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The lithium terbium polyphosphate LiTb(PO3)4 was prepared by the flux method using a large excess of H3PO4. It was structurally characterized by single-crystal X-ray diffraction and found to be isotypic with LiYb(PO3)4. The basic structural units are endless spiral chains, (PO3)n, along the b-axis direction. The Li+ and Tb3+ cations alternate on twofold axes and are four- and eight-coordinated, respectively. The results of an optical study of this material are also given and discussed.
Supporting information
Key indicators
- Single-crystal X-ray study
- T = 293 K
- Mean (P-O) = 0.003 Å
- R factor = 0.020
- wR factor = 0.054
- Data-to-parameter ratio = 11.6
checkCIF/PLATON results
No syntax errors found
Alert level C
CRYSC01_ALERT_1_C The word below has not been recognised as a standard
identifier.
colouless
CRYSC01_ALERT_1_C No recognised colour has been given for crystal colour.
PLAT062_ALERT_4_C Rescale T(min) & T(max) by ..................... 0.77
PLAT153_ALERT_1_C The su's on the Cell Axes are Equal (x 100000) . 200 Ang.
Alert level G
ABSTM02_ALERT_3_G When printed, the submitted absorption T values will be
replaced by the scaled T values. Since the ratio of scaled T's
is identical to the ratio of reported T values, the scaling
does not imply a change to the absorption corrections used in
the study.
Ratio of Tmax expected/reported 0.773
Tmax scaled 0.500 Tmin scaled 0.182
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature 293 K
PLAT200_ALERT_1_G Check the Reported _diffrn_ambient_temperature . 293 K
0 ALERT level A = In general: serious problem
0 ALERT level B = Potentially serious problem
4 ALERT level C = Check and explain
3 ALERT level G = General alerts; check
5 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
1 ALERT type 3 Indicator that the structure quality may be low
1 ALERT type 4 Improvement, methodology, query or suggestion
0 ALERT type 5 Informative message, check
Data collection: CAD-4 EXPRESS (Duisenberg, 1992; Macíček & Yordanov, 1992); cell refinement: CAD-4 EXPRESS; data reduction: XCAD4 (Harms & Wocadlo, 1995); program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997); molecular graphics: DIAMOND (Brandenburg, 1998); software used to prepare material for publication: SHELXL97.
lithium terbium polyphosphate
top
Crystal data top
LiTb(PO3)4 | F(000) = 896 |
Mr = 481.74 | Dx = 3.569 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71069 Å |
Hall symbol: -C 2yc | Cell parameters from 25 reflections |
a = 16.358 (2) Å | θ = 10.7–14.7° |
b = 7.050 (2) Å | µ = 8.67 mm−1 |
c = 9.629 (2) Å | T = 293 K |
β = 126.15 (1)° | Plate, colourless |
V = 896.7 (4) Å3 | 0.28 × 0.16 × 0.08 mm |
Z = 4 | |
Data collection top
Enraf–Nonius CAD-4 diffractometer | 951 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.016 |
Graphite monochromator | θmax = 26.9°, θmin = 3.1° |
ω/2θ scans | h = −20→17 |
Absorption correction: ψ scan (North et al., 1968) | k = −1→8 |
Tmin = 0.236, Tmax = 0.646 | l = −1→12 |
1324 measured reflections | 2 standard reflections every 120 min |
974 independent reflections | intensity decay: 1% |
Refinement top
Refinement on F2 | Primary atom site location: heavy-atom method |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.020 | w = 1/[σ2(Fo2) + (0.0344P)2 + 5.8217P] where P = (Fo2 + 2Fc2)/3 |
wR(F2) = 0.054 | (Δ/σ)max < 0.001 |
S = 1.08 | Δρmax = 1.38 e Å−3 |
974 reflections | Δρmin = −1.15 e Å−3 |
84 parameters | Extinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4 |
0 restraints | Extinction coefficient: 0.0025 (2) |
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 | |
Li | 0.0000 | 0.705 (1) | 0.2500 | 0.018 (2) | |
Tb | 0.0000 | 0.20252 (3) | 0.2500 | 0.0065 (1) | |
P1 | 0.13795 (7) | 0.5530 (1) | 0.6151 (1) | 0.0064 (2) | |
P2 | 0.14715 (7) | 0.1520 (1) | 0.6974 (1) | 0.0068 (2) | |
O1 | 0.1137 (2) | 0.7167 (4) | 0.6825 (4) | 0.0121 (6) | |
O2 | 0.0719 (2) | 0.0871 (4) | 0.7268 (4) | 0.0106 (5) | |
O3 | 0.1286 (2) | 0.1149 (4) | 0.5286 (3) | 0.0116 (5) | |
O4 | 0.1578 (2) | 0.3762 (4) | 0.7340 (3) | 0.0108 (5) | |
O5 | 0.2555 (2) | 0.0801 (4) | 0.8536 (3) | 0.0104 (5) | |
O6 | 0.0653 (2) | 0.5027 (4) | 0.4280 (3) | 0.0097 (5) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Li | 0.024 (6) | 0.016 (6) | 0.016 (5) | 0.000 | 0.013 (5) | 0.000 |
Tb | 0.0053 (2) | 0.0071 (2) | 0.0066 (2) | 0.000 | 0.0031 (1) | 0.000 |
P1 | 0.0045 (4) | 0.0069 (5) | 0.0069 (4) | −0.0004 (3) | 0.0029 (4) | −0.0002 (3) |
P2 | 0.0047 (4) | 0.0079 (4) | 0.0075 (4) | 0.0000 (3) | 0.0035 (4) | 0.0011 (3) |
O1 | 0.011 (1) | 0.012 (1) | 0.016 (1) | −0.000 (1) | 0.009 (1) | −0.003 (1) |
O2 | 0.006 (1) | 0.011 (1) | 0.017 (1) | 0.000 (1) | 0.008 (1) | 0.002 (1) |
O3 | 0.012 (1) | 0.012 (1) | 0.009 (1) | 0.001 (1) | 0.005 (1) | 0.000 (1) |
O4 | 0.016 (1) | 0.007 (1) | 0.010 (1) | −0.000 (1) | 0.008 (1) | 0.000 (1) |
O5 | 0.006 (1) | 0.016 (1) | 0.010 (1) | 0.001 (1) | 0.005 (1) | 0.002 (1) |
O6 | 0.005 (1) | 0.012 (1) | 0.008 (1) | −0.002 (1) | 0.002 (1) | 0.000 (1) |
Geometric parameters (Å, º) top
Li—O2i | 1.974 (8) | Tb—O2vi | 2.432 (3) |
Li—O2ii | 1.974 (8) | Tb—O6 | 2.530 (3) |
Li—O6iii | 1.987 (7) | Tb—O6iii | 2.530 (3) |
Li—O6 | 1.987 (7) | P1—O1 | 1.488 (3) |
Li—Tbiv | 3.509 (10) | P1—O6 | 1.502 (3) |
Li—Tb | 3.541 (10) | P1—O4 | 1.591 (3) |
Tb—O3iii | 2.312 (3) | P1—O5vii | 1.596 (3) |
Tb—O3 | 2.312 (3) | P2—O2 | 1.488 (3) |
Tb—O1i | 2.374 (3) | P2—O3 | 1.490 (3) |
Tb—O1ii | 2.374 (3) | P2—O5 | 1.586 (3) |
Tb—O2v | 2.432 (3) | P2—O4 | 1.606 (3) |
| | | |
O2i—Li—O2ii | 84.0 (4) | O6—P1—O5vii | 105.0 (1) |
O2i—Li—O6iii | 119.23 (11) | O4—P1—O5vii | 102.8 (1) |
O2ii—Li—O6iii | 125.26 (11) | O2—P2—O3 | 119.6 (2) |
O2i—Li—O6 | 125.26 (11) | O2—P2—O5 | 107.9 (1) |
O2ii—Li—O6 | 119.23 (11) | O3—P2—O5 | 111.9 (2) |
O6iii—Li—O6 | 88.4 (4) | O2—P2—O4 | 104.8 (1) |
O1—P1—O6 | 118.7 (2) | O3—P2—O4 | 109.8 (1) |
O1—P1—O4 | 106.7 (2) | O5—P2—O4 | 101.0 (2) |
O6—P1—O4 | 111.1 (1) | P1—O4—P2 | 131.5 (2) |
O1—P1—O5vii | 111.5 (2) | P2—O5—P1viii | 134.6 (2) |
Symmetry codes: (i) x, −y+1, z−1/2; (ii) −x, −y+1, −z+1; (iii) −x, y, −z+1/2; (iv) x, y+1, z; (v) −x, −y, −z+1; (vi) x, −y, z−1/2; (vii) −x+1/2, y+1/2, −z+3/2; (viii) −x+1/2, y−1/2, −z+3/2. |
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