supplementary materials


Acta Cryst. (2013). E69, i71    [ doi:10.1107/S1600536813026391 ]

Tetrayttrium difluoride disilicate orthosilicate, Y4F2[Si2O7][SiO4]

M. C. Schäfer, I. Hartenbach and T. Schleid

Abstract top

In the crystal structure of Y4F2[Si2O7][SiO4], three fundamental building blocks are present, viz. anionic disilicate and orthosilicate units ([Si2O7]6- and [SiO4]4-) and cationic [F2Y4]10+ entities. The latter are built up by two [FY3]8+ triangles sharing a common edge. The four crystallographically independent Y3+ cations display coordination numbers of eight for one and of seven for the other three cations, provided by oxide and fluoride anions. The overall arrangement of the building blocks can be considered as layer-like parallel to the ac plane.

Comment top

Y4F2[Si2O7][SiO4] crystallizes isotypically with the already known erbium analogue Er4F2[Si2O7][SiO4] (Müller-Bunz & Schleid, 2001). The crystal structure comprises two different oxidosilicate anions, namely a pyroanionic bitetrahedral disilicate unit [Si2O7]6– with eclipsed conformation (Fig. 1, top left) and an orthosilicate tetrahedron [SiO4]4– (Fig. 1, top right), just like in the mineral allanite (old name orthite) (Rumanova & Nikoleva, 1959). Together with these two anionic building blocks, discrete cationic [F2Y4]10+ entities (Fig. 1, bottom) complete the crystal structure of Y4F2[Si2O7][SiO4]. For the formation of the latter, two almost planar [FY3]8+ triangles are fused together via one common edge, resulting in a butterfly-shaped [F2Y4]10+ unit comprising an angle between the two triangular planes of 161.65 (5)°. Two of the four crystallographically distinct Y3+ cations (Y2, Y3) display just one fluoride anion in their coordination sphere, while the other two (F1, F4) have contact with two F anions each. O2– anions complete the coordination environments of the yttrium cations resulting in distorted bi- (Y1) or monocapped (Y2-4) trigonal prisms. The cationic [F2Y4]10+ as well as the anionic [Si2O7]6– and [SiO4]4– building blocks are arranged layer-like parallel to the ac plane in the crystal structure of the title compound (Fig. 2).

Related literature top

For isotypic Er4F2[Si2O7][SiO4], see: Müller-Bunz & Schleid (2001). For the minor by-product phase Y3F[Si3O10], see: Müller-Bunz & Schleid (1998). For the crystal structure of allanite (old name orthite), see: Rumanova & Nikoleva (1959).

Experimental top

Colourless lath-shaped single crystals of Y4F2[Si2O7][SiO4] were obtained by the reaction of yttrium sesquioxide (Y2O3), yttrium trifluoride (YF3), and silicon dioxide (SiO2) in the molar ratio 2:5:3 and an excess of cesium chloride (CsCl) as flux in evacuated silica ampoules within nine days at 973 K and a cooling rate of 10 Kh-1. Due to the stability of the product against air and moisture, the excess flux can the removed by washing with water. Besides the title compound, single crystals of thalenite-type Y3F[Si3O10] (Müller-Bunz & Schleid, 1998) were also found in the product mixture as minor by-product.

Refinement top

The highest and lowest electron densities are found 1.29 Å from atom F2 and and 1.28 Å from atom O8, respectively.

Computing details top

Data collection: COLLECT (Nonius, 1998); cell refinement: SCALEPACK (Otwinowski & Minor, 1997); data reduction: SCALEPACK and DENZO (Otwinowski & Minor, 1997); 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: SHELXL97 (Sheldrick, 2008).

Figures top
[Figure 1] Fig. 1. Disilicate ([Si2O7]6–: top left) and orthosilicate units ([SiO4]4–: top right) as well as butterfly-shaped cationic [F2Y4]10+ entities (bottom) in the crystal structure of Y4F2[Si2O7][SiO4]; displacement ellipsoids are drawn at the 80 % probability level.
[Figure 2] Fig. 2. View at the crystal structure of Y4F2[Si2O7][SiO4] along [100], emphasizing the layer-like arrangement as line-up of the cationic and anionic building blocks.
Tetrayttrium difluoride disilicate orthosilicate top
Crystal data top
Y4F2[Si2O7][SiO4]Z = 2
Mr = 653.91F(000) = 608
Triclinic, P1Dx = 4.359 Mg m3
Hall symbol: -P 1Mo Kα radiation, λ = 0.71073 Å
a = 6.4987 (5) ÅCell parameters from 5136 reflections
b = 6.6196 (5) Åθ = 0.4–28.3°
c = 13.2978 (9) ŵ = 23.52 mm1
α = 87.418 (4)°T = 293 K
β = 85.702 (4)°Lath-shaped, colourless
γ = 60.854 (3)°0.10 × 0.06 × 0.03 mm
V = 498.19 (6) Å3
Data collection top
Nonius KappaCCD
diffractometer
2427 independent reflections
Radiation source: fine-focus sealed tube1475 reflections with I > 2σ(I)
Graphite monochromatorRint = 0.120
ω and φ mscansθmax = 28.2°, θmin = 1.5°
Absorption correction: numerical
(X-SHAPE; Stoe & Cie, 1995)
h = 88
Tmin = 0.104, Tmax = 0.463k = 88
12473 measured reflectionsl = 1717
Refinement top
Refinement on F2Primary atom site location: structure-invariant direct methods
Least-squares matrix: fullSecondary atom site location: difference Fourier map
R[F2 > 2σ(F2)] = 0.055 w = 1/[σ2(Fo2) + (0.0233P)2]
where P = (Fo2 + 2Fc2)/3
wR(F2) = 0.107(Δ/σ)max < 0.001
S = 0.98Δρmax = 1.56 e Å3
2427 reflectionsΔρmin = 1.49 e Å3
182 parametersExtinction correction: SHELXL97 (Sheldrick, 2008), Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
0 restraintsExtinction coefficient: 0.0029 (6)
Crystal data top
Y4F2[Si2O7][SiO4]γ = 60.854 (3)°
Mr = 653.91V = 498.19 (6) Å3
Triclinic, P1Z = 2
a = 6.4987 (5) ÅMo Kα radiation
b = 6.6196 (5) ŵ = 23.52 mm1
c = 13.2978 (9) ÅT = 293 K
α = 87.418 (4)°0.10 × 0.06 × 0.03 mm
β = 85.702 (4)°
Data collection top
Nonius KappaCCD
diffractometer
2427 independent reflections
Absorption correction: numerical
(X-SHAPE; Stoe & Cie, 1995)
1475 reflections with I > 2σ(I)
Tmin = 0.104, Tmax = 0.463Rint = 0.120
12473 measured reflectionsθmax = 28.2°
Refinement top
R[F2 > 2σ(F2)] = 0.055Δρmax = 1.56 e Å3
wR(F2) = 0.107Δρmin = 1.49 e Å3
S = 0.98Absolute structure: ?
2427 reflectionsAbsolute structure parameter: ?
182 parametersRogers parameter: ?
0 restraints
Special details top

Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds 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 > 2sigma(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
xyzUiso*/Ueq
Y10.32290 (19)0.37903 (19)0.20317 (8)0.0102 (3)
Y20.94009 (19)0.27320 (19)0.02756 (8)0.0083 (3)
Y30.21943 (19)0.21311 (19)0.52890 (8)0.0083 (3)
Y40.82014 (19)0.30705 (19)0.32901 (8)0.0084 (3)
F10.0366 (11)0.2679 (11)0.1862 (5)0.0118 (14)
F20.2019 (11)0.2616 (11)0.3554 (5)0.0143 (15)
Si10.4925 (5)0.2508 (5)0.9343 (2)0.0098 (7)
Si20.2335 (5)0.1526 (5)0.7833 (2)0.0084 (7)
Si30.2675 (5)0.7298 (5)0.4207 (2)0.0078 (7)
O10.2654 (13)0.3396 (14)0.0197 (6)0.0120 (17)
O20.2523 (13)0.9039 (13)0.0181 (6)0.0117 (17)
O30.5550 (14)0.5023 (14)0.1127 (6)0.0145 (18)
O40.4646 (12)0.0987 (13)0.8473 (5)0.0086 (16)
O50.2042 (13)0.3248 (13)0.6867 (5)0.0081 (16)
O60.6842 (13)0.1117 (13)0.2472 (6)0.0122 (17)
O70.0069 (13)0.7152 (13)0.1437 (6)0.0116 (17)
O80.4064 (13)0.8414 (13)0.4786 (6)0.0092 (16)
O90.4233 (13)0.5444 (14)0.3321 (6)0.0132 (18)
O100.8272 (13)0.4057 (14)0.4931 (6)0.0135 (18)
O110.0157 (13)0.9376 (13)0.3873 (6)0.0089 (17)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Y10.0090 (5)0.0126 (6)0.0088 (6)0.0050 (4)0.0027 (4)0.0019 (4)
Y20.0088 (5)0.0079 (6)0.0077 (6)0.0035 (4)0.0013 (4)0.0008 (4)
Y30.0082 (5)0.0081 (6)0.0078 (6)0.0032 (4)0.0023 (4)0.0001 (4)
Y40.0079 (5)0.0088 (6)0.0076 (6)0.0034 (4)0.0011 (4)0.0008 (4)
F10.014 (3)0.013 (4)0.009 (3)0.005 (3)0.005 (3)0.001 (3)
F20.013 (3)0.019 (4)0.012 (4)0.009 (3)0.004 (3)0.003 (3)
Si10.0073 (15)0.0095 (16)0.0107 (16)0.0022 (13)0.0022 (12)0.0016 (12)
Si20.0083 (15)0.0058 (16)0.0077 (16)0.0005 (13)0.0002 (12)0.0019 (12)
Si30.0079 (15)0.0083 (16)0.0077 (16)0.0044 (13)0.0006 (12)0.0002 (12)
O10.016 (4)0.019 (4)0.009 (4)0.009 (3)0.005 (3)0.003 (3)
O20.011 (4)0.010 (4)0.016 (4)0.006 (3)0.001 (3)0.001 (3)
O30.017 (4)0.012 (4)0.010 (4)0.004 (3)0.003 (3)0.006 (3)
O40.009 (4)0.013 (4)0.011 (4)0.006 (3)0.005 (3)0.003 (3)
O50.010 (4)0.009 (4)0.009 (4)0.005 (3)0.002 (3)0.002 (3)
O60.009 (4)0.009 (4)0.019 (4)0.001 (3)0.001 (3)0.004 (3)
O70.011 (4)0.010 (4)0.009 (4)0.002 (3)0.002 (3)0.002 (3)
O80.009 (4)0.010 (4)0.012 (4)0.006 (3)0.004 (3)0.002 (3)
O90.014 (4)0.019 (4)0.009 (4)0.008 (3)0.000 (3)0.004 (3)
O100.012 (4)0.012 (4)0.009 (4)0.000 (3)0.003 (3)0.001 (3)
O110.009 (4)0.013 (4)0.010 (4)0.005 (3)0.006 (3)0.001 (3)
Geometric parameters (Å, º) top
Y1—O62.248 (7)Y3—Si3ii3.024 (3)
Y1—O32.286 (8)Y3—Si23.392 (3)
Y1—O72.330 (7)Y3—Y3i3.406 (2)
Y1—F12.337 (6)Y3—Si3x3.431 (3)
Y1—F22.353 (6)Y3—Y3ii3.559 (2)
Y1—O92.366 (7)Y4—F1iv2.223 (6)
Y1—O12.540 (8)Y4—O62.240 (8)
Y1—O4i2.856 (8)Y4—O11v2.269 (8)
Y1—Si2i3.296 (3)Y4—O92.272 (8)
Y1—Si2ii3.428 (3)Y4—O102.316 (8)
Y1—Y43.5649 (15)Y4—O5vi2.364 (7)
Y1—Y2iii3.7351 (15)Y4—F2iv2.400 (6)
Y2—O2iii2.216 (8)Y4—Si3vi3.352 (3)
Y2—F1iv2.239 (6)Y4—Y3vi3.6603 (16)
Y2—O7iii2.281 (8)Y4—Y3iv3.6740 (14)
Y2—O2v2.295 (7)Y4—Y1iv3.7852 (15)
Y2—O1iii2.322 (8)F1—Y4xi2.223 (6)
Y2—O1iv2.354 (7)F1—Y2xi2.239 (6)
Y2—O32.424 (8)F2—Y4xi2.400 (6)
Y2—Si1vi3.064 (3)Si1—O3vi1.613 (8)
Y2—Si1vii3.316 (3)Si1—O2vi1.626 (8)
Y2—Y2viii3.411 (2)Si1—O41.644 (8)
Y2—Y2ix3.486 (2)Si1—O1xii1.666 (8)
Y2—Y1iii3.7351 (15)Si2—O6i1.622 (8)
Y3—O52.236 (7)Si2—O7ii1.633 (8)
Y3—O8x2.257 (8)Si2—O51.637 (8)
Y3—O8vi2.273 (7)Si2—O41.657 (7)
Y3—O10xi2.305 (7)Si3—O111.621 (7)
Y3—F22.319 (6)Si3—O91.632 (8)
Y3—O11ii2.388 (8)Si3—O81.660 (7)
Y3—O10vi2.398 (8)Si3—O10vi1.684 (8)
O6—Y1—O378.8 (3)O6—Y4—O10138.3 (3)
O6—Y1—O7163.3 (3)O11v—Y4—O1084.6 (3)
O3—Y1—O785.3 (3)O9—Y4—O1090.6 (3)
O6—Y1—F1119.2 (2)F1iv—Y4—O5vi78.7 (2)
O3—Y1—F1142.5 (2)O6—Y4—O5vi136.0 (3)
O7—Y1—F176.9 (2)O11v—Y4—O5vi148.0 (3)
O6—Y1—F283.0 (3)O9—Y4—O5vi78.4 (3)
O3—Y1—F2151.4 (2)O10—Y4—O5vi75.9 (3)
O7—Y1—F2109.4 (2)F1iv—Y4—F2iv67.0 (2)
F1—Y1—F266.0 (2)O6—Y4—F2iv135.7 (3)
O6—Y1—O973.5 (3)O11v—Y4—F2iv77.8 (2)
O3—Y1—O979.2 (3)O9—Y4—F2iv147.8 (3)
O7—Y1—O998.5 (3)O10—Y4—F2iv70.5 (2)
F1—Y1—O9135.6 (2)O5vi—Y4—F2iv71.9 (2)
F2—Y1—O974.6 (2)Y4xi—F1—Y2xi128.6 (3)
O6—Y1—O1111.4 (3)Y4xi—F1—Y1112.2 (2)
O3—Y1—O175.0 (3)Y2xi—F1—Y1114.7 (3)
O7—Y1—O168.9 (3)Y3—F2—Y1149.1 (3)
F1—Y1—O167.9 (2)Y3—F2—Y4xi102.2 (2)
F2—Y1—O1132.7 (2)Y1—F2—Y4xi105.6 (2)
O9—Y1—O1152.0 (3)O3vi—Si1—O2vi115.4 (4)
O6—Y1—O4i56.4 (2)O3vi—Si1—O4109.4 (4)
O3—Y1—O4i103.4 (3)O2vi—Si1—O4108.6 (4)
O7—Y1—O4i133.9 (2)O3vi—Si1—O1xii99.6 (4)
F1—Y1—O4i68.9 (2)O2vi—Si1—O1xii113.6 (4)
F2—Y1—O4i84.1 (2)O4—Si1—O1xii110.0 (4)
O9—Y1—O4i127.5 (2)O6i—Si2—O7ii117.1 (4)
O1—Y1—O4i70.1 (2)O6i—Si2—O5114.0 (4)
O2iii—Y2—F1iv122.9 (3)O7ii—Si2—O5106.6 (4)
O2iii—Y2—O7iii79.4 (3)O6i—Si2—O497.8 (4)
F1iv—Y2—O7iii154.6 (3)O7ii—Si2—O4109.3 (4)
O2iii—Y2—O2v81.8 (3)O5—Si2—O4111.9 (4)
F1iv—Y2—O2v85.6 (2)O11—Si3—O9114.6 (4)
O7iii—Y2—O2v86.0 (3)O11—Si3—O8109.0 (4)
O2iii—Y2—O1iii108.9 (3)O9—Si3—O8115.8 (4)
F1iv—Y2—O1iii106.1 (2)O11—Si3—O10vi99.8 (4)
O7iii—Y2—O1iii73.6 (3)O9—Si3—O10vi107.4 (4)
O2v—Y2—O1iii154.3 (3)O8—Si3—O10vi108.9 (4)
O2iii—Y2—O1iv153.3 (3)Si1vii—O1—Y2iii99.1 (4)
F1iv—Y2—O1iv72.8 (2)Si1vii—O1—Y2xi129.2 (4)
O7iii—Y2—O1iv82.0 (3)Y2iii—O1—Y2xi96.4 (3)
O2v—Y2—O1iv78.1 (3)Si1vii—O1—Y1120.2 (4)
O1iii—Y2—O1iv83.6 (3)Y2iii—O1—Y1100.3 (3)
O2iii—Y2—O378.4 (3)Y2xi—O1—Y1103.8 (3)
F1iv—Y2—O378.6 (2)Si1vi—O2—Y2iii118.5 (4)
O7iii—Y2—O3121.1 (3)Si1vi—O2—Y2xiii139.1 (5)
O2v—Y2—O3142.0 (3)Y2iii—O2—Y2xiii98.2 (3)
O1iii—Y2—O363.6 (3)Si1vi—O3—Y1133.6 (5)
O1iv—Y2—O3127.9 (3)Si1vi—O3—Y296.7 (4)
O5—Y3—O8x124.4 (3)Y1—O3—Y2128.7 (3)
O5—Y3—O8vi84.1 (3)Si1—O4—Si2130.4 (5)
O8x—Y3—O8vi82.5 (3)Si1—O4—Y1i136.4 (4)
O5—Y3—O10xi102.1 (3)Si2—O4—Y1i89.8 (3)
O8x—Y3—O10xi112.7 (3)Si2—O5—Y3121.5 (4)
O8vi—Y3—O10xi154.3 (3)Si2—O5—Y4vi132.8 (4)
O5—Y3—F2155.0 (2)Y3—O5—Y4vi105.4 (3)
O8x—Y3—F279.2 (3)Si2i—O6—Y4138.9 (4)
O8vi—Y3—F291.6 (2)Si2i—O6—Y1115.8 (4)
O10xi—Y3—F272.2 (2)Y4—O6—Y1105.2 (3)
O5—Y3—O11ii79.8 (3)Si2ii—O7—Y2iii129.9 (4)
O8x—Y3—O11ii77.4 (3)Si2ii—O7—Y1118.8 (4)
O8vi—Y3—O11ii140.4 (3)Y2iii—O7—Y1108.2 (3)
O10xi—Y3—O11ii65.2 (3)Si3—O8—Y3xiv121.6 (4)
F2—Y3—O11ii117.1 (2)Si3—O8—Y3vi135.4 (4)
O5—Y3—O10vi76.7 (3)Y3xiv—O8—Y3vi97.5 (3)
O8x—Y3—O10vi147.8 (3)Si3—O9—Y4125.0 (4)
O8vi—Y3—O10vi75.5 (3)Si3—O9—Y1133.0 (4)
O10xi—Y3—O10vi81.6 (3)Y4—O9—Y1100.4 (3)
F2—Y3—O10vi78.4 (3)Si3vi—O10—Y3iv97.4 (3)
O11ii—Y3—O10vi133.8 (3)Si3vi—O10—Y4112.9 (4)
F1iv—Y4—O684.0 (3)Y3iv—O10—Y4105.3 (3)
F1iv—Y4—O11v99.0 (3)Si3vi—O10—Y3vi136.1 (4)
O6—Y4—O11v74.4 (3)Y3iv—O10—Y3vi98.4 (3)
F1iv—Y4—O9119.3 (2)Y4—O10—Y3vi101.9 (3)
O6—Y4—O975.5 (3)Si3—O11—Y4xiii145.4 (4)
O11v—Y4—O9127.5 (3)Si3—O11—Y3ii96.1 (4)
F1iv—Y4—O10135.4 (2)Y4xiii—O11—Y3ii116.6 (3)
Symmetry codes: (i) x+1, y, z+1; (ii) x, y+1, z+1; (iii) x+1, y+1, z; (iv) x+1, y, z; (v) x+1, y1, z; (vi) x+1, y+1, z+1; (vii) x, y, z1; (viii) x+2, y, z; (ix) x+2, y+1, z; (x) x, y1, z; (xi) x1, y, z; (xii) x, y, z+1; (xiii) x1, y+1, z; (xiv) x, y+1, z.

Experimental details

Crystal data
Chemical formulaY4F2[Si2O7][SiO4]
Mr653.91
Crystal system, space groupTriclinic, P1
Temperature (K)293
a, b, c (Å)6.4987 (5), 6.6196 (5), 13.2978 (9)
α, β, γ (°)87.418 (4), 85.702 (4), 60.854 (3)
V3)498.19 (6)
Z2
Radiation typeMo Kα
µ (mm1)23.52
Crystal size (mm)0.10 × 0.06 × 0.03
Data collection
DiffractometerNonius KappaCCD
diffractometer
Absorption correctionNumerical
(X-SHAPE; Stoe & Cie, 1995)
Tmin, Tmax0.104, 0.463
No. of measured, independent and
observed [I > 2σ(I)] reflections
12473, 2427, 1475
Rint0.120
(sin θ/λ)max1)0.664
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.055, 0.107, 0.98
No. of reflections2427
No. of parameters182
No. of restraints0
Δρmax, Δρmin (e Å3)1.56, 1.49

Computer programs: COLLECT (Nonius, 1998), SCALEPACK (Otwinowski & Minor, 1997), SCALEPACK and DENZO (Otwinowski & Minor, 1997), SHELXS97 (Sheldrick, 2008), SHELXL97 (Sheldrick, 2008), DIAMOND (Brandenburg, 2006).

Acknowledgements top

This work was supported by the State of Baden-Württemberg (Stuttgart) and the Deutsche Forschungsgemeinschaft (DFG, Frankfurt/Main) within the funding program Open Access Publishing.

references
References top

Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany.

Müller-Bunz, H. & Schleid, Th. (1998). Z. Anorg. Allg. Chem. 624, 1082–1084.

Müller-Bunz, H. & Schleid, Th. (2001). Z. Anorg. Allg. Chem. 627, 218–223.

Nonius (1998). COLLECT. Nonius BV, Delft, The Netherlands.

Otwinowski, Z. & Minor, W. (1997). Methods in Enzymology, Vol. 276, Macromolecular Crystallography, Part A, edited by C. W. Carter Jr & R. M. Sweet, pp. 307–326. New York: Academic Press.

Rumanova, I. M. & Nikoleva, T. V. (1959). Sov. Phys. Crystallogr. 4, 789–795.

Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122.

Stoe & Cie (1995). X-SHAPE. Stoe & Cie, Darmstadt, Germany.