The title compound, KMg(HP2O7)·2H2O, is isotypic with other members of the series KM(HP2O7)·2H2O, where M = Mn, Co and Zn. The structure consists of a three-dimensional framework of [MgHP2O7]- layers parallel to (100) linked by K+ cations and hydrogen-bonding interactions. The metal ions and water O atoms lie on mirror planes, as does the bridging O atom of the eclipsed (HP2O7)3- anion. The acid H atom of the diphosphate anion is split into two half-occupied positions around a center of inversion.
Supporting information
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (g-O) = 0.002 Å
- R factor = 0.033
- wR factor = 0.089
- Data-to-parameter ratio = 17.6
checkCIF/PLATON results
No syntax errors found
Alert level B
PLAT029_ALERT_3_B _diffrn_measured_fraction_theta_full Low ....... 0.94
Alert level C
REFLT03_ALERT_3_C Reflection count < 95% complete
From the CIF: _diffrn_reflns_theta_max 31.89
From the CIF: _diffrn_reflns_theta_full 31.89
From the CIF: _reflns_number_total 1353
TEST2: Reflns within _diffrn_reflns_theta_max
Count of symmetry unique reflns 1434
Completeness (_total/calc) 94.35%
PLAT199_ALERT_1_C Check the Reported _cell_measurement_temperature 293 K
PLAT200_ALERT_1_C Check the Reported _diffrn_ambient_temperature . 293 K
0 ALERT level A = In general: serious problem
1 ALERT level B = Potentially serious problem
3 ALERT level C = Check and explain
0 ALERT level G = General alerts; check
2 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: CrysAlis CCD (Oxford Diffraction, 2004); cell refinement: CrysAlis RED (Oxford Diffraction, 2004); data reduction: CrysAlis RED; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: ORTEP-3 for Windows (Farrugia, 1997) and PLATON (Spek, 2003); software used to prepare material for publication: WinGX (Farrugia, 1999).
potassium magnesium hydrogendiphosphate dihydrate
top
Crystal data top
KMg(HP2O7)(H2O)2 | F(000) = 552 |
Mr = 274.39 | Dx = 2.329 Mg m−3 |
Orthorhombic, Pnma | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2ac 2n | Cell parameters from 3218 reflections |
a = 15.5203 (13) Å | θ = 3.1–31.8° |
b = 7.7786 (6) Å | µ = 1.19 mm−1 |
c = 6.4822 (5) Å | T = 293 K |
V = 782.57 (11) Å3 | Prism, colourless |
Z = 4 | 0.15 × 0.12 × 0.10 mm |
Data collection top
Oxford XCALIBUR-2 CCD diffractometer | 1173 reflections with I > 2σ(I) |
Graphite monochromator | Rint = 0.030 |
ω scans | θmax = 31.9°, θmin = 3.4° |
Absorption correction: numerical (CrysAlis RED; Oxford Diffraction, 2004) | h = −18→22 |
Tmin = 0.754, Tmax = 0.825 | k = −11→11 |
6826 measured reflections | l = −9→9 |
1353 independent 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)] = 0.033 | Hydrogen site location: inferred from neighbouring sites |
wR(F2) = 0.089 | H atoms treated by a mixture of independent and constrained refinement |
S = 1.05 | w = 1/[σ2(Fo2) + (0.0498P)2] where P = (Fo2 + 2Fc2)/3 |
1353 reflections | (Δ/σ)max = 0.001 |
77 parameters | Δρmax = 0.46 e Å−3 |
3 restraints | Δρmin = −0.54 e Å−3 |
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 | Occ. (<1) |
P1 | 0.86405 (2) | 0.06195 (5) | 0.36157 (6) | 0.01036 (12) | |
O4 | 0.77213 (7) | 0.06553 (14) | 0.43220 (18) | 0.0151 (2) | |
O1 | 0.88901 (10) | 0.2500 | 0.2744 (2) | 0.0143 (3) | |
O5W | 0.89127 (12) | −0.2500 | 0.8112 (3) | 0.0198 (3) | |
H5W | 0.8945 (18) | −0.344 (3) | 0.708 (3) | 0.045 (5)* | |
O6W | 0.71889 (11) | −0.2500 | 0.3220 (3) | 0.0183 (3) | |
H6W | 0.7365 (16) | −0.147 (3) | 0.391 (3) | 0.045 (5)* | |
O2 | 0.92483 (7) | 0.03029 (16) | 0.54646 (17) | 0.0168 (3) | |
H2 | 0.977 (2) | −0.016 (7) | 0.516 (10) | 0.045 (5)* | 0.50 |
O3 | 0.88318 (7) | −0.05737 (14) | 0.18544 (17) | 0.0156 (2) | |
K1 | 0.96413 (3) | 0.2500 | −0.12003 (8) | 0.02210 (15) | |
Mg1 | 0.69513 (5) | 0.2500 | 0.56069 (11) | 0.01128 (17) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
P1 | 0.0097 (2) | 0.00918 (19) | 0.01219 (19) | 0.00038 (12) | 0.00041 (12) | −0.00174 (12) |
O4 | 0.0102 (5) | 0.0129 (5) | 0.0221 (6) | −0.0003 (4) | 0.0041 (4) | −0.0029 (4) |
O1 | 0.0175 (7) | 0.0105 (7) | 0.0149 (7) | 0.000 | 0.0051 (6) | 0.000 |
O5W | 0.0257 (9) | 0.0179 (8) | 0.0160 (8) | 0.000 | 0.0046 (7) | 0.000 |
O6W | 0.0209 (8) | 0.0138 (7) | 0.0204 (8) | 0.000 | 0.0027 (6) | 0.000 |
O2 | 0.0146 (5) | 0.0222 (6) | 0.0136 (5) | 0.0035 (4) | −0.0031 (4) | 0.0008 (4) |
O3 | 0.0146 (5) | 0.0149 (5) | 0.0173 (5) | 0.0007 (4) | 0.0005 (4) | −0.0074 (4) |
K1 | 0.0179 (3) | 0.0295 (3) | 0.0188 (3) | 0.000 | 0.00018 (18) | 0.000 |
Mg1 | 0.0101 (3) | 0.0105 (3) | 0.0132 (3) | 0.000 | 0.0008 (3) | 0.000 |
Geometric parameters (Å, º) top
P1—O4 | 1.4986 (11) | O3—K1vi | 2.8356 (12) |
P1—O3 | 1.5010 (11) | O3—K1 | 3.3490 (12) |
P1—O2 | 1.5450 (11) | K1—O2vii | 2.8225 (12) |
P1—O1 | 1.6153 (8) | K1—O2viii | 2.8225 (12) |
P1—K1 | 3.7813 (6) | K1—O3ix | 2.8356 (12) |
O4—Mg1 | 2.0447 (12) | K1—O3vi | 2.8356 (12) |
O1—P1i | 1.6153 (8) | K1—O6Wiv | 2.8652 (19) |
O1—K1 | 2.8099 (16) | K1—O5Wiii | 3.0074 (19) |
O5W—Mg1ii | 2.1010 (19) | K1—O3i | 3.3490 (12) |
O5W—K1iii | 3.0074 (19) | K1—Mg1x | 3.6057 (9) |
O5W—H5W | 0.989 (16) | K1—P1i | 3.7813 (6) |
O6W—Mg1iv | 2.1566 (18) | Mg1—O4i | 2.0447 (12) |
O6W—K1ii | 2.8652 (19) | Mg1—O3ii | 2.0920 (12) |
O6W—H6W | 0.959 (16) | Mg1—O3xi | 2.0920 (12) |
O2—K1v | 2.8225 (12) | Mg1—O5Wiv | 2.1010 (19) |
O2—H2 | 0.91 (2) | Mg1—O6Wii | 2.1566 (18) |
O3—Mg1iv | 2.0920 (12) | Mg1—K1xii | 3.6057 (9) |
| | | |
O4—P1—O3 | 115.61 (7) | O3ix—K1—O6Wiv | 143.99 (3) |
O4—P1—O2 | 110.32 (7) | O3vi—K1—O6Wiv | 143.99 (3) |
O3—P1—O2 | 111.76 (7) | O1—K1—O5Wiii | 72.78 (5) |
O4—P1—O1 | 108.57 (7) | O2vii—K1—O5Wiii | 132.16 (3) |
O3—P1—O1 | 104.26 (7) | O2viii—K1—O5Wiii | 132.16 (3) |
O2—P1—O1 | 105.62 (8) | O3ix—K1—O5Wiii | 58.39 (3) |
P1—O4—Mg1 | 133.94 (7) | O3vi—K1—O5Wiii | 58.39 (3) |
P1—O1—P1i | 129.80 (10) | O6Wiv—K1—O5Wiii | 145.80 (5) |
P1—O1—K1 | 114.70 (5) | O1—K1—O3i | 46.08 (2) |
P1i—O1—K1 | 114.70 (5) | O2vii—K1—O3i | 143.52 (4) |
Mg1ii—O5W—K1iii | 87.93 (6) | O2viii—K1—O3i | 86.53 (3) |
Mg1ii—O5W—H5W | 123.4 (15) | O3ix—K1—O3i | 91.41 (3) |
K1iii—O5W—H5W | 114.2 (16) | O3vi—K1—O3i | 141.19 (2) |
Mg1iv—O6W—K1ii | 135.76 (8) | O6Wiv—K1—O3i | 72.88 (3) |
Mg1iv—O6W—H6W | 100.9 (15) | O5Wiii—K1—O3i | 83.47 (3) |
K1ii—O6W—H6W | 102.8 (15) | O1—K1—O3 | 46.08 (2) |
P1—O2—K1v | 129.02 (7) | O2vii—K1—O3 | 86.53 (3) |
P1—O2—H2 | 116 (4) | O2viii—K1—O3 | 143.52 (4) |
K1v—O2—H2 | 102 (4) | O3ix—K1—O3 | 141.19 (2) |
P1—O3—Mg1iv | 128.46 (7) | O3vi—K1—O3 | 91.41 (3) |
P1—O3—K1vi | 127.29 (6) | O6Wiv—K1—O3 | 72.88 (3) |
Mg1iv—O3—K1vi | 92.82 (4) | O5Wiii—K1—O3 | 83.47 (3) |
P1—O3—K1 | 94.73 (5) | O3i—K1—O3 | 91.11 (4) |
Mg1iv—O3—K1 | 120.05 (5) | O4i—Mg1—O4 | 89.14 (7) |
K1vi—O3—K1 | 88.59 (3) | O4i—Mg1—O3ii | 178.54 (6) |
O1—K1—O2vii | 127.39 (4) | O4—Mg1—O3ii | 89.68 (4) |
O1—K1—O2viii | 127.39 (4) | O4i—Mg1—O3xi | 89.68 (4) |
O2vii—K1—O2viii | 74.53 (5) | O4—Mg1—O3xi | 178.54 (6) |
O1—K1—O3ix | 118.87 (4) | O3ii—Mg1—O3xi | 91.49 (7) |
O2vii—K1—O3ix | 112.71 (4) | O4i—Mg1—O5Wiv | 93.41 (5) |
O2viii—K1—O3ix | 75.29 (3) | O4—Mg1—O5Wiv | 93.41 (5) |
O1—K1—O3vi | 118.87 (4) | O3ii—Mg1—O5Wiv | 85.80 (5) |
O2vii—K1—O3vi | 75.29 (3) | O3xi—Mg1—O5Wiv | 85.80 (5) |
O2viii—K1—O3vi | 112.71 (4) | O4i—Mg1—O6Wii | 87.61 (5) |
O3ix—K1—O3vi | 63.80 (5) | O4—Mg1—O6Wii | 87.61 (5) |
O1—K1—O6Wiv | 73.02 (5) | O3ii—Mg1—O6Wii | 93.20 (5) |
O2vii—K1—O6Wiv | 71.66 (4) | O3xi—Mg1—O6Wii | 93.20 (5) |
O2viii—K1—O6Wiv | 71.66 (4) | O5Wiv—Mg1—O6Wii | 178.57 (8) |
Symmetry codes: (i) x, −y+1/2, z; (ii) −x+3/2, −y, z+1/2; (iii) −x+2, −y, −z+1; (iv) −x+3/2, −y, z−1/2; (v) x, y, z+1; (vi) −x+2, −y, −z; (vii) x, y, z−1; (viii) x, −y+1/2, z−1; (ix) −x+2, y+1/2, −z; (x) x+1/2, y, −z+1/2; (xi) −x+3/2, y+1/2, z+1/2; (xii) x−1/2, y, −z+1/2. |
Hydrogen-bond geometry (Å, º) top
D—H···A | D—H | H···A | D···A | D—H···A |
O6W—H6W···O4 | 0.96 (2) | 1.76 (2) | 2.6864 (13) | 161 (2) |
O5W—H5W···O2xiii | 0.99 (2) | 1.85 (2) | 2.8231 (13) | 166 (2) |
O2—H2···O2iii | 0.91 (2) | 1.57 (2) | 2.455 (2) | 161 (4) |
Symmetry codes: (iii) −x+2, −y, −z+1; (xiii) x, −y−1/2, z. |