Syntheses, crystal structures and optical properties of two one-dimensional germanophosphates: HRb₃Ge₂(HPO₄)₆ and CsGe(HPO₄)₂(OH)

Germanophosphates, as a young class of metal phosphates, have been less reported but might possess more diverse structural types and potential appli­cations. Here, two one-dimensional (1D) alkali-metal germanophosphates (GePOs), namely, hydrogen hexa­kis­(μ-hydrogen phosphato)digermaniumtrirubidium, HRb₃Ge₂(HPO₄)₆ (1), and caesium bis­(μ-hydrogen phosphato)(μ-hydroxido)germanium, CsGe(HPO₄)₂(OH) (2), have been prepared by the solvothermal method. Compound 1 shows 1D [Ge(HPO₄)₆]_∞ chains along the c axis formed by GeO₆ octa­hedra and PO₄ tetra­hedra, with Rb⁺ cations dissociated between the chains. Compound 2 also exhibits 1D [Ge(HPO₄)₄(OH)₂]_∞ chains constructed from adjacent Ge(HPO₄)₄(OH)₂ octa­hedra, with Cs⁺ cations dissociated between the chains. XRD, TGA, IR and UV–Vis–NIR absorption spectra are presented and discussed for both compounds.

Computing details

For both structures, data collection: APEX2 (Bruker, 2015); cell refinement: SAINT (Bruker, 2015); data reduction: SAINT (Bruker, 2015); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg & Putz, 2005); software used to prepare material for publication: PLATON (Spek, 2009).

Hydrogen hexakis(µ-hydrogen phosphato)digermaniumtrirubidium (1)

Crystal data

HRb3Ge2(HPO4)6	Dx = 3.090 Mg m^−3
Mr = 978.47	Mo Kα radiation, λ = 0.71073 Å
Trigonal, R3	Cell parameters from 3159 reflections
a = 14.5940 (9) Å	θ = 2.9–27.4°
c = 8.5522 (6) Å	µ = 10.33 mm^−1
V = 1577.46 (18) Å^3	T = 293 K
Z = 3	Needle, colorless
F(000) = 1389	0.10 × 0.05 × 0.03 mm

Data collection

Bruker APEXII CCD diffractometer	624 independent reflections
Radiation source: fine-focus sealed tube	573 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.035
ω scans	θmax = 25.0°, θmin = 2.9°
Absorption correction: multi-scan (SADABS; Bruker, 2015)	h = −17→17
Tmin = 0.209, Tmax = 0.356	k = −17→17
4050 measured reflections	l = −9→10

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: mixed
R[F^2 > 2σ(F^2)] = 0.031	H-atom parameters constrained
wR(F^2) = 0.085	w = 1/[σ^2(Fo^2) + (0.0392P)^2 + 22.1168P] where P = (Fo^2 + 2Fc^2)/3
S = 1.14	(Δ/σ)max < 0.001
624 reflections	Δρmax = 0.67 e Å^−3
57 parameters	Δρmin = −1.41 e Å^−3
3 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0039 (4)

Special details

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.

Single-crystal X-ray diffraction (XRD) data for 1 and 2 were collected on a Bruker D8 VENTURE CMOS X-ray diffractometer equipped with graphite-monochromated Mo Kα radiation (λ = 0.71073 Å) at 293 K. The data sets were corrected for Lorentz and polarization factors as well as absorption by the multi-scan method (Bruker 2015). Both structures were solved by direct methods and refined by full matrix least-squares fitting on F² using SHELX-97 (Sheldrick, 2008).

The two structures were also checked with the program PLATON, and no higher symmetry was found (Spek 2009). Crystallographic data and structural refinements for both compounds are listed in Table 1. Further details of the crystal structure studies could be obtained from the FIZ Karlsruhe, 76344 Eggenstein-Leopoldshafen, Germany (Fax: [phone]; E-mail: [e-mail]), on quoting the depository numbers 434780 for HRb₃Ge₂(PO₄)₆ and 434779 for CsGe(HPO₄)₂(OH).

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

	x	y	z	Uiso*/Ueq
Ge1	0.0000	0.0000	0.5000	0.0134 (4)
Ge2	0.0000	0.0000	0.0000	0.0060 (3)
P1	−0.18052 (8)	−0.09530 (8)	0.25180 (12)	0.0090 (4)
O1	−0.1119 (2)	−0.1008 (2)	0.1201 (3)	0.0094 (6)
O2	−0.1134 (2)	−0.0155 (2)	0.3784 (3)	0.0127 (7)
O3	−0.2594 (3)	−0.0655 (3)	0.1890 (4)	0.0189 (8)
O4	−0.2388 (3)	−0.2088 (3)	0.3194 (4)	0.0248 (9)
H4	−0.2940	−0.2175	0.3671	0.037*
Rb1	−0.1667	−0.3333	0.1667	0.0622 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ge1	0.0178 (4)	0.0178 (4)	0.0044 (6)	0.0089 (2)	0.000	0.000
Ge2	0.0070 (4)	0.0070 (4)	0.0041 (6)	0.0035 (2)	0.000	0.000
P1	0.0095 (6)	0.0105 (6)	0.0076 (6)	0.0055 (5)	0.0025 (4)	0.0020 (4)
O1	0.0096 (14)	0.0098 (14)	0.0077 (15)	0.0041 (12)	0.0025 (11)	0.0011 (11)
O2	0.0159 (16)	0.0160 (16)	0.0087 (15)	0.0099 (13)	−0.0007 (12)	−0.0018 (12)
O3	0.0141 (16)	0.0293 (19)	0.0173 (17)	0.0138 (15)	−0.0020 (13)	−0.0008 (14)
O4	0.0237 (19)	0.0154 (17)	0.035 (2)	0.0099 (16)	0.0213 (16)	0.0102 (15)
Rb1	0.0430 (6)	0.0249 (5)	0.1166 (11)	0.0153 (4)	0.0279 (6)	−0.0043 (5)

Geometric parameters (Å, º)

Ge1—O2	1.870 (3)	P1—Rb1^v	3.7966 (11)
Ge1—O2^i	1.870 (3)	P1—Rb1^ix	4.0674 (11)
Ge1—O2^ii	1.870 (3)	O1—Rb1	3.098 (3)
Ge1—O2^iii	1.870 (3)	O2—Rb1^v	3.609 (3)
Ge1—O2^iv	1.870 (3)	O3—Rb1^v	2.960 (3)
Ge1—O2^v	1.870 (3)	O3—Rb1^ix	3.317 (3)
Ge2—O1^vi	1.866 (3)	O4—Rb1	2.834 (3)
Ge2—O1^v	1.866 (3)	Rb1—O4^x	2.834 (3)
Ge2—O1^vii	1.866 (3)	Rb1—O3^xi	2.960 (3)
Ge2—O1^iii	1.866 (3)	Rb1—O3^iii	2.960 (3)
Ge2—O1^viii	1.866 (3)	Rb1—O1^x	3.098 (3)
Ge2—O1	1.866 (3)	Rb1—O3^vi	3.317 (3)
P1—O3	1.518 (3)	Rb1—O3^xii	3.317 (3)
P1—O2	1.532 (3)	Rb1—O2^iii	3.609 (3)
P1—O1	1.536 (3)	Rb1—O2^xi	3.609 (3)
P1—O4	1.547 (3)	Rb1—P1^x	3.6525 (11)
P1—Rb1	3.6526 (11)
O2—Ge1—O2^i	180.0	O4—Rb1—O3^iii	101.20 (10)
O2—Ge1—O2^ii	87.95 (13)	O4^x—Rb1—O3^iii	78.80 (10)
O2^i—Ge1—O2^ii	92.05 (13)	O3^xi—Rb1—O3^iii	180.0
O2—Ge1—O2^iii	92.05 (13)	O4—Rb1—O1	48.09 (8)
O2^i—Ge1—O2^iii	87.95 (13)	O4^x—Rb1—O1	131.91 (8)
O2^ii—Ge1—O2^iii	180.0	O3^xi—Rb1—O1	108.92 (8)
O2—Ge1—O2^iv	87.95 (13)	O3^iii—Rb1—O1	71.07 (8)
O2^i—Ge1—O2^iv	92.05 (13)	O4—Rb1—O1^x	131.91 (8)
O2^ii—Ge1—O2^iv	92.05 (13)	O4^x—Rb1—O1^x	48.09 (8)
O2^iii—Ge1—O2^iv	87.95 (13)	O3^xi—Rb1—O1^x	71.07 (8)
O2—Ge1—O2^v	92.05 (13)	O3^iii—Rb1—O1^x	108.93 (8)
O2^i—Ge1—O2^v	87.95 (13)	O1—Rb1—O1^x	180.0
O2^ii—Ge1—O2^v	87.95 (13)	O4—Rb1—O3^vi	94.05 (10)
O2^iii—Ge1—O2^v	92.05 (13)	O4^x—Rb1—O3^vi	85.95 (10)
O2^iv—Ge1—O2^v	180.00 (19)	O3^xi—Rb1—O3^vi	83.23 (10)
O1^vi—Ge2—O1^v	180.0 (2)	O3^iii—Rb1—O3^vi	96.77 (10)
O1^vi—Ge2—O1^vii	92.61 (12)	O1—Rb1—O3^vi	62.18 (8)
O1^v—Ge2—O1^vii	87.39 (12)	O1^x—Rb1—O3^vi	117.82 (8)
O1^vi—Ge2—O1^iii	87.39 (12)	O4—Rb1—O3^xii	85.95 (10)
O1^v—Ge2—O1^iii	92.61 (12)	O4^x—Rb1—O3^xii	94.05 (10)
O1^vii—Ge2—O1^iii	180.0 (2)	O3^xi—Rb1—O3^xii	96.77 (10)
O1^vi—Ge2—O1^viii	92.61 (12)	O3^iii—Rb1—O3^xii	83.23 (10)
O1^v—Ge2—O1^viii	87.39 (12)	O1—Rb1—O3^xii	117.82 (8)
O1^vii—Ge2—O1^viii	92.61 (12)	O1^x—Rb1—O3^xii	62.18 (8)
O1^iii—Ge2—O1^viii	87.39 (12)	O3^vi—Rb1—O3^xii	180.0
O1^vi—Ge2—O1	87.39 (12)	O4—Rb1—O2^iii	59.42 (9)
O1^v—Ge2—O1	92.61 (12)	O4^x—Rb1—O2^iii	120.59 (9)
O1^vii—Ge2—O1	87.39 (12)	O3^xi—Rb1—O2^iii	137.06 (8)
O1^iii—Ge2—O1	92.61 (12)	O3^iii—Rb1—O2^iii	42.94 (8)
O1^viii—Ge2—O1	180.0	O1—Rb1—O2^iii	50.03 (7)
O3—P1—O2	108.72 (18)	O1^x—Rb1—O2^iii	129.97 (7)
O3—P1—O1	111.33 (18)	O3^vi—Rb1—O2^iii	107.55 (7)
O2—P1—O1	111.82 (17)	O3^xii—Rb1—O2^iii	72.45 (7)
O3—P1—O4	110.4 (2)	O4—Rb1—O2^xi	120.58 (9)
O2—P1—O4	110.49 (19)	O4^x—Rb1—O2^xi	59.42 (9)
O1—P1—O4	104.00 (17)	O3^xi—Rb1—O2^xi	42.94 (8)
O3—P1—Rb1	127.78 (14)	O3^iii—Rb1—O2^xi	137.07 (8)
O2—P1—Rb1	123.02 (12)	O1—Rb1—O2^xi	129.97 (7)
O1—P1—Rb1	57.06 (11)	O1^x—Rb1—O2^xi	50.03 (7)
O4—P1—Rb1	47.03 (12)	O3^vi—Rb1—O2^xi	72.45 (7)
O3—P1—Rb1^v	46.35 (13)	O3^xii—Rb1—O2^xi	107.55 (7)
O2—P1—Rb1^v	71.25 (12)	O2^iii—Rb1—O2^xi	180.0
O1—P1—Rb1^v	101.79 (11)	O4—Rb1—P1	23.54 (6)
O4—P1—Rb1^v	150.91 (14)	O4^x—Rb1—P1	156.46 (6)
Rb1—P1—Rb1^v	156.79 (3)	O3^xi—Rb1—P1	94.46 (6)
O3—P1—Rb1^ix	50.57 (13)	O3^iii—Rb1—P1	85.53 (6)
O2—P1—Rb1^ix	151.27 (12)	O1—Rb1—P1	24.59 (5)
O1—P1—Rb1^ix	68.28 (11)	O1^x—Rb1—P1	155.41 (5)
O4—P1—Rb1^ix	96.72 (15)	O3^vi—Rb1—P1	78.51 (6)
Rb1—P1—Rb1^ix	82.24 (2)	O3^xii—Rb1—P1	101.49 (6)
Rb1^v—P1—Rb1^ix	80.53 (2)	O2^iii—Rb1—P1	50.14 (5)
P1—O1—Ge2	134.32 (18)	O2^xi—Rb1—P1	129.86 (5)
P1—O1—Rb1	98.35 (13)	O4—Rb1—P1^x	156.46 (6)
Ge2—O1—Rb1	125.39 (13)	O4^x—Rb1—P1^x	23.54 (6)
P1—O2—Ge1	132.57 (19)	O3^xi—Rb1—P1^x	85.54 (6)
P1—O2—Rb1^v	85.05 (12)	O3^iii—Rb1—P1^x	94.47 (6)
Ge1—O2—Rb1^v	133.90 (14)	O1—Rb1—P1^x	155.41 (5)
P1—O3—Rb1^v	111.87 (17)	O1^x—Rb1—P1^x	24.59 (5)
P1—O3—Rb1^ix	108.74 (16)	O3^vi—Rb1—P1^x	101.49 (6)
Rb1^v—O3—Rb1^ix	108.13 (10)	O3^xii—Rb1—P1^x	78.51 (6)
P1—O4—Rb1	109.43 (16)	O2^iii—Rb1—P1^x	129.86 (5)
O4—Rb1—O4^x	180.0	O2^xi—Rb1—P1^x	50.14 (5)
O4—Rb1—O3^xi	78.80 (10)	P1—Rb1—P1^x	180.0
O4^x—Rb1—O3^xi	101.20 (10)
O3—P1—O1—Ge2	73.9 (3)	Ge2—O1—Rb1—O1^x	178 (3)
O2—P1—O1—Ge2	−47.9 (3)	P1—O1—Rb1—O3^vi	127.75 (15)
O4—P1—O1—Ge2	−167.2 (3)	Ge2—O1—Rb1—O3^vi	−66.21 (15)
Rb1—P1—O1—Ge2	−164.0 (3)	P1—O1—Rb1—O3^xii	−52.25 (15)
Rb1^v—P1—O1—Ge2	26.4 (3)	Ge2—O1—Rb1—O3^xii	113.79 (15)
Rb1^ix—P1—O1—Ge2	101.1 (2)	P1—O1—Rb1—O2^iii	−79.73 (14)
O3—P1—O1—Rb1	−122.06 (16)	Ge2—O1—Rb1—O2^iii	86.31 (16)
O2—P1—O1—Rb1	116.11 (15)	P1—O1—Rb1—O2^xi	100.26 (14)
O4—P1—O1—Rb1	−3.13 (19)	Ge2—O1—Rb1—O2^xi	−93.69 (16)
Rb1^v—P1—O1—Rb1	−169.56 (5)	Ge2—O1—Rb1—P1	166.0 (3)
Rb1^ix—P1—O1—Rb1	−94.88 (8)	P1—O1—Rb1—P1^x	180.0
O1^vi—Ge2—O1—P1	−172.1 (3)	Ge2—O1—Rb1—P1^x	−14.0 (3)
O1^v—Ge2—O1—P1	7.9 (3)	O3—P1—Rb1—O4	−83.2 (3)
O1^vii—Ge2—O1—P1	−79.34 (16)	O2—P1—Rb1—O4	88.0 (2)
O1^iii—Ge2—O1—P1	100.66 (16)	O1—P1—Rb1—O4	−175.8 (3)
O1^viii—Ge2—O1—P1	154 (3)	Rb1^v—P1—Rb1—O4	−149.1 (2)
O1^vi—Ge2—O1—Rb1	27.40 (11)	Rb1^ix—P1—Rb1—O4	−106.7 (2)
O1^v—Ge2—O1—Rb1	−152.60 (11)	O3—P1—Rb1—O4^x	96.8 (3)
O1^vii—Ge2—O1—Rb1	120.1 (2)	O2—P1—Rb1—O4^x	−92.0 (2)
O1^iii—Ge2—O1—Rb1	−59.9 (2)	O1—P1—Rb1—O4^x	4.2 (3)
O1^viii—Ge2—O1—Rb1	−7 (2)	O4—P1—Rb1—O4^x	180.0
O3—P1—O2—Ge1	−177.7 (2)	Rb1^v—P1—Rb1—O4^x	30.9 (2)
O1—P1—O2—Ge1	−54.4 (3)	Rb1^ix—P1—Rb1—O4^x	73.3 (2)
O4—P1—O2—Ge1	60.9 (3)	O3—P1—Rb1—O3^xi	−35.0 (2)
Rb1—P1—O2—Ge1	9.6 (3)	O2—P1—Rb1—O3^xi	136.17 (16)
Rb1^v—P1—O2—Ge1	−149.9 (3)	O1—P1—Rb1—O3^xi	−127.68 (15)
Rb1^ix—P1—O2—Ge1	−138.72 (17)	O4—P1—Rb1—O3^xi	48.2 (2)
O3—P1—O2—Rb1^v	−27.78 (16)	Rb1^v—P1—Rb1—O3^xi	−100.93 (10)
O1—P1—O2—Rb1^v	95.54 (14)	Rb1^ix—P1—Rb1—O3^xi	−58.58 (6)
O4—P1—O2—Rb1^v	−149.12 (15)	O3—P1—Rb1—O3^iii	145.0 (2)
Rb1—P1—O2—Rb1^v	159.55 (6)	O2—P1—Rb1—O3^iii	−43.83 (16)
Rb1^ix—P1—O2—Rb1^v	11.2 (3)	O1—P1—Rb1—O3^iii	52.32 (15)
O2^i—Ge1—O2—P1	68.8 (11)	O4—P1—Rb1—O3^iii	−131.8 (2)
O2^ii—Ge1—O2—P1	−168.7 (3)	Rb1^v—P1—Rb1—O3^iii	79.07 (10)
O2^iii—Ge1—O2—P1	11.3 (3)	Rb1^ix—P1—Rb1—O3^iii	121.42 (6)
O2^iv—Ge1—O2—P1	−76.60 (16)	O3—P1—Rb1—O1	92.6 (2)
O2^v—Ge1—O2—P1	103.40 (16)	O2—P1—Rb1—O1	−96.1 (2)
O2^i—Ge1—O2—Rb1^v	−67.4 (10)	O4—P1—Rb1—O1	175.8 (3)
O2^ii—Ge1—O2—Rb1^v	55.10 (9)	Rb1^v—P1—Rb1—O1	26.75 (14)
O2^iii—Ge1—O2—Rb1^v	−124.90 (9)	Rb1^ix—P1—Rb1—O1	69.10 (13)
O2^iv—Ge1—O2—Rb1^v	147.2 (2)	O3—P1—Rb1—O1^x	−87.4 (2)
O2^v—Ge1—O2—Rb1^v	−32.8 (2)	O2—P1—Rb1—O1^x	83.9 (2)
O2—P1—O3—Rb1^v	37.6 (2)	O1—P1—Rb1—O1^x	180.0
O1—P1—O3—Rb1^v	−86.03 (18)	O4—P1—Rb1—O1^x	−4.2 (3)
O4—P1—O3—Rb1^v	158.97 (16)	Rb1^v—P1—Rb1—O1^x	−153.25 (14)
Rb1—P1—O3—Rb1^v	−150.19 (7)	Rb1^ix—P1—Rb1—O1^x	−110.90 (13)
Rb1^ix—P1—O3—Rb1^v	−119.4 (2)	O3—P1—Rb1—O3^vi	47.12 (18)
O2—P1—O3—Rb1^ix	156.94 (14)	O2—P1—Rb1—O3^vi	−141.68 (16)
O1—P1—O3—Rb1^ix	33.3 (2)	O1—P1—Rb1—O3^vi	−45.53 (14)
O4—P1—O3—Rb1^ix	−81.68 (19)	O4—P1—Rb1—O3^vi	130.3 (2)
Rb1—P1—O3—Rb1^ix	−30.8 (2)	Rb1^v—P1—Rb1—O3^vi	−18.78 (10)
Rb1^v—P1—O3—Rb1^ix	119.4 (2)	Rb1^ix—P1—Rb1—O3^vi	23.57 (6)
O3—P1—O4—Rb1	123.13 (18)	O3—P1—Rb1—O3^xii	−132.88 (18)
O2—P1—O4—Rb1	−116.55 (17)	O2—P1—Rb1—O3^xii	38.32 (16)
O1—P1—O4—Rb1	3.6 (2)	O1—P1—Rb1—O3^xii	134.47 (14)
Rb1^v—P1—O4—Rb1	155.40 (16)	O4—P1—Rb1—O3^xii	−49.7 (2)
Rb1^ix—P1—O4—Rb1	72.82 (15)	Rb1^v—P1—Rb1—O3^xii	161.22 (10)
P1—O4—Rb1—O4^x	−132 (2)	Rb1^ix—P1—Rb1—O3^xii	−156.43 (6)
P1—O4—Rb1—O3^xi	−130.8 (2)	O3—P1—Rb1—O2^iii	171.90 (19)
P1—O4—Rb1—O3^iii	49.2 (2)	O2—P1—Rb1—O2^iii	−16.89 (13)
P1—O4—Rb1—O1	−2.32 (14)	O1—P1—Rb1—O2^iii	79.26 (15)
P1—O4—Rb1—O1^x	177.68 (14)	O4—P1—Rb1—O2^iii	−104.9 (2)
P1—O4—Rb1—O3^vi	−48.5 (2)	Rb1^v—P1—Rb1—O2^iii	106.00 (10)
P1—O4—Rb1—O3^xii	131.5 (2)	Rb1^ix—P1—Rb1—O2^iii	148.35 (6)
P1—O4—Rb1—O2^iii	59.50 (18)	O3—P1—Rb1—O2^xi	−8.10 (19)
P1—O4—Rb1—O2^xi	−120.50 (18)	O2—P1—Rb1—O2^xi	163.11 (13)
P1—O4—Rb1—P1^x	180.0	O1—P1—Rb1—O2^xi	−100.74 (15)
P1—O1—Rb1—O4	2.23 (13)	O4—P1—Rb1—O2^xi	75.1 (2)
Ge2—O1—Rb1—O4	168.3 (2)	Rb1^v—P1—Rb1—O2^xi	−74.00 (10)
P1—O1—Rb1—O4^x	−177.77 (13)	Rb1^ix—P1—Rb1—O2^xi	−31.65 (6)
Ge2—O1—Rb1—O4^x	−11.7 (2)	O3—P1—Rb1—P1^x	−40 (6)
P1—O1—Rb1—O3^xi	56.53 (15)	O2—P1—Rb1—P1^x	131 (6)
Ge2—O1—Rb1—O3^xi	−137.43 (15)	O1—P1—Rb1—P1^x	−133 (6)
P1—O1—Rb1—O3^iii	−123.47 (15)	O4—P1—Rb1—P1^x	43 (6)
Ge2—O1—Rb1—O3^iii	42.57 (15)	Rb1^v—P1—Rb1—P1^x	−106 (6)
P1—O1—Rb1—O1^x	12 (3)	Rb1^ix—P1—Rb1—P1^x	−63 (6)

Symmetry codes: (i) −x, −y, −z+1; (ii) y, −x+y, −z+1; (iii) −y, x−y, z; (iv) x−y, x, −z+1; (v) −x+y, −x, z; (vi) x−y, x, −z; (vii) y, −x+y, −z; (viii) −x, −y, −z; (ix) −y−2/3, x−y−1/3, z−1/3; (x) −x−1/3, −y−2/3, −z+1/3; (xi) y−1/3, −x+y−2/3, −z+1/3; (xii) −x+y−1/3, −x−2/3, z+1/3.

Caesium bis(µ-hydrogen phosphato)(µ-hydroxido)germanium (2)

Crystal data

CsGe(HPO4)2(OH)	Z = 4
Mr = 414.48	F(000) = 768
Triclinic, P1	Dx = 3.535 Mg m^−3
a = 8.3453 (18) Å	Mo Kα radiation, λ = 0.71073 Å
b = 9.642 (2) Å	Cell parameters from 9806 reflections
c = 9.739 (2) Å	θ = 2.5–25.7°
α = 89.762 (7)°	µ = 8.97 mm^−1
β = 83.744 (7)°	T = 293 K
γ = 88.946 (7)°	Block, colorless
V = 778.9 (3) Å^3	0.19 × 0.18 × 0.17 mm

Data collection

Bruker APEXII CCD diffractometer	2964 independent reflections
Radiation source: fine-focus sealed tube	2830 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.028
ω scans	θmax = 25.8°, θmin = 2.1°
Absorption correction: multi-scan (SADABS; Bruker, 2015)	h = −10→10
Tmin = 0.280, Tmax = 0.311	k = −11→11
14635 measured reflections	l = −11→11

Refinement

Refinement on F^2	Secondary atom site location: difference Fourier map
Least-squares matrix: full	Hydrogen site location: mixed
R[F^2 > 2σ(F^2)] = 0.018	H-atom parameters constrained
wR(F^2) = 0.041	w = 1/[σ^2(Fo^2) + (0.011P)^2 + 2.0108P] where P = (Fo^2 + 2Fc^2)/3
S = 1.13	(Δ/σ)max = 0.001
2964 reflections	Δρmax = 1.30 e Å^−3
239 parameters	Δρmin = −1.28 e Å^−3
5 restraints	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
Primary atom site location: structure-invariant direct methods	Extinction coefficient: 0.0209 (4)

Special details

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.

Single-crystal X-ray diffraction (XRD) data for 1 and 2 were collected on a Bruker D8 VENTURE CMOS X-ray diffractometer equipped with graphite-monochromated Mo Kα radiation (λ = 0.71073 Å) at 293 K. The data sets were corrected for Lorentz and polarization factors as well as absorption by the multi-scan method (Bruker 2015). Both structures were solved by direct methods and refined by full matrix least-squares fitting on F² using SHELX-97 (Sheldrick, 2008).

The two structures were also checked with the program PLATON, and no higher symmetry was found (Spek 2009). Crystallographic data and structural refinements for both compounds are listed in Table 1. Further details of the crystal structure studies could be obtained from the FIZ Karlsruhe, 76344 Eggenstein-Leopoldshafen, Germany (Fax: [phone]; E-mail: [e-mail]), on quoting the depository numbers 434780 for HRb₃Ge₂(PO₄)₆ and 434779 for CsGe(HPO₄)₂(OH).

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

	x	y	z	Uiso*/Ueq
Cs1	0.53759 (3)	0.49188 (2)	0.74968 (2)	0.02483 (8)
Cs2	0.49086 (3)	0.95214 (2)	0.75897 (2)	0.02301 (8)
Ge1	0.0000	0.5000	0.5000	0.00664 (10)
Ge2	0.0000	1.0000	1.0000	0.00610 (10)
Ge3	−0.02953 (4)	0.75319 (3)	0.75247 (3)	0.00695 (9)
P1	0.16306 (9)	0.70983 (8)	1.01348 (8)	0.00873 (16)
P2	0.26668 (9)	0.72894 (8)	0.51864 (8)	0.00904 (16)
P3	−0.14881 (9)	0.79728 (8)	0.46030 (8)	0.00807 (16)
P4	0.26266 (9)	1.23661 (8)	0.97819 (8)	0.00862 (16)
O1	0.1613 (2)	0.8692 (2)	1.0303 (2)	0.0108 (4)
O2	0.3425 (3)	0.6677 (2)	0.9728 (3)	0.0247 (6)
H2	0.4157	0.7273	1.0108	0.037*
O3	0.0928 (3)	0.6338 (2)	1.1385 (2)	0.0226 (5)
O4	0.0733 (3)	0.6707 (2)	0.8903 (2)	0.0136 (5)
O5	0.1890 (3)	0.5991 (2)	0.4688 (2)	0.0196 (5)
O6	0.4391 (3)	0.7024 (2)	0.5405 (2)	0.0176 (5)
O7	0.2669 (3)	0.8410 (3)	0.4026 (3)	0.0238 (6)
H7	0.1697	0.8603	0.3920	0.036*
O8	0.1674 (3)	0.7838 (2)	0.6486 (2)	0.0183 (5)
O9	−0.0328 (3)	0.8873 (2)	0.3757 (2)	0.0168 (5)
O10	−0.1201 (3)	0.6422 (2)	0.4311 (2)	0.0172 (5)
O11	−0.3218 (3)	0.8349 (2)	0.4243 (2)	0.0160 (5)
H11	−0.3961	0.7792	0.4546	0.024*
O12	−0.1501 (3)	0.8218 (2)	0.6171 (2)	0.0132 (5)
O13	0.2274 (2)	1.2636 (2)	1.1349 (2)	0.0114 (4)
O14	0.1596 (2)	1.1205 (2)	0.9308 (2)	0.0106 (4)
O15	0.2241 (3)	1.3697 (2)	0.8955 (2)	0.0168 (5)
H15	0.1225	1.3736	0.8955	0.025*
O16	0.4380 (3)	1.2028 (2)	0.9440 (2)	0.0182 (5)
O17	−0.0094 (2)	0.9338 (2)	0.8203 (2)	0.0091 (4)
H17	0.0154	0.9868	0.7502	0.014*
O18	−0.0470 (2)	0.5718 (2)	0.6813 (2)	0.0094 (4)
H18	−0.0500	0.5059	0.7399	0.014*

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Cs1	0.02997 (14)	0.02251 (13)	0.01964 (13)	0.00446 (9)	0.00711 (9)	0.00099 (9)
Cs2	0.03330 (14)	0.01654 (12)	0.01917 (12)	0.00343 (9)	−0.00336 (9)	−0.00077 (8)
Ge1	0.0087 (2)	0.0053 (2)	0.0058 (2)	−0.00113 (16)	−0.00007 (16)	−0.00103 (16)
Ge2	0.0077 (2)	0.0048 (2)	0.0057 (2)	−0.00114 (16)	−0.00021 (16)	−0.00104 (16)
Ge3	0.00913 (16)	0.00629 (15)	0.00538 (16)	−0.00071 (11)	−0.00041 (11)	−0.00136 (11)
P1	0.0106 (4)	0.0066 (4)	0.0094 (4)	0.0008 (3)	−0.0035 (3)	−0.0010 (3)
P2	0.0078 (4)	0.0094 (4)	0.0095 (4)	−0.0022 (3)	0.0008 (3)	−0.0008 (3)
P3	0.0100 (4)	0.0075 (4)	0.0069 (4)	−0.0001 (3)	−0.0017 (3)	0.0012 (3)
P4	0.0083 (4)	0.0085 (4)	0.0088 (4)	−0.0031 (3)	0.0008 (3)	−0.0011 (3)
O1	0.0114 (10)	0.0072 (10)	0.0144 (11)	0.0012 (8)	−0.0046 (8)	−0.0019 (8)
O2	0.0113 (12)	0.0188 (12)	0.0452 (16)	0.0042 (10)	−0.0084 (11)	−0.0174 (11)
O3	0.0393 (15)	0.0156 (12)	0.0129 (12)	−0.0026 (11)	−0.0029 (11)	0.0048 (10)
O4	0.0182 (11)	0.0085 (10)	0.0155 (11)	0.0009 (9)	−0.0089 (9)	−0.0016 (9)
O5	0.0163 (12)	0.0216 (12)	0.0193 (12)	−0.0115 (10)	0.0077 (9)	−0.0112 (10)
O6	0.0097 (11)	0.0208 (12)	0.0225 (13)	−0.0009 (9)	−0.0022 (9)	0.0027 (10)
O7	0.0145 (12)	0.0292 (14)	0.0273 (14)	−0.0027 (10)	−0.0004 (10)	0.0171 (11)
O8	0.0170 (12)	0.0160 (12)	0.0200 (12)	−0.0078 (9)	0.0087 (9)	−0.0085 (10)
O9	0.0142 (11)	0.0216 (12)	0.0145 (12)	−0.0034 (9)	−0.0015 (9)	0.0093 (10)
O10	0.0308 (13)	0.0115 (11)	0.0104 (11)	0.0084 (9)	−0.0089 (10)	−0.0014 (9)
O11	0.0115 (11)	0.0174 (12)	0.0197 (12)	−0.0008 (9)	−0.0043 (9)	0.0067 (9)
O12	0.0213 (12)	0.0103 (10)	0.0083 (11)	0.0027 (9)	−0.0036 (9)	−0.0009 (8)
O13	0.0103 (10)	0.0137 (11)	0.0101 (11)	−0.0020 (8)	−0.0007 (8)	−0.0022 (9)
O14	0.0120 (10)	0.0112 (10)	0.0084 (10)	−0.0053 (8)	0.0001 (8)	−0.0013 (8)
O15	0.0186 (12)	0.0130 (11)	0.0187 (12)	−0.0051 (9)	−0.0006 (9)	0.0056 (9)
O16	0.0096 (11)	0.0237 (13)	0.0207 (12)	−0.0025 (9)	0.0022 (9)	−0.0085 (10)
O17	0.0168 (11)	0.0049 (10)	0.0055 (10)	−0.0016 (8)	−0.0002 (8)	0.0003 (8)
O18	0.0163 (11)	0.0058 (10)	0.0060 (10)	−0.0012 (8)	−0.0009 (8)	0.0001 (8)

Geometric parameters (Å, º)

Ge1—O10	1.850 (2)	P1—O2	1.554 (2)
Ge1—O10^i	1.850 (2)	P2—O6	1.495 (2)
Ge1—O5	1.855 (2)	P2—O5	1.525 (2)
Ge1—O5^i	1.855 (2)	P2—O8	1.526 (2)
Ge1—O18^i	1.897 (2)	P2—O7	1.560 (2)
Ge1—O18	1.897 (2)	P3—O9	1.490 (2)
Ge2—O14	1.853 (2)	P3—O10	1.533 (2)
Ge2—O14^ii	1.853 (2)	P3—O12	1.545 (2)
Ge2—O1	1.873 (2)	P3—O11	1.559 (2)
Ge2—O1^ii	1.873 (2)	P4—O16	1.495 (2)
Ge2—O17^ii	1.876 (2)	P4—O14	1.527 (2)
Ge2—O17	1.876 (2)	P4—O13	1.545 (2)
Ge3—O4	1.841 (2)	P4—O15	1.559 (2)
Ge3—O12	1.856 (2)	O2—H2	0.9506
Ge3—O8	1.861 (2)	O7—H7	0.8462
Ge3—O17	1.882 (2)	O11—H11	0.8550
Ge3—O13^ii	1.889 (2)	O13—Ge3^ii	1.889 (2)
Ge3—O18	1.898 (2)	O15—H15	0.8480
P1—O3	1.489 (2)	O17—H17	0.8608
P1—O4	1.534 (2)	O18—H18	0.8513
P1—O1	1.546 (2)
O10—Ge1—O10^i	179.999 (1)	O13^ii—Ge3—O18	91.33 (9)
O10—Ge1—O5	92.19 (11)	O3—P1—O4	109.23 (14)
O10^i—Ge1—O5	87.81 (11)	O3—P1—O1	114.11 (13)
O10—Ge1—O5^i	87.81 (11)	O4—P1—O1	109.86 (12)
O10^i—Ge1—O5^i	92.19 (11)	O3—P1—O2	111.68 (15)
O5—Ge1—O5^i	180.0	O4—P1—O2	106.05 (13)
O10—Ge1—O18^i	89.66 (9)	O1—P1—O2	105.57 (13)
O10^i—Ge1—O18^i	90.34 (9)	O6—P2—O5	111.57 (14)
O5—Ge1—O18^i	87.44 (9)	O6—P2—O8	112.17 (14)
O5^i—Ge1—O18^i	92.56 (9)	O5—P2—O8	109.56 (13)
O10—Ge1—O18	90.34 (9)	O6—P2—O7	106.46 (13)
O10^i—Ge1—O18	89.66 (9)	O5—P2—O7	107.99 (14)
O5—Ge1—O18	92.56 (9)	O8—P2—O7	108.92 (14)
O5^i—Ge1—O18	87.44 (9)	O9—P3—O10	113.27 (14)
O18^i—Ge1—O18	180.0	O9—P3—O12	112.81 (13)
O14—Ge2—O14^ii	179.999 (1)	O10—P3—O12	108.67 (12)
O14—Ge2—O1	88.74 (9)	O9—P3—O11	108.06 (13)
O14^ii—Ge2—O1	91.26 (9)	O10—P3—O11	107.29 (13)
O14—Ge2—O1^ii	91.26 (9)	O12—P3—O11	106.37 (13)
O14^ii—Ge2—O1^ii	88.74 (9)	O16—P4—O14	110.62 (13)
O1—Ge2—O1^ii	180.00 (9)	O16—P4—O13	109.31 (13)
O14—Ge2—O17^ii	91.00 (9)	O14—P4—O13	111.80 (12)
O14^ii—Ge2—O17^ii	89.00 (9)	O16—P4—O15	107.53 (14)
O1—Ge2—O17^ii	88.66 (9)	O14—P4—O15	107.32 (12)
O1^ii—Ge2—O17^ii	91.34 (9)	O13—P4—O15	110.15 (13)
O14—Ge2—O17	89.00 (9)	P1—O1—Ge2	129.61 (13)
O14^ii—Ge2—O17	91.00 (9)	P1—O2—H2	113.1
O1—Ge2—O17	91.34 (9)	P1—O4—Ge3	140.17 (14)
O1^ii—Ge2—O17	88.66 (9)	P2—O5—Ge1	140.44 (15)
O17^ii—Ge2—O17	179.999 (1)	P2—O7—H7	107.6
O4—Ge3—O12	173.79 (10)	P2—O8—Ge3	139.43 (14)
O4—Ge3—O8	90.84 (11)	P3—O10—Ge1	136.28 (14)
O12—Ge3—O8	93.99 (11)	P3—O11—H11	116.0
O4—Ge3—O17	93.90 (9)	P3—O12—Ge3	134.60 (14)
O12—Ge3—O17	90.37 (9)	P4—O13—Ge3^ii	128.12 (12)
O8—Ge3—O17	85.61 (9)	P4—O14—Ge2	140.51 (13)
O4—Ge3—O13^ii	88.98 (10)	P4—O15—H15	106.5
O12—Ge3—O13^ii	86.53 (10)	Ge2—O17—Ge3	131.47 (11)
O8—Ge3—O13^ii	175.25 (9)	Ge2—O17—H17	120.3
O17—Ge3—O13^ii	89.66 (9)	Ge3—O17—H17	107.3
O4—Ge3—O18	86.45 (9)	Ge1—O18—Ge3	131.38 (11)
O12—Ge3—O18	89.36 (9)	Ge1—O18—H18	109.9
O8—Ge3—O18	93.40 (9)	Ge3—O18—H18	116.2
O17—Ge3—O18	178.95 (9)

Symmetry codes: (i) −x, −y+1, −z+1; (ii) −x, −y+2, −z+2.