Acta Cryst. (2008). E64, i75 [ doi:10.1107/S160053680803287X ]
A new compound, dipotassium holmium(III) phosphate(V) tungstate(VI), K2Ho(PO4)(WO4), has been obtained during investigation of the K2O-P2O5-WO3-HoF3 phase system using the flux technique. The compound is isotypic with K2Bi(PO4)(WO4). Its framework structure consists of flat ![[infinity]](/logos/entities/infin_rmgif.gif)
2[HoPO4] layers parallel to (100) that are made up of 1[HoO8] zigzag chains interlinked via slightly distorted PO4 tetrahedra. WO4 tetrahedra are attached above and below these layers, leaving space for the K+ counter-cations. The HoO8, PO4 and WO4 units exhibit 2 symmetry.
Single crystals of the title compound were grown from a multicomponent high-temperature solution. A mixture of 4.645 g K2W2O7, 0.865 g KPO3, and 1.150 g K4P2O7 was heated in a platinum crucible up to 1173 K which is above the melting temperature. Then 0.200 g of HoF3 were added to this melt under stirring. The final mixture was held at this temperature for 1 h and cooled down to room temperature with a rate of 30 Kh-1. The solidified melt was leached out with warm water to dissolve the superfluous flux. The final product consisted of beige needle-like crystals with a maximum length of up to 5 mm.
The highest peak and the deepest hole of the final Fourier map are located 0.58 Å from atom W1 and 1.11 Å from the same atom, respectively.
Data collection: CrysAlis CCD (Oxford Diffraction, 2005); cell refinement: CrysAlis RED (Oxford Diffraction, 2005); data reduction: CrysAlis RED (Oxford Diffraction, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: WinGX (Farrugia, 1999).
![[Figure 1]](./wm2196fig1thm.gif)
| Fig. 1. The layered structure of K2Ho(PO4)(WO4), leaving space where the K+ ions are located. |
![[Figure 2]](./wm2196fig2thm.gif)
| Fig. 2. View of K2Ho(PO4)(WO4) with displacement ellipsoids drawn at the 50% probability level. [Symmetry codes: (i) 1,5-x; y; 1-z; (ii) 1-x; 0.5-y; z]. |
| K2Ho(PO4)(WO4) | F(000) = 2064 |
| Mr = 585.95 | Dx = 4.727 Mg m−3 |
| Orthorhombic, Ibca | Mo Kα radiation, λ = 0.71073 Å |
| Hall symbol: -I 2b 2c | Cell parameters from 8608 reflections |
| a = 6.882 (1) Å | θ = 3.4–33.0° |
| b = 12.1485 (18) Å | µ = 24.72 mm−1 |
| c = 19.695 (3) Å | T = 293 K |
| V = 1646.6 (4) Å3 | Prism, pale beige |
| Z = 8 | 0.10 × 0.09 × 0.07 mm |
| Oxford Diffraction XCalibur-3 CCD diffractometer | 1561 independent reflections |
| Radiation source: fine-focus sealed tube | 1257 reflections with I > 2σ(I) |
| graphite | Rint = 0.055 |
| φ and ω scans | θmax = 33.0°, θmin = 3.4° |
| Absorption correction: multi-scan based on the method by Blessing (1995) | h = −10→10 |
| Tmin = 0.102, Tmax = 0.177 | k = −18→18 |
| 8608 measured reflections | l = −30→29 |
| Refinement on F2 | 0 restraints |
| Least-squares matrix: full | w = 1/[σ2(Fo2) + (0.0397P)2 + 3.2575P] where P = (Fo2 + 2Fc2)/3 |
| R[F2 > 2σ(F2)] = 0.029 | (Δ/σ)max < 0.001 |
| wR(F2) = 0.071 | Δρmax = 1.90 e Å−3 |
| S = 1.15 | Δρmin = −1.73 e Å−3 |
| 1561 reflections | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
| 62 parameters | Extinction coefficient: 0.00010 (2) |
| K2Ho(PO4)(WO4) | V = 1646.6 (4) Å3 |
| Mr = 585.95 | Z = 8 |
| Orthorhombic, Ibca | Mo Kα radiation |
| a = 6.882 (1) Å | µ = 24.72 mm−1 |
| b = 12.1485 (18) Å | T = 293 K |
| c = 19.695 (3) Å | 0.10 × 0.09 × 0.07 mm |
| Oxford Diffraction XCalibur-3 CCD diffractometer | 1561 independent reflections |
| Absorption correction: multi-scan based on the method by Blessing (1995) | 1257 reflections with I > 2σ(I) |
| Tmin = 0.102, Tmax = 0.177 | Rint = 0.055 |
| 8608 measured reflections | θmax = 33.0° |
| R[F2 > 2σ(F2)] = 0.029 | Δρmax = 1.90 e Å−3 |
| wR(F2) = 0.071 | Δρmin = −1.73 e Å−3 |
| S = 1.15 | Absolute structure: ? |
| 1561 reflections | Flack parameter: ? |
| 62 parameters | Rogers parameter: ? |
| 0 restraints |
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. |
| x | y | z | Uiso*/Ueq | ||
| W1 | 0.5 | 0.25 | 0.334530 (12) | 0.01088 (5) | |
| Ho1 | 0.75 | 0.325113 (17) | 0.5 | 0.00662 (5) | |
| K1 | 0.96872 (15) | 0.07992 (10) | 0.34389 (5) | 0.0196 (2) | |
| P1 | 0.75 | 0.07042 (10) | 0.5 | 0.0065 (2) | |
| O1 | 0.7088 (4) | 0.2796 (3) | 0.38536 (17) | 0.0146 (7) | |
| O2 | 0.4420 (6) | 0.3643 (4) | 0.2845 (2) | 0.0269 (8) | |
| O3 | 0.7308 (4) | −0.0047 (2) | 0.43834 (16) | 0.0102 (6) | |
| O4 | 0.9229 (4) | 0.1514 (2) | 0.49215 (17) | 0.0105 (6) |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| W1 | 0.01432 (9) | 0.01167 (9) | 0.00666 (9) | −0.00095 (8) | 0 | 0 |
| Ho1 | 0.00652 (9) | 0.00523 (9) | 0.00811 (10) | 0 | −0.00005 (9) | 0 |
| K1 | 0.0204 (4) | 0.0248 (5) | 0.0137 (4) | −0.0002 (4) | 0.0021 (3) | 0.0039 (4) |
| P1 | 0.0064 (5) | 0.0034 (5) | 0.0098 (6) | 0 | 0.0000 (5) | 0 |
| O1 | 0.0154 (14) | 0.0171 (14) | 0.0113 (14) | −0.0035 (11) | −0.0012 (11) | −0.0031 (11) |
| O2 | 0.0308 (17) | 0.0296 (19) | 0.0203 (17) | −0.0008 (17) | 0.0013 (15) | 0.0126 (16) |
| O3 | 0.0126 (13) | 0.0079 (11) | 0.0101 (13) | −0.0018 (10) | −0.0002 (11) | −0.0010 (9) |
| O4 | 0.0052 (10) | 0.0066 (11) | 0.0198 (16) | −0.0017 (9) | 0.0011 (10) | −0.0016 (11) |
| W1—O2i | 1.749 (4) | Ho1—K1vii | 3.8119 (11) |
| W1—O2 | 1.749 (4) | Ho1—K1vi | 3.8119 (12) |
| W1—O1 | 1.788 (3) | K1—O3 | 2.683 (3) |
| W1—O1i | 1.788 (3) | K1—O2v | 2.689 (4) |
| W1—K1 | 3.8352 (12) | K1—O3x | 2.747 (3) |
| W1—K1i | 3.8352 (12) | K1—O1vi | 2.916 (3) |
| W1—K1ii | 4.0181 (13) | K1—O2xi | 2.934 (5) |
| W1—K1iii | 4.0181 (13) | K1—O4 | 3.063 (3) |
| W1—K1iv | 4.0821 (12) | K1—O1 | 3.122 (4) |
| W1—K1v | 4.0821 (12) | K1—O2i | 3.133 (4) |
| Ho1—O4vi | 2.274 (3) | K1—P1 | 3.4251 (11) |
| Ho1—O4vii | 2.274 (3) | K1—Ho1vi | 3.8119 (11) |
| Ho1—O1 | 2.342 (3) | K1—K1iii | 3.9511 (13) |
| Ho1—O1viii | 2.342 (3) | P1—O3 | 1.525 (3) |
| Ho1—O3ix | 2.401 (3) | P1—O3viii | 1.525 (3) |
| Ho1—O3ii | 2.401 (3) | P1—O4 | 1.552 (3) |
| Ho1—O4viii | 2.428 (3) | P1—O4viii | 1.552 (3) |
| Ho1—O4 | 2.428 (3) | P1—Ho1xii | 2.9802 (13) |
| Ho1—P1ix | 2.9802 (13) | P1—K1viii | 3.4251 (11) |
| Ho1—P1 | 3.0941 (13) | ||
| O2i—W1—O2 | 111.4 (3) | O3x—K1—O4 | 61.07 (8) |
| O2i—W1—O1 | 106.94 (17) | O1vi—K1—O4 | 69.23 (9) |
| O2—W1—O1 | 109.83 (19) | O2xi—K1—O4 | 130.90 (10) |
| O2i—W1—O1i | 109.83 (19) | O3—K1—O1 | 76.52 (9) |
| O2—W1—O1i | 106.94 (17) | O2v—K1—O1 | 100.44 (12) |
| O1—W1—O1i | 111.9 (2) | O3x—K1—O1 | 117.21 (9) |
| O4vi—Ho1—O4vii | 165.59 (15) | O1vi—K1—O1 | 84.72 (10) |
| O4vi—Ho1—O1 | 94.81 (11) | O2xi—K1—O1 | 156.62 (10) |
| O4vii—Ho1—O1 | 88.59 (11) | O4—K1—O1 | 58.09 (8) |
| O4vi—Ho1—O1viii | 88.59 (11) | O3—K1—O2i | 77.94 (10) |
| O4vii—Ho1—O1viii | 94.81 (11) | O2v—K1—O2i | 78.50 (9) |
| O1—Ho1—O1viii | 152.68 (18) | O3x—K1—O2i | 156.48 (11) |
| O4vi—Ho1—O3ix | 88.91 (10) | O1vi—K1—O2i | 131.64 (12) |
| O4vii—Ho1—O3ix | 78.65 (10) | O2xi—K1—O2i | 103.49 (13) |
| O1—Ho1—O3ix | 133.18 (11) | O4—K1—O2i | 101.64 (9) |
| O1viii—Ho1—O3ix | 73.88 (12) | O1—K1—O2i | 54.04 (10) |
| O4vi—Ho1—O3ii | 78.65 (10) | O3—P1—O3viii | 106.4 (2) |
| O4vii—Ho1—O3ii | 88.91 (10) | O3—P1—O4 | 111.52 (16) |
| O1—Ho1—O3ii | 73.88 (12) | O3viii—P1—O4 | 113.10 (16) |
| O1viii—Ho1—O3ii | 133.18 (12) | O3—P1—O4viii | 113.10 (16) |
| O3ix—Ho1—O3ii | 61.17 (15) | O3viii—P1—O4viii | 111.52 (16) |
| O4vi—Ho1—O4viii | 126.77 (7) | O4—P1—O4viii | 101.3 (2) |
| O4vii—Ho1—O4viii | 67.63 (12) | W1—O1—Ho1 | 133.20 (16) |
| O1—Ho1—O4viii | 78.27 (12) | W1—O1—K1vi | 124.93 (16) |
| O1viii—Ho1—O4viii | 78.03 (12) | Ho1—O1—K1vi | 92.27 (11) |
| O3ix—Ho1—O4viii | 133.56 (10) | W1—O1—K1 | 99.08 (14) |
| O3ii—Ho1—O4viii | 143.86 (10) | Ho1—O1—K1 | 111.49 (12) |
| O4vi—Ho1—O4 | 67.63 (12) | K1vi—O1—K1 | 86.88 (9) |
| O4vii—Ho1—O4 | 126.77 (8) | W1—O2—K1v | 132.6 (2) |
| O1—Ho1—O4 | 78.03 (12) | W1—O2—K1ii | 115.89 (19) |
| O1viii—Ho1—O4 | 78.27 (12) | K1v—O2—K1ii | 95.86 (13) |
| O3ix—Ho1—O4 | 143.86 (10) | W1—O2—K1i | 99.64 (16) |
| O3ii—Ho1—O4 | 133.56 (10) | K1v—O2—K1i | 120.18 (15) |
| O4viii—Ho1—O4 | 59.26 (13) | K1ii—O2—K1i | 81.21 (11) |
| O3—K1—O2v | 152.62 (12) | P1—O3—Ho1xii | 96.20 (15) |
| O3—K1—O3x | 78.69 (8) | P1—O3—K1 | 105.64 (14) |
| O2v—K1—O3x | 124.78 (11) | Ho1xii—O3—K1 | 130.32 (12) |
| O3—K1—O1vi | 119.65 (10) | P1—O3—K1iii | 142.66 (16) |
| O2v—K1—O1vi | 86.67 (12) | Ho1xii—O3—K1iii | 95.30 (9) |
| O3x—K1—O1vi | 60.35 (9) | K1—O3—K1iii | 93.37 (11) |
| O3—K1—O2xi | 93.55 (11) | P1—O4—Ho1vi | 146.28 (18) |
| O2v—K1—O2xi | 78.59 (14) | P1—O4—Ho1 | 99.72 (13) |
| O3x—K1—O2xi | 80.53 (10) | Ho1vi—O4—Ho1 | 111.83 (11) |
| O1vi—K1—O2xi | 118.34 (11) | P1—O4—K1 | 89.66 (13) |
| O3—K1—O4 | 52.05 (8) | Ho1vi—O4—K1 | 89.92 (10) |
| O2v—K1—O4 | 148.06 (12) | Ho1—O4—K1 | 110.96 (11) |
| Symmetry codes: (i) −x+1, −y+1/2, z; (ii) −x+3/2, y+1/2, z; (iii) x−1/2, −y, z; (iv) x−1/2, y, −z+1/2; (v) −x+3/2, −y+1/2, −z+1/2; (vi) −x+2, −y+1/2, z; (vii) x−1/2, −y+1/2, −z+1; (viii) −x+3/2, y, −z+1; (ix) x, y+1/2, −z+1; (x) x+1/2, −y, z; (xi) −x+3/2, y−1/2, z; (xii) x, y−1/2, −z+1. |
| W1—O2 | 1.749 (4) | Ho1—O3ii | 2.401 (3) |
| W1—O1 | 1.788 (3) | Ho1—O4 | 2.428 (3) |
| Ho1—O4i | 2.274 (3) | P1—O3 | 1.525 (3) |
| Ho1—O1 | 2.342 (3) | P1—O4 | 1.552 (3) |
| Symmetry codes: (i) x−1/2, −y+1/2, −z+1; (ii) x, y+1/2, −z+1. |
Ben Amara, M. & Dabbabi, M. (1987). Acta Cryst. C43, 616–618.
Blessing, R. H. (1995). Acta Cryst. A51, 33–38.
Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany.
Farrugia, L. J. (1999). J. Appl. Cryst. 32, 837–838.
Marsh, R. E. (1987). Acta Cryst. C43, 2470.
Oxford Diffraction (2005). CrysAlis CCD and CrysAlis RED. Oxford Diffraction Ltd, Abington, Oxfordshire, England.
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.
Zatovsky, I. V., Terebilenko, K. V., Slobodyanik, N. S. & Baumer, V. N. (2006). J. Solid State Chem. 179, 3550–3555.
Zatovsky, I. V., Terebilenko, K. V., Slobodyanik, N. S., Baumer, V. N. & Shishkin, O. V. (2006). Acta Cryst. E62, i193–i195.
The co-existence of different anionic units in crystal structures represents an interesting field of investigation. One of the first structural examples of a combination of PO4 with MoO4/WO4 tetrahedra, viz. Na2Y(MoO4)(PO4), was reported to be monoclinic with space group C2/c (Ben Amara & Dabbabi, 1987). Later this structure was reinvestigated and described as orthorhombic, space group Ibca (Marsh, 1987). Recently, the compounds K2Bi(PO4)(MO4) (M=Mo, W) with isotypic structures were obtained by application of the flux method (Zatovsky, Terebilenko, Slobodyanik & Baumer, 2006; Zatovsky, Terebilenko, Slobodyanik, Baumer & Shishkin, 2006). Herein, we report the flux synthesis and crystal structure of a new member of the A2B(PO4)(AO4) (A = Na, K; B = lanthanide, Y, Bi; M = Mo, W) family.
One of the characteristic features of this structure type is the "segregation" of slightly distorted PO4 and WO4 tetrahedra into adjacent layers (Fig. 1). The first layer with composition 2∞[HoPO4] contains 1∞[HoO8] zigzag chains (Fig. 2). The connection between neighboring chains is achieved via PO4 tetrahedra. On the top and on the bottom of the 2∞[HoPO4] layer, WO4 tetrahedra are attached. All [HoO8], PO4 and WO4 units exhibit 2 symmetry with bond lengths in the typical ranges (Table 1). The K+ cations are situated in the resulting interlayer space and are surrounded by 8 oxygen atoms with K—O bond lengths ranging from 2.683 (4) Å to 3.133 (4) Å.