Crystals of the title compound, calcium dipotassium diphosphate, have been synthesized from a melt and structurally characterized using single-crystal X-ray diffraction. The CaK2P2O7 structure can be described as a layer structure, with alternating [K2P2O72−]∞ and [Ca2+]∞ layers parallel to the ab plane. Ca2+ is coordinated by six O atoms in a distorted octahedron. K+ is coordinated by nine O atoms in two different polyhedra.
Supporting information
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (P-O) = 0.001 Å
- R factor = 0.025
- wR factor = 0.067
- Data-to-parameter ratio = 18.5
checkCIF/PLATON results
No syntax errors found
Alert level C
ABSTM02_ALERT_3_C The ratio of expected to reported Tmax/Tmin(RR) is > 1.10
Tmin and Tmax reported: 0.784 0.862
Tmin and Tmax expected: 0.555 0.859
RR = 1.408
Please check that your absorption correction is appropriate.
PLAT060_ALERT_3_C Ratio Tmax/Tmin (Exp-to-Rep) (too) Large ....... 1.42
0 ALERT level A = In general: serious problem
0 ALERT level B = Potentially serious problem
2 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
0 ALERT type 4 Improvement, methodology, query or suggestion
Data collection: COLLECT (Nonius, 1999); cell refinement: HKL SCALEPACK (Otwinowski & Minor, 1997); data reduction: DENZO (Otwinowski & Minor, 1997) and SCALEPACK; program(s) used to solve structure: SIR97 (Altomare et al., 1999); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ATOMS (Dowty, 2000); software used to prepare material for publication: SHELXL97 and local procedures.
Calcium dipotassium diphosphate
top
Crystal data top
CaK2(P2O7) | F(000) = 576 |
Mr = 292.23 | Dx = 2.763 Mg m−3 |
Monoclinic, P21/n | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yn | Cell parameters from 4000 reflections |
a = 9.8180 (3) Å | θ = 3.0–30.0° |
b = 5.6760 (3) Å | µ = 2.53 mm−1 |
c = 13.0060 (7) Å | T = 293 K |
β = 104.220 (3)° | Fragment, colourless |
V = 702.58 (6) Å3 | 0.24 × 0.22 × 0.06 mm |
Z = 4 | |
Data collection top
Nonius KappaCCD diffractometer | 2038 independent reflections |
Radiation source: fine-focus sealed tube, KappaCCD | 1948 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.072 |
φ and ω scans | θmax = 30.0°, θmin = 3.2° |
Absorption correction: multi-scan '(SORTAV; Blessing 1995)' | h = −13→13 |
Tmin = 0.784, Tmax = 0.862 | k = −7→7 |
31100 measured reflections | l = −18→18 |
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)] = 0.025 | w = 1/[σ2(Fo2) + (0.0295P)2 + 0.5877P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.067 | (Δ/σ)max = 0.001 |
S = 1.09 | Δρmax = 0.82 e Å−3 |
2038 reflections | Δρmin = −1.05 e Å−3 |
110 parameters | Extinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.0499 (17) |
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 | |
Ca | 0.25171 (3) | 0.23853 (4) | 0.51853 (2) | 0.00852 (9) | |
K1 | 0.64355 (4) | 0.73001 (6) | 0.17826 (3) | 0.01786 (10) | |
K2 | 0.12771 (4) | 0.23766 (6) | 0.14143 (4) | 0.02614 (12) | |
P1 | 0.53029 (4) | 0.24480 (6) | 0.35836 (3) | 0.00791 (10) | |
P2 | 0.44736 (4) | 0.22007 (6) | 0.12604 (3) | 0.00866 (10) | |
O1 | 0.42978 (13) | 0.23579 (19) | 0.42959 (9) | 0.0181 (2) | |
O2 | 0.62764 (11) | 0.45501 (19) | 0.37887 (9) | 0.0171 (2) | |
O3 | 0.60418 (10) | 0.01248 (18) | 0.35197 (8) | 0.0125 (2) | |
O4 | 0.42554 (11) | 0.2964 (2) | 0.24223 (8) | 0.0145 (2) | |
O5 | 0.39011 (12) | −0.02855 (19) | 0.10984 (9) | 0.0186 (2) | |
O6 | 0.60300 (11) | 0.23677 (19) | 0.13299 (9) | 0.0155 (2) | |
O7 | 0.35742 (12) | 0.3965 (2) | 0.05331 (9) | 0.0186 (2) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Ca | 0.00860 (15) | 0.00917 (14) | 0.00784 (15) | −0.00006 (8) | 0.00212 (10) | −0.00006 (8) |
K1 | 0.01652 (19) | 0.01471 (17) | 0.0235 (2) | 0.00157 (10) | 0.00707 (15) | −0.00086 (11) |
K2 | 0.01418 (18) | 0.01741 (18) | 0.0477 (3) | 0.00060 (11) | 0.00924 (17) | 0.00472 (14) |
P1 | 0.00845 (17) | 0.00860 (17) | 0.00708 (17) | 0.00028 (10) | 0.00266 (13) | −0.00060 (10) |
P2 | 0.00877 (17) | 0.00927 (17) | 0.00759 (17) | 0.00049 (11) | 0.00132 (12) | 0.00003 (11) |
O1 | 0.0200 (6) | 0.0218 (6) | 0.0166 (5) | 0.0027 (4) | 0.0127 (4) | 0.0020 (4) |
O2 | 0.0152 (5) | 0.0124 (5) | 0.0229 (5) | −0.0033 (4) | 0.0029 (4) | −0.0056 (4) |
O3 | 0.0135 (4) | 0.0104 (4) | 0.0134 (4) | 0.0025 (4) | 0.0032 (4) | 0.0008 (4) |
O4 | 0.0122 (5) | 0.0221 (5) | 0.0089 (4) | 0.0062 (4) | 0.0016 (4) | −0.0017 (4) |
O5 | 0.0187 (5) | 0.0124 (5) | 0.0214 (5) | −0.0028 (4) | −0.0014 (4) | −0.0036 (4) |
O6 | 0.0115 (5) | 0.0203 (5) | 0.0163 (5) | 0.0005 (4) | 0.0066 (4) | 0.0017 (4) |
O7 | 0.0208 (5) | 0.0186 (5) | 0.0147 (5) | 0.0065 (4) | 0.0008 (4) | 0.0057 (4) |
Geometric parameters (Å, º) top
Ca—O7i | 2.3018 (11) | K2—O7 | 2.9124 (12) |
Ca—O5ii | 2.3090 (11) | K2—O4 | 2.9149 (11) |
Ca—O1 | 2.3214 (12) | K2—O2i | 2.9332 (11) |
Ca—O2iii | 2.3309 (11) | K2—O1xi | 2.9597 (13) |
Ca—O6iv | 2.3312 (11) | K2—O1ii | 2.9849 (12) |
Ca—O3v | 2.3869 (10) | K2—O1i | 3.0050 (12) |
Ca—K2vi | 3.6473 (5) | K2—O4i | 3.0372 (11) |
Ca—K1iv | 3.6878 (5) | K2—O5 | 3.0999 (12) |
Ca—K1iii | 3.8274 (5) | K2—P2 | 3.1949 (5) |
Ca—K2ii | 3.8686 (5) | K2—P1i | 3.1992 (5) |
Ca—K2i | 3.8758 (5) | K2—P1ii | 3.2702 (5) |
Ca—K1vii | 3.9531 (5) | P1—O2 | 1.5109 (11) |
K1—O5viii | 2.7881 (12) | P1—O1 | 1.5112 (12) |
K1—O2ix | 2.8373 (11) | P1—O3 | 1.5171 (10) |
K1—O6 | 2.8684 (11) | P1—O4 | 1.6314 (11) |
K1—O3viii | 2.8729 (11) | P1—K2ii | 3.1992 (5) |
K1—O3ix | 2.8796 (11) | P1—K2i | 3.2702 (5) |
K1—O6viii | 2.9434 (11) | P1—K1xii | 3.3523 (5) |
K1—O6ix | 3.0363 (12) | P1—K2vi | 3.5706 (6) |
K1—O2 | 3.0772 (12) | P2—O7 | 1.5056 (11) |
K1—O7x | 3.0939 (12) | P2—O6 | 1.5115 (11) |
K1—P1ix | 3.3522 (5) | P2—O5 | 1.5145 (11) |
K1—P2viii | 3.3565 (5) | P2—O4 | 1.6359 (11) |
K1—P2 | 3.4505 (5) | P2—K1xiii | 3.3565 (5) |
K2—O3ii | 2.7785 (11) | P2—K1x | 3.8477 (5) |
| | | |
O7i—Ca—O5ii | 92.95 (4) | O3ii—K2—O5 | 172.63 (4) |
O7i—Ca—O1 | 97.15 (4) | O7—K2—O5 | 49.43 (3) |
O5ii—Ca—O1 | 92.16 (4) | O4—K2—O5 | 48.76 (3) |
O7i—Ca—O2iii | 169.19 (4) | O2i—K2—O5 | 116.18 (3) |
O5ii—Ca—O2iii | 96.78 (4) | O1xi—K2—O5 | 106.17 (3) |
O1—Ca—O2iii | 87.20 (4) | O1ii—K2—O5 | 121.39 (3) |
O7i—Ca—O6iv | 90.45 (4) | O1i—K2—O5 | 66.21 (3) |
O5ii—Ca—O6iv | 93.80 (4) | O4i—K2—O5 | 85.09 (3) |
O1—Ca—O6iv | 170.08 (4) | O2—P1—O1 | 113.48 (6) |
O2iii—Ca—O6iv | 84.23 (4) | O2—P1—O3 | 113.94 (6) |
O7i—Ca—O3v | 85.36 (4) | O1—P1—O3 | 113.40 (6) |
O5ii—Ca—O3v | 178.27 (4) | O2—P1—O4 | 104.44 (6) |
O1—Ca—O3v | 87.66 (4) | O1—P1—O4 | 102.44 (6) |
O2iii—Ca—O3v | 84.93 (4) | O3—P1—O4 | 107.85 (6) |
O6iv—Ca—O3v | 86.62 (4) | O7—P2—O6 | 115.10 (6) |
O5viii—K1—O2ix | 113.40 (3) | O7—P2—O5 | 113.08 (6) |
O5viii—K1—O6 | 110.26 (3) | O6—P2—O5 | 113.70 (6) |
O2ix—K1—O6 | 117.67 (3) | O7—P2—O4 | 102.39 (6) |
O5viii—K1—O3viii | 72.23 (3) | O6—P2—O4 | 106.74 (6) |
O2ix—K1—O3viii | 102.88 (3) | O5—P2—O4 | 104.29 (6) |
O6—K1—O3viii | 131.87 (3) | P1—O1—Ca | 172.06 (8) |
O5viii—K1—O3ix | 153.80 (3) | P1—O1—K2vi | 100.99 (6) |
O2ix—K1—O3ix | 52.72 (3) | Ca—O1—K2vi | 86.47 (4) |
O6—K1—O3ix | 68.54 (3) | P1—O1—K2i | 86.83 (5) |
O3viii—K1—O3ix | 129.28 (2) | Ca—O1—K2i | 92.99 (4) |
O5viii—K1—O6viii | 52.38 (3) | K2vi—O1—K2i | 111.55 (4) |
O2ix—K1—O6viii | 65.46 (3) | P1—O1—K2ii | 83.17 (5) |
O6—K1—O6viii | 155.18 (5) | Ca—O1—K2ii | 92.25 (4) |
O3viii—K1—O6viii | 64.80 (3) | K2vi—O1—K2ii | 105.58 (4) |
O3ix—K1—O6viii | 118.05 (3) | K2i—O1—K2ii | 142.74 (5) |
O5viii—K1—O6ix | 137.88 (3) | P1—O2—Caiii | 154.27 (7) |
O2ix—K1—O6ix | 70.23 (3) | P1—O2—K1xii | 96.06 (5) |
O6—K1—O6ix | 102.89 (3) | Caiii—O2—K1xii | 99.33 (4) |
O3viii—K1—O6ix | 66.36 (3) | P1—O2—K2ii | 85.78 (5) |
O3ix—K1—O6ix | 63.53 (3) | Caiii—O2—K2ii | 86.92 (3) |
O6viii—K1—O6ix | 101.13 (3) | K1xii—O2—K2ii | 159.53 (5) |
O5viii—K1—O2 | 107.02 (3) | P1—O2—K1 | 114.36 (6) |
O2ix—K1—O2 | 131.21 (2) | Caiii—O2—K1 | 88.99 (4) |
O6—K1—O2 | 69.24 (3) | K1xii—O2—K1 | 78.34 (3) |
O3viii—K1—O2 | 64.63 (3) | K2ii—O2—K1 | 82.33 (3) |
O3ix—K1—O2 | 97.05 (3) | P1—O3—Cav | 133.53 (6) |
O6viii—K1—O2 | 129.26 (3) | P1—O3—K2i | 94.58 (5) |
O6ix—K1—O2 | 61.51 (3) | Cav—O3—K2i | 89.50 (3) |
O5viii—K1—O7x | 90.82 (3) | P1—O3—K1xiii | 133.36 (6) |
O2ix—K1—O7x | 70.29 (3) | Cav—O3—K1xiii | 92.92 (3) |
O6—K1—O7x | 66.83 (3) | K2i—O3—K1xiii | 88.88 (3) |
O3viii—K1—O7x | 157.85 (3) | P1—O3—K1xii | 94.23 (5) |
O3ix—K1—O7x | 64.19 (3) | Cav—O3—K1xii | 88.37 (3) |
O6viii—K1—O7x | 93.68 (3) | K2i—O3—K1xii | 169.65 (4) |
O6ix—K1—O7x | 126.58 (3) | K1xiii—O3—K1xii | 81.11 (3) |
O2—K1—O7x | 135.98 (3) | P1—O4—P2 | 127.72 (7) |
O3ii—K2—O7 | 123.92 (3) | P1—O4—K2 | 136.93 (6) |
O3ii—K2—O4 | 131.38 (3) | P2—O4—K2 | 84.19 (4) |
O7—K2—O4 | 49.71 (3) | P1—O4—K2ii | 80.40 (4) |
O3ii—K2—O2i | 67.74 (3) | P2—O4—K2ii | 139.13 (6) |
O7—K2—O2i | 149.45 (4) | K2—O4—K2ii | 92.40 (3) |
O4—K2—O2i | 147.54 (3) | P2—O5—Cai | 140.48 (7) |
O3ii—K2—O1xi | 69.18 (3) | P2—O5—K1xiii | 98.16 (5) |
O7—K2—O1xi | 90.73 (3) | Cai—O5—K1xiii | 106.36 (4) |
O4—K2—O1xi | 140.32 (3) | P2—O5—K2 | 79.60 (5) |
O2i—K2—O1xi | 65.97 (3) | Cai—O5—K2 | 90.10 (4) |
O3ii—K2—O1ii | 51.95 (3) | K1xiii—O5—K2 | 154.54 (5) |
O7—K2—O1ii | 72.00 (3) | P2—O6—Caxiv | 138.43 (7) |
O4—K2—O1ii | 97.09 (3) | P2—O6—K1 | 99.25 (5) |
O2i—K2—O1ii | 113.44 (3) | Caxiv—O6—K1 | 89.73 (4) |
O1xi—K2—O1ii | 68.45 (4) | P2—O6—K1xiii | 92.05 (5) |
O3ii—K2—O1i | 116.63 (3) | Caxiv—O6—K1xiii | 96.40 (4) |
O7—K2—O1i | 106.12 (3) | K1—O6—K1xiii | 155.18 (5) |
O4—K2—O1i | 109.79 (3) | P2—O6—K1xii | 131.55 (6) |
O2i—K2—O1i | 50.35 (3) | Caxiv—O6—K1xii | 89.98 (3) |
O1xi—K2—O1i | 74.42 (4) | K1—O6—K1xii | 78.55 (3) |
O1ii—K2—O1i | 142.74 (5) | K1xiii—O6—K1xii | 77.42 (3) |
O3ii—K2—O4i | 101.83 (3) | P2—O7—Caii | 163.47 (7) |
O7—K2—O4i | 134.10 (3) | P2—O7—K2 | 86.46 (5) |
O4—K2—O4i | 98.43 (3) | Caii—O7—K2 | 95.31 (4) |
O2i—K2—O4i | 49.15 (3) | P2—O7—K1x | 108.56 (6) |
O1xi—K2—O4i | 110.59 (3) | Caii—O7—K1x | 84.88 (3) |
O1ii—K2—O4i | 153.21 (3) | K2—O7—K1x | 119.59 (4) |
O1i—K2—O4i | 47.86 (3) | | |
Symmetry codes: (i) −x+1/2, y−1/2, −z+1/2; (ii) −x+1/2, y+1/2, −z+1/2; (iii) −x+1, −y+1, −z+1; (iv) x−1/2, −y+1/2, z+1/2; (v) −x+1, −y, −z+1; (vi) x+1/2, −y+1/2, z+1/2; (vii) x−1/2, −y+3/2, z+1/2; (viii) x, y+1, z; (ix) −x+3/2, y+1/2, −z+1/2; (x) −x+1, −y+1, −z; (xi) x−1/2, −y+1/2, z−1/2; (xii) −x+3/2, y−1/2, −z+1/2; (xiii) x, y−1, z; (xiv) x+1/2, −y+1/2, z−1/2. |