2xiii—P1—O1	108.47 (5)
O4iii—Ba1—O5v	71.89 (3)	O2—P1—O1	108.47 (5)
O2—Ba1—O5v	110.43 (3)	P2—O1—P1	131.52 (9)
O2iv—Ba1—O5v	49.81 (3)	P1—O2—Ba1xvi	136.86 (5)
O3i—Ba1—O5	78.63 (3)	P1—O2—Ba2iii	95.57 (5)
O3ii—Ba1—O5	146.01 (3)	Ba1xvi—O2—Ba2iii	95.66 (3)
O2ii—Ba1—O5	129.77 (3)	P1—O2—Ba1	104.14 (5)
O2i—Ba1—O5	67.45 (3)	Ba1xvi—O2—Ba1	112.16 (4)
O4iii—Ba1—O5	71.89 (3)	Ba2iii—O2—Ba1	106.55 (3)
O2—Ba1—O5	49.81 (3)	P2—O3—Ba2xvi	101.17 (4)
O2iv—Ba1—O5	110.43 (3)	P2—O3—Ba1xvi	136.36 (5)
O5v—Ba1—O5	130.97 (5)	Ba2xvi—O3—Ba1xvi	111.02 (4)
O5vi—Ba2—O3ii	110.68 (3)	P2—O3—Ba2xv	93.55 (5)
O5vi—Ba2—O3i	110.68 (3)	Ba2xvi—O3—Ba2xv	103.61 (3)
O3ii—Ba2—O3i	69.25 (4)	Ba1xvi—O3—Ba2xv	106.11 (3)
O5vi—Ba2—O2iii	74.14 (3)	P2xviii—O4—Ba1iii	160.15 (8)
O3ii—Ba2—O2iii	169.56 (3)	P2xviii—O4—Ba2xix	93.46 (3)
O3i—Ba2—O2iii	118.44 (3)	Ba1iii—O4—Ba2xix	92.23 (3)
O5vi—Ba2—O2vii	74.14 (3)	P2xviii—O4—Ba2xx	93.46 (3)
O3ii—Ba2—O2vii	118.44 (3)	Ba1iii—O4—Ba2xx	92.23 (3)
O3i—Ba2—O2vii	169.56 (3)	Ba2xix—O4—Ba2xx	146.51 (5)
O2iii—Ba2—O2vii	53.01 (4)	P1—O5—Ba2xxi	161.87 (9)
O5vi—Ba2—O3viii	144.15 (3)	P1—O5—Ba1xxii	94.30 (3)
O3ii—Ba2—O3viii	104.688 (19)	Ba2xxi—O5—Ba1xxii	93.20 (3)
O3i—Ba2—O3viii	76.39 (3)	P1—O5—Ba1	94.30 (3)
O2iii—Ba2—O3viii	71.99 (3)	Ba2xxi—O5—Ba1	93.20 (3)
O2vii—Ba2—O3viii	94.29 (3)	Ba1xxii—O5—Ba1	130.97 (5)
O5vi—Ba2—O3ix	144.15 (3)

Table 1

Selected bond lengths (Å)

Ba1—O3i	2.7585 (10)
Ba1—O2ii	2.7591 (10)
Ba1—O4iii	2.7978 (13)
Ba1—O2	2.8392 (10)
Ba1—O5	3.0850 (6)
Ba2—O5iv	2.5794 (13)
Ba2—O3ii	2.7377 (10)
Ba2—O2iii	2.8133 (10)
Ba2—O3v	2.9094 (10)
Ba2—O4vi	2.9313 (4)
P1—O5	1.5067 (13)
P1—O2vii	1.5208 (11)
P1—O2	1.5208 (11)
P1—O1	1.6148 (13)
P2—O4viii	1.5175 (13)
P2—O3vii	1.5236 (11)
P2—O3	1.5236 (11)
P2—O1	1.6012 (14)

Symmetry codes: (i) ; (ii) ; (iii) ; (iv) ; (v) ; (vi) ; (vii) ; (viii) .