inorganic compounds
K3Gd(PO4)2
aDepartment of Physics and Chemistry, Henan Polytechnic University, Jiaozuo, Henan 454000, People's Republic of China
*Correspondence e-mail: iamzd@hpu.edu.cn
The title compound, tripotassium gadolinium(III) bis[orthophosphate(V)], was synthesized by a high-temperature solution reaction. Of the 12 atoms of the 4)2]3− which extend parallel to (100) and are built up from isolated PO4 tetrahedra and GdO7 monocapped prisms through corner- and edge-sharing. The K+ ions, which have coordination numbers of 10, 9 and 11, help to stack the anionic sheets along [100] into a three-dimensional structure.
(1 × Gd, 2 × P, 3 × K, 6 × O), all but two O atoms (which are in general positions) lie on mirror planes. The features sheets of composition [Gd(PORelated literature
For the structures, properties and applications of phosphates with general formula M3RE(PO4)2 (M = alkali metal, RE = rare earth metal), see: K3Lu(PO4)2 (Efremov et al., 1981); K3(La0.99Nd0.01)(PO4)2 (Hong & Chinn, 1976); Na3Ce(PO4)2 (Karpov et al., 1980); K3Eu(PO4)2 (Morozov et al., 2001); K3Sm(PO4)2 (Toumi et al., 1999); K3Ce(PO4)2 (Zah-Letho et al., 1988).
Experimental
Crystal data
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Data collection: CrystalClear (Rigaku, 2004); cell CrystalClear; data reduction: CrystalClear; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2004); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).
Supporting information
https://doi.org/10.1107/S160053681003103X/wm2378sup1.cif
contains datablocks I, global. DOI:Structure factors: contains datablock I. DOI: https://doi.org/10.1107/S160053681003103X/wm2378Isup2.hkl
The finely ground reagents K2CO3, Gd2O3, and NH4H2PO4 were mixed in the molar ratio K: Gd: P = 12: 1: 10, placed in a Pt crucible, and heated at 573 K for 4 h. The mixture was re-ground and heated at 1173 K for 20 h, then cooled to 573 K at a rate of 4 K h-1, and finally quenched to room temperature. A few colorless crystals of the title compound with prismatic shape were obtained.
The highest peak in the difference
is 1.10 Å from Gd1 while the deepest hole is 0.85 Å from the same atom.Inorganic phosphates with general formula M3RE(PO4)2 have been investigated in the past years due to their interesting optical properties, in which M is a alkali metal cation and RE is a trivalent rare-earth cation: K3Lu(PO4)2, 3 (Efremov et al., 1981); K3(La0.99Nd0.01)(PO4)2, P21/m (Hong & Chinn, 1976); Na3Ce(PO4)2, Pca21 (Karpov et al., 1980); K3Eu(PO4)2, P21/m (Morozov et al., 2001); K3Sm(PO4)2, P21/m (Toumi et al., 1999); K3Ce(PO4)2, P21/m (Zah-Letho et al., 1988). We report herein the synthesis and of K3Gd(PO4)2 which is isotypic with all structures crystallizing in P21/m.
PAs shown in Fig. 1, the
of K3Gd(PO4)2 features two-dimensional sheets with composition [Gd(PO4)2]3- extending in the bc plane and constructed from isolated PO4 tetrahedra and isolated GdO7 monocapped prisms through corner- and edge-sharing. The K+ cations, with coordination numbers of 10 (K1), 9 (K2) and 11 (K3), are situated between these sheets and join them through coulombic action to the O2- anions, eventually forming the three-dimensional framework of K3Gd(PO4)2 (Fig. 2).For the structures, properties and applications of phosphates with general formula M3RE(PO4)2 (M = alkali metal, RE = rare earth metal), see: K3Lu(PO4)2 (Efremov et al., 1981); K3(La0.99Nd0.01)(PO4)2 (Hong & Chinn, 1976); Na3Ce(PO4)2 (Karpov et al., 1980); K3Eu(PO4)2 (Morozov et al., 2001); K3Sm(PO4)2 (Toumi et al., 1999); K3Ce(PO4)2 (Zah-Letho et al., 1988).
Data collection: CrystalClear (Rigaku, 2004); cell
CrystalClear (Rigaku, 2004); data reduction: CrystalClear (Rigaku, 2004); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2004); software used to prepare material for publication: SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).K3Gd(PO4)2 | F(000) = 430 |
Mr = 464.49 | Dx = 3.919 Mg m−3 |
Monoclinic, P21/m | Mo Kα radiation, λ = 0.71073 Å |
Hall symbol: -P 2yb | Cell parameters from 1264 reflections |
a = 7.4153 (15) Å | θ = 2.2–27.5° |
b = 5.6206 (11) Å | µ = 10.43 mm−1 |
c = 9.445 (2) Å | T = 293 K |
β = 90.723 (14)° | Prism, colourless |
V = 393.62 (14) Å3 | 0.30 × 0.10 × 0.10 mm |
Z = 2 |
Rigaku Mercury70 CCD diffractometer | 993 independent reflections |
Radiation source: fine-focus sealed tube | 946 reflections with I > 2σ(I) |
Graphite Monochromator monochromator | Rint = 0.045 |
Detector resolution: 14.6306 pixels mm-1 | θmax = 27.5°, θmin = 2.2° |
ω scans | h = −9→9 |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | k = −7→7 |
Tmin = 0.304, Tmax = 0.624 | l = −12→12 |
3036 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)] = 0.027 | w = 1/[σ2(Fo2) + (0.0356P)2] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.065 | (Δ/σ)max < 0.001 |
S = 1.03 | Δρmax = 2.38 e Å−3 |
993 reflections | Δρmin = −2.68 e Å−3 |
80 parameters | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.0314 (17) |
K3Gd(PO4)2 | V = 393.62 (14) Å3 |
Mr = 464.49 | Z = 2 |
Monoclinic, P21/m | Mo Kα radiation |
a = 7.4153 (15) Å | µ = 10.43 mm−1 |
b = 5.6206 (11) Å | T = 293 K |
c = 9.445 (2) Å | 0.30 × 0.10 × 0.10 mm |
β = 90.723 (14)° |
Rigaku Mercury70 CCD diffractometer | 993 independent reflections |
Absorption correction: multi-scan (ABSCOR; Higashi, 1995) | 946 reflections with I > 2σ(I) |
Tmin = 0.304, Tmax = 0.624 | Rint = 0.045 |
3036 measured reflections |
R[F2 > 2σ(F2)] = 0.027 | 80 parameters |
wR(F2) = 0.065 | 0 restraints |
S = 1.03 | Δρmax = 2.38 e Å−3 |
993 reflections | Δρmin = −2.68 e Å−3 |
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 | ||
Gd1 | 0.00699 (3) | 0.2500 | 0.29011 (3) | 0.00731 (15) | |
P1 | 0.80967 (19) | 0.2500 | 0.57350 (15) | 0.0076 (3) | |
P2 | 0.2303 (2) | 0.2500 | 0.91166 (15) | 0.0066 (3) | |
K1 | 0.20438 (17) | 0.7500 | 0.08160 (13) | 0.0119 (3) | |
K2 | 0.50495 (17) | 0.2500 | 0.19219 (13) | 0.0142 (3) | |
K3 | 0.36353 (18) | 0.2500 | 0.59102 (14) | 0.0142 (3) | |
O1 | 1.0137 (6) | 0.2500 | 0.5478 (4) | 0.0169 (10) | |
O2 | 0.7564 (4) | 0.4735 (5) | 0.6577 (3) | 0.0123 (6) | |
O3 | 0.7177 (6) | 0.2500 | 0.4266 (4) | 0.0116 (9) | |
O4 | 0.8481 (4) | −0.0269 (5) | 0.1623 (3) | 0.0129 (6) | |
O5 | 0.4337 (6) | 0.2500 | 0.8991 (5) | 0.0163 (9) | |
O6 | 0.1744 (6) | 0.2500 | 1.0689 (4) | 0.0113 (9) |
U11 | U22 | U33 | U12 | U13 | U23 | |
Gd1 | 0.0066 (2) | 0.0068 (2) | 0.0085 (2) | 0.000 | −0.00097 (12) | 0.000 |
P1 | 0.0065 (7) | 0.0086 (8) | 0.0076 (7) | 0.000 | −0.0012 (5) | 0.000 |
P2 | 0.0070 (7) | 0.0052 (7) | 0.0076 (6) | 0.000 | −0.0009 (5) | 0.000 |
K1 | 0.0137 (6) | 0.0100 (7) | 0.0118 (6) | 0.000 | −0.0001 (5) | 0.000 |
K2 | 0.0101 (7) | 0.0186 (8) | 0.0138 (6) | 0.000 | −0.0021 (5) | 0.000 |
K3 | 0.0126 (6) | 0.0136 (7) | 0.0165 (6) | 0.000 | −0.0002 (5) | 0.000 |
O1 | 0.007 (2) | 0.031 (3) | 0.012 (2) | 0.000 | −0.0023 (16) | 0.000 |
O2 | 0.0176 (16) | 0.0087 (15) | 0.0105 (14) | −0.0023 (12) | 0.0007 (12) | −0.0019 (11) |
O3 | 0.0087 (19) | 0.015 (2) | 0.0110 (19) | 0.000 | −0.0010 (16) | 0.000 |
O4 | 0.0152 (15) | 0.0081 (15) | 0.0152 (14) | −0.0033 (12) | −0.0016 (12) | −0.0018 (12) |
O5 | 0.010 (2) | 0.021 (3) | 0.018 (2) | 0.000 | 0.0017 (16) | 0.000 |
O6 | 0.013 (2) | 0.014 (2) | 0.0076 (19) | 0.000 | 0.0012 (16) | 0.000 |
Gd1—O4i | 2.287 (3) | K1—O4xii | 3.030 (3) |
Gd1—O4ii | 2.287 (3) | K1—O6xiii | 3.132 (4) |
Gd1—O2iii | 2.390 (3) | K2—O6v | 2.700 (4) |
Gd1—O2iv | 2.390 (3) | K2—O3 | 2.702 (4) |
Gd1—O1i | 2.434 (4) | K2—O5v | 2.812 (4) |
Gd1—O6v | 2.444 (4) | K2—O2iv | 2.872 (3) |
Gd1—O3i | 2.517 (4) | K2—O2iii | 2.872 (3) |
P1—O1 | 1.535 (4) | K2—O5vii | 2.9761 (15) |
P1—O3 | 1.538 (4) | K2—O5iii | 2.9761 (16) |
P1—O2 | 1.541 (3) | K2—O4vi | 2.999 (3) |
P1—O2vi | 1.541 (3) | K2—O4 | 2.999 (3) |
P2—O5 | 1.515 (4) | K3—O1i | 2.621 (4) |
P2—O6 | 1.547 (4) | K3—O3vii | 2.8785 (11) |
P2—O4vii | 1.545 (3) | K3—O3iii | 2.8785 (11) |
P2—O4viii | 1.545 (3) | K3—O2iv | 2.945 (3) |
K1—O5iii | 2.687 (5) | K3—O2iii | 2.945 (3) |
K1—O2viii | 2.776 (3) | K3—O5 | 2.949 (4) |
K1—O2iii | 2.776 (3) | K3—O3 | 3.067 (4) |
K1—O4ix | 2.803 (3) | K3—O4viii | 3.092 (3) |
K1—O4x | 2.803 (3) | K3—O4vii | 3.092 (3) |
K1—O6v | 2.8215 (7) | K3—O2 | 3.227 (3) |
K1—O6xi | 2.8215 (7) | K3—O2vi | 3.227 (3) |
K1—O4ii | 3.030 (3) | ||
O4i—Gd1—O4ii | 85.75 (15) | O3vii—K3—O5 | 95.24 (9) |
O4i—Gd1—O2iii | 157.36 (10) | O3iii—K3—O5 | 95.24 (9) |
O4ii—Gd1—O2iii | 92.20 (11) | O2iv—K3—O5 | 146.60 (6) |
O4i—Gd1—O2iv | 92.20 (11) | O2iii—K3—O5 | 146.60 (6) |
O4ii—Gd1—O2iv | 157.36 (10) | O1i—K3—O3 | 140.64 (13) |
O2iii—Gd1—O2iv | 81.09 (14) | O3vii—K3—O3 | 98.65 (8) |
O4i—Gd1—O1i | 122.12 (9) | O3iii—K3—O3 | 98.65 (8) |
O4ii—Gd1—O1i | 122.12 (9) | O2iv—K3—O3 | 81.26 (9) |
O2iii—Gd1—O1i | 77.78 (10) | O2iii—K3—O3 | 81.26 (9) |
O2iv—Gd1—O1i | 77.78 (10) | O5—K3—O3 | 110.96 (12) |
O4i—Gd1—O6v | 79.20 (10) | O1i—K3—O4viii | 66.82 (11) |
O4ii—Gd1—O6v | 79.20 (10) | O3vii—K3—O4viii | 109.38 (10) |
O2iii—Gd1—O6v | 78.27 (10) | O3iii—K3—O4viii | 62.60 (10) |
O2iv—Gd1—O6v | 78.27 (10) | O2iv—K3—O4viii | 131.63 (9) |
O1i—Gd1—O6v | 148.30 (14) | O2iii—K3—O4viii | 103.66 (8) |
O4i—Gd1—O3i | 80.43 (10) | O5—K3—O4viii | 48.81 (9) |
O4ii—Gd1—O3i | 80.43 (10) | O3—K3—O4viii | 145.84 (9) |
O2iii—Gd1—O3i | 121.51 (9) | O1i—K3—O4vii | 66.82 (11) |
O2iv—Gd1—O3i | 121.51 (9) | O3vii—K3—O4vii | 62.60 (10) |
O1i—Gd1—O3i | 59.63 (13) | O3iii—K3—O4vii | 109.38 (10) |
O6v—Gd1—O3i | 152.07 (14) | O2iv—K3—O4vii | 103.66 (8) |
O1—P1—O3 | 106.5 (2) | O2iii—K3—O4vii | 131.63 (9) |
O1—P1—O2 | 109.94 (15) | O5—K3—O4vii | 48.81 (9) |
O3—P1—O2 | 110.60 (15) | O3—K3—O4vii | 145.84 (9) |
O1—P1—O2vi | 109.94 (15) | O4viii—K3—O4vii | 47.86 (11) |
O3—P1—O2vi | 110.60 (15) | O1i—K3—O2 | 156.87 (6) |
O2—P1—O2vi | 109.2 (2) | O3vii—K3—O2 | 125.38 (10) |
O5—P2—O6 | 110.7 (2) | O3iii—K3—O2 | 79.56 (10) |
O5—P2—O4vii | 109.50 (16) | O2iv—K3—O2 | 128.60 (6) |
O6—P2—O4vii | 109.28 (15) | O2iii—K3—O2 | 102.30 (8) |
O5—P2—O4viii | 109.50 (16) | O5—K3—O2 | 70.11 (10) |
O6—P2—O4viii | 109.28 (15) | O3—K3—O2 | 47.34 (8) |
O4vii—P2—O4viii | 108.5 (2) | O4viii—K3—O2 | 99.24 (8) |
O5iii—K1—O2viii | 81.16 (11) | O4vii—K3—O2 | 118.45 (9) |
O5iii—K1—O2iii | 81.16 (11) | P2—K3—O2 | 95.98 (7) |
O2viii—K1—O2iii | 53.82 (12) | O1i—K3—O2vi | 156.87 (6) |
O5iii—K1—O4ix | 100.61 (10) | O3vii—K3—O2vi | 79.56 (10) |
O2viii—K1—O4ix | 172.75 (9) | O3iii—K3—O2vi | 125.38 (10) |
O2iii—K1—O4ix | 119.30 (8) | O2iv—K3—O2vi | 102.30 (8) |
O5iii—K1—O4x | 100.61 (10) | O2iii—K3—O2vi | 128.60 (6) |
O2viii—K1—O4x | 119.30 (8) | O5—K3—O2vi | 70.11 (10) |
O2iii—K1—O4x | 172.75 (9) | O3—K3—O2vi | 47.34 (8) |
O4ix—K1—O4x | 67.45 (12) | O4viii—K3—O2vi | 118.45 (9) |
O5iii—K1—O6v | 94.64 (9) | O4vii—K3—O2vi | 99.24 (8) |
O2viii—K1—O6v | 119.72 (11) | P2—K3—O2vi | 95.98 (7) |
O2iii—K1—O6v | 66.06 (10) | O2—K3—O2vi | 45.82 (11) |
O4ix—K1—O6v | 53.27 (10) | P1—O1—Gd1xiv | 98.6 (2) |
O4x—K1—O6v | 120.53 (11) | P1—O1—K3xiv | 162.0 (3) |
O5iii—K1—O6xi | 94.64 (9) | Gd1xiv—O1—K3xiv | 99.39 (14) |
O2viii—K1—O6xi | 66.06 (10) | P1—O2—Gd1iii | 116.36 (16) |
O2iii—K1—O6xi | 119.72 (11) | P1—O2—K1iii | 93.68 (14) |
O4ix—K1—O6xi | 120.53 (11) | Gd1iii—O2—K1iii | 92.46 (10) |
O4x—K1—O6xi | 53.27 (10) | P1—O2—K2iii | 151.02 (17) |
O6v—K1—O6xi | 169.79 (18) | Gd1iii—O2—K2iii | 92.56 (9) |
O5iii—K1—O4ii | 148.85 (8) | K1iii—O2—K2iii | 82.58 (8) |
O2viii—K1—O4ii | 92.65 (9) | P1—O2—K3iii | 95.46 (13) |
O2iii—K1—O4ii | 70.83 (9) | Gd1iii—O2—K3iii | 92.00 (9) |
O4ix—K1—O4ii | 82.21 (9) | K1iii—O2—K3iii | 166.79 (12) |
O4x—K1—O4ii | 108.90 (7) | K2iii—O2—K3iii | 84.80 (9) |
O6v—K1—O4ii | 61.97 (10) | P1—O2—K3 | 79.54 (13) |
O6xi—K1—O4ii | 110.76 (11) | Gd1iii—O2—K3 | 162.12 (12) |
O5iii—K1—O4xii | 148.85 (8) | K1iii—O2—K3 | 94.66 (9) |
O2viii—K1—O4xii | 70.83 (9) | K2iii—O2—K3 | 72.18 (7) |
O2iii—K1—O4xii | 92.65 (9) | K3iii—O2—K3 | 77.70 (8) |
O4ix—K1—O4xii | 108.90 (7) | P1—O3—Gd1xiv | 95.21 (19) |
O4x—K1—O4xii | 82.21 (9) | P1—O3—K2 | 170.6 (2) |
O6v—K1—O4xii | 110.76 (11) | Gd1xiv—O3—K2 | 94.17 (13) |
O6xi—K1—O4xii | 61.97 (10) | P1—O3—K3vii | 98.18 (9) |
O4ii—K1—O4xii | 48.89 (11) | Gd1xiv—O3—K3vii | 98.59 (8) |
O5iii—K1—O6xiii | 156.91 (13) | K2—O3—K3vii | 80.39 (9) |
O2viii—K1—O6xiii | 119.07 (9) | P1—O3—K3iii | 98.18 (9) |
O2iii—K1—O6xiii | 119.07 (9) | Gd1xiv—O3—K3iii | 98.59 (8) |
O4ix—K1—O6xiii | 60.83 (9) | K2—O3—K3iii | 80.39 (9) |
O4x—K1—O6xiii | 60.83 (9) | K3vii—O3—K3iii | 155.01 (17) |
O6v—K1—O6xiii | 84.90 (9) | P1—O3—K3 | 85.20 (16) |
O6xi—K1—O6xiii | 84.90 (9) | Gd1xiv—O3—K3 | 179.59 (17) |
O4ii—K1—O6xiii | 48.27 (9) | K2—O3—K3 | 85.42 (12) |
O4xii—K1—O6xiii | 48.27 (9) | K3vii—O3—K3 | 81.34 (8) |
O6v—K2—O3 | 150.53 (13) | K3iii—O3—K3 | 81.34 (8) |
O6v—K2—O5v | 54.35 (12) | P2vii—O4—Gd1xiv | 168.2 (2) |
O3—K2—O5v | 155.12 (13) | P2vii—O4—K1x | 91.81 (14) |
O6v—K2—O2iv | 66.32 (9) | Gd1xiv—O4—K1x | 96.97 (10) |
O3—K2—O2iv | 89.20 (10) | P2vii—O4—K2 | 98.57 (15) |
O5v—K2—O2iv | 111.49 (10) | Gd1xiv—O4—K2 | 91.67 (10) |
O6v—K2—O2iii | 66.32 (9) | K1x—O4—K2 | 71.34 (8) |
O3—K2—O2iii | 89.20 (10) | P2vii—O4—K1xv | 82.80 (13) |
O5v—K2—O2iii | 111.49 (10) | Gd1xiv—O4—K1xv | 88.25 (10) |
O2iv—K2—O2iii | 65.51 (12) | K1x—O4—K1xv | 97.79 (9) |
O6v—K2—O5vii | 90.93 (9) | K2—O4—K1xv | 169.05 (11) |
O3—K2—O5vii | 98.48 (9) | P2vii—O4—K3vii | 79.62 (13) |
O5v—K2—O5vii | 75.07 (9) | Gd1xiv—O4—K3vii | 98.11 (10) |
O2iv—K2—O5vii | 74.84 (10) | K1x—O4—K3vii | 141.08 (12) |
O2iii—K2—O5vii | 139.49 (10) | K2—O4—K3vii | 72.55 (7) |
O6v—K2—O5iii | 90.93 (9) | K1xv—O4—K3vii | 118.30 (10) |
O3—K2—O5iii | 98.48 (9) | P2—O5—K1iii | 171.6 (3) |
O5v—K2—O5iii | 75.07 (9) | P2—O5—K2xvi | 95.6 (2) |
O2iv—K2—O5iii | 139.49 (10) | K1iii—O5—K2xvi | 76.00 (12) |
O2iii—K2—O5iii | 74.84 (10) | P2—O5—K3 | 85.06 (19) |
O5vii—K2—O5iii | 141.57 (16) | K1iii—O5—K3 | 103.34 (14) |
O6v—K2—O4vi | 136.55 (9) | K2xvi—O5—K3 | 179.34 (17) |
O3—K2—O4vi | 65.80 (10) | P2—O5—K2vii | 100.29 (10) |
O5v—K2—O4vi | 93.23 (10) | K1iii—O5—K2vii | 82.16 (9) |
O2iv—K2—O4vi | 154.93 (10) | K2xvi—O5—K2vii | 104.93 (9) |
O2iii—K2—O4vi | 110.14 (8) | K3—O5—K2vii | 74.93 (9) |
O5vii—K2—O4vi | 109.26 (11) | P2—O5—K2iii | 100.29 (10) |
O5iii—K2—O4vi | 49.45 (10) | K1iii—O5—K2iii | 82.16 (9) |
O6v—K2—O4 | 136.55 (9) | K2xvi—O5—K2iii | 104.93 (9) |
O3—K2—O4 | 65.80 (9) | K3—O5—K2iii | 74.93 (9) |
O5v—K2—O4 | 93.23 (10) | K2vii—O5—K2iii | 141.57 (16) |
O2iv—K2—O4 | 110.14 (8) | P2—O6—Gd1xvi | 165.0 (3) |
O2iii—K2—O4 | 154.93 (10) | P2—O6—K2xvi | 99.3 (2) |
O5vii—K2—O4 | 49.45 (10) | Gd1xvi—O6—K2xvi | 95.71 (14) |
O5iii—K2—O4 | 109.26 (11) | P2—O6—K1xvi | 91.08 (8) |
O4vi—K2—O4 | 62.52 (12) | Gd1xvi—O6—K1xvi | 90.24 (8) |
O1i—K3—O3vii | 77.59 (8) | K2xvi—O6—K1xvi | 84.90 (9) |
O1i—K3—O3iii | 77.59 (8) | P2—O6—K1xvii | 91.08 (8) |
O3vii—K3—O3iii | 155.01 (17) | Gd1xvi—O6—K1xvii | 90.24 (8) |
O1i—K3—O2iv | 65.64 (10) | K2xvi—O6—K1xvii | 84.90 (9) |
O3vii—K3—O2iv | 51.52 (10) | K1xvi—O6—K1xvii | 169.79 (18) |
O3iii—K3—O2iv | 114.09 (11) | P2—O6—K1xiii | 79.26 (17) |
O1i—K3—O2iii | 65.64 (10) | Gd1xvi—O6—K1xiii | 85.73 (12) |
O3vii—K3—O2iii | 114.09 (11) | K2xvi—O6—K1xiii | 178.56 (15) |
O3iii—K3—O2iii | 51.52 (10) | K1xvi—O6—K1xiii | 95.10 (9) |
O2iv—K3—O2iii | 63.70 (12) | K1xvii—O6—K1xiii | 95.10 (9) |
O1i—K3—O5 | 108.39 (13) |
Symmetry codes: (i) x−1, y, z; (ii) x−1, −y+1/2, z; (iii) −x+1, −y+1, −z+1; (iv) −x+1, y−1/2, −z+1; (v) x, y, z−1; (vi) x, −y+1/2, z; (vii) −x+1, −y, −z+1; (viii) −x+1, y+1/2, −z+1; (ix) −x+1, y+1/2, −z; (x) −x+1, −y+1, −z; (xi) x, y+1, z−1; (xii) x−1, y+1, z; (xiii) −x, −y+1, −z+1; (xiv) x+1, y, z; (xv) x+1, y−1, z; (xvi) x, y, z+1; (xvii) x, y−1, z+1. |
Experimental details
Crystal data | |
Chemical formula | K3Gd(PO4)2 |
Mr | 464.49 |
Crystal system, space group | Monoclinic, P21/m |
Temperature (K) | 293 |
a, b, c (Å) | 7.4153 (15), 5.6206 (11), 9.445 (2) |
β (°) | 90.723 (14) |
V (Å3) | 393.62 (14) |
Z | 2 |
Radiation type | Mo Kα |
µ (mm−1) | 10.43 |
Crystal size (mm) | 0.30 × 0.10 × 0.10 |
Data collection | |
Diffractometer | Rigaku Mercury70 CCD diffractometer |
Absorption correction | Multi-scan (ABSCOR; Higashi, 1995) |
Tmin, Tmax | 0.304, 0.624 |
No. of measured, independent and observed [I > 2σ(I)] reflections | 3036, 993, 946 |
Rint | 0.045 |
(sin θ/λ)max (Å−1) | 0.649 |
Refinement | |
R[F2 > 2σ(F2)], wR(F2), S | 0.027, 0.065, 1.03 |
No. of reflections | 993 |
No. of parameters | 80 |
Δρmax, Δρmin (e Å−3) | 2.38, −2.68 |
Computer programs: CrystalClear (Rigaku, 2004), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2004), SHELXTL (Sheldrick, 2008) and PLATON (Spek, 2009).
Acknowledgements
The authors acknowledge the Doctoral Foundation of Henan Polytechnic University (B2010–92, 648483).
References
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This is an open-access article distributed under the terms of the Creative Commons Attribution (CC-BY) Licence, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are cited.
Inorganic phosphates with general formula M3RE(PO4)2 have been investigated in the past years due to their interesting optical properties, in which M is a alkali metal cation and RE is a trivalent rare-earth cation: K3Lu(PO4)2, space group P3 (Efremov et al., 1981); K3(La0.99Nd0.01)(PO4)2, P21/m (Hong & Chinn, 1976); Na3Ce(PO4)2, Pca21 (Karpov et al., 1980); K3Eu(PO4)2, P21/m (Morozov et al., 2001); K3Sm(PO4)2, P21/m (Toumi et al., 1999); K3Ce(PO4)2, P21/m (Zah-Letho et al., 1988). We report herein the synthesis and crystal structure of K3Gd(PO4)2 which is isotypic with all structures crystallizing in space group P21/m.
As shown in Fig. 1, the crystal structure of K3Gd(PO4)2 features two-dimensional sheets with composition [Gd(PO4)2]3- extending in the bc plane and constructed from isolated PO4 tetrahedra and isolated GdO7 monocapped prisms through corner- and edge-sharing. The K+ cations, with coordination numbers of 10 (K1), 9 (K2) and 11 (K3), are situated between these sheets and join them through coulombic action to the O2- anions, eventually forming the three-dimensional framework of K3Gd(PO4)2 (Fig. 2).