Acta Cryst. (2008). E64, i48 [ doi:10.1107/S1600536808021995 ]
A new polymorph of lutetium polyphosphate, Lu(PO3)3, was found to be isotypic with the trigonal form of Yb(PO3)3. Two of the three Lu atoms occupy special positions (Wyckoff positions 3a and 3b, site symmetry 
). The atomic arrangement consists of infinite helical polyphosphate chains running along the c axis, with a repeat period of 12 PO4 tetrahedra, joined with LuO6 octahedra.
Single crystals of Lu(PO3)3 were grown by a flux method. Lutetium oxide was dissolved in an excess of phosphoric acid using the molar ratio Lu:P = 1:20. The resulting solution was heated in a vitreous graphite crucible at 573 K for 5 days. The obtained colourless crystals were then isolated from the acid solution using hot water.
The highest peak and the deepest hole are located 0.75Å and 0.57 Å, respectively from O10 and Lu3.
Data collection: APEX2 (Bruker, 2005); cell refinement: APEX2 (Bruker, 2005); data reduction: APEX2 (Bruker, 2005); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2001); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).
![[Figure 1]](./fi2065fig1thm.gif)
| Fig. 1. A projection of the helical (PO3)n chains along b. |
![[Figure 2]](./fi2065fig2thm.gif)
| Fig. 2. A projection of Lu(PO3)3 along c, showing the arrangement of the LuO6 octahedra and PO4 tetrahedra. |
![[Figure 3]](./fi2065fig3thm.gif)
| Fig. 3. Projection of the Lu(PO3)3 polyphosphate, showing the lutetium coordination with displacement ellipsoids drawn at the 50% probability level. [Symmetry codes : (i) -y, x-y, z; (ii) -x+y, -x, z; (iii)-x+1/3, -y+2/3, -z+2/3; (iv) y+1/3, -x+y+2/3, -z+2/3; (v) x-y+1/3, x+2/3, -z+2/3; (vi) -x, -y, -z; (vii) -x+y+1/3, -x+2/3, z+2/3.] |
| Lu(PO3)3 | Z = 24 |
| Mr = 411.88 | F000 = 4512 |
| Trigonal, R3 | Dx = 3.587 Mg m−3 |
| Hall symbol: -R 3 | Mo Kα radiation λ = 0.71073 Å |
| a = 20.9106 (6) Å | Cell parameters from 25 reflections |
| b = 20.9106 (6) Å | θ = 2.8–34.1º |
| c = 12.0859 (7) Å | µ = 13.59 mm−1 |
| α = 90º | T = 100 (2) K |
| β = 90º | Cube, colourless |
| γ = 120º | 0.18 × 0.18 × 0.17 mm |
| V = 4576.6 (3) Å3 |
| Bruker APEXII CCD area-detector diffractometer | 3609 reflections with I > 2σ(I) |
| Monochromator: graphite | Rint = 0.054 |
| T = 100(2) K | θmax = 34.2º |
| ω scans | θmin = 2.0º |
| Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | h = −32→32 |
| Tmin = 0.102, Tmax = 0.104 | k = −32→32 |
| 25139 measured reflections | l = −18→18 |
| 4170 independent reflections |
| Refinement on F2 | Secondary atom site location: difference Fourier map |
| Least-squares matrix: full | w = 1/[σ2(Fo2) + (0.0212P)2] where P = (Fo2 + 2Fc2)/3 |
| R[F2 > 2σ(F2)] = 0.032 | (Δ/σ)max = 0.001 |
| wR(F2) = 0.061 | Δρmax = 2.34 e Å−3 |
| S = 1.05 | Δρmin = −2.07 e Å−3 |
| 4170 reflections | Extinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
| 159 parameters | Extinction coefficient: 0.000061 (8) |
| Primary atom site location: structure-invariant direct methods |
| Lu(PO3)3 | γ = 120º |
| Mr = 411.88 | V = 4576.6 (3) Å3 |
| Trigonal, R3 | Z = 24 |
| a = 20.9106 (6) Å | Mo Kα |
| b = 20.9106 (6) Å | µ = 13.59 mm−1 |
| c = 12.0859 (7) Å | T = 100 (2) K |
| α = 90º | 0.18 × 0.18 × 0.17 mm |
| β = 90º |
| Bruker APEXII CCD area-detector diffractometer | 4170 independent reflections |
| Absorption correction: multi-scan (SADABS; Sheldrick, 1996) | 3609 reflections with I > 2σ(I) |
| Tmin = 0.102, Tmax = 0.104 | Rint = 0.054 |
| 25139 measured reflections |
| R[F2 > 2σ(F2)] = 0.032 | 159 parameters |
| wR(F2) = 0.061 | Δρmax = 2.34 e Å−3 |
| S = 1.05 | Δρmin = −2.07 e Å−3 |
| 4170 reflections |
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 | ||
| Lu1 | 0.6667 | 0.3333 | 0.3333 | 0.00741 (8) | |
| Lu2 | 0.6667 | 0.3333 | −0.1667 | 0.01207 (9) | |
| Lu3 | 0.440661 (9) | 0.365196 (10) | 0.096806 (14) | 0.00780 (5) | |
| P1 | 0.63820 (6) | 0.45920 (6) | 0.16119 (9) | 0.00821 (19) | |
| P2 | 0.50313 (6) | 0.54494 (6) | 0.16810 (9) | 0.0096 (2) | |
| P3 | 0.39267 (6) | 0.30556 (6) | 0.37383 (10) | 0.0111 (2) | |
| P4 | 0.50120 (6) | 0.25039 (6) | −0.01904 (10) | 0.0107 (2) | |
| O1 | 0.44368 (17) | 0.46669 (17) | 0.1552 (3) | 0.0132 (6) | |
| O2 | 0.34108 (18) | 0.22020 (17) | 0.3991 (3) | 0.0132 (6) | |
| O3 | 0.54706 (18) | 0.58558 (18) | 0.0709 (3) | 0.0141 (6) | |
| O4 | 0.45503 (18) | 0.27392 (18) | 0.0416 (3) | 0.0168 (7) | |
| O5 | 0.55847 (17) | 0.42399 (18) | 0.1374 (3) | 0.0175 (7) | |
| O6 | 0.45659 (17) | 0.19780 (19) | −0.1185 (3) | 0.0155 (7) | |
| O7 | 0.66627 (18) | 0.41823 (18) | 0.2253 (3) | 0.0190 (7) | |
| O8 | 0.57293 (19) | 0.3097 (2) | −0.0609 (3) | 0.0247 (8) | |
| O9 | 0.6655 (2) | 0.5377 (2) | 0.2137 (4) | 0.0351 (11) | |
| O10 | 0.5156 (2) | 0.1948 (2) | 0.0471 (3) | 0.0315 (10) | |
| O11 | 0.3569 (2) | 0.3473 (2) | 0.4088 (4) | 0.0298 (9) | |
| O12 | 0.4182 (3) | 0.3127 (2) | 0.2586 (3) | 0.0364 (11) |
| U11 | U22 | U33 | U12 | U13 | U23 | |
| Lu1 | 0.00684 (11) | 0.00684 (11) | 0.00854 (19) | 0.00342 (6) | 0.000 | 0.000 |
| Lu2 | 0.01014 (13) | 0.01014 (13) | 0.0159 (2) | 0.00507 (6) | 0.000 | 0.000 |
| Lu3 | 0.00810 (8) | 0.00796 (8) | 0.00662 (8) | 0.00347 (7) | 0.00035 (6) | 0.00000 (6) |
| P1 | 0.0086 (5) | 0.0070 (5) | 0.0084 (5) | 0.0034 (4) | −0.0005 (4) | −0.0006 (4) |
| P2 | 0.0133 (5) | 0.0095 (5) | 0.0072 (5) | 0.0065 (4) | −0.0008 (4) | −0.0007 (4) |
| P3 | 0.0150 (5) | 0.0121 (5) | 0.0095 (5) | 0.0093 (4) | 0.0006 (4) | 0.0032 (4) |
| P4 | 0.0115 (5) | 0.0132 (5) | 0.0106 (5) | 0.0084 (4) | −0.0009 (4) | 0.0000 (4) |
| O1 | 0.0157 (15) | 0.0117 (14) | 0.0132 (15) | 0.0076 (13) | 0.0006 (12) | −0.0027 (12) |
| O2 | 0.0192 (16) | 0.0124 (15) | 0.0079 (14) | 0.0077 (13) | 0.0020 (12) | 0.0008 (11) |
| O3 | 0.0216 (17) | 0.0164 (16) | 0.0055 (14) | 0.0104 (14) | 0.0015 (12) | −0.0001 (12) |
| O4 | 0.0141 (16) | 0.0152 (16) | 0.0215 (18) | 0.0076 (13) | 0.0028 (13) | −0.0036 (13) |
| O5 | 0.0089 (14) | 0.0147 (16) | 0.0269 (19) | 0.0044 (13) | −0.0040 (13) | −0.0065 (14) |
| O6 | 0.0120 (15) | 0.0265 (18) | 0.0117 (15) | 0.0125 (14) | −0.0042 (12) | −0.0051 (13) |
| O7 | 0.0154 (16) | 0.0188 (17) | 0.0264 (19) | 0.0110 (14) | 0.0048 (14) | 0.0145 (14) |
| O8 | 0.0126 (16) | 0.027 (2) | 0.028 (2) | 0.0050 (15) | 0.0040 (14) | −0.0063 (16) |
| O9 | 0.023 (2) | 0.030 (2) | 0.060 (3) | 0.0199 (18) | −0.019 (2) | −0.030 (2) |
| O10 | 0.063 (3) | 0.025 (2) | 0.021 (2) | 0.033 (2) | −0.0207 (19) | −0.0072 (16) |
| O11 | 0.0202 (19) | 0.0148 (17) | 0.058 (3) | 0.0114 (15) | 0.0067 (18) | −0.0006 (18) |
| O12 | 0.063 (3) | 0.022 (2) | 0.0141 (19) | 0.014 (2) | 0.0127 (19) | 0.0068 (15) |
| Lu1—O7i | 2.207 (3) | Lu3—O3x | 2.229 (3) |
| Lu1—O7ii | 2.207 (3) | P1—O5 | 1.475 (3) |
| Lu1—O7iii | 2.207 (3) | P1—O7 | 1.477 (3) |
| Lu1—O7iv | 2.207 (3) | P1—O10iii | 1.569 (4) |
| Lu1—O7 | 2.207 (3) | P1—O9 | 1.578 (4) |
| Lu1—O7v | 2.207 (3) | P2—O3 | 1.472 (3) |
| Lu2—O8vi | 2.180 (3) | P2—O1 | 1.488 (3) |
| Lu2—O8iv | 2.180 (3) | P2—O6xi | 1.585 (3) |
| Lu2—O8iii | 2.180 (3) | P2—O2ii | 1.593 (3) |
| Lu2—O8 | 2.180 (3) | P3—O11 | 1.467 (4) |
| Lu2—O8vii | 2.180 (3) | P3—O12 | 1.472 (4) |
| Lu2—O8viii | 2.180 (3) | P3—O9i | 1.573 (4) |
| Lu3—O11ix | 2.134 (3) | P3—O2 | 1.587 (3) |
| Lu3—O12 | 2.176 (4) | P4—O8 | 1.478 (4) |
| Lu3—O4 | 2.180 (3) | P4—O4 | 1.478 (3) |
| Lu3—O5 | 2.189 (3) | P4—O10 | 1.560 (4) |
| Lu3—O1 | 2.207 (3) | P4—O6 | 1.581 (3) |
| O7i—Lu1—O7ii | 88.57 (14) | O4—Lu3—O5 | 87.21 (12) |
| O7i—Lu1—O7iii | 180.0 | O11ix—Lu3—O1 | 91.99 (13) |
| O7ii—Lu1—O7iii | 91.43 (14) | O12—Lu3—O1 | 95.32 (14) |
| O7i—Lu1—O7iv | 91.43 (14) | O4—Lu3—O1 | 171.70 (12) |
| O7ii—Lu1—O7iv | 180.0 | O5—Lu3—O1 | 84.56 (12) |
| O7iii—Lu1—O7iv | 88.57 (14) | O11ix—Lu3—O3x | 88.69 (15) |
| O7i—Lu1—O7 | 91.43 (14) | O12—Lu3—O3x | 174.96 (15) |
| O7ii—Lu1—O7 | 91.43 (14) | O4—Lu3—O3x | 95.25 (12) |
| O7iii—Lu1—O7 | 88.57 (14) | O5—Lu3—O3x | 96.14 (13) |
| O7iv—Lu1—O7 | 88.57 (14) | O1—Lu3—O3x | 84.56 (12) |
| O7i—Lu1—O7v | 88.57 (14) | O5—P1—O7 | 119.4 (2) |
| O7ii—Lu1—O7v | 88.57 (14) | O5—P1—O10iii | 106.7 (2) |
| O7iii—Lu1—O7v | 91.43 (14) | O7—P1—O10iii | 110.3 (2) |
| O7iv—Lu1—O7v | 91.43 (14) | O5—P1—O9 | 109.15 (19) |
| O7—Lu1—O7v | 180.0 | O7—P1—O9 | 110.6 (2) |
| O8vi—Lu2—O8iv | 180.0 | O10iii—P1—O9 | 98.7 (3) |
| O8vi—Lu2—O8iii | 90.92 (15) | O3—P2—O1 | 119.23 (19) |
| O8iv—Lu2—O8iii | 89.08 (15) | O3—P2—O6xi | 105.71 (18) |
| O8vi—Lu2—O8 | 90.92 (15) | O1—P2—O6xi | 109.44 (19) |
| O8iv—Lu2—O8 | 89.08 (15) | O3—P2—O2ii | 112.19 (18) |
| O8iii—Lu2—O8 | 89.08 (15) | O1—P2—O2ii | 106.01 (18) |
| O8vi—Lu2—O8vii | 89.08 (15) | O6xi—P2—O2ii | 103.12 (18) |
| O8iv—Lu2—O8vii | 90.92 (15) | O11—P3—O12 | 118.6 (3) |
| O8iii—Lu2—O8vii | 180.0 | O11—P3—O9i | 105.0 (2) |
| O8—Lu2—O8vii | 90.92 (15) | O12—P3—O9i | 108.6 (3) |
| O8vi—Lu2—O8viii | 89.08 (15) | O11—P3—O2 | 110.6 (2) |
| O8iv—Lu2—O8viii | 90.92 (15) | O12—P3—O2 | 107.7 (2) |
| O8iii—Lu2—O8viii | 90.92 (15) | O9i—P3—O2 | 105.49 (19) |
| O8—Lu2—O8viii | 180.0 | O8—P4—O4 | 116.6 (2) |
| O8vii—Lu2—O8viii | 89.08 (15) | O8—P4—O10 | 107.9 (2) |
| O11ix—Lu3—O12 | 86.28 (18) | O4—P4—O10 | 113.3 (2) |
| O11ix—Lu3—O4 | 96.31 (13) | O8—P4—O6 | 108.8 (2) |
| O12—Lu3—O4 | 85.59 (14) | O4—P4—O6 | 110.62 (18) |
| O11ix—Lu3—O5 | 173.76 (15) | O10—P4—O6 | 97.91 (19) |
| O12—Lu3—O5 | 88.86 (16) |
| Symmetry codes: (i) x−y+1/3, x−1/3, −z+2/3; (ii) y+1/3, −x+y+2/3, −z+2/3; (iii) −x+y+1, −x+1, z; (iv) −y+1, x−y, z; (v) −x+4/3, −y+2/3, −z+2/3; (vi) y+1/3, −x+y+2/3, −z−1/3; (vii) x−y+1/3, x−1/3, −z−1/3; (viii) −x+4/3, −y+2/3, −z−1/3; (ix) −x+y+1/3, −x+2/3, z−1/3; (x) −x+1, −y+1, −z; (xi) −y+2/3, x−y+1/3, z+1/3. |
This work was supported by the Ministry of Higher Education, Scientific Research and Technology of Tunisia.
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There is considerable scientific and technological interest in the synthesis, structure, and properties of yttrium and rare earth polyphosphates of the formula Ln(PO3)3, because these compounds offer thermal stability and richness of formulations and structures (Briche et al., 2006, Jouini, Férid, Gacon, Grosvalet et al., 2003, Jouini, Férid, Gacon & Trabelsi-Ayadi, 2003, Ternane et al., 2005, Graia et al., 2003). In this paper, we report the preparation and crystal structure refinement of the polyphosphate Lu(PO3)3, crystallizing in space group R-3 . The existence of the trigonal polymorph was originally reported by Anisimova for the Yb(PO3)3 polyphosphate (Anisimova et al., 1992). The monoclinic polymorph of Lu(PO3)3 was recently reported by Höppe and Yuan (Höppe & Sedlmaier, 2007, Yuan et al., 2008). The atomic arrangement of these structures is characterized by a three-dimensional framework built of (PO3)n chains that are formed by corner-sharing of PO4 tetrahedra. These two polymorphs differ by the polyphosphate chains configuration. The chains that were observed in monoclinic Lu(PO3)3 form infinite zigzag chains (PO3)n that extend along c with a period of six tetrahedra. In trigonal Lu(PO3)3, the (PO3)n chains are helical with a period of 12 tetrahedra (Fig.1) and are arranged about the 31 helical axis. The chains are joined to each other by LuO6 octahedra (Fig 2.), no oxygen atom is shared between adjacent LuO6 octahedra. Figure 3 shows the projection of Lu(PO3)3 with anisotropic displacement parameters drawn at the 50% probability level.