Reinvestigation of cadmium diphosphate

Bouchelaghem, W.; Benloucif, M.R.; Mayoufi, M.; Benmoussa, A.; Schenk, K.J.

doi:10.1107/S1600536806008397

Reinvestigation of cadmium diphosphate

W. Bouchelaghem, M. R. Benloucif, M. Mayoufi, A. Benmoussa and K. J. Schenk

The crystal structure of the title compound, Cd₂P₂O₇, has been reinvestigated by means of an image-plate diffraction system. The study confirms the previously determined structure [Calvo & Au (1969). Can. J. Chem. 47, 3409–3417], but provides a less biased model and higher precision. The structure consists of alternating layers of isolated P₂O₇ groups and edge-sharing CdO₆ octahedra forming corrugated chains along [1 $\overline{1}$ 0]. The layers and the parallel chains interconnect by means of corner-sharing. This room-temperature structure is actually the average of a modulated structure, which might partly rectify the unusual bond valences.

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Supporting information

	Crystallographic Information File (CIF) https://doi.org/10.1107/S1600536806008397/wm6128sup1.cif Contains datablocks global, I
	Structure factor file (CIF format) https://doi.org/10.1107/S1600536806008397/wm6128Isup2.hkl Contains datablock I

checkCIF report

Key indicators

Single-crystal X-ray study
T = 292 K
Mean (P-O) = 0.003 Å
R factor = 0.022
wR factor = 0.055
Data-to-parameter ratio = 11.8

checkCIF/PLATON results

No syntax errors found



Alert level A
REFLT03_ALERT_3_A  Reflection count < 85% complete (theta max?)
           From the CIF: _diffrn_reflns_theta_max           29.07
           From the CIF: _diffrn_reflns_theta_full          29.07
           From the CIF: _reflns_number_total               1189
           TEST2: Reflns within _diffrn_reflns_theta_max
           Count of symmetry unique reflns         1425
           Completeness (_total/calc)             83.44%

Author Response: We planned two runs, one at phi=0 deg and one at pohi=90 deg. Unfortunately, the crystal mysteriously disappeared after the first run.

PLAT029_ALERT_3_A _diffrn_measured_fraction_theta_full Low .......       0.83

Author Response: same answer as above!


Alert level C
PLAT155_ALERT_4_C The Triclinic Unitcell is NOT Reduced ..........          ?

   2 ALERT level A = In general: serious problem
   0 ALERT level B = Potentially serious problem
   1 ALERT level C = Check and explain
   0 ALERT level G = General alerts; check

   0 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   2 ALERT type 3 Indicator that the structure quality may be low
   1 ALERT type 4 Improvement, methodology, query or suggestion

Computing details top

Data collection: X-AREA (Stoe & Cie, 2005); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: DIRDIF (Beurskens et al., 1996); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: SHELXTL (Sheldrick, 1996) and CrystalMaker (Palmer, 2004); software used to prepare material for publication: SHELXL97 and PLATON (Spek, 2003).

Cadmium diphosphate top

Crystal data top

Cd₂(P₂O₇)	Z = 2
M_r = 398.74	F(000) = 364
Triclinic, P1	D_x = 4.964 (2) Mg m⁻³ D_m = 4.90 Mg m⁻³ D_m measured by Calvo & Au (1969)
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.6075 (13) Å	Cell parameters from 4542 reflections
b = 6.6371 (13) Å	θ = 3.1–29.4°
c = 6.7887 (14) Å	µ = 8.57 mm⁻¹
α = 95.82 (3)°	T = 292 K
β = 115.13 (3)°	Platelet, colourless
γ = 82.24 (3)°	0.50 × 0.40 × 0.15 mm
V = 266.75 (11) Å³

Data collection top

Stoe IPDS-2 diffractometer	1189 independent reflections
Radiation source: sealed X-ray tube, 12 x 0.4 mm long-fine focus	1162 reflections with I > 2σ(I)
Plane graphite monochromator	R_int = 0.052
Detector resolution: 6.67 pixels mm^-1	θ_max = 29.1°, θ_min = 3.1°
ω scans	h = −8→8
Absorption correction: integration (X-RED; Stoe & Cie, 2005)	k = −9→8
T_min = 0.162, T_max = 0.314	l = −9→9
2251 measured reflections

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)] = 0.022	w = 1/[σ²(F_o²) + (0.0173P)² + 0.5407P] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.055	(Δ/σ)_max = 0.001
S = 1.25	Δρ_max = 0.54 e Å⁻³
1189 reflections	Δρ_min = −0.88 e Å⁻³
101 parameters	Extinction correction: SHELXL97 (Sheldrick, 1997), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.292 (7)

Special details top

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.

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

	x	y	z	U_iso*/U_eq
Cd1	0.27522 (4)	0.36011 (4)	0.33760 (4)	0.01039 (12)
Cd2	0.11672 (4)	0.16059 (3)	0.74836 (4)	0.00682 (12)
P1	0.36229 (15)	0.86612 (13)	0.18989 (15)	0.00487 (19)
P2	0.23622 (15)	0.65878 (12)	0.75488 (14)	0.00449 (19)
O1	0.4032 (4)	0.7487 (4)	0.9858 (4)	0.0078 (5)
O2	0.0690 (5)	0.8336 (4)	0.6354 (4)	0.0099 (5)
O3	0.6004 (4)	0.8650 (4)	0.3669 (4)	0.0082 (5)
O4	0.3913 (4)	0.5669 (4)	0.6495 (4)	0.0079 (5)
O5	0.2578 (5)	0.0810 (4)	0.1129 (4)	0.0091 (5)
O6	0.1009 (5)	0.5043 (4)	0.7858 (5)	0.0112 (5)
O7	0.2109 (4)	0.7452 (4)	0.2351 (4)	0.0096 (5)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Cd1	0.00774 (18)	0.01239 (17)	0.01146 (19)	−0.00300 (11)	0.00504 (13)	−0.00500 (11)
Cd2	0.00723 (17)	0.00594 (16)	0.00851 (18)	−0.00034 (10)	0.00447 (13)	0.00074 (10)
P1	0.0038 (4)	0.0065 (4)	0.0049 (4)	−0.0010 (3)	0.0022 (3)	0.0009 (3)
P2	0.0046 (4)	0.0042 (4)	0.0053 (4)	−0.0015 (3)	0.0026 (3)	−0.0006 (3)
O1	0.0040 (12)	0.0133 (11)	0.0068 (12)	−0.0027 (9)	0.0032 (10)	−0.0026 (9)
O2	0.0108 (13)	0.0076 (11)	0.0095 (13)	0.0006 (9)	0.0030 (11)	−0.0001 (9)
O3	0.0038 (12)	0.0110 (11)	0.0081 (12)	−0.0011 (9)	0.0009 (10)	−0.0004 (9)
O4	0.0075 (12)	0.0090 (11)	0.0096 (12)	−0.0022 (9)	0.0056 (10)	−0.0007 (9)
O5	0.0110 (13)	0.0057 (10)	0.0090 (12)	0.0011 (9)	0.0030 (10)	0.0019 (8)
O6	0.0097 (13)	0.0085 (11)	0.0188 (14)	−0.0042 (9)	0.0086 (11)	0.0000 (9)
O7	0.0080 (13)	0.0116 (11)	0.0130 (13)	−0.0015 (9)	0.0069 (10)	0.0042 (9)

Geometric parameters (Å, º) top

Cd1—O5	2.260 (2)	O1—O2	2.516 (4)
Cd1—O4ⁱ	2.283 (3)	O1—O6	2.567 (4)
Cd1—O4	2.296 (3)	O1—O7	4.698 (4)
Cd1—O6ⁱⁱ	2.338 (3)	O1—O3	5.052 (4)
Cd1—O3ⁱ	2.410 (3)	O1—O5	6.831 (4)
Cd1—O7	2.648 (3)	O2—Cd2^v	2.245 (2)
Cd2—O7ⁱⁱ	2.217 (3)	O2—Cd2ⁱⁱ	2.364 (3)
Cd2—O2ⁱⁱⁱ	2.245 (2)	O2—O6	2.452 (4)
Cd2—O6	2.263 (2)	O2—O4	2.554 (4)
Cd2—O3ⁱ	2.294 (3)	O3—Cd2ⁱ	2.294 (3)
Cd2—O5^iv	2.334 (3)	O3—Cd1ⁱ	2.410 (3)
Cd2—O2ⁱⁱ	2.364 (3)	O3—O1^vi	2.448 (4)
P1—O7	1.505 (3)	O3—O5^v	2.542 (4)
P1—O3	1.521 (3)	O3—O7	2.551 (4)
P1—O5^v	1.537 (3)	O3—O5	5.764 (4)
P1—O1^vi	1.626 (3)	O4—Cd1ⁱ	2.283 (3)
P1—P2^vi	2.9503 (16)	O4—O6	2.552 (4)
P2—O4	1.516 (3)	O5—P1ⁱⁱⁱ	1.537 (3)
P2—O2	1.520 (3)	O5—Cd2^vi	2.334 (3)
P2—O6	1.532 (3)	O5—O7	4.396 (3)
P2—O1	1.597 (3)	O6—Cd1ⁱⁱ	2.338 (3)
O1—P1^iv	1.626 (3)	O7—Cd2ⁱⁱ	2.217 (3)
O1—O4	2.447 (3)	O7—O1^vi	2.514 (4)
O1—O5^vii	2.506 (3)	O7—O5^v	2.555 (4)

O5—Cd1—O4ⁱ	93.56 (10)	P1—O3—Cd1ⁱ	119.78 (15)
O5—Cd1—O4	159.61 (9)	Cd2ⁱ—O3—Cd1ⁱ	106.58 (11)
O4ⁱ—Cd1—O4	80.41 (10)	Cd2ⁱ—O3—O1^vi	79.01 (10)
O5—Cd1—O6ⁱⁱ	102.73 (10)	Cd1ⁱ—O3—O1^vi	122.29 (12)
O4ⁱ—Cd1—O6ⁱⁱ	140.14 (10)	Cd2ⁱ—O3—O5^v	110.18 (13)
O4—Cd1—O6ⁱⁱ	94.07 (10)	Cd1ⁱ—O3—O5^v	142.61 (13)
O5—Cd1—O3ⁱ	87.81 (9)	O1^vi—O3—O5^v	60.26 (11)
O4ⁱ—Cd1—O3ⁱ	101.75 (10)	Cd2ⁱ—O3—O7	137.85 (12)
O4—Cd1—O3ⁱ	74.56 (9)	Cd1ⁱ—O3—O7	87.76 (11)
O6ⁱⁱ—Cd1—O3ⁱ	114.84 (10)	O1^vi—O3—O7	60.35 (10)
O5—Cd1—O7	127.01 (9)	O5^v—O3—O7	60.23 (11)
O4ⁱ—Cd1—O7	74.14 (9)	P1—O3—O1	95.95 (12)
O4—Cd1—O7	70.28 (9)	Cd2ⁱ—O3—O1	145.15 (10)
O6ⁱⁱ—Cd1—O7	66.95 (9)	O1^vi—O3—O1	126.09 (11)
O3ⁱ—Cd1—O7	144.80 (8)	O5^v—O3—O1	103.87 (10)
O7ⁱⁱ—Cd2—O2ⁱⁱⁱ	98.88 (10)	O7—O3—O1	67.26 (9)
O7ⁱⁱ—Cd2—O6	76.13 (10)	P1—O3—O5	64.60 (10)
O2ⁱⁱⁱ—Cd2—O6	166.83 (11)	Cd2ⁱ—O3—O5	103.49 (8)
O7ⁱⁱ—Cd2—O3ⁱ	160.31 (10)	Cd1ⁱ—O3—O5	65.94 (6)
O2ⁱⁱⁱ—Cd2—O3ⁱ	88.25 (10)	O1^vi—O3—O5	57.22 (9)
O6—Cd2—O3ⁱ	92.82 (10)	O5^v—O3—O5	98.57 (10)
O7ⁱⁱ—Cd2—O5^iv	87.31 (10)	O7—O3—O5	46.06 (8)
O2ⁱⁱⁱ—Cd2—O5^iv	91.72 (9)	O1—O3—O5	78.02 (6)
O6—Cd2—O5^iv	100.13 (10)	P2—O4—Cd1ⁱ	135.22 (14)
O3ⁱ—Cd2—O5^iv	110.93 (10)	P2—O4—Cd1	123.02 (14)
O7ⁱⁱ—Cd2—O2ⁱⁱ	88.90 (10)	Cd1ⁱ—O4—Cd1	99.59 (10)
O2ⁱⁱⁱ—Cd2—O2ⁱⁱ	75.37 (11)	Cd1ⁱ—O4—O1	99.69 (11)
O6—Cd2—O2ⁱⁱ	92.21 (10)	Cd1—O4—O1	160.58 (13)
O3ⁱ—Cd2—O2ⁱⁱ	75.09 (10)	Cd1ⁱ—O4—O6	158.84 (14)
O5^iv—Cd2—O2ⁱⁱ	165.82 (9)	Cd1—O4—O6	98.86 (11)
O7—P1—O3	114.94 (16)	O1—O4—O6	61.75 (11)
O7—P1—O5^v	114.27 (16)	Cd1ⁱ—O4—O2	124.46 (11)
O3—P1—O5^v	112.48 (15)	Cd1—O4—O2	109.55 (12)
O7—P1—O1^vi	106.77 (14)	O1—O4—O2	60.35 (11)
O3—P1—O1^vi	102.09 (14)	O6—O4—O2	57.39 (11)
O5^v—P1—O1^vi	104.78 (15)	P1ⁱⁱⁱ—O5—Cd1	124.47 (16)
O7—P1—P2^vi	90.46 (11)	P1ⁱⁱⁱ—O5—Cd2^vi	122.26 (14)
O3—P1—P2^vi	125.06 (11)	Cd1—O5—Cd2^vi	112.52 (11)
O5^v—P1—P2^vi	97.26 (11)	P1ⁱⁱⁱ—O5—O7	150.57 (14)
O4—P2—O2	114.55 (16)	Cd2^vi—O5—O7	84.11 (8)
O4—P2—O6	113.72 (14)	P1ⁱⁱⁱ—O5—O3	132.13 (13)
O2—P2—O6	106.92 (16)	Cd2^vi—O5—O3	89.34 (8)
O4—P2—O1	103.60 (14)	P1ⁱⁱⁱ—O5—O1	110.41 (12)
O2—P2—O1	107.62 (14)	Cd2^vi—O5—O1	126.84 (8)
O6—P2—O1	110.26 (16)	O3—O5—O1	46.35 (4)
P2—O1—P1^iv	132.56 (17)	P2—O6—Cd2	133.13 (16)
P1^iv—O1—O4	169.57 (16)	P2—O6—Cd1ⁱⁱ	108.83 (15)
P2—O1—O5^vii	115.01 (15)	Cd2—O6—Cd1ⁱⁱ	109.01 (11)
O4—O1—O5^vii	140.17 (15)	Cd2—O6—O2	150.13 (15)
P1^iv—O1—O2	109.67 (14)	Cd1ⁱⁱ—O6—O2	72.60 (11)
O4—O1—O2	61.93 (11)	Cd2—O6—O4	100.50 (12)
O5^vii—O1—O2	81.75 (12)	Cd1ⁱⁱ—O6—O4	128.31 (14)
P1^iv—O1—O6	109.62 (14)	O2—O6—O4	61.34 (11)
O4—O1—O6	61.14 (10)	Cd2—O6—O1	132.41 (14)
O5^vii—O1—O6	113.74 (13)	Cd1ⁱⁱ—O6—O1	117.66 (12)
O2—O1—O6	57.67 (11)	O2—O6—O1	60.11 (11)
P1^iv—O1—O7	145.57 (13)	O4—O6—O1	57.11 (10)
O5^vii—O1—O7	110.26 (11)	P1—O7—Cd2ⁱⁱ	130.49 (15)
O6—O1—O7	71.23 (9)	Cd2ⁱⁱ—O7—O1^vi	141.04 (14)
P2—O1—O3	66.36 (10)	Cd2ⁱⁱ—O7—O3	140.33 (13)
P1^iv—O1—O3	142.18 (12)	O1^vi—O7—O3	57.78 (10)
O5^vii—O1—O3	109.41 (10)	Cd2ⁱⁱ—O7—O5^v	97.56 (12)
O2—O1—O3	65.74 (9)	O1^vi—O7—O5^v	59.24 (10)
O6—O1—O3	99.06 (10)	O3—O7—O5^v	59.70 (11)
P1^iv—O1—O5	159.01 (11)	P1—O7—Cd1	129.13 (15)
O5^vii—O1—O5	145.04 (12)	Cd2ⁱⁱ—O7—Cd1	100.32 (10)
O2—O1—O5	63.35 (8)	O1^vi—O7—Cd1	104.30 (11)
O6—O1—O5	49.48 (8)	O3—O7—Cd1	106.39 (12)
O3—O1—O5	55.63 (5)	O5^v—O7—Cd1	161.96 (13)
P2—O2—Cd2^v	122.45 (15)	P1—O7—O5	119.05 (13)
P2—O2—Cd2ⁱⁱ	123.45 (14)	Cd2ⁱⁱ—O7—O5	107.18 (9)
Cd2^v—O2—Cd2ⁱⁱ	104.63 (11)	O1^vi—O7—O5	85.56 (9)
Cd2^v—O2—O6	139.52 (14)	O3—O7—O5	109.24 (11)
Cd2ⁱⁱ—O2—O6	115.07 (12)	O5^v—O7—O5	144.08 (13)
Cd2^v—O2—O1	85.91 (11)	P1—O7—O1	111.11 (13)
Cd2ⁱⁱ—O2—O1	153.02 (13)	Cd2ⁱⁱ—O7—O1	77.60 (8)
O6—O2—O1	62.22 (11)	O1^vi—O7—O1	138.50 (12)
Cd2^v—O2—O4	123.18 (13)	O3—O7—O1	82.68 (10)
Cd2ⁱⁱ—O2—O4	96.54 (11)	O5^v—O7—O1	113.42 (10)
O6—O2—O4	61.27 (10)	Cd1—O7—O1	73.11 (7)
O1—O2—O4	57.72 (10)	O5—O7—O1	97.32 (8)
P1—O3—Cd2ⁱ	116.43 (15)

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

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