Download citation
Download citation
link to html
Lithium yttrium orthosilicate oxyapatite [lithium nonayttrium hexakis­(silicate) dioxide], LiY9(SiO4)6O2, crystallizes in the centrosymmetric space group P63/m at both 295 and 100 K. The structure closely resembles those of fluorine apatite and sodium yttrium orthosilicate oxyapatite [sodium nonayttrium hexakis­(silicate) dioxide], NaY9(SiO4)6O2, which was also investigated, at 270 and 100 K, in this study. There are two different crystallographic sites for the Y3+ ion, which are coordinated by seven and nine O atoms. One-fourth of the nine-coordinated site is occupied by Li or Na atoms, thus maintaining charge balance. The Si atom occupies a tetrahedral site. The two compounds show no symmetry change between room temperature and 100 K, and the alterations in structural parameters are small.

Supporting information

cif

Crystallographic Information File (CIF) https://doi.org/10.1107/S0108270103023321/ln1182sup1.cif
Contains datablocks global, LiY296K, LiY100K, NaY270K, NaY100K

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270103023321/ln1182LiY296Ksup2.hkl
Contains datablock LiY296K

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270103023321/ln1182LiY100Ksup3.hkl
Contains datablock LiY100K

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270103023321/ln1182NaY270Ksup4.hkl
Contains datablock NaY270K

hkl

Structure factor file (CIF format) https://doi.org/10.1107/S0108270103023321/ln1182NaY100Ksup5.hkl
Contains datablock NaY100K

Comment top

Apatite-type compounds, general formula M10(XO4)6Z2, show a large chemical variety and occur as both natural and synthetic compounds, with high relevance in industrial and biological research (White & ZhiLi, 2003). In natural apatite, the Z site is usually occupied by F, Cl or OH atom, but in oxy-apatite, O atoms also occur on this site. The title compounds can be derived from Ca5(PO4)3F (apatite sensu strictu) by replacing Ca2+ by Y3+ [or other trivalent cations such as rare earth elements (REE)], PO43− by SiO44− and F by O2−. Charge balance is maintained in various ways in such orthosilicate oxy-apatites. If trivalent cations are assumed, the M site may contain cation defects (cation vacancies), as is the case in Gd9.330.67(SiO4)6O2 (Smolin & Shepelev, 1969), where □ denotes a cation vacancy, or in RE9.330.67(SiO4)6O2 (RE = La and Sm; Kuz'min & Belov, 1965). If a non-defect structure is assumed, and thus the M site is fully occupied, the compounds must contain some divalent cations, such as in Sm5(SiO4)3O, where some Sm3+ ions are reduced to Sm2+ (Morgan et al., 2002), or one monovalent cation may be replaced by one trivalent cation, such as in the title compounds, where one Y3+ ion is replaced by Na+ or Li+ ions. Additional compounds of this type are Nd8Mn2(SiO4)6O2 (Klüver & Müller-Buschbaum, 1975) and KNd9(SiO4)6O2 (Pushcharovskii et al., 1978). Except for the latter (space group P63), all others are in space group P63/m, which is also the symmetry of the parent phase apatite, Ca5(SiO4)3F.

We present here the structure refinement of the new compound LiY9(SiO4)6O2 at 100 and 295 K and compare the results with those for NaY9(SiO4)6O2 and Ca5(SiO4)3F. The crystal structure of NaY9(SiO4)6O2 was first described by Gunawardane et al. (1982). However, Gunawardane et al. (1982) only refined the Y3+ positions with anisotropic atomic displacement parameters. We also present a redetermination of the structure of NaY9(SiO4)6O2 at 270 and 100 K, giving full anisotropic atomic displacement parameters for all atoms.

The following description of the structures refers predominantly to the data sets for each compound recorded near room temperature. The lattice parameters of NaY9(SiO4)6O2 (at 270 K) are in perfect agreement with those given by Gunawardane et al. (1982) for their sample (which has a = 9.334 (2) Å and c = 6.759 (1) Å). At room temperature, the a lattice parameter for LiY9(SiO4)6O2 is similar to that of NaY9(SiO4)6O2 [a = 9.3386 (10) Å], whereas the c parameter is 0.027 Å smaller than that of the sodium compound. Fig. 1 shows the molecular structure of NaY9(SiO4)6O2, including the atomic nomenclature used in this paper, and Figs. 2 and 3 show polyhedral representations of the structure, viewed along (0001). At 295 K, the structure of LiY9(SiO4)6O2 consists of discrete SiO4 tetrahedra, with Si—O distances ranging between 1.600 (6) and 1.623 (4) Å; the mean value is 1.615 (5) Å. The bond lengths are very similar to those found for NaY9(SiO4)6O2 at 270 K [mean Si—O = 1.618 (5) Å]. The mean Si—O bond length in the silicate-oxy-apatite is ~0.09 Å larger than the average P—O bond length in fluorine-apatite (1.535 Å, Sundarsanen al., 1972), thus perfectly reflecting the difference in ionic radii between [IV]Si4+ and [IV]P5+ [0.26 and 0.17 Å, respectively (Shannon & Prewitt, 1969); the first superscript refers to the coordination number of the specific cation]. The bond-length distortion (deviation of individual bond lengths from their mean value; BLD; Renner & Lehmann, 1986) of the SiO4 bonds in LiY9(SiO4)6O2 is small [BLD = 0.52 (5)%], but it is somewhat larger than that in the sodium compound [BLD = 0.33 (5)%]. The tetrahedral angle variance (TAV; Robinson et al., 1971), which gives the deviation of individual bond angles from the ideal tetrahedral bond angle (109.47°), is slightly smaller [11.8 (2)°] in the lithium compound [cf. 12.6 (2)° for NaY9(SiO4)6O2]. The large values of the TAV show that the tetrahedron is distinctly distorted; however, this behaviour is observable not only in the two compounds investigated here but also in other silicate-oxy-apatites. Apatite itself [Ca5(PO4)3F; Sudarsanan et al.,1973] contains regular tetrahedral sites [BLD = 0.20 (5)% and TAV = 3.4 (2)°], mainly because the O3—P—O3(x,y,-z + 1/2) bond angle is much larger (i.e. more ideal) in apatite [107.4 (2)°, compared with 104.0 (3) and 103.4 (3)° in the lithium and sodium oxy-apatite, respectively]. The tetrahedral O—O edge opposite the O3—Si—O3(x,y,-z + 1/2) angle is common to the tetrahedron and the sevenfold coordinated Y1 polyhedron, while all four of the tetrahedral corners are also shared with four additional Y1 polyhedra. The small O3—Si—O3(x,y,-z + 1/2) bond angle reflects enhanced electrostatic repulsion across the common edge between the tetrahedron and the Y1 site. The edges opposite the O1—Si—O3 angles are common to the tetrahedral site and two neighbouring Y2 polyhedra, and one corner of the tetrahedron is also shared with a third Y2 site. The volume of the tetrahedron in LiY9(SiO4)6O2 (VTET = 2.15 Å3) is comparable to that in NaY9(SiO4)6O2 (VTET = 2.16 Å3).

Yttrium occupies two different sites, viz. Y1 [6(h)] and Y2 [4(f)]. The Y atom at 6(h) is coordinated by seven O atoms in a pentagonal bipyramidal geometry (one O1, one O2, four O3 and one O4 atom; Fig. 3). Atom O4 lies at position 2a (with z=1/4, 3/4) and fits into the cavity of triangles formed by three Y1 atoms (Fig. 2). A close resemblance between the two title compounds and fluorine apatite is evident here. In Ca5(PO4)3F, the F atom (substituted for the O atom) also lies at position 2a. Larger anions, such as Cl in chlorine apatite Ca5(PO4)5Cl, are found at position 2 b (with z=0, 1/2). In Ca5(PO4)3Cl, the Cl atom, corresponding to atom O4 in (I), is linked to six metal atoms. A central Y1O7 polyhedron shares five out of its seven corners with other Y3+O7 Y1 polyhedra via the four symmetry-related O3 atoms and atom O4. Viewed along the c axis, it becomes apparent that three Y1 sites share one central O4 atom at a common corner and are arranged in a trigonal way around the hexagonal axis. The O3 atoms are common corners of one Y1 polyhedron, one Y2 polyhedron and one tetrahedron, while atoms O1 and the O2 are common to two Y2 polyhedra and one tetrahedron. In LiY9(SiO4)6O2 at 295 K, the Y1—O bond distances range between 2.1973 (7) and 2.699 (6) Å [mean 2.380 (4) %A]. This latter value is larger than that in NaY9(SiO4)6O2 at 270 K [2.366 (4) Å], mainly because the Y1—O2(-y,x-y,z) bond length [2.700 (7) Å] is much longer in LiY9(SiO4)6O2 than in the sodium compound [2.634 (5) Å]. Atom O2 lies at the conjunction point of two Y2 polyhedra, one Y1 polyhedron (sharing common edges) and one tetrahedral site (shared corner). The shortest Y1—O bond length is that to the `free' O4 atom, which lies at position 2(a) (z = 1/4 and 3/4). Because the Y1—O2(-y,x-y,z) bond is longer, the bond-length distortion [3.48 (5)%] is higher for LiY9(SiO4)6O2 than for NaY9(SiO4)6O2 [BLD = 3.05 (5)%], and both values are higher than that for fluorine apatite, [BLD = 2.48 (5)%; Sundarsanan et al., 1972]. The volumes of the Y1 polyhedra are similar to one another (VY1 = 19.8 and 20.0 Å3 in the Na and the Li compounds, respectively). The average Y—O bond is ~0.06 Å smaller than the average Ca—O bond lengths ?in fluorine apatite? (Sundarsanan et al., 1972), again reflecting the size difference between Y3+ and Ca2+.

The Y3+ ion, together with the Na+ or Li+ ion at the 4(f) (Y2) position, is coordinated by nine atoms at average distances of 2.502 (5) and 2.521 (5) Å for the lithium and sodium compounds, respectively, forming a tricapped trigonal-prismatic geometry (Fig. 3). A central Y2—O polyhedron shares two common faces (one defined by the three symmetry-related O1 atoms, the other by three symmetry-related O2 atoms) with two neighbouring Y2 polyhedra, forming a face-sharing row in the [0 0 0 1] direction. In LiY9(SiO4)6O2 at 295 K, six out of the nine Y2—O bonds are between 2.312 (4) and 2.411 (4) Å (those forming shared faces), and the other three are longer [2.782 (6) Å]. All of the Y2—O bond lengths in LiY9(SiO4)6O2 are 0.013–0.025 Å shorter than those in NaY9(SiO4)6O2. As the row of Y2 polyhedra runs parallel the c axis and Li+ is found on the Y2 site, the fact that the c lattice parameter is shorter in LiY9(SiO4)6O2 than in the sodium analogue can be related directly to the replacement of the larger Na+ ion by the much smaller Li+ cation. While the volume of the Y1 site in LiY9(SiO4)6O2 is similar to that in NaY9(SiO4)6O2, the volume of the Y2 polyhedron is somewhat lower [VY2 = 29.82 (1) Å3 in LiY9(SiO4)6O2 and VY2 = 30.35 (1) Å3 in NaY9(SiO4)6O2]. For both compounds, the average Y2—O bond is longer than the average Y1—O bond, which is mainly due to the different coordination numbers of the two sites, and thus to the different ionic radii for the Y3+ ion. The O atoms show significant anisotropic vibration, which is most evident for atoms O2 and O3 in both compounds. This result shows that an isotropic description of the O atoms, as given by Gunawardane et al. (1982) for NaY9(SiO4)6O2, is not appropriate.

Both compounds also adopt P63/m symmetry at 100 K. No change of symmetry takes place. The the unit cell of LiY9(SiO4)6O2 contracts uniformly (by ~0.3%) in both both the a and c directions. From the available two points (100 and 295 K), a linear thermal-expansion coefficient (α = 13.7 × 10−5 K−1) can be estimated for both the a and the c lattice parameters. These thermal-expansion coefficients are much larger than those of NaY9(SiO4)6O2, where α is 6.6 × 10−5 and 2.1 × 10−5 K−1 for the a and c lattice parameters, respectively. The overall changes in individual and mean bond lengths upon cooling are small and, because of the rather large estimated standard deviations, are only slightly more than 1–2 s.u. ?Some trends of a more general nature may also be extracted.? For both compounds, the average Y2—O bond lengths, as well as the Y2 site polyhedral volumes, show the most significant change (contraction) upon cooling; the Y1—O bonds also contract upon cooling, but to a lesser extent. This behaviour shows the ninefold-coordinated and Li+/Na+-containing site to be more susceptible (less rigid) to temperature changes than the Y1 site. For both compounds, the average Si—O bond is not shortened with decreasing temperature but tends to increase. It has to be kept in mind that the overall changes are small and within 1 s.u. For bond lengths corrected for thermal motion, these effects are even more pronounced but are still only slightly larger than 1 s.u. At 100 K, the anisotropic atomic displacement parameters are generally smaller than those of the 270 and 295 K structures. For the Y– and the Si-atom site, these parameters decrease uniformly (by ~15%), while for the O-atom sites, these parameters decrease by 20–30%. Atoms O2, O3 and O4 still exhibit large anisotropic vibrations at 100 K.

Experimental top

Single crystals of the title compounds were obtained while attempting to synthesize the clinopyroxene compounds LiYSi2O6 and NaYSi2O6 using high-temperature solution (flux) growth methods. Li2CO3 (Na2CO3), Y2O3 and SiO2 were mixed in proportions corresponding to the chemical composition of LiYSi2O6 (NaYSi2O6). The carefully ground mixtures and Li2MoO4 (Na2MoO4), serving as the high-temperature solvent (nutrient–flux ratio 1:10), were placed into a covered platinum crucible, heated slowly to 1573 K (1473 K), maintained at this temperature for 24 h and then cooled slowly (2 K h−1) to 673 K. As synthesis experiments have shown, the clinopyroxene phases are not stable under these experimental conditions. After removing the high-temperature flux in the case of the lithium compound, the experimental product consisted of colourless prismatic- to-needle-like colourless crystals of LiY9(SiO4)6O2. For the NaY9(SiO4)6O2 compound, the product consisted of colourless cubic crystals of Y2Si2O7 (thortveitite type; Redhammer & Roth, 2003), thin large platelets of Na2Si2O5 and cubic colourless crystals of NaY9(SiO4)6O2. Semiquantitative EDX (energy-dispersive X-ray) analysis on the latter crystals using a Zeiss scanning electron microscope revealed the presence of Na, Y, Si and O atoms.

Refinement top

For the refinement of LiY9(SiO4)6O2, initial structure solution on the data set at 100 K showed that the compound exhibits the oxy-apatite structure type. Two different Y3+ [6(h) and 4(f)], one Si4+ [6(h)] and four different O2− positions were found. Subsequent structure refinements on the absorption-corrected data were performed, in the final stage of which all site occupancies were allowed to vary. A distinct cation deficit was found at the Y2 [4(f)] position, whereas all other positions (including the O-atom positions) showed fully occupied sites within 1 s.u. The occupancy at the Y2 position was 0.254 (corresponding to 3.048 Y3+ atoms per formula unit) instead of the required 0.3333 (4.0 Y3+ atoms per formula unit). For a cation deficient but charge-balanced compound [Y9.330.67(SiO4)6O2], the occupancy at the Y2 site should refine to 0.2778 (3.33 Y3+ atoms per formula unit). It was concluded that the Y2 site is fully occupied, the stoichiometric compound LiY9(SiO4)6O2 has been formed during synthesis and the Li+ ion occupies 0.25 of the Y2 [4(f)] site, whereas 0.75 are occupied by Y3+. Fixing the occupancies of the Y2 site to the above stoichiometry, but allowing all other sites to vary freely, the final refinement of the site occupation factors converged to 0.995 (5) Y1, 0.998 (9) Si, 1.001 (18) O1, 1.014 (18) O2, 0.998 (18) O3 and 1.00 (2) O4 at 100 K, and to 1.000 (9) Y1, 1.007 (14) Si, 1.00 (2) O1, 1.01 (2) O2, 1.01 (3) O3 and 1.00 (3) O4 at 295 K. These occupancies confirm a stoichiometric model, and thus all occupancies were fixed to their ideal values for all atoms in the final refinement stage. For the refinement of NaY9(SiO4)6O2, the initial structure model for the data at 100 K consisted of two different Y3+ sites, one Si4+ site and four different O2− positions. From the structure topology, it was found that the compound belongs to the apatite structure type. the Y3+ ion is on at the 6 h and 4f positions (instead of Ca2+ in e.g. fluorine-apatite; Sudarsanan et al., 1972), the Si4+ ion is on 6 h (instead of P5+), and atom O4 is found in the 2a position (instead of F). Subsequent structure refinements showed distinct cation deficits at the 4f position [3.08 Y3+ atoms per formula unit (apfu) instead of 4.0 required]. The deficit, however, was larger than expected for a charge-balanced cation defect oxy-apatite (3.33 apfu). From semiquantitative EDX analysis it was learnt that the compound contains significant amounts of Na+, which in turn was put in to the 4f position (0.25 Na+ + 0.75 Y3+). Refinements were also performed in which the site occupation of the 4f position was fixed; however, the occupancies of successive sites were allowed to vary. These refinements converged to site occupation values of 1.036 (8) Y1, 1.006 (12) Si, 1.019 (8) O1, 1.043 (8) O2, 1.043 (9) O3 and 1.056 (8) O4 at 100 K. As these results support a stoichiometric model, all occupancies were fixed at their ideal values in the final refinement stage.

Computing details top

For all compounds, data collection: X-AREA (Stoe & Cie, 2002); cell refinement: X-AREA; data reduction: X-AREA; program(s) used to solve structure: SHELXS97 (Sheldrick, 1997); program(s) used to refine structure: SHELXL97 (Sheldrick, 1997). Molecular graphics: Diamond (Brandenburg & Berndt 1999) for LiY296K, LiY100K; Diamond 2.0 (Brandenburg & Berndt 1999) for NaY270K, NaY100K. Software used to prepare material for publication: WinGX (Farrugia, 1999) for LiY296K, LiY100K; WinGX v1.64.05 (Farrugia, 1999) for NaY270K, NaY100K.

Figures top
[Figure 1] Fig. 1. A view of NaY9(SiO4)6O2 (95% probability displacement ellipsoids) at 270 K. [Symmetry codes: (i) x,y,1/2 − z; (ii) 1 − x + y,1 − x,z; (iii) x-y,x,-z; (iv) x-y,x,1/2 + z; (v) −y,x-y,z; (vi) 1 − x,1 − y,1/2 + z; (vii) y,1 − x + y,1/2 + z; (viii) x,1 + y,z.]
[Figure 2] Fig. 2. A polyhedral representation of NaY9(SiO4)6O2 at 270 K, viewed along [0 0 0 1]. Only the SiO4 tetrahedra are shown for clarity, with displacement ellipsoids at the 95% probability level.
[Figure 3] Fig. 3. A polyhedral representation of NaY9(SiO4)6O2 at 270 K, viewed along [0 0 0 1], showing the Y1 and Y2 polyhedra. The Y2 polyhdrea are only shown for z=3/4.
(LiY296K) top
Crystal data top
LiY9(SiO4)6O2Dx = 4.546 Mg m3
Mr = 1391.76Mo Kα radiation, λ = 0.71073 Å
Hexagonal, P63/mCell parameters from 3117 reflections
Hall symbol: -P 6cθ = 2.9–27.8°
a = 9.3376 (14) ŵ = 25.85 mm1
c = 6.7321 (10) ÅT = 295 K
V = 508.34 (13) Å3Prism, colourless
Z = 10.16 × 0.08 × 0.08 mm
F(000) = 646
Data collection top
STOE IPDS 2
diffractometer
325 reflections with I > 2σ(I)
Radiation source: sealed X-ray tubeRint = 0.091
rotation method scansθmax = 26.4°, θmin = 2.5°
Absorption correction: numerical
via equivalents using Stoe X-SHAPE and X-RED (Stoe & Cie, 1996)
h = 1111
Tmin = 0.023, Tmax = 0.167k = 1111
4204 measured reflectionsl = 88
382 independent reflections
Refinement top
Refinement on F20 restraints
Least-squares matrix: full w = 1/[σ2(Fo2) + (0.013P)2]
where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.031(Δ/σ)max < 0.001
wR(F2) = 0.054Δρmax = 0.98 e Å3
S = 1.07Δρmin = 0.57 e Å3
382 reflectionsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
46 parametersExtinction coefficient: 0.051 (3)
Crystal data top
LiY9(SiO4)6O2Z = 1
Mr = 1391.76Mo Kα radiation
Hexagonal, P63/mµ = 25.85 mm1
a = 9.3376 (14) ÅT = 295 K
c = 6.7321 (10) Å0.16 × 0.08 × 0.08 mm
V = 508.34 (13) Å3
Data collection top
STOE IPDS 2
diffractometer
382 independent reflections
Absorption correction: numerical
via equivalents using Stoe X-SHAPE and X-RED (Stoe & Cie, 1996)
325 reflections with I > 2σ(I)
Tmin = 0.023, Tmax = 0.167Rint = 0.091
4204 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.03146 parameters
wR(F2) = 0.0540 restraints
S = 1.07Δρmax = 0.98 e Å3
382 reflectionsΔρmin = 0.57 e Å3
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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Y10.23327 (8)0.23732 (9)0.250.0029 (3)
Y20.33330.66670.49869 (18)0.0083 (5)0.75
Li0.33330.66670.49869 (18)0.008 (3)0.25
Si0.4009 (3)0.0269 (3)0.250.0028 (8)
O4000.250.017 (3)
O10.6005 (7)0.1255 (7)0.250.0089 (19)
O20.3195 (8)0.1700 (7)0.250.0154 (19)
O30.3394 (7)0.0889 (6)0.0599 (6)0.0200 (16)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Y10.0045 (4)0.0025 (4)0.0016 (4)0.0017 (3)00
Y20.0067 (5)0.0067 (5)0.0114 (7)0.0033 (3)00
Li0.007 (5)0.007 (5)0.0114 (5)0.003 (2)00
Si0.0048 (12)0.0041 (12)0.0005 (10)0.0029 (9)00
O40.014 (4)0.014 (4)0.023 (6)0.007 (2)00
O10.010 (3)0.013 (3)0.008 (3)0.009 (3)00
O20.030 (4)0.004 (3)0.011 (3)0.008 (3)00
O30.042 (3)0.021 (3)0.012 (2)0.026 (2)0.0180 (18)0.0125 (16)
Geometric parameters (Å, º) top
Y1—O42.1973 (7)Y1—Y24.0004 (10)
Y1—O3i2.266 (4)Y2—O2v2.312 (4)
Y1—O1ii2.364 (6)Y2—O1vi2.411 (4)
Y1—O32.432 (4)Y2—O3vii2.782 (6)
Y1—O2iii2.699 (6)Y2—Sivi3.1793 (19)
Y1—Si3.064 (2)Si—O21.600 (6)
Y1—Siiii3.261 (2)Si—O11.614 (6)
Y1—Y1iv3.8059 (13)Si—O31.623 (4)
O4—Y1—O3i104.50 (14)O2iii—Y2—O1vi153.7 (2)
O3i—Y1—O3viii134.1 (3)O2ii—Y2—O1vi125.1 (2)
O4—Y1—O1ii152.85 (14)O2ii—Y2—O1x153.7 (2)
O3i—Y1—O1ii85.05 (13)O1vi—Y2—O1x76.19 (16)
O4—Y1—O384.62 (13)O2v—Y2—O3vii66.40 (16)
O3i—Y1—O3139.54 (17)O2iii—Y2—O3vii88.09 (18)
O3viii—Y1—O377.98 (9)O2ii—Y2—O3vii139.06 (15)
O1ii—Y1—O372.41 (18)O1vi—Y2—O3vii65.66 (17)
O4—Y1—O3ix84.62 (13)O1x—Y2—O3vii60.09 (16)
O3—Y1—O3ix63.50 (19)O1xi—Y2—O3vii126.79 (14)
O4—Y1—O2iii109.92 (13)O3vii—Y2—O3xii117.85 (4)
O3i—Y1—O2iii68.50 (13)O2—Si—O1113.9 (3)
O1ii—Y1—O2iii97.23 (19)O2—Si—O3111.1 (2)
O3—Y1—O2iii145.74 (11)O1—Si—O3108.1 (3)
O2v—Y2—O2iii73.33 (17)O3—Si—O3ix104.0 (3)
O2v—Y2—O1vi93.06 (15)
Symmetry codes: (i) xy, x, z+1/2; (ii) x+y+1, x+1, z; (iii) y, xy, z; (iv) x+y, x, z; (v) x, y+1, z; (vi) x+1, y+1, z+1; (vii) y, x+y+1, z+1/2; (viii) xy, x, z; (ix) x, y, z+1/2; (x) y, x+y+1, z+1; (xi) xy, x, z+1; (xii) x+1, y+1, z+1/2.
(LiY100K) top
Crystal data top
LiY9(SiO4)6O2Dx = 4.588 Mg m3
Mr = 1391.76Mo Kα radiation, λ = 0.71073 Å
Hexagonal, P63/mCell parameters from 4980 reflections
Hall symbol: -P 6cθ = 2.3–32.1°
a = 9.3108 (14) ŵ = 26.09 mm1
c = 6.7088 (10) ÅT = 100 K
V = 503.67 (13) Å3Prism, colourless
Z = 10.15 × 0.08 × 0.07 mm
F(000) = 646
Data collection top
STOE IPDS 2
diffractometer
455 reflections with I > 2σ(I)
Radiation source: sealed X-ray tubeRint = 0.065
rotation method scansθmax = 29.5°, θmin = 2.5°
Absorption correction: numerical
via equivalents using Stoe X-SHAPE and X-RED (Stoe & Cie, 1996)
h = 1212
Tmin = 0.087, Tmax = 0.149k = 1212
4987 measured reflectionsl = 89
508 independent reflections
Refinement top
Refinement on F20 restraints
Least-squares matrix: full w = 1/[σ2(Fo2) + (0.0091P)2 + 1.5231P]
where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.024(Δ/σ)max < 0.001
wR(F2) = 0.041Δρmax = 0.84 e Å3
S = 1.16Δρmin = 0.77 e Å3
508 reflectionsExtinction correction: SHELXL97, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
45 parametersExtinction coefficient: 0.0138 (11)
Crystal data top
LiY9(SiO4)6O2Z = 1
Mr = 1391.76Mo Kα radiation
Hexagonal, P63/mµ = 26.09 mm1
a = 9.3108 (14) ÅT = 100 K
c = 6.7088 (10) Å0.15 × 0.08 × 0.07 mm
V = 503.67 (13) Å3
Data collection top
STOE IPDS 2
diffractometer
508 independent reflections
Absorption correction: numerical
via equivalents using Stoe X-SHAPE and X-RED (Stoe & Cie, 1996)
455 reflections with I > 2σ(I)
Tmin = 0.087, Tmax = 0.149Rint = 0.065
4987 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.02445 parameters
wR(F2) = 0.0410 restraints
S = 1.16Δρmax = 0.84 e Å3
508 reflectionsΔρmin = 0.77 e Å3
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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Y10.23355 (5)0.23739 (5)0.250.00495 (15)
Y20.33330.66670.49900 (12)0.0101 (2)0.75
Li0.33330.66670.49900 (12)0.0101 (2)0.25
Si0.40061 (15)0.02708 (15)0.250.0054 (4)
O4000.250.0160 (19)
O10.6012 (4)0.1263 (4)0.250.0132 (11)
O20.3189 (5)0.1711 (4)0.250.0175 (11)
O30.3402 (4)0.0901 (3)0.0588 (4)0.0202 (6)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Y10.0058 (2)0.0046 (2)0.0044 (2)0.00260 (15)00
Y20.0080 (3)0.0080 (3)0.0143 (4)0.00402 (13)00
Li0.0080 (3)0.0080 (3)0.0143 (4)0.00402 (13)00
Si0.0063 (6)0.0054 (6)0.0057 (6)0.0038 (5)00
O40.008 (2)0.008 (2)0.032 (4)0.0040 (10)00
O10.0090 (17)0.0162 (18)0.017 (2)0.0085 (14)00
O20.033 (2)0.0078 (17)0.0124 (19)0.0103 (15)00
O30.0414 (16)0.0209 (12)0.0102 (13)0.0245 (12)0.0167 (12)0.0103 (10)
Geometric parameters (Å, º) top
Y1—O42.1926 (5)Y1—Y23.9894 (7)
Y1—O3i2.255 (3)Y2—O2iii2.301 (2)
Y1—O1ii2.355 (3)Y2—O1v2.398 (2)
Y1—O32.423 (3)Y2—O3vi2.765 (3)
Y1—O2iii2.690 (4)Y2—Siv3.1685 (12)
Y1—Si3.0496 (13)Si—O21.606 (3)
Y1—Siiii3.2514 (13)Si—O11.617 (3)
Y1—Y1iv3.7977 (9)Si—O31.624 (3)
O4—Y1—O3i104.52 (7)O2ix—Y2—O1v93.26 (8)
O3i—Y1—O3vii133.49 (16)O2ii—Y2—O1v125.17 (12)
O4—Y1—O1ii152.74 (8)O1v—Y2—O1x76.12 (9)
O3i—Y1—O1ii85.23 (7)O2iii—Y2—O3vi88.22 (11)
O4—Y1—O3viii84.84 (7)O2ix—Y2—O3vi66.20 (10)
O3i—Y1—O3viii78.09 (5)O2ii—Y2—O3vi138.67 (9)
O3vii—Y1—O3viii140.01 (11)O1v—Y2—O3vi65.62 (9)
O1ii—Y1—O3viii72.15 (10)O1x—Y2—O3vi60.40 (9)
O4—Y1—O384.84 (7)O1xi—Y2—O3vi126.92 (9)
O3viii—Y1—O363.91 (13)O2ii—Y2—O3xii66.20 (10)
O4—Y1—O2iii110.02 (7)O3vi—Y2—O3xii117.93 (3)
O3i—Y1—O2iii68.14 (8)O2—Si—O1113.9 (2)
O1ii—Y1—O2iii97.24 (11)O2—Si—O3111.39 (12)
O3viii—Y1—O2iii145.44 (7)O1—Si—O3107.66 (14)
O2iii—Y2—O2ix73.10 (10)O3—Si—O3viii104.4 (2)
O2iii—Y2—O1v153.76 (12)
Symmetry codes: (i) xy, x, z+1/2; (ii) x+y+1, x+1, z; (iii) y, xy, z; (iv) x+y, x, z; (v) x+1, y+1, z+1; (vi) y, x+y+1, z+1/2; (vii) xy, x, z; (viii) x, y, z+1/2; (ix) x, y+1, z; (x) y, x+y+1, z+1; (xi) xy, x, z+1; (xii) x+1, y+1, z+1/2.
(NaY270K) top
Crystal data top
NaY9(SiO4)6O2Dx = 4.579 Mg m3
Mr = 1407.72Mo Kα radiation, λ = 0.71073 Å
Hexagonal, P63/mCell parameters from 4465 reflections
Hall symbol: -P 6cθ = 3.1–32.3°
a = 9.3386 (10) ŵ = 25.77 mm1
c = 6.7589 (8) ÅT = 270 K
V = 510.47 (10) Å3Cuboid, colourless
Z = 10.15 × 0.14 × 0.10 mm
F(000) = 654
Data collection top
STOE IPDS 2
diffractometer
402 reflections with I > 2σ(I)
Radiation source: sealed X-ray tubeRint = 0.087
rotation method scansθmax = 28.2°, θmin = 2.5°
Absorption correction: numerical
via equivalents using Stoe X-SHAPE and X-RED (Stoe & Cie, 1996)
h = 1212
Tmin = 0.031, Tmax = 0.079k = 1212
5619 measured reflectionsl = 98
460 independent reflections
Refinement top
Refinement on F20 restraints
Least-squares matrix: full w = 1/[σ2(Fo2) + (0.0113P)2 + 2.1558P]
where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.035(Δ/σ)max < 0.001
wR(F2) = 0.053Δρmax = 0.70 e Å3
S = 1.20Δρmin = 0.87 e Å3
460 reflectionsExtinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
40 parametersExtinction coefficient: 0.0124 (11)
Crystal data top
NaY9(SiO4)6O2Z = 1
Mr = 1407.72Mo Kα radiation
Hexagonal, P63/mµ = 25.77 mm1
a = 9.3386 (10) ÅT = 270 K
c = 6.7589 (8) Å0.15 × 0.14 × 0.10 mm
V = 510.47 (10) Å3
Data collection top
STOE IPDS 2
diffractometer
460 independent reflections
Absorption correction: numerical
via equivalents using Stoe X-SHAPE and X-RED (Stoe & Cie, 1996)
402 reflections with I > 2σ(I)
Tmin = 0.031, Tmax = 0.079Rint = 0.087
5619 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.03540 parameters
wR(F2) = 0.0530 restraints
S = 1.20Δρmax = 0.70 e Å3
460 reflectionsΔρmin = 0.87 e Å3
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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Y10.23630 (7)0.24091 (8)0.250.0098 (2)
Y20.33330.66670.49809 (18)0.0140 (3)0.75
Na0.33330.66670.49809 (18)0.0140 (3)0.25
Si0.3976 (2)0.0261 (2)0.250.0080 (4)
O4000.250.0127 (16)
O10.5975 (6)0.1225 (6)0.250.0159 (10)
O20.3133 (7)0.1719 (6)0.250.0178 (10)
O30.3361 (5)0.0890 (5)0.0614 (6)0.0211 (9)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Y10.0118 (3)0.0112 (3)0.0080 (3)0.0071 (3)00
Y20.0143 (3)0.0143 (3)0.0134 (5)0.00714 (16)00
Na0.0143 (3)0.0143 (3)0.0134 (5)0.00714 (16)00
Si0.0084 (8)0.0075 (8)0.0084 (9)0.0042 (7)00
O40.007 (2)0.007 (2)0.024 (5)0.0035 (10)00
O10.009 (2)0.019 (2)0.022 (3)0.009 (2)00
O20.027 (3)0.007 (2)0.018 (3)0.008 (2)00
O30.039 (2)0.0228 (19)0.0108 (19)0.0222 (17)0.0127 (16)0.0096 (14)
Geometric parameters (Å, º) top
Y1—O42.2285 (7)Y2—O2v2.324 (4)
Y1—O3i2.267 (4)Y2—O1vi2.433 (4)
Y1—O1ii2.340 (5)Y2—O3vii2.807 (4)
Y1—O32.414 (4)Y2—Sivi3.1995 (17)
Y1—O2iii2.634 (5)Si—O21.607 (5)
Y1—Si3.0519 (18)Si—O11.618 (5)
Y1—Siiii3.2370 (19)Si—O31.623 (4)
Y1—Y1iv3.8599 (11)
O4—Y1—O3i102.90 (11)O2iii—Y2—O1vi155.20 (17)
O3i—Y1—O3viii136.4 (2)O2ii—Y2—O1vi123.50 (16)
O4—Y1—O1ii152.98 (12)O1vi—Y2—O1x76.44 (14)
O3i—Y1—O1ii86.33 (11)O1x—Y2—O1xi76.44 (13)
O3i—Y1—O3ix77.62 (8)O2v—Y2—O3vii65.38 (14)
O3viii—Y1—O3ix139.98 (16)O2iii—Y2—O3vii89.72 (15)
O4—Y1—O383.40 (10)O2ii—Y2—O3vii138.75 (13)
O1ii—Y1—O373.75 (14)O1vi—Y2—O3vii65.55 (13)
O3ix—Y1—O363.72 (19)O1x—Y2—O3vii59.76 (14)
O4—Y1—O2iii109.55 (11)O1xi—Y2—O3vii126.68 (13)
O3i—Y1—O2iii69.22 (11)O3vii—Y2—O3xii117.72 (4)
O1ii—Y1—O2iii97.47 (16)O2—Si—O1113.9 (3)
O3ix—Y1—O2iii146.25 (10)O2—Si—O3110.97 (18)
O2v—Y2—O2iii73.69 (14)O1—Si—O3108.5 (2)
O2v—Y2—O1vi93.14 (12)O3ix—Si—O3103.4 (3)
Symmetry codes: (i) xy, x, z+1/2; (ii) x+y+1, x+1, z; (iii) y, xy, z; (iv) x+y, x, z; (v) x, y+1, z; (vi) x+1, y+1, z+1; (vii) y, x+y+1, z+1/2; (viii) xy, x, z; (ix) x, y, z+1/2; (x) y, x+y+1, z+1; (xi) xy, x, z+1; (xii) x+1, y+1, z+1/2.
(NaY100K) top
Crystal data top
NaY9(SiO4)6O2Dx = 4.593 Mg m3
Mr = 1407.72Mo Kα radiation, λ = 0.71073 Å
Hexagonal, P63/mCell parameters from 5008 reflections
Hall symbol: -P 6cθ = 3.1–32.1°
a = 9.3274 (10) ŵ = 25.84 mm1
c = 6.7554 (7) ÅT = 100 K
V = 508.98 (9) Å3Cuboid, colourless
Z = 10.15 × 0.14 × 0.10 mm
F(000) = 654
Data collection top
STOE IPDS 2
diffractometer
534 reflections with I > 2σ(I)
Radiation source: sealed X-ray tubeRint = 0.086
rotation method scansθmax = 32.1°, θmin = 2.5°
Absorption correction: numerical
via equivalents using Stoe X-SHAPE and X-RED (Stoe & Cie, 1996)
h = 1313
Tmin = 0.027, Tmax = 0.073k = 1313
7439 measured reflectionsl = 109
637 independent reflections
Refinement top
Refinement on F20 restraints
Least-squares matrix: full w = 1/[σ2(Fo2) + (0.0168P)2 + 1.3664P]
where P = (Fo2 + 2Fc2)/3
R[F2 > 2σ(F2)] = 0.036(Δ/σ)max < 0.001
wR(F2) = 0.057Δρmax = 0.93 e Å3
S = 1.20Δρmin = 0.94 e Å3
637 reflectionsExtinction correction: SHELXL, Fc*=kFc[1+0.001xFc2λ3/sin(2θ)]-1/4
40 parametersExtinction coefficient: 0.0093 (8)
Crystal data top
NaY9(SiO4)6O2Z = 1
Mr = 1407.72Mo Kα radiation
Hexagonal, P63/mµ = 25.84 mm1
a = 9.3274 (10) ÅT = 100 K
c = 6.7554 (7) Å0.15 × 0.14 × 0.10 mm
V = 508.98 (9) Å3
Data collection top
STOE IPDS 2
diffractometer
637 independent reflections
Absorption correction: numerical
via equivalents using Stoe X-SHAPE and X-RED (Stoe & Cie, 1996)
534 reflections with I > 2σ(I)
Tmin = 0.027, Tmax = 0.073Rint = 0.086
7439 measured reflections
Refinement top
R[F2 > 2σ(F2)] = 0.03640 parameters
wR(F2) = 0.0570 restraints
S = 1.20Δρmax = 0.93 e Å3
637 reflectionsΔρmin = 0.94 e Å3
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.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Å2) top
xyzUiso*/UeqOcc. (<1)
Y10.23648 (6)0.24108 (6)0.250.00835 (14)
Y20.33330.66670.49839 (14)0.01172 (18)0.75
Na0.33330.66670.49839 (14)0.01172 (18)0.25
Si0.39754 (17)0.02623 (17)0.250.0071 (3)
O4000.250.0136 (13)
O10.5986 (5)0.1235 (5)0.250.0137 (8)
O20.3131 (6)0.1717 (5)0.250.0172 (8)
O30.3367 (4)0.0896 (4)0.0610 (5)0.0191 (6)
Atomic displacement parameters (Å2) top
U11U22U33U12U13U23
Y10.0097 (2)0.0098 (2)0.0071 (2)0.00599 (18)00
Y20.0116 (2)0.0116 (2)0.0120 (4)0.00580 (11)00
Na0.0116 (2)0.0116 (2)0.0120 (4)0.00580 (11)00
Si0.0076 (6)0.0059 (6)0.0079 (6)0.0034 (5)00
O40.0100 (17)0.0100 (17)0.021 (4)0.0050 (8)00
O10.0099 (16)0.0150 (18)0.018 (2)0.0076 (15)00
O20.028 (2)0.0086 (17)0.014 (2)0.0088 (16)00
O30.0341 (17)0.0193 (13)0.0120 (14)0.0195 (13)0.0116 (13)0.0084 (11)
Geometric parameters (Å, º) top
Y1—O42.2275 (5)Y2—O2iii2.325 (3)
Y1—O3i2.265 (3)Y2—O1iv2.425 (3)
Y1—O1ii2.334 (4)Y2—O3i2.797 (4)
Y1—O32.412 (3)Y2—Siv3.1945 (13)
Y1—O2iii2.628 (5)Si—O21.605 (4)
Y1—Si3.0468 (15)Si—O31.624 (3)
Y1—Siiii3.2337 (15)Si—O3vi1.624 (3)
Y1—Y1iii3.8581 (9)Si—O11.625 (4)
O4—Y1—O3i102.93 (9)O2viii—Y2—O1iv93.20 (10)
O3i—Y1—O3vii136.10 (18)O2ii—Y2—O1iv123.67 (14)
O4—Y1—O1ii152.74 (10)O1iv—Y2—O1v76.30 (11)
O3i—Y1—O1ii86.46 (9)O2iii—Y2—O3ix89.73 (13)
O4—Y1—O3vi83.51 (8)O2viii—Y2—O3ix65.27 (12)
O3i—Y1—O3vi77.66 (6)O1iv—Y2—O3ix65.42 (11)
O3vii—Y1—O3vi140.17 (13)O1v—Y2—O3ix60.03 (11)
O1ii—Y1—O3vi73.46 (12)O1x—Y2—O3ix126.69 (10)
O3vi—Y1—O363.90 (15)O2iii—Y2—O3xi138.63 (11)
O4—Y1—O2iii109.48 (9)O1x—Y2—O3xi65.42 (11)
O3i—Y1—O2iii69.09 (9)O3ix—Y2—O3xi117.75 (4)
O1ii—Y1—O2iii97.78 (14)O2—Si—O3111.05 (15)
O3—Y1—O2iii146.15 (8)O3—Si—O3vi103.7 (2)
O2iii—Y2—O2viii73.67 (12)O2—Si—O1114.1 (2)
O2iii—Y2—O1iv155.09 (14)O3—Si—O1108.23 (16)
Symmetry codes: (i) xy, x, z+1/2; (ii) x+y+1, x+1, z; (iii) y, xy, z; (iv) x+1, y+1, z+1; (v) y, x+y+1, z+1; (vi) x, y, z+1/2; (vii) xy, x, z; (viii) x, y+1, z; (ix) y, x+y+1, z+1/2; (x) xy, x, z+1; (xi) x+1, y+1, z+1/2.

Experimental details

(LiY296K)(LiY100K)(NaY270K)(NaY100K)
Crystal data
Chemical formulaLiY9(SiO4)6O2LiY9(SiO4)6O2NaY9(SiO4)6O2NaY9(SiO4)6O2
Mr1391.761391.761407.721407.72
Crystal system, space groupHexagonal, P63/mHexagonal, P63/mHexagonal, P63/mHexagonal, P63/m
Temperature (K)295100270100
a, c (Å)9.3376 (14), 6.7321 (10)9.3108 (14), 6.7088 (10)9.3386 (10), 6.7589 (8)9.3274 (10), 6.7554 (7)
V3)508.34 (13)503.67 (13)510.47 (10)508.98 (9)
Z1111
Radiation typeMo KαMo KαMo KαMo Kα
µ (mm1)25.8526.0925.7725.84
Crystal size (mm)0.16 × 0.08 × 0.080.15 × 0.08 × 0.070.15 × 0.14 × 0.100.15 × 0.14 × 0.10
Data collection
DiffractometerSTOE IPDS 2
diffractometer
STOE IPDS 2
diffractometer
STOE IPDS 2
diffractometer
STOE IPDS 2
diffractometer
Absorption correctionNumerical
via equivalents using Stoe X-SHAPE and X-RED (Stoe & Cie, 1996)
Numerical
via equivalents using Stoe X-SHAPE and X-RED (Stoe & Cie, 1996)
Numerical
via equivalents using Stoe X-SHAPE and X-RED (Stoe & Cie, 1996)
Numerical
via equivalents using Stoe X-SHAPE and X-RED (Stoe & Cie, 1996)
Tmin, Tmax0.023, 0.1670.087, 0.1490.031, 0.0790.027, 0.073
No. of measured, independent and
observed [I > 2σ(I)] reflections
4204, 382, 325 4987, 508, 455 5619, 460, 402 7439, 637, 534
Rint0.0910.0650.0870.086
(sin θ/λ)max1)0.6250.6930.6660.748
Refinement
R[F2 > 2σ(F2)], wR(F2), S 0.031, 0.054, 1.07 0.024, 0.041, 1.16 0.035, 0.053, 1.20 0.036, 0.057, 1.20
No. of reflections382508460637
No. of parameters46454040
Δρmax, Δρmin (e Å3)0.98, 0.570.84, 0.770.70, 0.870.93, 0.94

Computer programs: X-AREA (Stoe & Cie, 2002), X-AREA, SHELXS97 (Sheldrick, 1997), SHELXL97 (Sheldrick, 1997), Diamond (Brandenburg & Berndt 1999), Diamond 2.0 (Brandenburg & Berndt 1999), WinGX (Farrugia, 1999), WinGX v1.64.05 (Farrugia, 1999).

Selected geometric parameters (Å, º) for (LiY296K) top
Y1—O42.1973 (7)Y2—O1v2.411 (4)
Y1—O3i2.266 (4)Y2—O3vi2.782 (6)
Y1—O1ii2.364 (6)Si—O21.600 (6)
Y1—O32.432 (4)Si—O11.614 (6)
Y1—O2iii2.699 (6)Si—O31.623 (4)
Y2—O2iv2.312 (4)
O2—Si—O1113.9 (3)O1—Si—O3108.1 (3)
O2—Si—O3111.1 (2)O3—Si—O3vii104.0 (3)
Symmetry codes: (i) xy, x, z+1/2; (ii) x+y+1, x+1, z; (iii) y, xy, z; (iv) x, y+1, z; (v) x+1, y+1, z+1; (vi) y, x+y+1, z+1/2; (vii) x, y, z+1/2.
Selected geometric parameters (Å, º) for (LiY100K) top
Y1—O42.1926 (5)Y2—O1iv2.398 (2)
Y1—O3i2.255 (3)Y2—O3v2.765 (3)
Y1—O1ii2.355 (3)Si—O21.606 (3)
Y1—O32.423 (3)Si—O11.617 (3)
Y1—O2iii2.690 (4)Si—O31.624 (3)
Y2—O2iii2.301 (2)
O2—Si—O1113.9 (2)O1—Si—O3107.66 (14)
O2—Si—O3111.39 (12)O3—Si—O3vi104.4 (2)
Symmetry codes: (i) xy, x, z+1/2; (ii) x+y+1, x+1, z; (iii) y, xy, z; (iv) x+1, y+1, z+1; (v) y, x+y+1, z+1/2; (vi) x, y, z+1/2.
Selected geometric parameters (Å, º) for (NaY270K) top
Y1—O42.2285 (7)Y2—O1v2.433 (4)
Y1—O3i2.267 (4)Y2—O3vi2.807 (4)
Y1—O1ii2.340 (5)Si—O21.607 (5)
Y1—O32.414 (4)Si—O11.618 (5)
Y1—O2iii2.634 (5)Si—O31.623 (4)
Y2—O2iv2.324 (4)
O2—Si—O1113.9 (3)O1—Si—O3108.5 (2)
O2—Si—O3110.97 (18)O3vii—Si—O3103.4 (3)
Symmetry codes: (i) xy, x, z+1/2; (ii) x+y+1, x+1, z; (iii) y, xy, z; (iv) x, y+1, z; (v) x+1, y+1, z+1; (vi) y, x+y+1, z+1/2; (vii) x, y, z+1/2.
Selected geometric parameters (Å, º) for (NaY100K) top
Y1—O42.2275 (5)Y2—O1iv2.425 (3)
Y1—O3i2.265 (3)Y2—O3i2.797 (4)
Y1—O1ii2.334 (4)Si—O21.605 (4)
Y1—O32.412 (3)Si—O31.624 (3)
Y1—O2iii2.628 (5)Si—O11.625 (4)
Y2—O2iii2.325 (3)
O2—Si—O3111.05 (15)O2—Si—O1114.1 (2)
O3—Si—O3v103.7 (2)O3—Si—O1108.23 (16)
Symmetry codes: (i) xy, x, z+1/2; (ii) x+y+1, x+1, z; (iii) y, xy, z; (iv) x+1, y+1, z+1; (v) x, y, z+1/2.
 

Follow Acta Cryst. C
Sign up for e-alerts
Follow Acta Cryst. on Twitter
Follow us on facebook
Sign up for RSS feeds