A high-pressure single-crystal synchrotron diffraction study of NH₄RbTe₄O₉·2H₂O: stability of three different TeO_x coordination polyhedra

The crystal structure of ammonium rubidium nona­oxotetra­tellurate(IV) dihydrate has been studied as a function of pressure up to 7.40 GPa. The ambient-pressure structure is characterized by the co-existence of three different Te-O polyhedra (TeO₃, TeO₄ and TeO₅), which are connected to form layers. NH₄⁺, H₂O and Rb⁺ are incorporated between the layers. Both the Rb1 position, which is located on a twofold axis, and the Rb2 position are partially occupied. The three different types of coordination polyhedra around Te⁴⁺ are stable up to at least 5.05 GPa. No phase transition is observed. The fit of the unit-cell volume as a function of pressure gives a zero-pressure bulk modulus of 34 (1) GPa with a zero-pressure volume of V₀ = 2620 (4) Å³ [B' = 1.4 (2)].

S1. Comment

The high-pressure behaviour of compounds with elements containing lone-pair electrons is far from uniform (Grzechnik, 2007). While in some compounds the application of pressure leads to phase transitions in which the coordination number around the lone-pair cation is increased, e.g. in Bi₂Ga₄O₉ (Friedrich et al., 2010), BiB₃O₆ (Dinnebier et al., 2009) or PbS (Grzechnik & Friese, 2010a), in others first-order phase transitions with breaking of bonds are observed, e.g. lilianite, Pb₃Bi₂S₆ (Olsen et al., 2008), and heyrovskyite, Pb₆Bi₂S₉ (Olsen et al., 2011). Pressure-induced amorphization is also observed in compounds containing lone-electron pairs, e.g. in Bi₄M₃O₁₂ compounds with M = Si, Ge or Ti (Arora et al., 2004; Meng et al., 1998; Grzechnik, 2009), in Tl₂CO₃ (Grzechnik & Friese, 2008, 2010b) or in Tl₂MoO₄ (Machon et al., 2010).

At atmospheric pressure, the coordination numbers (CN) of Te⁴⁺ cations in oxides range from 3 to 7 (Marukhnov et al., 2007). The higher the CN the more the stereoactivity of the lone pair is supressed. To the best of our knowledge, only two compounds containing Te⁴⁺ have been studied under high pressure: TlTeVO₅ (Grzechnik et al., 2009) and (NH₄)₂WTe₂O₈ (Grzechnik et al., 2010). With increasing pressure, the CN of Te⁴⁺ in TlTeVO₅ is increased from 4 at ambient pressure to 5 at higher pressures, and thus follows the trend observed for many other compounds with lone-electron pairs. For (NH₄)₂WTe₂O₈, on the other hand, the behaviour with increasing pressure is rather unusual. In the ambient-pressure structure, two distinct Te⁴⁺ sites are present, both of them being fourfold coordinated by oxygen (Kim et al., 2007). Surprisingly, at high pressure (5.09 GPa) the CN of one of the Te⁴⁺ sites is reduced from 3 to 4, resulting in two different coordination polyhedra for the two symmetrically independent Te⁴⁺ sites (Grzechnik et al., 2010). This seems to be the only known case where the CN around a lone-pair element is decreased with increasing pressure, indicating an increase in the stereoactivity of the lone pair at higher pressures.

The compound studied here, NH₄RbTe₄O₉.2H₂O, is exceptional, as three different coordination polyhedra around Te⁴⁺ exist simultaneously at ambient pressure, namely TeO₃, TeO₄ and TeO₅ (Fig. 1). The three polyhedra are connected to form [Te₄O₉]^2- layers in the ab plane (Fig. 2). NH₄⁺ and Rb⁺ cations are incorporated between the layers and provide the necessary charge balance and, in addition, water molecules are located between the layers (Kim & Halasyamani, 2008). Given the unusual behaviour of (NH₄)₂WTe₂O₈ under pressure and the unique structure of NH₄RbTe₄O₉.2H₂O characterized by the coexistence of three different coordination polyhedra around Te⁴⁺, we thought it would be worthwhile to carry out a high-pressure study of this compound.

Measurements at ambient pressure using laboratory equipment on crystals coming from the same batch as those investigated earlier by Kim & Halasyamani (2008) confirm the previous structure determination (see Fig. 1). However, in the earlier structure determination the Rb1 position, located on a two-fold axis, is fully occupied and the Rb2 position, located on a general position, is only half occupied, whereas our refinement of the occupation factors indicates that both Rb positions are partially occupied. In addition, in the earlier publication the N position could be approximated by a single position, while our data are best approximated assuming two atomic positions, both of them with an occupancy of 0.5. Refinement of the data at higher pressures does not lead to significantly different occupation factors for Rb⁺ and NH₄⁺. Only at the highest pressure at which structure refinement was carried out (5.05 GPa) is the N position better approximated by a single position.

Our studies based on synchrotron data show that the compound is stable up to at least 5.05 GPa, and there are no indications of a structural phase transition (Fig. 3). At 7.40 GPa, only lattice parameters could be extracted from the experiment, which nevertheless provided no evidence for the presence of a phase transition. The unit-cell volume could be fitted with a Murnaghan equation of state with a zero-pressure bulk modulus B₀ = 34 (1) GPa and a zero-pressure volume V₀ = 2620 (4) ų [B' = 1.4 (2)]. The bulk compressibility can be nearly entirely attributed to changes in the [Te₄O₉]^2- interlayer distance. A comparison with other compounds containing elements with lone-pair electrons shows that the high compressibility of the title compound is comparable with that of TlTeVO₅ [32 (1) GPa; Grzechnik et al., 2009], which contains both Tl⁺ and Te⁴⁺ cations, or with the compressibilites of Tl⁺-containing compounds, e.g. Tl₂MoO₄ (B₀ = 24.6; Machon et al., 2010) or Tl₂SeO₄ [B₀ = 29 (1); Grzechnik et al., 2008].

At ambient pressure, atom Te1 is coordinated by three O atoms, atoms Te2 and Te4 by four O atoms, and atom Te3 by five O atoms (Table 1). The shapes of the coordination polyhedra around the three symmetrically independent Te ions, as well as the average Te—O distances, do not change substantially with increasing pressure (Fig. 2, Table 1), although a detailed comparison is difficult as the estimated errors in the Te—O distances are very large for the high-pressure data. This is a consequence of the limited availibility of data, due to the restricted access to reciprocal space in the diamond anvil cell experiment, which in combination with the relatively large unit cell and the low symmetry of the compound leads to a low data-to-parameter ratio. All these observations suggest that the application of pressure has no pronounced influence on the stereochemical activity of the lone-pair electrons in NH₄RbTe₄O₉.2H₂O.

Related literature

For related literature, see: Arora et al. (2004); Boehler (2006); Dinnebier et al. (2009); Friedrich et al. (2010); Friese et al. (2009); Grzechnik (2007, 2009); Grzechnik & Friese (2008, 2010a, 2010b); Grzechnik et al. (2010); Grzechnik, Breczewski & Friese (2008); Grzechnik, Halasyamani, Chang & Friese (2009); Kabsch (2010); Kim & Halasyamani (2008); Kim et al. (2007); Machon et al. (2010); Mao et al. (1986); Marukhnov et al. (2007); Meng et al. (1998); Olsen et al. (2008, 2011); Petříček et al. (2006); Posse et al. (2011); Stoe & Cie (2005, 2006).

S2. Experimental

The crystals were synthesized according to the method described by Kim & Halasyamani (2008). Ambient-pressure data were measured on a crystal mounted on a glass pin on a Stoe IPDS 2T diffractometer and integrated using the X-AREA program (Stoe & Cie, 2006). A series of other crystals were tested on the same diffractometer and the best one was chosen for the high-pressure experiments. High-pressure data were collected at 1.13, 2.52, 3.45, 5.05 and 7.40 GPa in an Almax-type diamond anvil cell (Boehler, 2006) at room temperature on beamline D3 of the DORIS III storage ring at DESY at a wavelength of 0.3978 Å. A 0.250 mm hole was drilled into a stainless steel gasket preindented to a thickness of about 0.120 mm. A 1:1 mixture of pentane and isopentane was used as the pressure medium. The ruby luminescence method (Mao et al., 1986) was used for pressure calibration. For the high-pressure measurements up to 5.05 GPa, the intensities were indexed and integrated using the program XDS (Kabsch, 2010). Further data treatment was carried out according to the procedures described by Posse et al. (2011). Reflections affected by overlap with diamond reflections or strong gasket rings were identified according to the criteria described by Friese et al. (2009). The faces of the crystals were optimized using the program X-SHAPE (Stoe & Cie, 2005) and a numerical absorption correction was applied with the program JANA2006 (Petříček et al., 2006). The data at 7.40 GPa were not of sufficient quality for structure refinement, although lattice parameters could still be extracted.

S3. Refinement

Coordinates from Kim & Halasyamani (2008) were used as a starting model. Correction factors for resonant scattering were taken from the DABAX library (https://www.esrf.eu/UsersAndScience/Experiments/TBS/SciSoft/xop2.3/Main). For the refinement at ambient pressure, all atoms were treated anisotropically. Occupancies for the Rb positions were refined, but restrained to give a full occupancy per formula unit. For nitrogen, the assumption of one single position as in Kim & Halasyamani (2008) led to very large displacement parameters. Therefore, split atom positions were introduced. Refinement of occupation factors led to an equal occupancy for both positions and these were fixed to 0.5 in the final refinement cycles. As only some of the H atoms could be located in the difference Fourier maps, H atoms were not included in the model.

For the high-pressure data, measured at the synchrotron, Te ions were refined anisotropically, and Rb, O and N were refined isotropically. Occupation factors for Rb and N were fixed at the ambient-pressure values for all pressures, as trial refinements showed no significant deviations. The displacement parameters of the O atoms forming the coordination polyhedra of Te were restrained to be equal, as were those of the two water O atoms (O10 and O11).

The relatively large positive and negative residual densities for the high-pressure data can be explained by the experimental set up, so not all parts of reciprocal space were accessible. The high-pressure data are also affected by larger experimental errors than the ambient-pressure data. This might lead to artefacts in the electron density. Difference density maxima/distances from closest atom sites: ambient: 0.403 Å from Rb1; 1.13 GPa: 0.481 Å from Rb1; 2.52 GPa: 0.552 Å from Rb1; 3.45 GPa: 0.700 Å from Rb2; 5.05 GPa: 1.48Å from O11. Difference density minima/distances from closest atom sites: ambient: 1.544 Å from Te1; 1.13 GPa: 1.480 Å from Te1; 2.52 GPa: 1.420 Å from Te1; 3.45 GPa: 1.64 Å from O2; 5.05 GPa: 1.60 Å from O11.

Computing details

Data collection: X-AREA (Stoe & Cie, 2006) for I_ambient; Automar (Marresearch, 2009) for I_1.13GPa, I_2.52GPa, I_3.45GPa, I_5.05GPa. Cell refinement: X-AREA (Stoe & Cie, 2006) for I_ambient; XDS (Kabsch, 2010) for I_1.13GPa, I_2.52GPa, I_3.45GPa, I_5.05GPa. Data reduction: X-AREA (Stoe & Cie, 2006) and JANA2006 (Petříček et al., 2006) for I_ambient; XDS (Kabsch, 2010) and JANA2006 (Petříček et al., 2006) for I_1.13GPa, I_2.52GPa, I_3.45GPa, I_5.05GPa. For all compounds, program(s) used to solve structure: coordinates from Kim & Halasyamani (2008); program(s) used to refine structure: JANA2006 (Petříček et al., 2006); molecular graphics: ATOMS (Dowty, 1999); software used to prepare material for publication: JANA2006 (Petříček et al., 2006).

Figures

	Fig. 1. The atom-numbering scheme for the title compound, with atomic displacement ellipsoids drawn at the 50% probability level for ambient-pressure data. [Symmetry codes: (i) -x, y - 1/2, -z + 1/2; (ii) -x + 1/2, -y + 1/2, -z + 1/2.]
	Fig. 2. Partial views along [010] (top) and [100] (bottom) of the structure of NH4RbTe4O9.2H2O at ambient pressure (left) and 5.05 GPa (right). Te—O bonds are indicated. Rb cations are shown as large circles, Te cations as middle-sized circles and O atoms as small circles. N atoms are indicated by hatched circles.
	Fig. 3. Lattice parameters and unit-cell volume of NH4RbTe4O9.2H2O as a function of pressure. The solid line is the fit of the Murnaghan equation of state to the compressibility data.

(I_ambient) ammonium rubidium nonaoxotetratellurate(IV) dihydrate

Crystal data

NH4RbTe4O9·2H2O	F(000) = 2784
Mr = 793.9	Ambient conditions
Monoclinic, I2/a	Dx = 3.942 Mg m^−3
Hall symbol: -I 2ya	Mo Kα radiation, λ = 0.71069 Å
a = 18.999 (1) Å	Cell parameters from 2941 reflections
b = 6.7318 (4) Å	θ = 3.2–31.8°
c = 21.1835 (11) Å	µ = 12.41 mm^−1
β = 101.887 (4)°	T = 293 K
V = 2651.2 (3) Å^3	Irregular, light yellow
Z = 8	0.18 × 0.12 × 0.06 mm

Data collection

Stoe IPDS 2T diffractometer	2836 reflections with I > 3σ(I)
Radiation source: X-ray tube	Rint = 0.060
ϕ scans	θmax = 31.8°, θmin = 3.2°
Absorption correction: numerical (JANA2006; Petříček et al., 2006)	h = −28→28
Tmin = 0.055, Tmax = 0.226	k = −9→9
22317 measured reflections	l = −31→31
4518 independent reflections

Refinement

Refinement on F	6 constraints
R[F^2 > 2σ(F^2)] = 0.037	H-atom parameters not defined
wR(F^2) = 0.043	Weighting scheme based on measured s.u.'s w = 1/(σ^2(F) + 0.0001F^2)
S = 1.50	(Δ/σ)max = 0.017
4518 reflections	Δρmax = 3.11 e Å^−3
163 parameters	Δρmin = −2.15 e Å^−3
0 restraints

Special details

Experimental. Stoe IPDS 2T

Refinement. Occupation factors of Rb were refined, but restrained to give a full occupancy per formula. Trial refinement of occupation factors for N1/N1A show them to be 0.5:0.5 within error (fixed at these values). Displacement parameters of N1 and N1A constrained to be equal.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Te1	0.12062 (3)	0.60950 (8)	0.30889 (3)	0.02009 (16)
Te2	0.05612 (3)	0.11337 (9)	0.19897 (3)	0.01965 (15)
Te3	0.21968 (3)	0.18854 (8)	0.31354 (3)	0.01775 (15)
Te4	0.31367 (3)	0.66521 (8)	0.35614 (3)	0.02181 (16)
Rb1	0.25	0.4054 (3)	0.5	0.0366 (6)	0.781 (6)
Rb2	0.03410 (8)	0.0994 (2)	0.39071 (8)	0.0289 (5)	0.610 (3)
O1	0.0584 (3)	0.6722 (10)	0.3644 (3)	0.0256 (19)
O2	0.2061 (3)	0.7075 (10)	0.3678 (3)	0.028 (2)
O3	0.1400 (4)	0.3445 (9)	0.3419 (3)	0.027 (2)
O4	−0.0014 (4)	−0.0224 (10)	0.2450 (3)	0.028 (2)
O5	0.4268 (3)	0.5892 (10)	0.3580 (3)	0.0254 (19)
O6	0.1446 (4)	0.0212 (9)	0.2614 (3)	0.027 (2)
O7	0.2100 (3)	0.3968 (9)	0.2501 (3)	0.0212 (17)
O8	0.3027 (3)	0.3939 (9)	0.3732 (3)	0.0253 (19)
O9	0.3443 (4)	0.7642 (10)	0.4381 (3)	0.032 (2)
O10	0.0819 (6)	0.3721 (14)	0.0598 (5)	0.062 (4)
O11	0.3214 (5)	0.5041 (12)	0.0465 (4)	0.045 (3)
N1	0.0849 (11)	0.497 (3)	0.4794 (8)	0.033 (5)	0.5
N1A	0.0470 (12)	0.531 (3)	0.4898 (8)	0.033 (5)	0.5

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Te1	0.0175 (3)	0.0198 (2)	0.0238 (3)	0.0016 (2)	0.0061 (2)	0.0003 (2)
Te2	0.0159 (3)	0.0214 (2)	0.0217 (3)	−0.0034 (2)	0.0041 (2)	−0.0005 (2)
Te3	0.0154 (2)	0.0175 (2)	0.0198 (3)	0.0006 (2)	0.00242 (19)	0.0012 (2)
Te4	0.0242 (3)	0.0191 (2)	0.0212 (3)	−0.0026 (2)	0.0026 (2)	−0.0009 (2)
Rb1	0.0425 (11)	0.0446 (11)	0.0280 (9)	0	0.0196 (8)	0
Rb2	0.0208 (7)	0.0218 (7)	0.0465 (9)	0.0051 (6)	0.0125 (6)	0.0079 (6)
O1	0.018 (3)	0.033 (3)	0.026 (3)	0.008 (3)	0.006 (2)	−0.004 (3)
O2	0.017 (3)	0.031 (3)	0.033 (4)	−0.001 (3)	0.003 (3)	−0.010 (3)
O3	0.026 (3)	0.022 (3)	0.037 (4)	0.002 (3)	0.016 (3)	0.002 (3)
O4	0.023 (3)	0.032 (3)	0.031 (4)	−0.003 (3)	0.010 (3)	0.004 (3)
O5	0.019 (3)	0.032 (3)	0.025 (3)	−0.005 (3)	0.003 (2)	−0.007 (3)
O6	0.024 (3)	0.023 (3)	0.029 (3)	−0.007 (3)	−0.005 (3)	0.000 (3)
O7	0.023 (3)	0.018 (3)	0.025 (3)	0.005 (2)	0.010 (2)	0.001 (2)
O8	0.025 (3)	0.022 (3)	0.027 (3)	−0.001 (3)	0.002 (3)	0.000 (3)
O9	0.035 (4)	0.034 (4)	0.027 (4)	−0.004 (3)	0.003 (3)	−0.012 (3)
O10	0.059 (6)	0.056 (6)	0.079 (7)	−0.019 (5)	0.031 (5)	−0.009 (5)
O11	0.056 (6)	0.041 (4)	0.038 (5)	−0.002 (4)	0.012 (4)	−0.002 (3)
N1	0.048 (11)	0.035 (7)	0.012 (5)	−0.009 (7)	−0.002 (6)	0.002 (4)
N1A	0.048 (11)	0.035 (7)	0.012 (5)	−0.009 (7)	−0.002 (6)	0.002 (4)

Geometric parameters (Å, º)

Te1—O1	1.879 (7)	Rb1—O8	3.055 (7)
Te1—O2	1.949 (6)	Rb1—O8^iii	3.055 (7)
Te1—O3	1.924 (6)	Rb1—O9	3.425 (8)
Te2—O1^i	2.343 (6)	Rb1—O9^iii	3.425 (8)
Te2—O4	1.849 (7)	Rb1—O11^ii	3.140 (8)
Te2—O5^ii	1.893 (7)	Rb1—O11^iv	3.140 (8)
Te2—O6	2.012 (6)	Rb1—N1	3.14 (2)
Te3—O3	2.033 (7)	Rb1—N1^iii	3.14 (2)
Te3—O6	1.968 (6)	Rb2—O1^v	2.983 (7)
Te3—O7	1.925 (6)	Rb2—O3	2.948 (7)
Te3—O7^ii	2.161 (7)	Rb2—O4	3.130 (7)
Te3—O8	2.275 (6)	Rb2—O5^vi	2.906 (6)
Te4—O2	2.127 (7)	Rb2—O10^i	3.042 (11)
Te4—O5	2.202 (7)	Rb2—O11^ii	2.878 (9)
Te4—O8	1.882 (6)	Rb2—N1	3.297 (18)
Te4—O9	1.839 (7)	N1—N1A	0.83 (3)
Rb1—O2	3.422 (7)	N1A—N1A^vii	1.97 (3)
Rb1—O2^iii	3.422 (7)
O1—Te1—O2	94.1 (3)	O8—Rb1—O9^iii	130.28 (17)
O1—Te1—O3	94.5 (3)	O8—Rb1—O11^ii	84.3 (2)
O1—Te1—O4^viii	74.7 (3)	O8—Rb1—O11^iv	93.1 (2)
O2—Te1—O3	90.6 (3)	O8—Rb1—N1	112.5 (3)
O2—Te1—O4^viii	167.8 (3)	O8—Rb1—N1^iii	68.2 (3)
O3—Te1—O4^viii	85.6 (2)	O8^iii—Rb1—O9	130.28 (17)
O1^i—Te2—O4	78.8 (3)	O8^iii—Rb1—O9^iii	52.37 (17)
O1^i—Te2—O5^ii	91.0 (2)	O8^iii—Rb1—O11^ii	93.1 (2)
O1^i—Te2—O6	168.8 (3)	O8^iii—Rb1—O11^iv	84.3 (2)
O4—Te2—O5^ii	100.2 (3)	O8^iii—Rb1—N1	68.2 (3)
O4—Te2—O6	90.3 (3)	O8^iii—Rb1—N1^iii	112.5 (3)
O5^ii—Te2—O6	88.1 (3)	O9—Rb1—O9^iii	90.30 (18)
O3—Te3—O6	87.9 (3)	O9—Rb1—O11^ii	136.5 (2)
O3—Te3—O7	82.0 (3)	O9—Rb1—O11^iv	120.9 (2)
O3—Te3—O7^ii	156.3 (2)	O9—Rb1—N1	113.3 (4)
O3—Te3—O8	89.8 (2)	O9—Rb1—N1^iii	47.8 (4)
O6—Te3—O7	94.1 (3)	O9^iii—Rb1—O11^ii	120.9 (2)
O6—Te3—O7^ii	88.1 (3)	O9^iii—Rb1—O11^iv	136.5 (2)
O6—Te3—O8	177.3 (2)	O9^iii—Rb1—N1	47.8 (4)
O7—Te3—O7^ii	75.0 (2)	O9^iii—Rb1—N1^iii	113.3 (4)
O7—Te3—O8	84.3 (2)	O11^ii—Rb1—O11^iv	57.2 (2)
O7^ii—Te3—O8	93.5 (2)	O11^ii—Rb1—N1	76.9 (4)
O2—Te4—O5	170.6 (2)	O11^ii—Rb1—N1^iii	124.8 (4)
O2—Te4—O8	87.8 (3)	O11^iv—Rb1—N1	124.8 (4)
O2—Te4—O9	88.1 (3)	O11^iv—Rb1—N1^iii	76.9 (4)
O5—Te4—O8	85.2 (3)	N1—Rb1—N1^iii	157.4 (5)
O5—Te4—O9	87.1 (3)	O1^v—Rb2—O3	109.33 (19)
O8—Te4—O9	101.3 (3)	O1^v—Rb2—O4	64.77 (17)
O2—Rb1—O2^iii	107.08 (16)	O1^v—Rb2—O5^vi	141.15 (17)
O2—Rb1—O8	50.53 (17)	O1^v—Rb2—O10^i	74.4 (2)
O2—Rb1—O8^iii	131.76 (17)	O1^v—Rb2—O11^ii	71.5 (2)
O2—Rb1—O9	47.64 (15)	O1^v—Rb2—N1	148.2 (3)
O2—Rb1—O9^iii	80.54 (17)	O3—Rb2—O4	79.91 (19)
O2—Rb1—O11^ii	104.37 (18)	O3—Rb2—O5^vi	90.48 (19)
O2—Rb1—O11^iv	142.7 (2)	O3—Rb2—O10^i	176.0 (2)
O2—Rb1—N1	72.6 (4)	O3—Rb2—O11^ii	69.1 (2)
O2—Rb1—N1^iii	93.8 (3)	O3—Rb2—N1	66.7 (4)
O2^iii—Rb1—O8	131.76 (17)	O4—Rb2—O5^vi	87.47 (18)
O2^iii—Rb1—O8^iii	50.53 (17)	O4—Rb2—O10^i	100.6 (2)
O2^iii—Rb1—O9	80.54 (17)	O4—Rb2—O11^ii	112.5 (2)
O2^iii—Rb1—O9^iii	47.64 (15)	O4—Rb2—N1	138.8 (3)
O2^iii—Rb1—O11^ii	142.7 (2)	O5^vi—Rb2—O10^i	85.6 (2)
O2^iii—Rb1—O11^iv	104.37 (18)	O5^vi—Rb2—O11^ii	147.1 (2)
O2^iii—Rb1—N1	93.8 (3)	O5^vi—Rb2—N1	70.1 (4)
O2^iii—Rb1—N1^iii	72.6 (4)	O10^i—Rb2—O11^ii	114.1 (3)
O8—Rb1—O8^iii	177.08 (18)	O10^i—Rb2—N1	111.1 (4)
O8—Rb1—O9	52.37 (17)	O11^ii—Rb2—N1	78.1 (4)

Symmetry codes: (i) −x, y−1/2, −z+1/2; (ii) −x+1/2, −y+1/2, −z+1/2; (iii) −x+1/2, y, −z+1; (iv) x, −y+1/2, z+1/2; (v) x, y−1, z; (vi) x−1/2, −y+1, z; (vii) −x, −y+1, −z+1; (viii) −x, y+1/2, −z+1/2.

(I_1.13GPa) ammonium rubidium nonaoxotetratellurate(IV) dihydrate

Crystal data

NH4RbTe4O9·2H2O	F(000) = 2784
Mr = 793.9	Pressure = 1.13 GPa
Monoclinic, I2/a	Dx = 4.112 Mg m^−3
Hall symbol: -I 2ya	Synchrotron radiation, λ = 0.3978 Å
a = 18.770 (4) Å	Cell parameters from 2941 reflections
b = 6.645 (4) Å	θ = 1.2–20.9°
c = 20.800 (7) Å	µ = 2.22 mm^−1
β = 101.61 (18)°	T = 293 K
V = 2541 (3) Å^3	Irregular, light yellow
Z = 8	0.22 × 0.12 × 0.03 mm

Data collection

Huber four-circle diffractometer with Marresearch MarCCD165 area detector	987 reflections with I > 3σ(I)
Radiation source: HASYLAB	Rint = 0.189
ϕ scans	θmax = 20.9°, θmin = 1.2°
Absorption correction: numerical (JANA2006; Petříček et al., 2006)	h = −33→32
Tmin = 0.532, Tmax = 0.786	k = −11→11
2941 measured reflections	l = −18→13
987 independent reflections

Refinement

Refinement on F	0 constraints
R[F^2 > 2σ(F^2)] = 0.125	H-atom parameters not defined
wR(F^2) = 0.115	Weighting scheme based on measured s.u.'s w = 1/(σ^2(F) + 0.0001F^2)
S = 3.38	(Δ/σ)max = 0.004
987 reflections	Δρmax = 4.36 e Å^−3
85 parameters	Δρmin = −3.28 e Å^−3
0 restraints

Special details

Experimental. Pressure = 1.13 GPa; Almax diamond anvil cell Beamline D3, HASYLAB MarCCD165 detector

Refinement. Te anisotropic; Rb, O and N isotropic; all displacement parameters of oxygen coordinating Te (O1—O9) set equal; displacement parameters of oxygen belonging to water moelcules (O10, O11) restricted to be equal. Occupation factors of Rb and N fixed to values from ambient pressure dataset.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Te1	0.1211 (2)	0.6159 (6)	0.3071 (5)	0.020 (5)
Te2	0.0556 (2)	0.1224 (5)	0.1987 (5)	0.030 (5)
Te3	0.2200 (2)	0.1902 (5)	0.3163 (5)	0.015 (4)
Te4	0.3146 (2)	0.6700 (6)	0.3544 (5)	0.029 (5)
Rb1	0.25	0.4185 (13)	0.5	0.026 (2)*	0.78
Rb2	0.0345 (4)	0.1016 (11)	0.3951 (10)	0.0154 (16)*	0.61
O1	0.0529 (19)	0.672 (5)	0.359 (4)	0.019 (3)*
O2	0.205 (2)	0.718 (5)	0.358 (4)	0.019 (3)*
O3	0.1397 (19)	0.359 (4)	0.343 (4)	0.019 (3)*
O4	−0.007 (2)	−0.016 (5)	0.246 (5)	0.019 (3)*
O5	0.429 (2)	0.581 (5)	0.358 (4)	0.019 (3)*
O6	0.1492 (19)	0.024 (5)	0.263 (4)	0.019 (3)*
O7	0.2115 (19)	0.405 (5)	0.249 (4)	0.019 (3)*
O8	0.3003 (19)	0.400 (5)	0.374 (4)	0.019 (3)*
O9	0.3445 (19)	0.789 (5)	0.428 (4)	0.019 (3)*
O10	0.077 (2)	0.368 (5)	0.057 (5)	0.025 (7)*
O11	0.313 (2)	0.496 (5)	0.040 (5)	0.025 (7)*
N1	0.098 (4)	0.487 (11)	0.507 (10)	0.009 (13)*	0.5
N1A	0.052 (4)	0.535 (11)	0.487 (9)	0.009 (13)*	0.5

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Te1	0.0139 (17)	0.0175 (18)	0.027 (14)	0.0014 (17)	−0.001 (4)	0.005 (3)
Te2	0.0112 (16)	0.0155 (17)	0.065 (14)	−0.0060 (16)	0.009 (4)	−0.002 (3)
Te3	0.0127 (16)	0.0156 (17)	0.016 (12)	0.0000 (15)	−0.003 (3)	0.000 (3)
Te4	0.0200 (19)	0.0134 (17)	0.049 (15)	−0.0050 (16)	0.000 (4)	−0.004 (3)

Geometric parameters (Å, º)

Te1—O1	1.87 (7)	Rb1—O8	2.97 (8)
Te1—O2	1.84 (5)	Rb1—O8^iii	2.97 (8)
Te1—O3	1.87 (4)	Rb1—O11^ii	3.04 (4)
Te2—O1^i	2.17 (5)	Rb1—O11^iv	3.04 (4)
Te2—O4	1.92 (7)	Rb1—N1	2.93 (9)
Te2—O5^ii	1.85 (6)	Rb1—N1^iii	2.93 (9)
Te2—O6	2.09 (5)	Rb2—O1^v	2.99 (4)
Te3—O3	2.05 (5)	Rb2—O3	2.97 (6)
Te3—O6	1.90 (5)	Rb2—O4	3.14 (9)
Te3—O7	1.99 (7)	Rb2—O5^vi	2.88 (4)
Te3—O7^ii	2.14 (7)	Rb2—O10^i	2.93 (6)
Te3—O8	2.21 (5)	Rb2—O10^iv	3.31 (9)
Te4—O2	2.09 (4)	Rb2—O11^ii	2.99 (4)
Te4—O5	2.22 (4)	Rb2—N1A	3.44 (12)
Te4—O8	1.87 (4)	N1—N1A	0.94 (12)
Te4—O9	1.71 (8)	N1A—N1A^vii	2.16 (16)
O1—Te1—O2	102 (3)	O8^iii—Rb1—N1^iii	123 (4)
O1—Te1—O3	92 (3)	O11^ii—Rb1—O11^iv	50.3 (13)
O1—Te1—O4^viii	72 (3)	O11^ii—Rb1—N1	80.0 (19)
O2—Te1—O3	92 (2)	O11^ii—Rb1—N1^iii	117 (2)
O2—Te1—O4^viii	173 (4)	O11^iv—Rb1—N1	117 (2)
O3—Te1—O4^viii	85.8 (17)	O11^iv—Rb1—N1^iii	80.0 (19)
O1^i—Te2—O4	76 (3)	N1—Rb1—N1^iii	162 (2)
O1^i—Te2—O5^ii	90 (2)	O1^v—Rb2—O3	109.9 (17)
O1^i—Te2—O6	168 (2)	O1^v—Rb2—O4	62.2 (17)
O4—Te2—O5^ii	99 (3)	O1^v—Rb2—O5^vi	137.6 (15)
O4—Te2—O6	93 (2)	O1^v—Rb2—O10^i	72.8 (16)
O5^ii—Te2—O6	88 (2)	O1^v—Rb2—O10^iv	107.3 (18)
O3—Te3—O6	90 (2)	O1^v—Rb2—O11^ii	76.0 (12)
O3—Te3—O7	81 (3)	O1^v—Rb2—N1A	160 (3)
O3—Te3—O7^ii	155 (3)	O3—Rb2—O4	80.6 (18)
O3—Te3—O8	88.1 (18)	O3—Rb2—O5^vi	87.2 (13)
O6—Te3—O7	93 (3)	O3—Rb2—O10^i	176.2 (11)
O6—Te3—O7^ii	84 (2)	O3—Rb2—O10^iv	107.1 (17)
O6—Te3—O8	176 (2)	O3—Rb2—O11^ii	69.1 (16)
O7—Te3—O7^ii	75 (2)	O3—Rb2—N1A	74 (3)
O7—Te3—O8	83 (2)	O4—Rb2—O5^vi	84.0 (18)
O7^ii—Te3—O8	96 (2)	O4—Rb2—O10^i	98.6 (19)
O2—Te4—O5	172 (2)	O4—Rb2—O10^iv	169.0 (10)
O2—Te4—O8	87.4 (16)	O4—Rb2—O11^ii	114.9 (19)
O2—Te4—O9	93 (3)	O4—Rb2—N1A	137 (3)
O5—Te4—O8	85.3 (16)	O5^vi—Rb2—O10^i	89.0 (13)
O5—Te4—O9	87 (2)	O5^vi—Rb2—O10^iv	103.9 (19)
O8—Te4—O9	107 (3)	O5^vi—Rb2—O11^ii	145.4 (11)
O8—Rb1—O8^iii	175.2 (9)	O5^vi—Rb2—N1A	61 (2)
O8—Rb1—O11^ii	84.1 (19)	O10^i—Rb2—O10^iv	74.2 (19)
O8—Rb1—O11^iv	91.5 (19)	O10^i—Rb2—O11^ii	114.5 (18)
O8—Rb1—N1	123 (4)	O10^i—Rb2—N1A	104 (3)
O8—Rb1—N1^iii	58 (4)	O10^iv—Rb2—O11^ii	63 (2)
O8^iii—Rb1—O11^ii	91.5 (19)	O10^iv—Rb2—N1A	53 (3)
O8^iii—Rb1—O11^iv	84.1 (19)	O11^ii—Rb2—N1A	87.4 (18)
O8^iii—Rb1—N1	58 (4)

Symmetry codes: (i) −x, y−1/2, −z+1/2; (ii) −x+1/2, −y+1/2, −z+1/2; (iii) −x+1/2, y, −z+1; (iv) x, −y+1/2, z+1/2; (v) x, y−1, z; (vi) x−1/2, −y+1, z; (vii) −x, −y+1, −z+1; (viii) −x, y+1/2, −z+1/2.

(I_2.52GPa) ammonium rubidium nonaoxotetratellurate(IV) dihydrate

Crystal data

NH4RbTe4O9·2H2O	F(000) = 2784
Mr = 793.9	Pressure 2.52 GPa
Monoclinic, I2/a	Dx = 4.290 Mg m^−3
Hall symbol: -I 2ya	Synchrotron radiation, λ = 0.3978 Å
a = 18.604 (4) Å	Cell parameters from 3724 reflections
b = 6.583 (2) Å	θ = 1.3–22.3°
c = 20.295 (11) Å	µ = 2.22 mm^−1
β = 101.5 (2)°	T = 293 K
V = 2436 (2) Å^3	Irregular, light yellow
Z = 8	0.22 × 0.12 × 0.03 mm

Data collection

Huber four-circle diffractometer with Marresearch MarCCD165 area detector	1119 reflections with I > 3σ(I)
Radiation source: HASYLAB	Rint = 0.139
ϕ scans	θmax = 22.3°, θmin = 1.3°
Absorption correction: numerical (JANA2006; Petříček et al., 2006)	h = −32→32
Tmin = 0.553, Tmax = 0.824	k = −12→12
3724 measured reflections	l = −24→14
1119 independent reflections

Refinement

Refinement on F	0 constraints
R[F^2 > 2σ(F^2)] = 0.108	H-atom parameters not defined
wR(F^2) = 0.092	Weighting scheme based on measured s.u.'s w = 1/(σ^2(F) + 0.0001F^2)
S = 2.97	(Δ/σ)max = 0.027
1119 reflections	Δρmax = 3.99 e Å^−3
85 parameters	Δρmin = −3.83 e Å^−3
0 restraints

Special details

Experimental. Pressure = 2.52 GPa; Almax diamond anvil cell Beamline D3, HASYLAB MarCCD165 detector

Refinement. Te anisotropic; Rb, O and N isotropic; all displacement parameters of oxygen coordinating Te (O1—O9) set equal; displacement parameters of oxygen belonging to water moelcules (O10, O11) restricted to be equal. Occupation factors of Rb and N fixed to values from ambient pressure dataset.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Te1	0.12072 (16)	0.6219 (4)	0.3053 (3)	0.019 (3)
Te2	0.05491 (15)	0.1309 (4)	0.1980 (3)	0.024 (3)
Te3	0.22035 (16)	0.1918 (4)	0.3181 (3)	0.018 (3)
Te4	0.31567 (17)	0.6748 (4)	0.3533 (4)	0.021 (3)
Rb1	0.25	0.4304 (10)	0.5	0.0243 (17)*	0.78
Rb2	0.0347 (3)	0.1072 (7)	0.3973 (6)	0.0127 (11)*	0.61
O1	0.0565 (14)	0.687 (4)	0.361 (3)	0.016 (2)*
O2	0.2094 (14)	0.715 (3)	0.365 (3)	0.016 (2)*
O3	0.1391 (14)	0.355 (3)	0.342 (3)	0.016 (2)*
O4	−0.0040 (15)	−0.005 (3)	0.249 (3)	0.016 (2)*
O5	0.4315 (14)	0.584 (3)	0.360 (3)	0.016 (2)*
O6	0.1422 (15)	0.024 (4)	0.261 (3)	0.016 (2)*
O7	0.2128 (14)	0.404 (3)	0.250 (3)	0.016 (2)*
O8	0.3024 (14)	0.402 (3)	0.378 (3)	0.016 (2)*
O9	0.3466 (14)	0.795 (4)	0.436 (3)	0.016 (2)*
O10	0.0753 (16)	0.360 (4)	0.055 (3)	0.022 (5)*
O11	0.3186 (15)	0.496 (4)	0.040 (3)	0.022 (5)*
N1	0.095 (3)	0.510 (8)	0.484 (7)	0.012 (9)*	0.5
N1A	0.049 (3)	0.532 (8)	0.488 (7)	0.012 (9)*	0.5

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Te1	0.0155 (13)	0.0136 (12)	0.028 (9)	0.0011 (11)	0.007 (3)	−0.001 (2)
Te2	0.0140 (12)	0.0120 (12)	0.049 (9)	−0.0040 (10)	0.011 (3)	−0.0028 (19)
Te3	0.0150 (13)	0.0127 (12)	0.028 (9)	0.0003 (10)	0.006 (3)	0.0021 (19)
Te4	0.0224 (14)	0.0119 (12)	0.030 (9)	−0.0045 (11)	0.007 (3)	−0.005 (2)

Geometric parameters (Å, º)

Te1—O1	1.86 (5)	Rb1—O8	2.84 (6)
Te1—O2	1.94 (4)	Rb1—O8^iii	2.84 (6)
Te1—O3	1.91 (3)	Rb1—O9	3.41 (4)
Te2—O1^i	2.21 (3)	Rb1—O9^iii	3.41 (4)
Te2—O4	1.87 (5)	Rb1—O11^ii	3.13 (3)
Te2—O5^ii	1.88 (4)	Rb1—O11^iv	3.13 (3)
Te2—O6	1.99 (4)	Rb1—N1	2.89 (6)
Te3—O3	1.99 (3)	Rb1—N1^iii	2.89 (6)
Te3—O6	2.00 (3)	Rb2—O1^v	2.91 (3)
Te3—O7	1.95 (5)	Rb2—O3	2.92 (4)
Te3—O7^ii	2.13 (5)	Rb2—O4	3.05 (6)
Te3—O8	2.23 (3)	Rb2—O5^vi	2.80 (3)
Te4—O2	2.05 (3)	Rb2—O10^i	2.92 (4)
Te4—O5	2.22 (3)	Rb2—O10^iv	3.15 (6)
Te4—O8	1.90 (3)	Rb2—O11^ii	2.85 (3)
Te4—O9	1.83 (5)	Rb2—N1	3.26 (8)
Rb1—O2	3.29 (5)	Rb2—N1A	3.32 (9)
Rb1—O2^iii	3.29 (5)	N1—N1A	0.87 (11)
Rb1—O3	3.48 (5)	N1A—N1A^vii	2.04 (12)
Rb1—O3^iii	3.48 (5)
O1—Te1—O2	97 (2)	O3^iii—Rb1—N1^iii	62 (3)
O1—Te1—O3	93.0 (18)	O8—Rb1—O8^iii	172.3 (7)
O1—Te1—O4^viii	73.9 (18)	O8—Rb1—O9	54.1 (10)
O2—Te1—O3	89.0 (13)	O8—Rb1—O9^iii	132.8 (10)
O2—Te1—O4^viii	169 (2)	O8—Rb1—O11^ii	84.6 (13)
O3—Te1—O4^viii	86.3 (12)	O8—Rb1—O11^iv	88.5 (13)
O1^i—Te2—O4	78.0 (18)	O8—Rb1—N1	115 (3)
O1^i—Te2—O5^ii	90.6 (15)	O8—Rb1—N1^iii	66 (3)
O1^i—Te2—O6	165.3 (15)	O8^iii—Rb1—O9	132.8 (10)
O4—Te2—O5^ii	98.9 (18)	O8^iii—Rb1—O9^iii	54.1 (10)
O4—Te2—O6	88.1 (18)	O8^iii—Rb1—O11^ii	88.5 (13)
O5^ii—Te2—O6	86.9 (17)	O8^iii—Rb1—O11^iv	84.6 (13)
O3—Te3—O6	86.5 (14)	O8^iii—Rb1—N1	66 (3)
O3—Te3—O7	80.8 (18)	O8^iii—Rb1—N1^iii	115 (3)
O3—Te3—O7^ii	152.8 (19)	O9—Rb1—O9^iii	90.6 (9)
O3—Te3—O8	90.2 (13)	O9—Rb1—O11^ii	138.7 (15)
O6—Te3—O7	92.6 (17)	O9—Rb1—O11^iv	120.9 (9)
O6—Te3—O7^ii	85.2 (17)	O9—Rb1—N1	114.9 (18)
O6—Te3—O8	175.3 (11)	O9—Rb1—N1^iii	47 (2)
O7—Te3—O7^ii	73.7 (16)	O9^iii—Rb1—O11^ii	120.9 (9)
O7—Te3—O8	83.6 (16)	O9^iii—Rb1—O11^iv	138.7 (15)
O7^ii—Te3—O8	96.3 (15)	O9^iii—Rb1—N1	47 (2)
O2—Te4—O5	167.0 (19)	O9^iii—Rb1—N1^iii	114.9 (18)
O2—Te4—O8	85.1 (12)	O11^ii—Rb1—O11^iv	52.1 (9)
O2—Te4—O9	88.4 (18)	O11^ii—Rb1—N1	77.7 (13)
O5—Te4—O8	84.3 (11)	O11^ii—Rb1—N1^iii	122.6 (14)
O5—Te4—O9	86.4 (16)	O11^iv—Rb1—N1	122.6 (14)
O8—Te4—O9	102 (2)	O11^iv—Rb1—N1^iii	77.7 (13)
O2—Rb1—O2^iii	110.4 (10)	N1—Rb1—N1^iii	159.1 (15)
O2—Rb1—O3	47.0 (7)	O1^v—Rb2—O3	107.4 (11)
O2—Rb1—O3^iii	147.7 (7)	O1^v—Rb2—O4	62.6 (12)
O2—Rb1—O8	51.1 (9)	O1^v—Rb2—O5^vi	138.2 (11)
O2—Rb1—O8^iii	134.7 (9)	O1^v—Rb2—O10^i	72.2 (11)
O2—Rb1—O9	47.9 (8)	O1^v—Rb2—O10^iv	107.6 (12)
O2—Rb1—O9^iii	82.4 (12)	O1^v—Rb2—O11^ii	73.4 (9)
O2—Rb1—O11^ii	106.3 (12)	O1^v—Rb2—N1	149.4 (14)
O2—Rb1—O11^iv	138.2 (14)	O1^v—Rb2—N1A	160 (2)
O2—Rb1—N1	75 (3)	O3—Rb2—O4	78.6 (12)
O2—Rb1—N1^iii	93 (2)	O3—Rb2—O5^vi	87.8 (9)
O2^iii—Rb1—O3	147.7 (7)	O3—Rb2—O10^i	176.7 (15)
O2^iii—Rb1—O3^iii	47.0 (7)	O3—Rb2—O10^iv	107.9 (12)
O2^iii—Rb1—O8	134.7 (9)	O3—Rb2—O11^ii	69.7 (12)
O2^iii—Rb1—O8^iii	51.1 (9)	O3—Rb2—N1	65 (2)
O2^iii—Rb1—O9	82.4 (12)	O3—Rb2—N1A	76 (2)
O2^iii—Rb1—O9^iii	47.9 (8)	O4—Rb2—O5^vi	83.8 (13)
O2^iii—Rb1—O11^ii	138.2 (14)	O4—Rb2—O10^i	98.4 (13)
O2^iii—Rb1—O11^iv	106.3 (12)	O4—Rb2—O10^iv	169.9 (7)
O2^iii—Rb1—N1	93 (2)	O4—Rb2—O11^ii	113.5 (14)
O2^iii—Rb1—N1^iii	75 (3)	O4—Rb2—N1	136 (2)
O3—Rb1—O3^iii	163.6 (6)	O4—Rb2—N1A	137 (2)
O3—Rb1—O8	55.5 (9)	O5^vi—Rb2—O10^i	90.4 (9)
O3—Rb1—O8^iii	123.2 (9)	O5^vi—Rb2—O10^iv	103.9 (13)
O3—Rb1—O9	90.5 (11)	O5^vi—Rb2—O11^ii	147.1 (8)
O3—Rb1—O9^iii	101.0 (9)	O5^vi—Rb2—N1	72.4 (14)
O3—Rb1—O11^ii	59.7 (11)	O5^vi—Rb2—N1A	61.0 (17)
O3—Rb1—O11^iv	104.4 (11)	O10^i—Rb2—O10^iv	75.3 (13)
O3—Rb1—N1	62 (3)	O10^i—Rb2—O11^ii	113.0 (12)
O3—Rb1—N1^iii	122 (3)	O10^i—Rb2—N1	118 (2)
O3^iii—Rb1—O8	123.2 (9)	O10^i—Rb2—N1A	106 (2)
O3^iii—Rb1—O8^iii	55.5 (9)	O10^iv—Rb2—O11^ii	63.3 (14)
O3^iii—Rb1—O9	101.0 (9)	O10^iv—Rb2—N1	54 (2)
O3^iii—Rb1—O9^iii	90.5 (11)	O10^iv—Rb2—N1A	53 (2)
O3^iii—Rb1—O11^ii	104.4 (11)	O11^ii—Rb2—N1	76.2 (13)
O3^iii—Rb1—O11^iv	59.7 (11)	O11^ii—Rb2—N1A	89.5 (15)
O3^iii—Rb1—N1	122 (3)

Symmetry codes: (i) −x, y−1/2, −z+1/2; (ii) −x+1/2, −y+1/2, −z+1/2; (iii) −x+1/2, y, −z+1; (iv) x, −y+1/2, z+1/2; (v) x, y−1, z; (vi) x−1/2, −y+1, z; (vii) −x, −y+1, −z+1; (viii) −x, y+1/2, −z+1/2.

(I_3.45GPa) ammonium rubidium nonaoxotetratellurate(IV) dihydrate

Crystal data

NH4RbTe4O9·2H2O	F(000) = 2784
Mr = 793.9	Pressure 3.45 GPa
Monoclinic, I2/a	Dx = 4.394 Mg m^−3
Hall symbol: -I 2ya	Synchrotron radiation, λ = 0.3978 Å
a = 18.501 (3) Å	Cell parameters from 3087 reflections
b = 6.542 (1) Å	θ = 1.3–22.1°
c = 20.045 (7) Å	µ = 2.22 mm^−1
β = 101.41 (10)°	T = 293 K
V = 2378.2 (13) Å^3	Irregular, light yellow
Z = 8	0.22 × 0.12 × 0.03 mm

Data collection

Huber four-circle diffractometer with Marresearch MarCCD165 area detector	1036 reflections with I > 3σ(I)
Radiation source: HASYLAB	Rint = 0.133
ϕ scans	θmax = 22.1°, θmin = 1.3°
Absorption correction: numerical (JANA2006; Petříček et al., 2006)	h = −32→34
Tmin = 0.554, Tmax = 0.824	k = −12→12
3087 measured reflections	l = −18→23
1036 independent reflections

Refinement

Refinement on F	0 constraints
R[F^2 > 2σ(F^2)] = 0.098	H-atom parameters not defined
wR(F^2) = 0.085	Weighting scheme based on measured s.u.'s w = 1/(σ^2(F) + 0.0001F^2)
S = 2.70	(Δ/σ)max = 0.016
1036 reflections	Δρmax = 3.43 e Å^−3
85 parameters	Δρmin = −2.90 e Å^−3
0 restraints

Special details

Experimental. Pressure = 3.45 GPa; Almax diamond anvil cell Beamline D3, HASYLAB MarCCD165 detector

Refinement. Te anisotropic; Rb, O and N isotropic all displacement parameters of oxygen coordinating Te (O1—O9) set equal; displacement parameters of oxygen belonging to water moelcules (O10, O11) restricted to be equal Occupation factors of Rb and N fixed to values from ambient pressure dataset.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Te1	0.12091 (16)	0.6245 (4)	0.3045 (3)	0.017 (3)
Te2	0.05480 (16)	0.1351 (4)	0.1979 (3)	0.024 (3)
Te3	0.22050 (16)	0.1923 (4)	0.3190 (3)	0.018 (3)
Te4	0.31619 (17)	0.6774 (4)	0.3521 (4)	0.023 (3)
Rb1	0.25	0.4378 (10)	0.5	0.0244 (16)*	0.78
Rb2	0.0349 (3)	0.1098 (7)	0.3985 (6)	0.0106 (10)*	0.61
O1	0.0542 (14)	0.695 (4)	0.361 (3)	0.018 (2)*
O2	0.2093 (15)	0.724 (3)	0.366 (3)	0.018 (2)*
O3	0.1435 (14)	0.355 (3)	0.353 (3)	0.018 (2)*
O4	−0.0058 (16)	0.001 (3)	0.251 (3)	0.018 (2)*
O5	0.4288 (15)	0.583 (3)	0.358 (3)	0.018 (2)*
O6	0.1429 (15)	0.018 (4)	0.260 (3)	0.018 (2)*
O7	0.2085 (15)	0.400 (3)	0.244 (3)	0.018 (2)*
O8	0.3045 (15)	0.407 (3)	0.379 (3)	0.018 (2)*
O9	0.3480 (14)	0.799 (4)	0.436 (3)	0.018 (2)*
O10	0.0737 (16)	0.354 (4)	0.052 (3)	0.023 (5)*
O11	0.3162 (16)	0.492 (4)	0.041 (3)	0.023 (5)*
N1	0.094 (3)	0.520 (7)	0.483 (6)	0.002 (8)*	0.5
N1A	0.055 (3)	0.514 (7)	0.472 (6)	0.002 (8)*	0.5

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Te1	0.0138 (13)	0.0154 (12)	0.022 (9)	−0.0004 (11)	0.005 (3)	0.0019 (19)
Te2	0.0141 (12)	0.0102 (11)	0.050 (9)	−0.0018 (10)	0.010 (3)	−0.0002 (18)
Te3	0.0150 (13)	0.0111 (12)	0.029 (9)	0.0002 (10)	0.007 (3)	0.0034 (18)
Te4	0.0193 (14)	0.0135 (12)	0.037 (9)	−0.0021 (11)	0.006 (3)	−0.003 (2)

Geometric parameters (Å, º)

Te1—O1	1.89 (5)	Rb1—O8	2.82 (6)
Te1—O2	1.95 (4)	Rb1—O8^iii	2.82 (6)
Te1—O3	2.01 (3)	Rb1—O9	3.39 (4)
Te2—O1^i	2.16 (3)	Rb1—O9^iii	3.39 (4)
Te2—O4	1.90 (5)	Rb1—O11^ii	3.11 (3)
Te2—O5^ii	1.88 (4)	Rb1—O11^iv	3.11 (3)
Te2—O6	2.00 (4)	Rb1—N1	2.89 (5)
Te3—O3	2.00 (4)	Rb1—N1^iii	2.89 (5)
Te3—O6	2.02 (4)	Rb2—O1^v	2.85 (3)
Te3—O7	2.01 (5)	Rb2—O3	2.86 (4)
Te3—O7^ii	2.08 (5)	Rb2—O4	3.00 (6)
Te3—O8	2.25 (3)	Rb2—O5^vi	2.81 (3)
Te4—O2	2.07 (3)	Rb2—O10^i	2.94 (4)
Te4—O5	2.15 (3)	Rb2—O10^iv	3.02 (6)
Te4—O8	1.87 (3)	Rb2—O11^ii	2.86 (3)
Te4—O9	1.84 (5)	Rb2—N1	3.25 (7)
Rb1—O2	3.24 (5)	Rb2—N1A	3.02 (7)
Rb1—O2^iii	3.24 (5)	N1—N1A	0.72 (8)
Rb1—O3	3.26 (5)	N1A—N1A^vii	2.50 (12)
Rb1—O3^iii	3.26 (5)
O1—Te1—O2	96.1 (19)	O3^iii—Rb1—N1^iii	61 (2)
O1—Te1—O3	91.4 (18)	O8—Rb1—O8^iii	171.7 (7)
O1—Te1—O4^viii	74.2 (18)	O8—Rb1—O9	53.9 (10)
O2—Te1—O3	85.7 (13)	O8—Rb1—O9^iii	133.6 (11)
O2—Te1—O4^viii	169 (2)	O8—Rb1—O11^ii	83.9 (12)
O3—Te1—O4^viii	90.4 (12)	O8—Rb1—O11^iv	88.6 (13)
O1^i—Te2—O4	78.4 (18)	O8—Rb1—N1	116 (2)
O1^i—Te2—O5^ii	93.0 (15)	O8—Rb1—N1^iii	66 (2)
O1^i—Te2—O6	165.6 (13)	O8^iii—Rb1—O9	133.6 (11)
O4—Te2—O5^ii	99.5 (17)	O8^iii—Rb1—O9^iii	53.9 (10)
O4—Te2—O6	88.6 (18)	O8^iii—Rb1—O11^ii	88.6 (13)
O5^ii—Te2—O6	82.8 (18)	O8^iii—Rb1—O11^iv	83.9 (12)
O3—Te3—O6	91.4 (15)	O8^iii—Rb1—N1	66 (2)
O3—Te3—O7	85.1 (18)	O8^iii—Rb1—N1^iii	116 (2)
O3—Te3—O7^ii	159.4 (18)	O9—Rb1—O9^iii	91.4 (9)
O3—Te3—O8	87.3 (13)	O9—Rb1—O11^ii	137.8 (14)
O6—Te3—O7	88.9 (17)	O9—Rb1—O11^iv	121.3 (9)
O6—Te3—O7^ii	86.9 (17)	O9—Rb1—N1	115.0 (15)
O6—Te3—O8	175.5 (16)	O9—Rb1—N1^iii	46.9 (16)
O7—Te3—O7^ii	74.3 (16)	O9^iii—Rb1—O11^ii	121.3 (9)
O7—Te3—O8	86.7 (16)	O9^iii—Rb1—O11^iv	137.8 (14)
O7^ii—Te3—O8	92.8 (15)	O9^iii—Rb1—N1	46.9 (16)
O2—Te4—O5	167 (2)	O9^iii—Rb1—N1^iii	115.0 (15)
O2—Te4—O8	86.3 (13)	O11^ii—Rb1—O11^iv	50.9 (9)
O2—Te4—O9	87.6 (18)	O11^ii—Rb1—N1	78.8 (11)
O5—Te4—O8	83.0 (12)	O11^ii—Rb1—N1^iii	122.1 (12)
O5—Te4—O9	86.6 (17)	O11^iv—Rb1—N1	122.1 (12)
O8—Te4—O9	101 (2)	O11^iv—Rb1—N1^iii	78.8 (11)
O2—Rb1—O2^iii	109.4 (10)	N1—Rb1—N1^iii	158.6 (13)
O2—Rb1—O3	49.0 (8)	O1^v—Rb2—O3	108.5 (11)
O2—Rb1—O3^iii	148.1 (7)	O1^v—Rb2—O4	62.4 (12)
O2—Rb1—O8	52.4 (9)	O1^v—Rb2—O5^vi	136.0 (11)
O2—Rb1—O8^iii	133.9 (9)	O1^v—Rb2—O10^i	71.2 (11)
O2—Rb1—O9	48.3 (9)	O1^v—Rb2—O10^iv	108.8 (12)
O2—Rb1—O9^iii	81.9 (12)	O1^v—Rb2—O11^ii	74.3 (9)
O2—Rb1—O11^ii	106.6 (12)	O1^v—Rb2—N1	151.2 (12)
O2—Rb1—O11^iv	139.2 (14)	O1^v—Rb2—N1A	162.2 (17)
O2—Rb1—N1	74 (2)	O3—Rb2—O4	82.5 (13)
O2—Rb1—N1^iii	93 (2)	O3—Rb2—O5^vi	90.1 (9)
O2^iii—Rb1—O3	148.1 (7)	O3—Rb2—O10^i	178.6 (12)
O2^iii—Rb1—O3^iii	49.0 (8)	O3—Rb2—O10^iv	104.1 (12)
O2^iii—Rb1—O8	133.9 (9)	O3—Rb2—O11^ii	65.6 (11)
O2^iii—Rb1—O8^iii	52.4 (9)	O3—Rb2—N1	61 (2)
O2^iii—Rb1—O9	81.9 (12)	O3—Rb2—N1A	69 (2)
O2^iii—Rb1—O9^iii	48.3 (9)	O4—Rb2—O5^vi	82.0 (13)
O2^iii—Rb1—O11^ii	139.2 (14)	O4—Rb2—O10^i	98.5 (13)
O2^iii—Rb1—O11^iv	106.6 (12)	O4—Rb2—O10^iv	170.7 (7)
O2^iii—Rb1—N1	93 (2)	O4—Rb2—O11^ii	113.3 (14)
O2^iii—Rb1—N1^iii	74 (2)	O4—Rb2—N1	135 (2)
O3—Rb1—O3^iii	160.8 (6)	O4—Rb2—N1A	132 (2)
O3—Rb1—O8	57.4 (10)	O5^vi—Rb2—O10^i	91.0 (9)
O3—Rb1—O8^iii	121.0 (10)	O5^vi—Rb2—O10^iv	104.4 (13)
O3—Rb1—O9	92.5 (11)	O5^vi—Rb2—O11^ii	147.9 (8)
O3—Rb1—O9^iii	100.9 (10)	O5^vi—Rb2—N1	72.7 (13)
O3—Rb1—O11^ii	58.1 (11)	O5^vi—Rb2—N1A	61.6 (15)
O3—Rb1—O11^iv	103.1 (10)	O10^i—Rb2—O10^iv	74.8 (13)
O3—Rb1—N1	61 (2)	O10^i—Rb2—O11^ii	113.0 (12)
O3—Rb1—N1^iii	123 (2)	O10^i—Rb2—N1	118 (2)
O3^iii—Rb1—O8	121.0 (10)	O10^i—Rb2—N1A	111 (2)
O3^iii—Rb1—O8^iii	57.4 (10)	O10^iv—Rb2—O11^ii	64.8 (14)
O3^iii—Rb1—O9	100.9 (10)	O10^iv—Rb2—N1	54.4 (19)
O3^iii—Rb1—O9^iii	92.5 (11)	O10^iv—Rb2—N1A	57 (2)
O3^iii—Rb1—O11^ii	103.1 (10)	O11^ii—Rb2—N1	77.1 (12)
O3^iii—Rb1—O11^iv	58.1 (11)	O11^ii—Rb2—N1A	89.1 (13)
O3^iii—Rb1—N1	123 (2)

Symmetry codes: (i) −x, y−1/2, −z+1/2; (ii) −x+1/2, −y+1/2, −z+1/2; (iii) −x+1/2, y, −z+1; (iv) x, −y+1/2, z+1/2; (v) x, y−1, z; (vi) x−1/2, −y+1, z; (vii) −x, −y+1, −z+1; (viii) −x, y+1/2, −z+1/2.

(I_5.05GPa) ammonium rubidium nonaoxotetratellurate(IV) dihydrate

Crystal data

NH4RbTe4O9·2H2O	F(000) = 2784
Mr = 793.9	Pressure = 5.05 GPa
Monoclinic, I2/a	Dx = 4.576 Mg m^−3
Hall symbol: -I 2ya	Synchrotron radiation, λ = 0.3978 Å
a = 18.344 (4) Å	Cell parameters from 2411 reflections
b = 6.473 (3) Å	θ = 1.3–22.3°
c = 19.62 (1) Å	µ = 2.49 mm^−1
β = 101.4 (2)°	T = 293 K
V = 2283 (2) Å^3	Irregular, light yellow
Z = 8	0.22 × 0.12 × 0.03 mm

Data collection

Huber four-circle diffractometer with Marresearch MarCCD165 area detector	644 reflections with I > 3σ(I)
Radiation source: HASYLAB	Rint = 0.229
ϕ scans	θmax = 18.9°, θmin = 1.3°
Absorption correction: numerical (JANA2006; Petříček et al., 2006)	h = −27→27
Tmin = 0.498, Tmax = 0.783	k = −10→10
2411 measured reflections	l = −17→11
645 independent reflections

Refinement

Refinement on F	0 constraints
R[F^2 > 2σ(F^2)] = 0.119	H-atom parameters not defined
wR(F^2) = 0.096	Weighting scheme based on measured s.u.'s w = 1/(σ^2(F) + 0.0001F^2)
S = 3.13	(Δ/σ)max = 0.020
645 reflections	Δρmax = 3.87 e Å^−3
82 parameters	Δρmin = −3.50 e Å^−3
1 restraint

Special details

Experimental. Pressure = 5.05 GPa; Almax diamond anvil cell Beamline D3, HASYLAB MarCCD165 detector

Refinement. Te anisotropic; Rb, O and N isotropic; all displacement parameters of oxygen coordinating Te (O1—O9) set equal; displacement parameters of oxygen belonging to water moelcules (O10, O11) restricted to be equal. Occupation factors of Rb fixed to values from ambient pressure dataset.

Fractional atomic coordinates and isotropic or equivalent isotropic displacement parameters (Ų)

	x	y	z	Uiso*/Ueq	Occ. (<1)
Te1	0.1212 (3)	0.6280 (7)	0.3042 (6)	0.023 (6)
Te2	0.0552 (3)	0.1415 (6)	0.1987 (6)	0.016 (6)
Te3	0.2209 (3)	0.1936 (6)	0.3211 (5)	0.012 (6)
Te4	0.3169 (3)	0.6809 (7)	0.3503 (6)	0.018 (6)
Rb1	0.25	0.4503 (16)	0.5	0.020 (3)*	0.78
Rb2	0.0346 (5)	0.1128 (13)	0.4000 (12)	0.010 (2)*	0.61
O1	0.055 (2)	0.693 (6)	0.365 (5)	0.017 (4)*
O2	0.209 (2)	0.723 (6)	0.360 (5)	0.017 (4)*
O3	0.146 (2)	0.360 (6)	0.362 (5)	0.017 (4)*
O4	0.005 (3)	0.005 (5)	0.272 (5)	0.017 (4)*
O5	0.427 (2)	0.586 (6)	0.361 (5)	0.017 (4)*
O6	0.147 (2)	0.013 (6)	0.266 (5)	0.017 (4)*
O7	0.213 (2)	0.397 (5)	0.249 (5)	0.017 (4)*
O8	0.304 (3)	0.406 (5)	0.370 (5)	0.017 (4)*
O9	0.352 (2)	0.796 (6)	0.430 (5)	0.017 (4)*
O10	0.069 (3)	0.350 (6)	0.039 (4)	0.033 (10)*
O11	0.316 (3)	0.486 (7)	0.051 (6)	0.033 (10)*
N1	0.078 (3)	0.528 (7)	0.491 (6)	0.013 (13)*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Te1	0.019 (3)	0.008 (2)	0.043 (18)	0.001 (2)	0.007 (6)	0.006 (4)
Te2	0.013 (2)	0.006 (2)	0.023 (17)	−0.0007 (18)	−0.012 (5)	−0.003 (3)
Te3	0.015 (2)	0.004 (2)	0.015 (16)	0.0009 (19)	0.001 (5)	−0.002 (3)
Te4	0.019 (3)	0.009 (2)	0.022 (17)	−0.001 (2)	−0.003 (6)	0.002 (4)

Geometric parameters (Å, º)

Te1—O1	1.91 (8)	Rb1—O3	3.05 (8)
Te1—O2	1.86 (6)	Rb1—O3^iii	3.05 (8)
Te1—O3	2.07 (6)	Rb1—O8	2.92 (10)
Te2—O1^i	2.19 (5)	Rb1—O8^iii	2.92 (10)
Te2—O4	2.05 (9)	Rb1—O9	3.37 (7)
Te2—O5^ii	1.94 (7)	Rb1—O9^iii	3.37 (7)
Te2—O6	2.09 (6)	Rb1—O11^ii	3.15 (5)
Te3—O3	2.03 (6)	Rb1—O11^iv	3.15 (5)
Te3—O6	1.95 (6)	Rb1—N1	3.17 (5)
Te3—O7	1.92 (8)	Rb1—N1^iii	3.17 (5)
Te3—O7^ii	2.08 (8)	Rb2—O1^v	2.84 (5)
Te3—O8	2.13 (5)	Rb2—O3	2.81 (6)
Te4—O2	2.04 (5)	Rb2—O4	2.56 (10)
Te4—O5	2.09 (4)	Rb2—O5^vi	2.77 (4)
Te4—O8	1.85 (4)	Rb2—O10^i	2.97 (6)
Te4—O9	1.74 (9)	Rb2—O10^iv	2.68 (8)
Rb1—O2	3.23 (9)	Rb2—O11^ii	2.79 (5)
Rb1—O2^iii	3.23 (9)	Rb2—N1	3.23 (7)
O1—Te1—O2	98 (3)	O3^iii—Rb1—O11^iv	54.0 (18)
O1—Te1—O3	86 (3)	O3^iii—Rb1—N1	122 (3)
O2—Te1—O3	84 (2)	O3^iii—Rb1—N1^iii	62 (2)
O1^i—Te2—O4	89 (3)	O8—Rb1—O8^iii	168.6 (11)
O1^i—Te2—O5^ii	91 (2)	O8—Rb1—O9	53.4 (16)
O1^i—Te2—O6	163.7 (19)	O8—Rb1—O9^iii	136.8 (17)
O4—Te2—O5^ii	104 (3)	O8—Rb1—O11^ii	79 (2)
O4—Te2—O6	79 (3)	O8—Rb1—O11^iv	91 (2)
O5^ii—Te2—O6	82 (3)	O8—Rb1—N1	118 (2)
O3—Te3—O6	95 (2)	O8—Rb1—N1^iii	64 (2)
O3—Te3—O7	89 (3)	O8^iii—Rb1—O9	136.8 (17)
O3—Te3—O7^ii	159 (3)	O8^iii—Rb1—O9^iii	53.4 (16)
O3—Te3—O8	88 (2)	O8^iii—Rb1—O11^ii	91 (2)
O6—Te3—O7	93 (3)	O8^iii—Rb1—O11^iv	79 (2)
O6—Te3—O7^ii	84 (3)	O8^iii—Rb1—N1	64 (2)
O6—Te3—O8	173 (4)	O8^iii—Rb1—N1^iii	118 (2)
O7—Te3—O7^ii	71 (3)	O9—Rb1—O9^iii	96.8 (15)
O7—Te3—O8	80 (3)	O9—Rb1—O11^ii	132 (2)
O7^ii—Te3—O8	91 (3)	O9—Rb1—O11^iv	121.0 (14)
O2—Te4—O5	166 (3)	O9—Rb1—N1	119.9 (15)
O2—Te4—O8	87 (2)	O9—Rb1—N1^iii	45.0 (16)
O2—Te4—O9	93 (3)	O9^iii—Rb1—O11^ii	121.0 (14)
O5—Te4—O8	82.0 (19)	O9^iii—Rb1—O11^iv	132 (2)
O5—Te4—O9	82 (3)	O9^iii—Rb1—N1	45.0 (16)
O8—Te4—O9	105 (4)	O9^iii—Rb1—N1^iii	119.9 (15)
O2—Rb1—O2^iii	113.7 (16)	O11^ii—Rb1—O11^iv	53.0 (17)
O2—Rb1—O3	49.4 (13)	O11^ii—Rb1—N1	78.9 (13)
O2—Rb1—O3^iii	149.5 (12)	O11^ii—Rb1—N1^iii	118.3 (15)
O2—Rb1—O8	51.2 (15)	O11^iv—Rb1—N1	118.3 (15)
O2—Rb1—O8^iii	137.3 (15)	O11^iv—Rb1—N1^iii	78.9 (13)
O2—Rb1—O9	49.1 (14)	N1—Rb1—N1^iii	161.8 (12)
O2—Rb1—O9^iii	86 (2)	O1^v—Rb2—O3	109.9 (18)
O2—Rb1—O11^ii	102 (2)	O1^v—Rb2—O4	61 (2)
O2—Rb1—O11^iv	140 (2)	O1^v—Rb2—O5^vi	136.7 (18)
O2—Rb1—N1	79 (2)	O1^v—Rb2—O10^i	71.1 (18)
O2—Rb1—N1^iii	91 (2)	O1^v—Rb2—O10^iv	108 (2)
O2^iii—Rb1—O3	149.5 (12)	O1^v—Rb2—O11^ii	72.3 (15)
O2^iii—Rb1—O3^iii	49.4 (13)	O1^v—Rb2—N1	153.6 (18)
O2^iii—Rb1—O8	137.3 (15)	O3—Rb2—O4	85 (2)
O2^iii—Rb1—O8^iii	51.2 (15)	O3—Rb2—O5^vi	92.2 (15)
O2^iii—Rb1—O9	86 (2)	O3—Rb2—O10^i	172 (2)
O2^iii—Rb1—O9^iii	49.1 (14)	O3—Rb2—O10^iv	100 (2)
O2^iii—Rb1—O11^ii	140 (2)	O3—Rb2—O11^ii	60.4 (18)
O2^iii—Rb1—O11^iv	102 (2)	O3—Rb2—N1	64 (2)
O2^iii—Rb1—N1	91 (2)	O4—Rb2—O5^vi	85 (2)
O2^iii—Rb1—N1^iii	79 (2)	O4—Rb2—O10^i	102.3 (18)
O3—Rb1—O3^iii	157.8 (11)	O4—Rb2—O10^iv	169.3 (13)
O3—Rb1—O8	57.8 (17)	O4—Rb2—O11^ii	106 (2)
O3—Rb1—O8^iii	119.7 (17)	O4—Rb2—N1	138 (2)
O3—Rb1—O9	93.9 (19)	O5^vi—Rb2—O10^i	92.2 (16)
O3—Rb1—O9^iii	100.8 (16)	O5^vi—Rb2—O10^iv	103 (2)
O3—Rb1—O11^ii	54.0 (18)	O5^vi—Rb2—O11^ii	148.4 (13)
O3—Rb1—O11^iv	104.1 (17)	O5^vi—Rb2—N1	69.6 (17)
O3—Rb1—N1	62 (2)	O10^i—Rb2—O10^iv	71.6 (17)
O3—Rb1—N1^iii	122 (3)	O10^i—Rb2—O11^ii	113.2 (19)
O3^iii—Rb1—O8	119.7 (17)	O10^i—Rb2—N1	111 (2)
O3^iii—Rb1—O8^iii	57.8 (17)	O10^iv—Rb2—O11^ii	70 (2)
O3^iii—Rb1—O9	100.8 (16)	O10^iv—Rb2—N1	52 (2)
O3^iii—Rb1—O9^iii	93.9 (19)	O11^ii—Rb2—N1	83.3 (16)
O3^iii—Rb1—O11^ii	104.1 (17)

Symmetry codes: (i) −x, y−1/2, −z+1/2; (ii) −x+1/2, −y+1/2, −z+1/2; (iii) −x+1/2, y, −z+1; (iv) x, −y+1/2, z+1/2; (v) x, y−1, z; (vi) x−1/2, −y+1, z.