research papers
The crystal structure of monoclinic KGd(WO4)2 (KGW) has been refined at room temperature by using single-crystal X-ray diffraction data. The unit-cell parameters are a = 10.652 (4), b = 10.374 (6), c = 7.582 (2) Å, β = 130.80 (2)°, with Z = 4, in space group C2/c. The linear thermal expansion tensor has been determined and the principal axes are [302], [010] and [106]. The principal axis with maximum thermal expansion ( = 23.44 × 10−6 K−1), , was located 12° from the c axis. Undoped crystals of KGW and crystals that were partially doped by Pr, Nd, Ho, Er, Tm and Yb were grown by the top-seeding-solution growth slow-cooling method. The effect of doping on the KGW structure was observed in the cell parameters and in morphological changes. The changes in parameters follow the changes in lanthanide ionic radii. The doped crystals show {021} and {21} faces in addition to the {110}, {11}, {010}, {130} and {310} faces which basically follow the habit of the undoped KGW crystals. The development of the faces is related to the number of the most important periodic bond chains parallel to them.
Supporting information
Crystallographic Information File (CIF) https://doi.org/10.1107/S0021889800013352/os0053sup1.cif | |
Structure factor file (SHELXL table format) https://doi.org/10.1107/S0021889800013352/os0053sup2.sft | |
Portable Document Format (PDF) file https://doi.org/10.1107/S0021889800013352/os0053sup3.pdf |
Computing details top
Program(s) used to solve structure: SHELXS86 (Sheldrick, 1990); program(s) used to refine structure: SHELXL93 (Sheldrick, 1993).
Gadollinium potassium wolframate top
Crystal data top
GdKO8W2 | F(000) = 1180 |
Mr = 692.05 | Dx = 7.248 Mg m−3 |
Monoclinic, C2/c | Mo Kα radiation, λ = 0.71069 Å |
a = 10.652 (4) Å | Cell parameters from 25 reflections |
b = 10.374 (6) Å | θ = 12–21° |
c = 7.582 (2) Å | µ = 47.18 mm−1 |
β = 130.80 (2)° | T = 293 K |
V = 634.2 (5) Å3 | Sphere, colourless |
Z = 4 | 0.4 mm (radius) |
Data collection top
Enraf-Nonius CAD-4 diffractometer | 865 reflections with I > 2σ(I) |
Radiation source: fine-focus sealed tube | Rint = 0.000 |
Graphite monochromator | θmax = 29.9°, θmin = 3.2° |
ω–2θ scans | h = −14→11 |
Absorption correction: spherical | k = 0→14 |
l = 0→10 | |
926 measured reflections | 3 standard reflections every 120 min |
926 independent reflections | intensity decay: none |
Refinement top
Refinement on F2 | 0 restraints |
Least-squares matrix: full | Primary atom site location: structure-invariant direct methods |
R[F2 > 2σ(F2)] = 0.053 | Secondary atom site location: difference Fourier map |
wR(F2) = 0.193 | Calculated w = 1/[σ2(Fo2) + (0.1088P)2 + 6.2657P] P = (Fo2 + 2Fc2)/3 |
S = 1.11 | Δρmax = 0.59 e Å−3 |
876 reflections | Δρmin = −0.84 e Å−3 |
56 parameters |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
x | y | z | Uiso*/Ueq | ||
Gd | 0.0000 | 0.72769 (6) | 0.2500 | 0.0133 (2) | |
W | 0.19491 (4) | −0.00007 (3) | 0.73586 (6) | 0.0131 (2) | |
K | 0.5000 | 0.2000 (3) | 0.7500 | 0.0166 (5) | |
O1 | 0.3726 (14) | −0.0741 (12) | 0.8106 (18) | 0.046 (2) | |
O2 | 0.0258 (14) | −0.1090 (12) | 0.4713 (17) | 0.045 (2) | |
O3 | 0.2690 (13) | 0.1593 (12) | 0.8686 (17) | 0.045 (2) | |
O4 | 0.1905 (14) | −0.0749 (12) | 0.9381 (18) | 0.044 (2) |
Atomic displacement parameters (Å2) top
U11 | U22 | U33 | U12 | U13 | U23 | |
Gd | 0.0148 (4) | 0.0130 (4) | 0.0138 (3) | 0.000 | 0.0101 (3) | 0.000 |
W | 0.0148 (4) | 0.0127 (3) | 0.0137 (3) | −0.00005 (9) | 0.0101 (3) | −0.00021 (9) |
K | 0.0178 (13) | 0.0175 (11) | 0.0159 (11) | 0.000 | 0.0117 (11) | 0.000 |
O1 | 0.060 (7) | 0.039 (5) | 0.048 (5) | −0.003 (5) | 0.039 (5) | −0.003 (5) |
O2 | 0.056 (6) | 0.040 (5) | 0.046 (5) | −0.001 (4) | 0.036 (5) | 0.001 (4) |
O3 | 0.051 (6) | 0.044 (5) | 0.044 (5) | −0.001 (5) | 0.033 (5) | 0.000 (4) |
O4 | 0.055 (6) | 0.044 (5) | 0.043 (4) | 0.002 (5) | 0.037 (5) | 0.000 (5) |
Geometric parameters (Å, º) top
W—O4 | 1.747 (10) | W—K | 3.798 (2) |
W—O1 | 1.758 (12) | Gd—Kv | 3.8018 (10) |
W—O3 | 1.825 (12) | Gd—Kxv | 3.8018 (10) |
W—O2 | 1.955 (11) | Gd—O2xvi | 2.271 (12) |
W—O2i | 2.109 (11) | Gd—O1xvii | 2.325 (12) |
W—O4ii | 2.359 (9) | Gd—O3viii | 2.371 (10) |
Gd—O2iii | 2.271 (12) | Gd—O3xviii | 2.650 (11) |
Gd—O1iv | 2.325 (12) | Gd—Wvi | 3.5492 (15) |
Gd—O3v | 2.371 (10) | Gd—Wxviii | 3.5492 (15) |
Gd—O3vi | 2.650 (11) | K—O4viii | 2.796 (13) |
K—O4vii | 2.796 (13) | K—O4xix | 2.821 (12) |
K—O4ii | 2.821 (12) | K—O1xix | 2.956 (11) |
K—O1ii | 2.956 (11) | K—O2vii | 3.038 (12) |
K—O2viii | 3.038 (12) | K—O3xx | 3.152 (11) |
K—O3 | 3.152 (11) | K—O1xx | 3.309 (12) |
K—O1 | 3.309 (12) | O1—Gdiv | 2.325 (12) |
W—Wi | 3.260 (3) | O1—Kxix | 2.956 (11) |
W—Wii | 3.791 (2) | O2—Wi | 2.109 (11) |
W—Wix | 3.791 (2) | O2—Gdxiii | 2.271 (12) |
W—Gdx | 3.549 (2) | O2—Kxiv | 3.038 (12) |
W—Gdxi | 3.845 (2) | O3—Gdxi | 2.371 (10) |
W—Gdxii | 3.961 (2) | O3—Gdxviii | 2.650 (11) |
W—Gdxiii | 3.983 (2) | O4—Wix | 2.359 (9) |
W—Kix | 3.675 (2) | O4—Kxiv | 2.796 (13) |
W—Kxiv | 3.780 (3) | O4—Kxix | 2.821 (12) |
O2iii—Gd—O2xvi | 83.5 (6) | Kxix—W—Kxiv | 68.09 (4) |
O2iii—Gd—O1iv | 148.5 (4) | O4—W—K | 137.0 (4) |
O2xvi—Gd—O1iv | 99.8 (4) | O1—W—K | 60.6 (4) |
O2iii—Gd—O1xvii | 99.8 (4) | O3—W—K | 55.7 (3) |
O2xvi—Gd—O1xvii | 148.5 (4) | O2—W—K | 122.8 (3) |
O1iv—Gd—O1xvii | 93.5 (6) | O2i—W—K | 104.2 (3) |
O2iii—Gd—O3v | 130.7 (4) | O4ii—W—K | 47.8 (3) |
O2xvi—Gd—O3v | 78.1 (4) | Gdxviii—W—K | 94.05 (6) |
O1iv—Gd—O3v | 80.1 (4) | Kxix—W—K | 97.54 (6) |
O1xvii—Gd—O3v | 76.2 (4) | Kxiv—W—K | 157.60 (7) |
O2iii—Gd—O3viii | 78.1 (4) | O4vii—K—O4viii | 66.8 (5) |
O2xvi—Gd—O3viii | 130.7 (4) | O4vii—K—O4ii | 150.8 (3) |
O1iv—Gd—O3viii | 76.2 (4) | O4viii—K—O4ii | 84.0 (4) |
O1xvii—Gd—O3viii | 80.1 (4) | O4vii—K—O4xix | 84.0 (4) |
O3v—Gd—O3viii | 145.2 (6) | O4viii—K—O4xix | 150.8 (3) |
O2iii—Gd—O3vi | 80.6 (4) | O4ii—K—O4xix | 125.2 (5) |
O2xvi—Gd—O3vi | 60.2 (4) | O4vii—K—O1ii | 126.1 (3) |
O1iv—Gd—O3vi | 74.3 (4) | O4viii—K—O1ii | 98.5 (3) |
O1xvii—Gd—O3vi | 151.3 (4) | O4ii—K—O1ii | 55.1 (3) |
O3v—Gd—O3vi | 125.2 (4) | O4xix—K—O1ii | 99.5 (3) |
O3viii—Gd—O3vi | 71.8 (4) | O4vii—K—O1xix | 98.5 (3) |
O2iii—Gd—O3xviii | 60.2 (4) | O4viii—K—O1xix | 126.1 (3) |
O2xvi—Gd—O3xviii | 80.6 (4) | O4ii—K—O1xix | 99.5 (3) |
O1iv—Gd—O3xviii | 151.3 (4) | O4xix—K—O1xix | 55.1 (3) |
O1xvii—Gd—O3xviii | 74.3 (4) | O1ii—K—O1xix | 127.5 (5) |
O3v—Gd—O3xviii | 71.8 (4) | O4vii—K—O2viii | 57.7 (3) |
O3viii—Gd—O3xviii | 125.2 (4) | O4viii—K—O2viii | 56.3 (3) |
O3vi—Gd—O3xviii | 127.5 (5) | O4ii—K—O2viii | 107.2 (3) |
O2iii—Gd—Wvi | 68.7 (3) | O4xix—K—O2viii | 107.7 (3) |
O2xvi—Gd—Wvi | 34.4 (3) | O1ii—K—O2viii | 152.7 (3) |
O1iv—Gd—Wvi | 96.4 (3) | O1xix—K—O2viii | 71.8 (3) |
O1xvii—Gd—Wvi | 168.5 (3) | O4vii—K—O2vii | 56.3 (3) |
O3v—Gd—Wvi | 111.3 (3) | O4viii—K—O2vii | 57.7 (3) |
O3viii—Gd—Wvi | 96.5 (3) | O4ii—K—O2vii | 107.7 (3) |
O3vi—Gd—Wvi | 30.0 (2) | O4xix—K—O2vii | 107.2 (3) |
O3xviii—Gd—Wvi | 99.3 (3) | O1ii—K—O2vii | 71.8 (3) |
O2iii—Gd—Wxviii | 34.4 (3) | O1xix—K—O2vii | 152.7 (3) |
O2xvi—Gd—Wxviii | 68.7 (3) | O2viii—K—O2vii | 98.6 (5) |
O1iv—Gd—Wxviii | 168.5 (3) | O4vii—K—O3 | 114.1 (3) |
O1xvii—Gd—Wxviii | 96.4 (3) | O4viii—K—O3 | 79.4 (3) |
O3v—Gd—Wxviii | 96.5 (3) | O4ii—K—O3 | 58.3 (3) |
O3viii—Gd—Wxviii | 111.3 (3) | O4xix—K—O3 | 113.7 (3) |
O3vi—Gd—Wxviii | 99.3 (3) | O1ii—K—O3 | 113.2 (3) |
O3xviii—Gd—Wxviii | 30.0 (3) | O1xix—K—O3 | 59.2 (3) |
Wvi—Gd—Wxviii | 74.48 (4) | O2viii—K—O3 | 56.4 (3) |
O2iii—Gd—Kv | 135.6 (3) | O2vii—K—O3 | 136.8 (3) |
O2xvi—Gd—Kv | 53.0 (3) | O4vii—K—O3xx | 79.4 (3) |
O1iv—Gd—Kv | 51.0 (3) | O4viii—K—O3xx | 114.1 (3) |
O1xvii—Gd—Kv | 121.7 (3) | O4ii—K—O3xx | 113.7 (3) |
O3v—Gd—Kv | 55.8 (3) | O4xix—K—O3xx | 58.3 (3) |
O3viii—Gd—Kv | 121.2 (3) | O1ii—K—O3xx | 59.2 (3) |
O3vi—Gd—Kv | 70.6 (2) | O1xix—K—O3xx | 113.2 (3) |
O3xviii—Gd—Kv | 113.5 (2) | O2viii—K—O3xx | 136.8 (3) |
Wvi—Gd—Kv | 69.44 (5) | O2vii—K—O3xx | 56.4 (3) |
Wxviii—Gd—Kv | 118.12 (5) | O3—K—O3xx | 164.6 (5) |
O2iii—Gd—Kxv | 53.0 (3) | O4vii—K—O1 | 150.8 (3) |
O2xvi—Gd—Kxv | 135.6 (3) | O4viii—K—O1 | 124.2 (3) |
O1iv—Gd—Kxv | 121.7 (3) | O4ii—K—O1 | 50.3 (3) |
O1xvii—Gd—Kxv | 51.0 (3) | O4xix—K—O1 | 81.3 (3) |
O3v—Gd—Kxv | 121.2 (3) | O1ii—K—O1 | 81.3 (2) |
O3viii—Gd—Kxv | 55.8 (3) | O1xix—K—O1 | 52.5 (4) |
O3vi—Gd—Kxv | 113.5 (2) | O2viii—K—O1 | 103.4 (3) |
O3xviii—Gd—Kxv | 70.6 (2) | O2vii—K—O1 | 152.7 (3) |
Wvi—Gd—Kxv | 118.12 (5) | O3—K—O1 | 51.5 (3) |
Wxviii—Gd—Kxv | 69.44 (5) | O3xx—K—O1 | 113.1 (3) |
Kv—Gd—Kxv | 171.34 (10) | O4vii—K—O1xx | 124.2 (3) |
O4—W—O1 | 99.4 (5) | O4viii—K—O1xx | 150.8 (3) |
O4—W—O3 | 99.7 (5) | O4ii—K—O1xx | 81.3 (3) |
O1—W—O3 | 103.4 (5) | O4xix—K—O1xx | 50.3 (3) |
O4—W—O2 | 96.2 (5) | O1ii—K—O1xx | 52.5 (4) |
O1—W—O2 | 98.9 (5) | O1xix—K—O1xx | 81.3 (2) |
O3—W—O2 | 150.0 (5) | O2viii—K—O1xx | 152.7 (3) |
O4—W—O2i | 103.6 (5) | O2vii—K—O1xx | 103.4 (3) |
O1—W—O2i | 156.3 (5) | O3—K—O1xx | 113.1 (3) |
O3—W—O2i | 78.1 (5) | O3xx—K—O1xx | 51.5 (3) |
O2—W—O2i | 73.4 (6) | O1—K—O1xx | 61.5 (4) |
O4—W—O4ii | 172.6 (3) | W—O1—Gdiv | 151.6 (6) |
O1—W—O4ii | 78.3 (5) | W—O1—Kxix | 99.3 (4) |
O3—W—O4ii | 87.7 (4) | Gdiv—O1—Kxix | 91.3 (4) |
O2—W—O4ii | 77.3 (4) | W—O1—K | 91.9 (4) |
O2i—W—O4ii | 78.2 (4) | Gdiv—O1—K | 102.5 (4) |
O4—W—Gdxviii | 88.6 (4) | Kxix—O1—K | 127.5 (4) |
O1—W—Gdxviii | 149.9 (4) | W—O2—Wi | 106.6 (6) |
O3—W—Gdxviii | 46.6 (3) | W—O2—Gdxiii | 140.8 (6) |
O2—W—Gdxviii | 109.0 (4) | Wi—O2—Gdxiii | 108.2 (4) |
O2i—W—Gdxviii | 37.4 (3) | W—O2—Kxiv | 96.0 (4) |
O4ii—W—Gdxviii | 96.9 (3) | Wi—O2—Kxiv | 107.7 (4) |
O4—W—Kxix | 47.9 (4) | Gdxiii—O2—Kxiv | 90.3 (4) |
O1—W—Kxix | 52.6 (3) | W—O3—Gdxi | 132.4 (6) |
O3—W—Kxix | 99.3 (3) | W—O3—Gdxviii | 103.4 (4) |
O2—W—Kxix | 110.2 (3) | Gdxi—O3—Gdxviii | 108.2 (4) |
O2i—W—Kxix | 151.1 (3) | W—O3—K | 95.8 (4) |
O4ii—W—Kxix | 130.7 (3) | Gdxi—O3—K | 85.8 (3) |
Gdxviii—W—Kxix | 123.14 (4) | Gdxviii—O3—K | 135.8 (4) |
O4—W—Kxiv | 43.8 (4) | W—O4—Wix | 134.3 (7) |
O1—W—Kxiv | 97.3 (4) | W—O4—Kxiv | 110.5 (5) |
O3—W—Kxiv | 141.0 (3) | Wix—O4—Kxiv | 108.5 (4) |
O2—W—Kxiv | 53.0 (3) | W—O4—Kxix | 104.7 (5) |
O2i—W—Kxiv | 95.6 (3) | Wix—O4—Kxix | 93.9 (3) |
O4ii—W—Kxiv | 129.1 (3) | Kxiv—O4—Kxix | 96.0 (4) |
Gdxviii—W—Kxiv | 108.14 (5) |
Symmetry codes: (i) −x, −y, −z+1; (ii) x, −y, z−1/2; (iii) x, y+1, z; (iv) −x+1/2, −y+1/2, −z+1; (v) x−1/2, y+1/2, z−1; (vi) x, −y+1, z−1/2; (vii) x+1/2, y+1/2, z; (viii) −x+1/2, y+1/2, −z+3/2; (ix) x, −y, z+1/2; (x) x, −y+1, z+1/2; (xi) x+1/2, y−1/2, z+1; (xii) x+1/2, −y+1/2, z+1/2; (xiii) x, y−1, z; (xiv) x−1/2, y−1/2, z; (xv) x−1/2, y+1/2, z; (xvi) −x, y+1, −z+1/2; (xvii) x−1/2, −y+1/2, z−1/2; (xviii) −x, −y+1, −z+1; (xix) −x+1, −y, −z+2; (xx) −x+1, y, −z+3/2. |