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Dysprosium disilicate (Dy
2Si
2O
7) is triclinic with
a = 6.6158 (2),
b = 6.6604 (2),
c = 12.0551 (4) Å, α = 94.373 (2), β = 90.836 (2), γ = 91.512 (2)°,
V = 529.4 (1) Å
3, space group
P,
Z = 4 and
Dx = 6.156 g cm
−3. The structure (single-crystal X-ray,
R = 0.033,
wR = 0.041) is built from a linear triple tetrahedral group [Si
3O
10] and isolated [SiO
4] tetrahedron cross-linked by Dy
3+ in one sixfold and three eightfold coordinated positions, and corresponds to the presently revised type B structure of Ho
2Si
2O
7. The formation of the unusual linear triple tetrahedral group in the type B structure allows for a more continuous transition in the mean size of REE
3+O
n (REE = rare earth element) polyhedra in REE disilicates through the 4
f transition metal series. The crystal of Dy
2Si
2O
7 investigated was complexly twinned such that the diffraction pattern was also consistent with a larger dimensionally monoclinic unit cell (
a = 22.5354,
b = 14.2102,
c = 6.6158 Å, β = 91.788°), which resulted in an apparent superstructure of the type B structure in space group
C1. Lattice coincidence with the type B unit cell appears to have been maintained during crystal synthesis and quenching by the complex sector-zoned growth twin.
Supporting information
Data collection: COLLECT (Nonius, 1997); cell refinement: COLLECT (Nonius, 1997); data reduction: SUNY Buffalo DATAP77; program(s) used to solve structure: SHELXTL PC Siemens; program(s) used to refine structure: SUNY Buffalo LINEX77; molecular graphics: Shape Software ATOMS, ORTEP-3 for Windows.
dysprosium disilicate
top
Crystal data top
Dy2Si2O7 | Z = 4 |
Mr = 493.17 | Dx = 6.156 Mg m−3 |
Triclinic, P1 | Mo Kα radiation, λ = 0.70926 Å |
a = 6.6158 (2) Å | Cell parameters from 32768 reflections |
b = 6.6604 (2) Å | θ = 2–35° |
c = 12.0551 (4) Å | µ = 28.45 mm−1 |
α = 94.373 (2)° | T = 293 K |
β = 90.836 (2)° | Prism, colorless |
γ = 91.512 (2)° | 0.11 × 0.10 × 0.05 mm |
V = 529.39 Å3 | |
Data collection top
Nonius KappaCCD diffractometer | 4470 independent reflections |
Radiation source: fine-focus sealed tube | 3220 reflections with I ≥ 3σ(I) |
Graphite monochromator | Rint = 0.107 |
area detector and scans | θmax = 35°, θmin = 2° |
Absorption correction: gaussian (Coppens, Leiserowitz & Rabinovich, 1965) | h = −10→10 |
Tmin = 0.144, Tmax = 0.380 | k = −5→9 |
32768 measured reflections | l = 0→19 |
Refinement top
Refinement on F | Primary atom site location: structure-invariant direct methods |
Least-squares matrix: full | Secondary atom site location: difference Fourier map |
R[F2 > 2σ(F2)] = 0.033 | w = 1/[σ(F)2 + (0.025F)2],
except w = 0 if I < 3σ(I) |
wR(F2) = 0.041 | (Δ/σ)max = 0.001 |
S = 0.98 | Δρmax = 4.65 e Å−3 |
4470 reflections | Δρmin = −4.70 e Å−3 |
204 parameters | Extinction correction: B-C type 1 Lorentzian isotropic, Coppens & Hamilton (1970) |
0 restraints | Extinction coefficient: 0.31 (2) |
Crystal data top
Dy2Si2O7 | γ = 91.512 (2)° |
Mr = 493.17 | V = 529.39 Å3 |
Triclinic, P1 | Z = 4 |
a = 6.6158 (2) Å | Mo Kα radiation |
b = 6.6604 (2) Å | µ = 28.45 mm−1 |
c = 12.0551 (4) Å | T = 293 K |
α = 94.373 (2)° | 0.11 × 0.10 × 0.05 mm |
β = 90.836 (2)° | |
Data collection top
Nonius KappaCCD diffractometer | 4470 independent reflections |
Absorption correction: gaussian (Coppens, Leiserowitz & Rabinovich, 1965) | 3220 reflections with I ≥ 3σ(I) |
Tmin = 0.144, Tmax = 0.380 | Rint = 0.107 |
32768 measured reflections | |
Refinement top
R[F2 > 2σ(F2)] = 0.033 | 204 parameters |
wR(F2) = 0.041 | 0 restraints |
S = 0.98 | Δρmax = 4.65 e Å−3 |
4470 reflections | Δρmin = −4.70 e Å−3 |
Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top | x | y | z | Uiso*/Ueq | |
Dy(1) | 0.94853 (4) | 0.33132 (4) | 0.11643 (2) | 0.00588 (9) | |
Dy(2) | 0.88556 (4) | 0.09387 (4) | 0.35971 (2) | 0.00579 (9) | |
Dy(3) | 0.37254 (4) | 0.78116 (4) | 0.36895 (2) | 0.00749 (9) | |
Dy(4) | 0.66787 (4) | 0.82973 (4) | 0.10747 (2) | 0.00742 (9) | |
Si(1) | 0.1553 (2) | 0.8528 (2) | 0.1164 (1) | 0.0048 (3) | |
Si(2) | 0.4873 (3) | 0.3370 (2) | 0.1759 (1) | 0.0061 (3) | |
Si(3) | 0.3777 (3) | 0.2743 (2) | 0.4048 (1) | 0.0064 (3) | |
Si(4) | 0.1433 (3) | 0.3702 (2) | 0.6180 (1) | 0.0056 (3) | |
O(1) | 0.6418 (6) | 0.4938 (6) | 0.1256 (3) | 0.0076 (7) | |
O(2) | 0.6179 (7) | 0.1419 (6) | 0.2095 (4) | 0.0120 (8) | |
O(3) | 0.2978 (7) | 0.2990 (7) | 0.0947 (3) | 0.0097 (8) | |
O(4) | 0.4055 (6) | 0.4283 (6) | 0.3065 (3) | 0.0072 (7) | |
O(5) | 0.5836 (7) | 0.1702 (6) | 0.4454 (4) | 0.0090 (8) | |
O(6) | 0.2276 (6) | 0.0965 (6) | 0.3755 (4) | 0.0100 (8) | |
O(7) | 0.2885 (7) | 0.4229 (6) | 0.5118 (3) | 0.0093 (8) | |
O(8) | 0.2841 (7) | 0.2167 (7) | 0.6875 (4) | 0.0118 (8) | |
O(9) | 0.9629 (7) | 0.2255 (6) | 0.5700 (4) | 0.0113 (8) | |
O(10) | 0.0732 (7) | 0.5777 (6) | 0.6854 (4) | 0.0109 (8) | |
O(11) | 0.2411 (7) | 0.9129 (7) | 0.9994 (3) | 0.0111 (8) | |
O(12) | 0.3462 (6) | 0.7886 (7) | 0.1888 (4) | 0.0095 (8) | |
O(13) | 0.9982 (6) | 0.6683 (6) | 0.0809 (3) | 0.0077 (8) | |
O(14) | 0.0029 (6) | 0.0165 (6) | 0.1830 (3) | 0.0075 (7) | |
Atomic displacement parameters (Å2) top | U11 | U22 | U33 | U12 | U13 | U23 |
Dy(1) | 0.0081 (1) | 0.0071 (1) | 0.0026 (1) | −0.00055 (9) | 0.00044 (9) | 0.00098 (9) |
Dy(2) | 0.0061 (1) | 0.0076 (1) | 0.0037 (1) | −0.00091 (9) | 0.00145 (9) | 0.00084 (9) |
Dy(3) | 0.0078 (1) | 0.0126 (1) | 0.0020 (1) | 0.0012 (1) | 0.00071 (9) | −0.00059 (9) |
Dy(4) | 0.0100 (1) | 0.0072 (1) | 0.0054 (1) | 0.00030 (9) | 0.00416 (9) | 0.00193 (9) |
Si(1) | 0.0049 (7) | 0.0072 (7) | 0.0024 (6) | −0.0016 (5) | 0.0017 (5) | 0.0014 (5) |
Si(2) | 0.0075 (7) | 0.0070 (7) | 0.0039 (7) | −0.0010 (5) | 0.0007 (5) | 0.0026 (5) |
Si(3) | 0.0073 (7) | 0.0070 (7) | 0.0050 (7) | −0.0016 (5) | 0.0001 (5) | 0.0016 (5) |
Si(4) | 0.0060 (7) | 0.0044 (6) | 0.0063 (7) | −0.0014 (5) | 0.0001 (5) | 0.0005 (5) |
O(1) | 0.006 (2) | 0.011 (2) | 0.005 (2) | 0.003 (1) | 0.001 (1) | 0.001 (1) |
O(2) | 0.019 (2) | 0.007 (2) | 0.010 (2) | 0.003 (2) | −0.002 (2) | 0.002 (1) |
O(3) | 0.009 (2) | 0.019 (2) | 0.002 (2) | −0.002 (2) | −0.001 (1) | 0.002 (1) |
O(4) | 0.011 (2) | 0.010 (2) | 0.001 (2) | −0.004 (1) | 0.000 (1) | 0.003 (1) |
O(5) | 0.008 (2) | 0.014 (2) | 0.005 (2) | −0.004 (1) | 0.001 (1) | 0.004 (1) |
O(6) | 0.005 (2) | 0.010 (2) | 0.014 (2) | 0.002 (1) | −0.002 (2) | −0.006 (2) |
O(7) | 0.013 (2) | 0.010 (2) | 0.005 (2) | −0.002 (2) | 0.006 (1) | −0.004 (1) |
O(8) | 0.006 (2) | 0.016 (2) | 0.015 (2) | 0.003 (2) | 0.000 (2) | 0.004 (2) |
O(9) | 0.014 (2) | 0.011 (2) | 0.008 (2) | −0.006 (2) | −0.004 (2) | 0.001 (1) |
O(10) | 0.017 (2) | 0.010 (2) | 0.006 (2) | 0.005 (2) | −0.001 (2) | 0.000 (1) |
O(11) | 0.019 (2) | 0.010 (2) | 0.003 (2) | −0.008 (2) | 0.006 (2) | −0.003 (1) |
O(12) | 0.006 (2) | 0.016 (2) | 0.007 (2) | −0.004 (2) | 0.000 (1) | 0.000 (1) |
O(13) | 0.006 (2) | 0.008 (2) | 0.008 (2) | −0.006 (1) | 0.001 (1) | −0.003 (1) |
O(14) | 0.008 (2) | 0.006 (2) | 0.008 (2) | −0.002 (1) | −0.001 (1) | 0.001 (1) |
Geometric parameters (Å, º) top
Dy(1)—O(1) | 2.325 (2) | Dy(4)—O(2)vi | 2.367 (4) |
Dy(1)—O(2) | 2.789 (3) | Dy(4)—O(3)vii | 2.537 (4) |
Dy(1)—O(3)i | 2.343 (1) | Dy(4)—O(8)ii | 2.531 (5) |
Dy(1)—O(10)ii | 2.427 (4) | Dy(4)—O(11)viii | 2.295 (4) |
Dy(1)—O(11)ii | 2.380 (3) | Dy(4)—O(12) | 2.374 (2) |
Dy(1)—O(13) | 2.333 (4) | Dy(4)—O(13) | 2.475 (2) |
Dy(1)—O(13)iii | 2.410 (4) | Dy(4)—O(14)ix | 2.629 (2) |
Dy(1)—O(14)i | 2.336 (4) | Si(1)—O(11)x | 1.602 (4) |
Dy(2)—O(2) | 2.558 (3) | Si(1)—O(12) | 1.610 (3) |
Dy(2)—O(5) | 2.313 (2) | Si(1)—O(13)xi | 1.616 (3) |
Dy(2)—O(6)i | 2.267 (4) | Si(1)—O(14)vi | 1.673 (3) |
Dy(2)—O(8)iv | 2.354 (4) | Si(2)—O(1) | 1.600 (4) |
Dy(2)—O(9) | 2.656 (4) | Si(2)—O(2) | 1.652 (4) |
Dy(2)—O(9)v | 2.571 (4) | Si(2)—O(3) | 1.582 (3) |
Dy(2)—O(10)ii | 2.304 (4) | Si(2)—O(4) | 1.744 (4) |
Dy(2)—O(14)i | 2.304 (4) | Si(3)—O(4) | 1.635 (4) |
Dy(3)—O(4) | 2.429 (4) | Si(3)—O(5) | 1.630 (3) |
Dy(3)—O(5)ii | 2.250 (4) | Si(3)—O(6) | 1.542 (3) |
Dy(3)—O(6)vi | 2.328 (4) | Si(3)—O(7) | 1.688 (4) |
Dy(3)—O(8)ii | 2.381 (1) | Si(4)—O(7) | 1.665 (4) |
Dy(3)—O(9)ii | 2.348 (1) | Si(4)—O(8) | 1.665 (4) |
Dy(3)—O(12) | 2.181 (4) | Si(4)—O(9)xi | 1.588 (3) |
Dy(4)—O(1) | 2.267 (4) | Si(4)—O(10) | 1.630 (4) |
| | | |
O(11)x—Si(1)—O(12) | 106.8 (3) | O(4)—Si(3)—O(6) | 114.4 (2) |
O(11)x—Si(1)—O(13)xi | 103.1 (2) | O(4)—Si(3)—O(7) | 103.3 (2) |
O(11)x—Si(1)—O(14)vi | 116.8 (2) | O(5)—Si(3)—O(6) | 104.8 (2) |
O(12)—Si(1)—O(13)xi | 113.6 (2) | O(5)—Si(3)—O(7) | 109.0 (2) |
O(12)—Si(1)—O(14)vi | 114.9 (2) | O(6)—Si(3)—O(7) | 109.7 (2) |
O(13)xi—Si(1)—O(14)vi | 101.1 (2) | O(7)—Si(4)—O(8) | 103.2 (2) |
O(1)—Si(2)—O(2) | 107.6 (2) | O(7)—Si(4)—O(9)xi | 107.6 (2) |
O(1)—Si(2)—O(3) | 109.4 (2) | O(7)—Si(4)—O(10) | 110.2 (2) |
O(1)—Si(2)—O(4) | 111.0 (2) | O(8)—Si(4)—O(9)xi | 102.7 (2) |
O(2)—Si(2)—O(3) | 118.8 (3) | O(8)—Si(4)—O(10) | 117.2 (2) |
O(2)—Si(2)—O(4) | 100.6 (2) | O(9)xi—Si(4)—O(10) | 114.8 (3) |
O(3)—Si(2)—O(4) | 109.1 (2) | Si(2)—O(4)—Si(3) | 119.7 (3) |
O(4)—Si(3)—O(5) | 115.7 (2) | Si(3)—O(7)—Si(4) | 131.4 (3) |
Symmetry codes: (i) x+1, y, z; (ii) −x+1, −y+1, −z+1; (iii) −x+2, −y+1, −z; (iv) −x+1, −y, −z+1; (v) −x+2, −y, −z+1; (vi) x, y+1, z; (vii) −x+1, −y+1, −z; (viii) −x+1, −y+2, −z+1; (ix) x+1, y+1, z; (x) x, y, z−1; (xi) x−1, y, z. |
Experimental details
Crystal data |
Chemical formula | Dy2Si2O7 |
Mr | 493.17 |
Crystal system, space group | Triclinic, P1 |
Temperature (K) | 293 |
a, b, c (Å) | 6.6158 (2), 6.6604 (2), 12.0551 (4) |
α, β, γ (°) | 94.373 (2), 90.836 (2), 91.512 (2) |
V (Å3) | 529.39 |
Z | 4 |
Radiation type | Mo Kα |
µ (mm−1) | 28.45 |
Crystal size (mm) | 0.11 × 0.10 × 0.05 |
|
Data collection |
Diffractometer | Nonius KappaCCD diffractometer |
Absorption correction | Gaussian (Coppens, Leiserowitz & Rabinovich, 1965) |
Tmin, Tmax | 0.144, 0.380 |
No. of measured, independent and observed [I ≥ 3σ(I)] reflections | 32768, 4470, 3220 |
Rint | 0.107 |
(sin θ/λ)max (Å−1) | 0.809 |
|
Refinement |
R[F2 > 2σ(F2)], wR(F2), S | 0.033, 0.041, 0.98 |
No. of reflections | 4470 |
No. of parameters | 204 |
Δρmax, Δρmin (e Å−3) | 4.65, −4.70 |
Selected geometric parameters (Å, º) topDy(1)—O(1) | 2.325 (2) | Dy(2)—O(14)i | 2.304 (4) |
Dy(1)—O(2) | 2.789 (3) | Dy(3)—O(4) | 2.429 (4) |
Dy(1)—O(3)i | 2.343 (1) | Dy(3)—O(5)ii | 2.250 (4) |
Dy(1)—O(10)ii | 2.427 (4) | Dy(3)—O(6)vi | 2.328 (4) |
Dy(1)—O(11)ii | 2.380 (3) | Dy(3)—O(8)ii | 2.381 (1) |
Dy(1)—O(13) | 2.333 (4) | Dy(3)—O(9)ii | 2.348 (1) |
Dy(1)—O(13)iii | 2.410 (4) | Dy(3)—O(12) | 2.181 (4) |
Dy(1)—O(14)i | 2.336 (4) | Dy(4)—O(1) | 2.267 (4) |
Dy(2)—O(2) | 2.558 (3) | Dy(4)—O(2)vi | 2.367 (4) |
Dy(2)—O(5) | 2.313 (2) | Dy(4)—O(3)vii | 2.537 (4) |
Dy(2)—O(6)i | 2.267 (4) | Dy(4)—O(8)ii | 2.531 (5) |
Dy(2)—O(8)iv | 2.354 (4) | Dy(4)—O(11)viii | 2.295 (4) |
Dy(2)—O(9) | 2.656 (4) | Dy(4)—O(12) | 2.374 (2) |
Dy(2)—O(9)v | 2.571 (4) | Dy(4)—O(13) | 2.475 (2) |
Dy(2)—O(10)ii | 2.304 (4) | Dy(4)—O(14)ix | 2.629 (2) |
| | | |
O(11)x—Si(1)—O(12) | 106.8 (3) | O(4)—Si(3)—O(6) | 114.4 (2) |
O(11)x—Si(1)—O(13)xi | 103.1 (2) | O(4)—Si(3)—O(7) | 103.3 (2) |
O(11)x—Si(1)—O(14)vi | 116.8 (2) | O(5)—Si(3)—O(6) | 104.8 (2) |
O(12)—Si(1)—O(13)xi | 113.6 (2) | O(5)—Si(3)—O(7) | 109.0 (2) |
O(12)—Si(1)—O(14)vi | 114.9 (2) | O(6)—Si(3)—O(7) | 109.7 (2) |
O(13)xi—Si(1)—O(14)vi | 101.1 (2) | O(7)—Si(4)—O(8) | 103.2 (2) |
O(1)—Si(2)—O(2) | 107.6 (2) | O(7)—Si(4)—O(9)xi | 107.6 (2) |
O(1)—Si(2)—O(3) | 109.4 (2) | O(7)—Si(4)—O(10) | 110.2 (2) |
O(1)—Si(2)—O(4) | 111.0 (2) | O(8)—Si(4)—O(9)xi | 102.7 (2) |
O(2)—Si(2)—O(3) | 118.8 (3) | O(8)—Si(4)—O(10) | 117.2 (2) |
O(2)—Si(2)—O(4) | 100.6 (2) | O(9)xi—Si(4)—O(10) | 114.8 (3) |
O(3)—Si(2)—O(4) | 109.1 (2) | Si(2)—O(4)—Si(3) | 119.7 (3) |
O(4)—Si(3)—O(5) | 115.7 (2) | Si(3)—O(7)—Si(4) | 131.4 (3) |
Symmetry codes: (i) x+1, y, z; (ii) −x+1, −y+1, −z+1; (iii) −x+2, −y+1, −z; (iv) −x+1, −y, −z+1; (v) −x+2, −y, −z+1; (vi) x, y+1, z; (vii) −x+1, −y+1, −z; (viii) −x+1, −y+2, −z+1; (ix) x+1, y+1, z; (x) x, y, z−1; (xi) x−1, y, z. |
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