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

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

doi:10.1107/S1600536813026391

inorganic compounds

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ISSN: 2056-9890

Volume 69| Part 10| October 2013| Page i71

doi:10.1107/S1600536813026391

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

Marion C. Schäfer,^a,^b Ingo Hartenbach ^b and Thomas Schleid ^b ^*

^aDepartment of Chemistry and Biochemistry, University of Delaware, 304A Drake Hall, Newark, DE 19716, USA, and ^bInstitut für Anorganische Chemie, Universität Stuttgart, Pfaffenwaldring 55, 70569 Stuttgart, Germany
^*Correspondence e-mail: schleid@iac.uni-stuttgart.de

(Received 9 August 2013; accepted 24 September 2013; online 28 September 2013)

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.

CCDC reference: 962944

Related literature

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

Crystal data

Y₄F₂[Si₂O₇][SiO₄]
M_r = 653.91
Triclinic, $[P \overline 1]$
a = 6.4987 (5) Å
b = 6.6196 (5) Å
c = 13.2978 (9) Å
α = 87.418 (4)°
β = 85.702 (4)°
γ = 60.854 (3)°
V = 498.19 (6) Å³
Z = 2
Mo Kα radiation
μ = 23.52 mm⁻¹
T = 293 K
0.10 × 0.06 × 0.03 mm

Data collection

Nonius KappaCCD diffractometer
Absorption correction: numerical (X-SHAPE; Stoe & Cie, 1995 ) T_min = 0.104, T_max = 0.463
12473 measured reflections
2427 independent reflections
1475 reflections with I > 2σ(I)
R_int = 0.120

Refinement

R[F² > 2σ(F²)] = 0.055
wR(F²) = 0.107
S = 0.98
2427 reflections
182 parameters
Δρ_max = 1.56 e Å⁻³
Δρ_min = −1.49 e Å⁻³

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.

Supporting information

CCDC reference: 962944

Crystal structure: contains datablocks I, publication_text. DOI: 10.1107/S1600536813026391/wm2768sup1.cif

Structure factors: contains datablock I. DOI: 10.1107/S1600536813026391/wm2768Isup2.hkl

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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. O^2– 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.

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

	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.
	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
M_r = 653.91	F(000) = 608
Triclinic, P1	D_x = 4.359 Mg m⁻³
Hall symbol: -P 1	Mo Kα radiation, λ = 0.71073 Å
a = 6.4987 (5) Å	Cell parameters from 5136 reflections
b = 6.6196 (5) Å	θ = 0.4–28.3°
c = 13.2978 (9) Å	µ = 23.52 mm⁻¹
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 tube	1475 reflections with I > 2σ(I)
Graphite monochromator	R_int = 0.120
ω and ϕ mscans	θ_max = 28.2°, θ_min = 1.5°
Absorption correction: numerical (X-SHAPE; Stoe & Cie, 1995)	h = −8→8
T_min = 0.104, T_max = 0.463	k = −8→8
12473 measured reflections	l = −17→17

Refinement top

Refinement on F²	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F² > 2σ(F²)] = 0.055	w = 1/[σ²(F_o²) + (0.0233P)²] where P = (F_o² + 2F_c²)/3
wR(F²) = 0.107	(Δ/σ)_max < 0.001
S = 0.98	Δρ_max = 1.56 e Å⁻³
2427 reflections	Δρ_min = −1.49 e Å⁻³
182 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc²λ³/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0029 (6)

Crystal data top

Y₄F₂[Si₂O₇][SiO₄]	γ = 60.854 (3)°
M_r = 653.91	V = 498.19 (6) Å³
Triclinic, P1	Z = 2
a = 6.4987 (5) Å	Mo Kα radiation
b = 6.6196 (5) Å	µ = 23.52 mm⁻¹
c = 13.2978 (9) Å	T = 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)
T_min = 0.104, T_max = 0.463	R_int = 0.120
12473 measured reflections

Refinement top

R[F² > 2σ(F²)] = 0.055	182 parameters
wR(F²) = 0.107	0 restraints
S = 0.98	Δρ_max = 1.56 e Å⁻³
2427 reflections	Δρ_min = −1.49 e Å⁻³

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

	x	y	z	U_iso*/U_eq
Y1	0.32290 (19)	0.37903 (19)	0.20317 (8)	0.0102 (3)
Y2	0.94009 (19)	0.27320 (19)	0.02756 (8)	0.0083 (3)
Y3	0.21943 (19)	0.21311 (19)	0.52890 (8)	0.0083 (3)
Y4	0.82014 (19)	0.30705 (19)	0.32901 (8)	0.0084 (3)
F1	0.0366 (11)	0.2679 (11)	0.1862 (5)	0.0118 (14)
F2	0.2019 (11)	0.2616 (11)	0.3554 (5)	0.0143 (15)
Si1	0.4925 (5)	0.2508 (5)	0.9343 (2)	0.0098 (7)
Si2	0.2335 (5)	0.1526 (5)	0.7833 (2)	0.0084 (7)
Si3	0.2675 (5)	0.7298 (5)	0.4207 (2)	0.0078 (7)
O1	0.2654 (13)	0.3396 (14)	0.0197 (6)	0.0120 (17)
O2	0.2523 (13)	0.9039 (13)	0.0181 (6)	0.0117 (17)
O3	0.5550 (14)	0.5023 (14)	0.1127 (6)	0.0145 (18)
O4	0.4646 (12)	0.0987 (13)	0.8473 (5)	0.0086 (16)
O5	0.2042 (13)	0.3248 (13)	0.6867 (5)	0.0081 (16)
O6	0.6842 (13)	0.1117 (13)	0.2472 (6)	0.0122 (17)
O7	0.0069 (13)	0.7152 (13)	0.1437 (6)	0.0116 (17)
O8	0.4064 (13)	0.8414 (13)	0.4786 (6)	0.0092 (16)
O9	0.4233 (13)	0.5444 (14)	0.3321 (6)	0.0132 (18)
O10	0.8272 (13)	0.4057 (14)	0.4931 (6)	0.0135 (18)
O11	0.0157 (13)	0.9376 (13)	0.3873 (6)	0.0089 (17)

Atomic displacement parameters (Å²) top

	U¹¹	U²²	U³³	U¹²	U¹³	U²³
Y1	0.0090 (5)	0.0126 (6)	0.0088 (6)	−0.0050 (4)	−0.0027 (4)	0.0019 (4)
Y2	0.0088 (5)	0.0079 (6)	0.0077 (6)	−0.0035 (4)	−0.0013 (4)	−0.0008 (4)
Y3	0.0082 (5)	0.0081 (6)	0.0078 (6)	−0.0032 (4)	−0.0023 (4)	−0.0001 (4)
Y4	0.0079 (5)	0.0088 (6)	0.0076 (6)	−0.0034 (4)	−0.0011 (4)	−0.0008 (4)
F1	0.014 (3)	0.013 (4)	0.009 (3)	−0.005 (3)	−0.005 (3)	−0.001 (3)
F2	0.013 (3)	0.019 (4)	0.012 (4)	−0.009 (3)	−0.004 (3)	0.003 (3)
Si1	0.0073 (15)	0.0095 (16)	0.0107 (16)	−0.0022 (13)	−0.0022 (12)	−0.0016 (12)
Si2	0.0083 (15)	0.0058 (16)	0.0077 (16)	−0.0005 (13)	−0.0002 (12)	−0.0019 (12)
Si3	0.0079 (15)	0.0083 (16)	0.0077 (16)	−0.0044 (13)	0.0006 (12)	0.0002 (12)
O1	0.016 (4)	0.019 (4)	0.009 (4)	−0.009 (3)	0.005 (3)	−0.003 (3)
O2	0.011 (4)	0.010 (4)	0.016 (4)	−0.006 (3)	0.001 (3)	0.001 (3)
O3	0.017 (4)	0.012 (4)	0.010 (4)	−0.004 (3)	−0.003 (3)	0.006 (3)
O4	0.009 (4)	0.013 (4)	0.011 (4)	−0.006 (3)	−0.005 (3)	0.003 (3)
O5	0.010 (4)	0.009 (4)	0.009 (4)	−0.005 (3)	0.002 (3)	−0.002 (3)
O6	0.009 (4)	0.009 (4)	0.019 (4)	−0.001 (3)	−0.001 (3)	−0.004 (3)
O7	0.011 (4)	0.010 (4)	0.009 (4)	−0.002 (3)	0.002 (3)	0.002 (3)
O8	0.009 (4)	0.010 (4)	0.012 (4)	−0.006 (3)	−0.004 (3)	−0.002 (3)
O9	0.014 (4)	0.019 (4)	0.009 (4)	−0.008 (3)	0.000 (3)	−0.004 (3)
O10	0.012 (4)	0.012 (4)	0.009 (4)	0.000 (3)	−0.003 (3)	−0.001 (3)
O11	0.009 (4)	0.013 (4)	0.010 (4)	−0.005 (3)	−0.006 (3)	0.001 (3)

Geometric parameters (Å, º) top

Y1—O6	2.248 (7)	Y3—Si3ⁱⁱ	3.024 (3)
Y1—O3	2.286 (8)	Y3—Si2	3.392 (3)
Y1—O7	2.330 (7)	Y3—Y3ⁱ	3.406 (2)
Y1—F1	2.337 (6)	Y3—Si3^x	3.431 (3)
Y1—F2	2.353 (6)	Y3—Y3ⁱⁱ	3.559 (2)
Y1—O9	2.366 (7)	Y4—F1^iv	2.223 (6)
Y1—O1	2.540 (8)	Y4—O6	2.240 (8)
Y1—O4ⁱ	2.856 (8)	Y4—O11^v	2.269 (8)
Y1—Si2ⁱ	3.296 (3)	Y4—O9	2.272 (8)
Y1—Si2ⁱⁱ	3.428 (3)	Y4—O10	2.316 (8)
Y1—Y4	3.5649 (15)	Y4—O5^vi	2.364 (7)
Y1—Y2ⁱⁱⁱ	3.7351 (15)	Y4—F2^iv	2.400 (6)
Y2—O2ⁱⁱⁱ	2.216 (8)	Y4—Si3^vi	3.352 (3)
Y2—F1^iv	2.239 (6)	Y4—Y3^vi	3.6603 (16)
Y2—O7ⁱⁱⁱ	2.281 (8)	Y4—Y3^iv	3.6740 (14)
Y2—O2^v	2.295 (7)	Y4—Y1^iv	3.7852 (15)
Y2—O1ⁱⁱⁱ	2.322 (8)	F1—Y4^xi	2.223 (6)
Y2—O1^iv	2.354 (7)	F1—Y2^xi	2.239 (6)
Y2—O3	2.424 (8)	F2—Y4^xi	2.400 (6)
Y2—Si1^vi	3.064 (3)	Si1—O3^vi	1.613 (8)
Y2—Si1^vii	3.316 (3)	Si1—O2^vi	1.626 (8)
Y2—Y2^viii	3.411 (2)	Si1—O4	1.644 (8)
Y2—Y2^ix	3.486 (2)	Si1—O1^xii	1.666 (8)
Y2—Y1ⁱⁱⁱ	3.7351 (15)	Si2—O6ⁱ	1.622 (8)
Y3—O5	2.236 (7)	Si2—O7ⁱⁱ	1.633 (8)
Y3—O8^x	2.257 (8)	Si2—O5	1.637 (8)
Y3—O8^vi	2.273 (7)	Si2—O4	1.657 (7)
Y3—O10^xi	2.305 (7)	Si3—O11	1.621 (7)
Y3—F2	2.319 (6)	Si3—O9	1.632 (8)
Y3—O11ⁱⁱ	2.388 (8)	Si3—O8	1.660 (7)
Y3—O10^vi	2.398 (8)	Si3—O10^vi	1.684 (8)

O6—Y1—O3	78.8 (3)	O6—Y4—O10	138.3 (3)
O6—Y1—O7	163.3 (3)	O11^v—Y4—O10	84.6 (3)
O3—Y1—O7	85.3 (3)	O9—Y4—O10	90.6 (3)
O6—Y1—F1	119.2 (2)	F1^iv—Y4—O5^vi	78.7 (2)
O3—Y1—F1	142.5 (2)	O6—Y4—O5^vi	136.0 (3)
O7—Y1—F1	76.9 (2)	O11^v—Y4—O5^vi	148.0 (3)
O6—Y1—F2	83.0 (3)	O9—Y4—O5^vi	78.4 (3)
O3—Y1—F2	151.4 (2)	O10—Y4—O5^vi	75.9 (3)
O7—Y1—F2	109.4 (2)	F1^iv—Y4—F2^iv	67.0 (2)
F1—Y1—F2	66.0 (2)	O6—Y4—F2^iv	135.7 (3)
O6—Y1—O9	73.5 (3)	O11^v—Y4—F2^iv	77.8 (2)
O3—Y1—O9	79.2 (3)	O9—Y4—F2^iv	147.8 (3)
O7—Y1—O9	98.5 (3)	O10—Y4—F2^iv	70.5 (2)
F1—Y1—O9	135.6 (2)	O5^vi—Y4—F2^iv	71.9 (2)
F2—Y1—O9	74.6 (2)	Y4^xi—F1—Y2^xi	128.6 (3)
O6—Y1—O1	111.4 (3)	Y4^xi—F1—Y1	112.2 (2)
O3—Y1—O1	75.0 (3)	Y2^xi—F1—Y1	114.7 (3)
O7—Y1—O1	68.9 (3)	Y3—F2—Y1	149.1 (3)
F1—Y1—O1	67.9 (2)	Y3—F2—Y4^xi	102.2 (2)
F2—Y1—O1	132.7 (2)	Y1—F2—Y4^xi	105.6 (2)
O9—Y1—O1	152.0 (3)	O3^vi—Si1—O2^vi	115.4 (4)
O6—Y1—O4ⁱ	56.4 (2)	O3^vi—Si1—O4	109.4 (4)
O3—Y1—O4ⁱ	103.4 (3)	O2^vi—Si1—O4	108.6 (4)
O7—Y1—O4ⁱ	133.9 (2)	O3^vi—Si1—O1^xii	99.6 (4)
F1—Y1—O4ⁱ	68.9 (2)	O2^vi—Si1—O1^xii	113.6 (4)
F2—Y1—O4ⁱ	84.1 (2)	O4—Si1—O1^xii	110.0 (4)
O9—Y1—O4ⁱ	127.5 (2)	O6ⁱ—Si2—O7ⁱⁱ	117.1 (4)
O1—Y1—O4ⁱ	70.1 (2)	O6ⁱ—Si2—O5	114.0 (4)
O2ⁱⁱⁱ—Y2—F1^iv	122.9 (3)	O7ⁱⁱ—Si2—O5	106.6 (4)
O2ⁱⁱⁱ—Y2—O7ⁱⁱⁱ	79.4 (3)	O6ⁱ—Si2—O4	97.8 (4)
F1^iv—Y2—O7ⁱⁱⁱ	154.6 (3)	O7ⁱⁱ—Si2—O4	109.3 (4)
O2ⁱⁱⁱ—Y2—O2^v	81.8 (3)	O5—Si2—O4	111.9 (4)
F1^iv—Y2—O2^v	85.6 (2)	O11—Si3—O9	114.6 (4)
O7ⁱⁱⁱ—Y2—O2^v	86.0 (3)	O11—Si3—O8	109.0 (4)
O2ⁱⁱⁱ—Y2—O1ⁱⁱⁱ	108.9 (3)	O9—Si3—O8	115.8 (4)
F1^iv—Y2—O1ⁱⁱⁱ	106.1 (2)	O11—Si3—O10^vi	99.8 (4)
O7ⁱⁱⁱ—Y2—O1ⁱⁱⁱ	73.6 (3)	O9—Si3—O10^vi	107.4 (4)
O2^v—Y2—O1ⁱⁱⁱ	154.3 (3)	O8—Si3—O10^vi	108.9 (4)
O2ⁱⁱⁱ—Y2—O1^iv	153.3 (3)	Si1^vii—O1—Y2ⁱⁱⁱ	99.1 (4)
F1^iv—Y2—O1^iv	72.8 (2)	Si1^vii—O1—Y2^xi	129.2 (4)
O7ⁱⁱⁱ—Y2—O1^iv	82.0 (3)	Y2ⁱⁱⁱ—O1—Y2^xi	96.4 (3)
O2^v—Y2—O1^iv	78.1 (3)	Si1^vii—O1—Y1	120.2 (4)
O1ⁱⁱⁱ—Y2—O1^iv	83.6 (3)	Y2ⁱⁱⁱ—O1—Y1	100.3 (3)
O2ⁱⁱⁱ—Y2—O3	78.4 (3)	Y2^xi—O1—Y1	103.8 (3)
F1^iv—Y2—O3	78.6 (2)	Si1^vi—O2—Y2ⁱⁱⁱ	118.5 (4)
O7ⁱⁱⁱ—Y2—O3	121.1 (3)	Si1^vi—O2—Y2^xiii	139.1 (5)
O2^v—Y2—O3	142.0 (3)	Y2ⁱⁱⁱ—O2—Y2^xiii	98.2 (3)
O1ⁱⁱⁱ—Y2—O3	63.6 (3)	Si1^vi—O3—Y1	133.6 (5)
O1^iv—Y2—O3	127.9 (3)	Si1^vi—O3—Y2	96.7 (4)
O5—Y3—O8^x	124.4 (3)	Y1—O3—Y2	128.7 (3)
O5—Y3—O8^vi	84.1 (3)	Si1—O4—Si2	130.4 (5)
O8^x—Y3—O8^vi	82.5 (3)	Si1—O4—Y1ⁱ	136.4 (4)
O5—Y3—O10^xi	102.1 (3)	Si2—O4—Y1ⁱ	89.8 (3)
O8^x—Y3—O10^xi	112.7 (3)	Si2—O5—Y3	121.5 (4)
O8^vi—Y3—O10^xi	154.3 (3)	Si2—O5—Y4^vi	132.8 (4)
O5—Y3—F2	155.0 (2)	Y3—O5—Y4^vi	105.4 (3)
O8^x—Y3—F2	79.2 (3)	Si2ⁱ—O6—Y4	138.9 (4)
O8^vi—Y3—F2	91.6 (2)	Si2ⁱ—O6—Y1	115.8 (4)
O10^xi—Y3—F2	72.2 (2)	Y4—O6—Y1	105.2 (3)
O5—Y3—O11ⁱⁱ	79.8 (3)	Si2ⁱⁱ—O7—Y2ⁱⁱⁱ	129.9 (4)
O8^x—Y3—O11ⁱⁱ	77.4 (3)	Si2ⁱⁱ—O7—Y1	118.8 (4)
O8^vi—Y3—O11ⁱⁱ	140.4 (3)	Y2ⁱⁱⁱ—O7—Y1	108.2 (3)
O10^xi—Y3—O11ⁱⁱ	65.2 (3)	Si3—O8—Y3^xiv	121.6 (4)
F2—Y3—O11ⁱⁱ	117.1 (2)	Si3—O8—Y3^vi	135.4 (4)
O5—Y3—O10^vi	76.7 (3)	Y3^xiv—O8—Y3^vi	97.5 (3)
O8^x—Y3—O10^vi	147.8 (3)	Si3—O9—Y4	125.0 (4)
O8^vi—Y3—O10^vi	75.5 (3)	Si3—O9—Y1	133.0 (4)
O10^xi—Y3—O10^vi	81.6 (3)	Y4—O9—Y1	100.4 (3)
F2—Y3—O10^vi	78.4 (3)	Si3^vi—O10—Y3^iv	97.4 (3)
O11ⁱⁱ—Y3—O10^vi	133.8 (3)	Si3^vi—O10—Y4	112.9 (4)
F1^iv—Y4—O6	84.0 (3)	Y3^iv—O10—Y4	105.3 (3)
F1^iv—Y4—O11^v	99.0 (3)	Si3^vi—O10—Y3^vi	136.1 (4)
O6—Y4—O11^v	74.4 (3)	Y3^iv—O10—Y3^vi	98.4 (3)
F1^iv—Y4—O9	119.3 (2)	Y4—O10—Y3^vi	101.9 (3)
O6—Y4—O9	75.5 (3)	Si3—O11—Y4^xiii	145.4 (4)
O11^v—Y4—O9	127.5 (3)	Si3—O11—Y3ⁱⁱ	96.1 (4)
F1^iv—Y4—O10	135.4 (2)	Y4^xiii—O11—Y3ⁱⁱ	116.6 (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, y−1, z; (vi) −x+1, −y+1, −z+1; (vii) x, y, z−1; (viii) −x+2, −y, −z; (ix) −x+2, −y+1, −z; (x) x, y−1, z; (xi) x−1, y, z; (xii) x, y, z+1; (xiii) x−1, y+1, z; (xiv) x, y+1, z.

Experimental details

Crystal data
Chemical formula	Y₄F₂[Si₂O₇][SiO₄]
M_r	653.91
Crystal system, space group	Triclinic, 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)
V (Å³)	498.19 (6)
Z	2
Radiation type	Mo Kα
µ (mm⁻¹)	23.52
Crystal size (mm)	0.10 × 0.06 × 0.03

Data collection
Diffractometer	Nonius KappaCCD diffractometer
Absorption correction	Numerical (X-SHAPE; Stoe & Cie, 1995)
T_min, T_max	0.104, 0.463
No. of measured, independent and observed [I > 2σ(I)] reflections	12473, 2427, 1475
R_int	0.120
(sin θ/λ)_max (Å⁻¹)	0.664

Refinement
R[F² > 2σ(F²)], wR(F²), S	0.055, 0.107, 0.98
No. of reflections	2427
No. of parameters	182
Δρ_max, Δρ_min (e Å⁻³)	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

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

Brandenburg, K. (2006). DIAMOND. Crystal Impact GbR, Bonn, Germany. Google Scholar
Müller-Bunz, H. & Schleid, Th. (1998). Z. Anorg. Allg. Chem. 624, 1082–1084. Google Scholar
Müller-Bunz, H. & Schleid, Th. (2001). Z. Anorg. Allg. Chem. 627, 218–223. Google Scholar
Nonius (1998). COLLECT. Nonius BV, Delft, The Netherlands. Google Scholar
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. Google Scholar
Rumanova, I. M. & Nikoleva, T. V. (1959). Sov. Phys. Crystallogr. 4, 789–795. Google Scholar
Sheldrick, G. M. (2008). Acta Cryst. A64, 112–122. Web of Science CrossRef CAS IUCr Journals Google Scholar
Stoe & Cie (1995). X-SHAPE. Stoe & Cie, Darmstadt, Germany. Google Scholar