The crystal structure of the title compound, Cd
2P
2O
7, 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 P
2O
7 groups and edge-sharing CdO
6 octahedra forming corrugated chains along [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.
Supporting information
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
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).
Crystal data top
Cd2(P2O7) | Z = 2 |
Mr = 398.74 | F(000) = 364 |
Triclinic, P1 | Dx = 4.964 (2) Mg m−3 Dm = 4.90 Mg m−3 Dm 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 | Rint = 0.052 |
Detector resolution: 6.67 pixels mm-1 | θmax = 29.1°, θmin = 3.1° |
ω scans | h = −8→8 |
Absorption correction: integration (X-RED; Stoe & Cie, 2005) | k = −9→8 |
Tmin = 0.162, Tmax = 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(Fo2) + (0.0173P)2 + 0.5407P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.055 | (Δ/σ)max = 0.001 |
S = 1.25 | Δρmax = 0.54 e Å−3 |
1189 reflections | Δρmin = −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 | Uiso*/Ueq | |
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—Cd2v | 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—O5iv | 2.334 (3) | O3—Cd1i | 2.410 (3) |
Cd2—O2ii | 2.364 (3) | O3—O1vi | 2.448 (4) |
P1—O7 | 1.505 (3) | O3—O5v | 2.542 (4) |
P1—O3 | 1.521 (3) | O3—O7 | 2.551 (4) |
P1—O5v | 1.537 (3) | O3—O5 | 5.764 (4) |
P1—O1vi | 1.626 (3) | O4—Cd1i | 2.283 (3) |
P1—P2vi | 2.9503 (16) | O4—O6 | 2.552 (4) |
P2—O4 | 1.516 (3) | O5—P1iii | 1.537 (3) |
P2—O2 | 1.520 (3) | O5—Cd2vi | 2.334 (3) |
P2—O6 | 1.532 (3) | O5—O7 | 4.396 (3) |
P2—O1 | 1.597 (3) | O6—Cd1ii | 2.338 (3) |
O1—P1iv | 1.626 (3) | O7—Cd2ii | 2.217 (3) |
O1—O4 | 2.447 (3) | O7—O1vi | 2.514 (4) |
O1—O5vii | 2.506 (3) | O7—O5v | 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—O1vi | 79.01 (10) |
O5—Cd1—O6ii | 102.73 (10) | Cd1i—O3—O1vi | 122.29 (12) |
O4i—Cd1—O6ii | 140.14 (10) | Cd2i—O3—O5v | 110.18 (13) |
O4—Cd1—O6ii | 94.07 (10) | Cd1i—O3—O5v | 142.61 (13) |
O5—Cd1—O3i | 87.81 (9) | O1vi—O3—O5v | 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) | O1vi—O3—O7 | 60.35 (10) |
O5—Cd1—O7 | 127.01 (9) | O5v—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) | O1vi—O3—O1 | 126.09 (11) |
O3i—Cd1—O7 | 144.80 (8) | O5v—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) | O1vi—O3—O5 | 57.22 (9) |
O6—Cd2—O3i | 92.82 (10) | O5v—O3—O5 | 98.57 (10) |
O7ii—Cd2—O5iv | 87.31 (10) | O7—O3—O5 | 46.06 (8) |
O2iii—Cd2—O5iv | 91.72 (9) | O1—O3—O5 | 78.02 (6) |
O6—Cd2—O5iv | 100.13 (10) | P2—O4—Cd1i | 135.22 (14) |
O3i—Cd2—O5iv | 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) |
O5iv—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—O5v | 114.27 (16) | Cd1i—O4—O2 | 124.46 (11) |
O3—P1—O5v | 112.48 (15) | Cd1—O4—O2 | 109.55 (12) |
O7—P1—O1vi | 106.77 (14) | O1—O4—O2 | 60.35 (11) |
O3—P1—O1vi | 102.09 (14) | O6—O4—O2 | 57.39 (11) |
O5v—P1—O1vi | 104.78 (15) | P1iii—O5—Cd1 | 124.47 (16) |
O7—P1—P2vi | 90.46 (11) | P1iii—O5—Cd2vi | 122.26 (14) |
O3—P1—P2vi | 125.06 (11) | Cd1—O5—Cd2vi | 112.52 (11) |
O5v—P1—P2vi | 97.26 (11) | P1iii—O5—O7 | 150.57 (14) |
O4—P2—O2 | 114.55 (16) | Cd2vi—O5—O7 | 84.11 (8) |
O4—P2—O6 | 113.72 (14) | P1iii—O5—O3 | 132.13 (13) |
O2—P2—O6 | 106.92 (16) | Cd2vi—O5—O3 | 89.34 (8) |
O4—P2—O1 | 103.60 (14) | P1iii—O5—O1 | 110.41 (12) |
O2—P2—O1 | 107.62 (14) | Cd2vi—O5—O1 | 126.84 (8) |
O6—P2—O1 | 110.26 (16) | O3—O5—O1 | 46.35 (4) |
P2—O1—P1iv | 132.56 (17) | P2—O6—Cd2 | 133.13 (16) |
P1iv—O1—O4 | 169.57 (16) | P2—O6—Cd1ii | 108.83 (15) |
P2—O1—O5vii | 115.01 (15) | Cd2—O6—Cd1ii | 109.01 (11) |
O4—O1—O5vii | 140.17 (15) | Cd2—O6—O2 | 150.13 (15) |
P1iv—O1—O2 | 109.67 (14) | Cd1ii—O6—O2 | 72.60 (11) |
O4—O1—O2 | 61.93 (11) | Cd2—O6—O4 | 100.50 (12) |
O5vii—O1—O2 | 81.75 (12) | Cd1ii—O6—O4 | 128.31 (14) |
P1iv—O1—O6 | 109.62 (14) | O2—O6—O4 | 61.34 (11) |
O4—O1—O6 | 61.14 (10) | Cd2—O6—O1 | 132.41 (14) |
O5vii—O1—O6 | 113.74 (13) | Cd1ii—O6—O1 | 117.66 (12) |
O2—O1—O6 | 57.67 (11) | O2—O6—O1 | 60.11 (11) |
P1iv—O1—O7 | 145.57 (13) | O4—O6—O1 | 57.11 (10) |
O5vii—O1—O7 | 110.26 (11) | P1—O7—Cd2ii | 130.49 (15) |
O6—O1—O7 | 71.23 (9) | Cd2ii—O7—O1vi | 141.04 (14) |
P2—O1—O3 | 66.36 (10) | Cd2ii—O7—O3 | 140.33 (13) |
P1iv—O1—O3 | 142.18 (12) | O1vi—O7—O3 | 57.78 (10) |
O5vii—O1—O3 | 109.41 (10) | Cd2ii—O7—O5v | 97.56 (12) |
O2—O1—O3 | 65.74 (9) | O1vi—O7—O5v | 59.24 (10) |
O6—O1—O3 | 99.06 (10) | O3—O7—O5v | 59.70 (11) |
P1iv—O1—O5 | 159.01 (11) | P1—O7—Cd1 | 129.13 (15) |
O5vii—O1—O5 | 145.04 (12) | Cd2ii—O7—Cd1 | 100.32 (10) |
O2—O1—O5 | 63.35 (8) | O1vi—O7—Cd1 | 104.30 (11) |
O6—O1—O5 | 49.48 (8) | O3—O7—Cd1 | 106.39 (12) |
O3—O1—O5 | 55.63 (5) | O5v—O7—Cd1 | 161.96 (13) |
P2—O2—Cd2v | 122.45 (15) | P1—O7—O5 | 119.05 (13) |
P2—O2—Cd2ii | 123.45 (14) | Cd2ii—O7—O5 | 107.18 (9) |
Cd2v—O2—Cd2ii | 104.63 (11) | O1vi—O7—O5 | 85.56 (9) |
Cd2v—O2—O6 | 139.52 (14) | O3—O7—O5 | 109.24 (11) |
Cd2ii—O2—O6 | 115.07 (12) | O5v—O7—O5 | 144.08 (13) |
Cd2v—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) | O1vi—O7—O1 | 138.50 (12) |
Cd2v—O2—O4 | 123.18 (13) | O3—O7—O1 | 82.68 (10) |
Cd2ii—O2—O4 | 96.54 (11) | O5v—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. |