Crystal structures of K₂[XSi₅O₁₂] (X = Fe²⁺, Co, Zn) and Rb₂[XSi₅O₁₂] (X = Mn) leucites: comparison of monoclinic P2₁/c and Iad polymorph structures and inverse relationship between tetrahedral cation (T = Si and X)—O bond distances and intertetra­hedral T—O—T angles

The leucite tectosilicate mineral analogues K₂X²⁺Si₅O₁₂ (X = Fe²⁺, Co, Zn) and Rb₂X²⁺Si₅O₁₂ (X = Mn) have been synthesized at elevated temperatures both dry at atmospheric pressure and at controlled water vapour pressure; for X = Co and Zn both dry and hydro­thermally synthesized samples are available. Rietveld refinement of X-ray data for hydro­thermal K₂X²⁺Si₅O₁₂ (X = Fe²⁺, Co, Zn) samples shows that they crystallize in the monoclinic space group P2₁/c and have tetrahedral cations (Si and X) ordered onto distinct framework sites [cf. hydro­thermal K₂MgSi₅O₁₂; Bell et al. (1994a), Acta Cryst. B50, 560–566]. Dry-synthesized K₂X²⁺Si₅O₁₂ (X = Co, Zn) and Rb₂X²⁺Si₅O₁₂ (X = Mn) samples crystallize in the cubic space group and with Si and X cations disordered in the tetrahedral framework sites as typified by dry K₂MgSi₅O₁₂. Both structure types have tetrahedrally coordinated SiO₄ and XO₄ sharing corners to form a partially substituted silicate framework. Extraframework K⁺ and Rb⁺ cations occupy large channels in the framework. Structural data for the ordered samples show that mean tetrahedral Si—O and X—O bond lengths cover the ranges 1.60 Å (Si—O) to 2.24 Å (Fe²⁺—O) and show an inverse relationship with the intertetrahedral angles (T—O—T) which range from 144.7° (Si—O—Si) to 124.6° (Si—O—Fe²⁺). For the compositions with both disordered and ordered tetrahedral cation structures (K₂MgSi₅O₁₂, K₂CoSi₅O₁₂, K₂ZnSi₅O₁₂, Rb₂MnSi₅O₁₂ and Cs₂CuSi₅O₁₂ leucites) the disordered polymorphs always have larger unit-cell volumes, larger intertetrahedral T—O—T angles and smaller mean T—O distances than their isochemical ordered polymorphs. The ordered samples clearly have more flexible frameworks than the disordered structures which allow the former to undergo a greater degree of tetrahedral collapse around the interframework cavity cations. Multivariant linear regression has been used to develop equations to predict intertetrahedral T—O—T angle variation depending on the independent variables Si—O and X—O bond lengths, cavity cation ideal radius, intratetrahedral (O—T—O) angle variance, and X cation electronegativity.

Computing details

For all structures, data collection: X'Pert Data Collector (PANalytical, 2006); program(s) used to refine structure: FULLPROF (Rodriguez-Carvajal, 2001); molecular graphics: VESTA (Momma & Izumi, 2008); software used to prepare material for publication: publCIF (Westrip, 2010).

(I)

Crystal data

K2ZnSi5O12	Dx = 2.642 (1) Mg m^−3
Mr = 476.00	Cu Kα radiation, λ = 1.540560 Å
Cubic, Ia3d	T = 293 K
Hall symbol: -I 4bd 2c 3	white
a = 13.3772 (2) Å	irregular, 10 × 5 mm
V = 2393.87 (6) Å^3	Specimen preparation: Prepared at 843 K and 50000 kPa
Z = 8

Data collection

PANalytical X'Pert Pro MPD diffractometer	Data collection mode: reflection
Radiation source: X-ray tube	Scan method: continuous
Graphite monochromator	2θmin = 15.041°, 2θmax = 99.918°, 2θstep = 0.017°
Specimen mounting: flat plate

Refinement

Rp = 4.538	Profile function: T-C-H Pseudo-Voigt
Rwp = 5.879	43 parameters
Rexp = 4.639	0 restraints
RBragg = 8.312	Background function: linear interpolation
5080 data points

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
K1	0.12500	0.12500	0.12500	0.243 (4)*
Si1	0.12500	0.6609 (5)	0.5891 (5)	0.126 (2)*	0.83328
Zn1	0.12500	0.6609 (5)	0.5891 (5)	0.126 (2)*	0.16670
O1	0.4738 (10)	0.3860 (5)	0.1461 (5)	0.177 (6)*	0.99998

Geometric parameters (Å, º)

K1—O1^i	3.471 (13)	K1—O1^xi	3.338 (7)
K1—O1^ii	3.471 (7)	K1—O1^xii	3.338 (13)
K1—O1^iii	3.471 (8)	Si1—O1^xiii	1.650 (12)
K1—O1^iv	3.471 (8)	Si1—O1^xiv	1.562 (10)
K1—O1^v	3.471 (13)	Si1—O1^xv	1.562 (10)
K1—O1^vi	3.471 (7)	Si1—O1^xvi	1.650 (12)
K1—O1^vii	3.338 (7)	Zn1—O1^xiii	1.650 (12)
K1—O1^viii	3.338 (13)	Zn1—O1^xiv	1.562 (10)
K1—O1^ix	3.338 (8)	Zn1—O1^xv	1.562 (10)
K1—O1^x	3.338 (8)	Zn1—O1^xvi	1.650 (12)
O1^xiii—Si1—O1^xiv	113.1 (10)	O1^xiii—Zn1—O1^xvi	106.9 (12)
O1^xiii—Si1—O1^xv	109.4 (9)	O1^xiv—Zn1—O1^xv	105.0 (7)
O1^xiii—Si1—O1^xvi	106.9 (12)	O1^xiv—Zn1—O1^xvi	109.4 (9)
O1^xiv—Si1—O1^xv	105.0 (7)	O1^xv—Zn1—O1^xvi	113.1 (10)
O1^xiv—Si1—O1^xvi	109.4 (9)	Si1^xvii—O1—Si1^vi	144.5 (7)
O1^xv—Si1—O1^xvi	113.1 (10)	Si1^xvii—O1—Zn1^vi	144.5 (7)
O1^xiii—Zn1—O1^xiv	113.1 (10)	Si1^vi—O1—Zn1^xvii	144.5 (7)
O1^xiii—Zn1—O1^xv	109.4 (9)	Zn1^xvii—O1—Zn1^vi	144.5 (7)

Symmetry codes: (i) −y+3/4, x−1/4, −z+1/4; (ii) −z+1/4, −y+3/4, x−1/4; (iii) x−1/4, −z+1/4, −y+3/4; (iv) −x+1/2, y−1/2, z; (v) y−1/2, z, −x+1/2; (vi) z, −x+1/2, y−1/2; (vii) y−1/4, x−1/4, z−1/4; (viii) z−1/4, y−1/4, x−1/4; (ix) x−1/4, z−1/4, y−1/4; (x) −x+1/2, −y+1/2, −z+1/2; (xi) −y+1/2, −z+1/2, −x+1/2; (xii) −z+1/2, −x+1/2, −y+1/2; (xiii) −x+1/2, −y+1, z+1/2; (xiv) y−1/4, −x+5/4, −z+3/4; (xv) −y+1/2, z+1/2, x; (xvi) x−1/4, −z+3/4, y+1/4; (xvii) −x+1/2, −y+1, z−1/2.

(II)

Crystal data

Rb2MnSi5O12	Dx = 2.972 (1) Mg m^−3
Mr = 557.92	Cu Kα radiation, λ = 1.540560 Å
Cubic, Ia3d	T = 293 K
Hall symbol: -I 4bd 2c 3	pale brown-pink
a = 13.5635 (3) Å	irregular, 10 × 10 mm
V = 2495.24 (10) Å^3	Specimen preparation: Prepared at 1193 K and 100 kPa
Z = 8

Data collection

PANalytical X'Pert Pro MPD diffractometer	Data collection mode: reflection
Radiation source: X-ray tube	Scan method: continuous
Graphite monochromator	2θmin = 15.281°, 2θmax = 100.158°, 2θstep = 0.017°
Specimen mounting: flat plate

Refinement

Rp = 4.679	Profile function: T-C-H Pseudo-Voigt
Rwp = 6.144	38 parameters
Rexp = 5.137	0 restraints
RBragg = 8.974	Background function: linear interpolation
5080 data points

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
Rb1	0.12500	0.12500	0.12500	0.1032 (19)*
Si1	0.12500	0.6618 (5)	0.5882 (5)	0.088 (3)*	0.83328
Mn1	0.12500	0.6618 (5)	0.5882 (5)	0.088 (3)*	0.16670
O1	0.4717 (9)	0.3882 (6)	0.1515 (6)	0.119 (5)*	0.99998

Geometric parameters (Å, º)

Rb1—O1^i	3.488 (12)	Rb1—O1^xi	3.308 (8)
Rb1—O1^ii	3.488 (8)	Rb1—O1^xii	3.308 (12)
Rb1—O1^iii	3.488 (9)	Si1—O1^xiii	1.708 (12)
Rb1—O1^iv	3.488 (9)	Si1—O1^xiv	1.596 (11)
Rb1—O1^v	3.488 (12)	Si1—O1^xv	1.596 (11)
Rb1—O1^vi	3.488 (8)	Si1—O1^xvi	1.708 (12)
Rb1—O1^vii	3.308 (8)	Mn1—O1^xiii	1.708 (12)
Rb1—O1^viii	3.308 (12)	Mn1—O1^xiv	1.596 (11)
Rb1—O1^ix	3.308 (9)	Mn1—O1^xv	1.596 (11)
Rb1—O1^x	3.308 (9)	Mn1—O1^xvi	1.708 (12)
O1^xiii—Si1—O1^xiv	115.8 (10)	O1^xiii—Mn1—O1^xvi	101.0 (10)
O1^xiii—Si1—O1^xv	112.1 (9)	O1^xiv—Mn1—O1^xv	100.7 (8)
O1^xiii—Si1—O1^xvi	101.0 (10)	O1^xiv—Mn1—O1^xvi	112.1 (9)
O1^xiv—Si1—O1^xv	100.7 (8)	O1^xv—Mn1—O1^xvi	115.8 (10)
O1^xiv—Si1—O1^xvi	112.1 (9)	Si1^xvii—O1—Si1^vi	139.4 (6)
O1^xv—Si1—O1^xvi	115.8 (10)	Si1^xvii—O1—Mn1^vi	139.4 (6)
O1^xiii—Mn1—O1^xiv	115.8 (10)	Si1^vi—O1—Mn1^xvii	139.4 (6)
O1^xiii—Mn1—O1^xv	112.1 (9)	Mn1^xvii—O1—Mn1^vi	139.4 (6)

Symmetry codes: (i) −y+3/4, x−1/4, −z+1/4; (ii) −z+1/4, −y+3/4, x−1/4; (iii) x−1/4, −z+1/4, −y+3/4; (iv) −x+1/2, y−1/2, z; (v) y−1/2, z, −x+1/2; (vi) z, −x+1/2, y−1/2; (vii) y−1/4, x−1/4, z−1/4; (viii) z−1/4, y−1/4, x−1/4; (ix) x−1/4, z−1/4, y−1/4; (x) −x+1/2, −y+1/2, −z+1/2; (xi) −y+1/2, −z+1/2, −x+1/2; (xii) −z+1/2, −x+1/2, −y+1/2; (xiii) −x+1/2, −y+1, z+1/2; (xiv) y−1/4, −x+5/4, −z+3/4; (xv) −y+1/2, z+1/2, x; (xvi) x−1/4, −z+3/4, y+1/4; (xvii) −x+1/2, −y+1, z−1/2.

(III)

Crystal data

K2FeSi5O12	V = 2339.54 (16) Å^3
Mr = 466.46	Z = 8
Monoclinic, P21/c	Dx = 2.649 (1) Mg m^−3
Hall symbol: -P 2ybc	Cu Kα radiation, λ = 1.540560 Å
a = 13.2574 (5) Å	T = 293 K
b = 13.6739 (6) Å	light brown
c = 12.9240 (5) Å	irregular, 15 × 15 mm
β = 93.048 (3)°	Specimen preparation: Prepared at 1073 K and 100000 kPa

Data collection

PANalytical X'Pert Pro MPD diffractometer	Data collection mode: reflection
Radiation source: X-ray tube	Scan method: continuous
Graphite monochromator	2θmin = 4.945°, 2θmax = 74.931°, 2θstep = 0.017°
Specimen mounting: flat plate

Refinement

Rp = 2.760	Profile function: T-C-H Pseudo-Voigt
Rwp = 4.051	169 parameters
Rexp = 2.992	48 restraints
RBragg = 6.944	Background function: linear interpolation
4189 data points

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

	x	y	z	Uiso*/Ueq
K1	0.132 (2)	0.113 (3)	0.087 (2)	0.115 (6)*
K2	0.641 (2)	0.397 (2)	0.848 (3)	0.115 (6)*
K3	0.373 (3)	0.353 (2)	0.374 (3)	0.115 (6)*
K4	0.875 (3)	0.145 (3)	0.662 (2)	0.115 (6)*
Si1	0.1181 (13)	0.6754 (11)	0.5693 (12)	0.051 (5)*
Si2	0.6509 (12)	0.8218 (12)	0.4065 (12)	0.051 (5)*
Si3	0.5844 (11)	0.1556 (11)	0.6500 (13)	0.051 (5)*
Si4	0.0885 (11)	0.3588 (12)	0.3450 (14)	0.051 (5)*
Fe5	0.6514 (10)	0.5613 (10)	0.1095 (11)	0.057 (7)*
Fe6	0.1840 (9)	0.9300 (10)	0.8664 (11)	0.057 (7)*
Si7	0.3891 (13)	0.8675 (11)	0.9452 (11)	0.051 (5)*
Si8	0.9005 (14)	0.3762 (11)	0.8762 (12)	0.051 (5)*
Si9	0.8554 (13)	0.9011 (12)	0.3835 (11)	0.051 (5)*
Si10	0.8748 (12)	0.6392 (12)	0.1231 (12)	0.051 (5)*
Si11	0.3961 (11)	0.1172 (12)	0.1599 (13)	0.051 (5)*
Si12	0.3313 (12)	0.5957 (13)	0.6484 (12)	0.051 (5)*
O1	0.4596 (12)	0.342 (5)	0.149 (4)	0.060 (6)*
O2	0.9665 (15)	0.145 (5)	0.846 (3)	0.060 (6)*
O3	0.180 (3)	0.4287 (15)	0.381 (5)	0.060 (6)*
O4	0.586 (4)	0.0651 (18)	0.568 (2)	0.060 (6)*
O5	0.354 (5)	0.1833 (18)	0.4710 (15)	0.060 (6)*
O6	0.913 (2)	0.370 (4)	0.544 (2)	0.060 (6)*
O7	0.6697 (14)	0.446 (3)	0.624 (4)	0.060 (6)*
O8	0.678 (2)	0.7120 (18)	0.368 (5)	0.060 (6)*
O9	0.325 (2)	0.628 (4)	0.7652 (19)	0.060 (6)*
O10	0.2084 (19)	0.063 (4)	0.334 (4)	0.060 (6)*
O11	0.142 (4)	0.7920 (13)	0.552 (4)	0.060 (6)*
O12	0.889 (5)	0.860 (4)	0.2745 (18)	0.060 (6)*
O13	0.9913 (12)	0.871 (5)	0.679 (2)	0.060 (6)*
O14	0.491 (3)	0.604 (3)	0.389 (6)	0.060 (6)*
O15	0.664 (4)	0.9807 (16)	0.881 (4)	0.060 (6)*
O16	0.136 (5)	0.5166 (13)	0.098 (4)	0.060 (6)*
O17	0.878 (6)	0.644 (4)	−0.0043 (13)	0.060 (6)*
O18	0.414 (2)	0.879 (4)	0.0669 (15)	0.060 (6)*
O19	0.217 (2)	0.888 (3)	0.111 (5)	0.060 (6)*
O20	0.136 (4)	0.2482 (15)	0.829 (4)	0.060 (6)*
O21	0.872 (5)	0.130 (3)	0.2560 (17)	0.060 (6)*
O22	0.7335 (15)	0.604 (4)	0.861 (4)	0.060 (6)*
O23	0.601 (5)	0.2450 (18)	0.085 (4)	0.060 (6)*
O24	0.438 (2)	0.393 (4)	0.7806 (15)	0.060 (6)*

Geometric parameters (Å, º)

K1—O2^i	3.74 (4)	K4—O19^vi	3.27 (7)
K1—O2^ii	3.88 (7)	K4—O21^xi	3.31 (6)
K1—O3^iii	2.83 (7)	K4—O23^xi	4.01 (7)
K1—O6^iv	3.76 (6)	Si1—O2^x	1.66 (4)
K1—O6^v	2.94 (4)	Si1—O6^vi	1.62 (4)
K1—O8^iv	2.89 (4)	Si1—O11	1.64 (3)
K1—O10	3.37 (6)	Si1—O19^xvi	1.63 (4)
K1—O12^iv	3.84 (6)	Si2—O1^xvii	1.62 (3)
K1—O13^vi	3.52 (4)	Si2—O5^vi	1.59 (3)
K1—O15^vi	3.00 (6)	Si2—O8	1.63 (4)
K1—O17^vii	3.49 (7)	Si2—O22^xviii	1.63 (5)
K1—O19^viii	3.28 (6)	Si3—O1^xi	1.65 (2)
K1—O20^ix	3.82 (6)	Si3—O4	1.63 (3)
K1—O20^iii	3.66 (5)	Si3—O9^xii	1.63 (3)
K2—O1^vi	3.81 (7)	Si3—O23^xi	1.62 (4)
K2—O4^x	3.98 (5)	Si4—O2^v	1.62 (2)
K2—O4^xi	3.02 (5)	Si4—O3	1.59 (4)
K2—O7	3.02 (6)	Si4—O12^iv	1.59 (3)
K2—O9^xii	3.99 (6)	Si4—O20^iii	1.61 (3)
K2—O11^xii	3.41 (6)	Fe5—O4^iii	1.99 (3)
K2—O14^vi	3.45 (8)	Fe5—O5^xvii	1.97 (3)
K2—O16^vi	3.23 (7)	Fe5—O10^xvii	1.96 (3)
K2—O18^vi	4.01 (6)	Fe5—O24^vi	2.00 (3)
K2—O21^xi	3.36 (7)	Fe6—O3^xvi	1.94 (3)
K2—O22	3.09 (6)	Fe6—O6^x	1.96 (4)
K2—O23^xiii	3.76 (6)	Fe6—O7^x	1.95 (2)
K2—O23^xi	3.93 (6)	Fe6—O21^vi	1.90 (4)
K2—O24	2.78 (4)	Si7—O7^x	1.58 (4)
K3—O1	3.19 (6)	Si7—O14^xvi	1.62 (5)
K3—O3	2.77 (5)	Si7—O18^xiii	1.60 (2)
K3—O5	2.66 (4)	Si7—O23^vi	1.59 (3)
K3—O7^vi	2.81 (5)	Si8—O11^xii	1.60 (4)
K3—O8^iv	3.71 (7)	Si8—O13^xix	1.64 (3)
K3—O8^vi	3.55 (7)	Si8—O16^vi	1.58 (3)
K3—O12^iv	3.88 (7)	Si8—O21^xi	1.58 (3)
K3—O14	3.77 (5)	Si9—O12	1.60 (4)
K3—O14^vi	3.52 (8)	Si9—O16^xvii	1.60 (3)
K3—O15^xii	3.67 (6)	Si9—O17^xvi	1.59 (3)
K3—O18^iv	2.91 (5)	Si9—O22^xviii	1.63 (3)
K3—O20^iii	3.45 (6)	Si10—O10^xvii	1.64 (5)
K3—O22^vi	3.33 (6)	Si10—O13^xviii	1.68 (2)
K3—O24^iii	3.69 (6)	Si10—O17	1.65 (2)
K4—O2	2.61 (5)	Si10—O20^vi	1.67 (3)
K4—O6	3.48 (6)	Si11—O8^iv	1.65 (3)
K4—O9^xii	2.87 (5)	Si11—O14^iv	1.67 (5)
K4—O10^ii	3.05 (7)	Si11—O15^vi	1.63 (4)
K4—O11^vi	2.89 (6)	Si11—O24^iii	1.63 (3)
K4—O12^xiv	3.19 (8)	Si12—O9	1.58 (3)
K4—O13^viii	4.05 (8)	Si12—O15^xii	1.62 (3)
K4—O16^iv	3.79 (6)	Si12—O18^xvi	1.60 (3)
K4—O17^xv	3.95 (8)	Si12—O19^xvi	1.59 (3)
O2^x—Si1—O6^vi	111 (3)	O16^xvii—Si9—O22^xviii	98 (4)
O2^x—Si1—O11	118 (4)	O17^xvi—Si9—O22^xviii	106 (4)
O2^x—Si1—O19^xvi	102 (3)	O10^xvii—Si10—O13^xviii	115 (3)
O6^vi—Si1—O11	107 (4)	O10^xvii—Si10—O17	115 (4)
O6^vi—Si1—O19^xvi	105 (4)	O10^xvii—Si10—O20^vi	113 (4)
O11—Si1—O19^xvi	114 (3)	O13^xviii—Si10—O17	111 (3)
O1^xvii—Si2—O5^vi	111 (4)	O13^xviii—Si10—O20^vi	91 (3)
O1^xvii—Si2—O8	103 (3)	O17—Si10—O20^vi	110 (3)
O1^xvii—Si2—O22^xviii	110 (3)	O8^iv—Si11—O14^iv	123 (4)
O5^vi—Si2—O8	107 (4)	O8^iv—Si11—O15^vi	107 (3)
O5^vi—Si2—O22^xviii	117 (4)	O8^iv—Si11—O24^iii	116 (4)
O8—Si2—O22^xviii	108 (4)	O14^iv—Si11—O15^vi	103 (4)
O1^xi—Si3—O4	93 (3)	O14^iv—Si11—O24^iii	95 (4)
O1^xi—Si3—O9^xii	135 (3)	O15^vi—Si11—O24^iii	112 (4)
O1^xi—Si3—O23^xi	98 (4)	O9—Si12—O15^xii	120 (4)
O4—Si3—O9^xii	103 (3)	O9—Si12—O18^xvi	130 (3)
O4—Si3—O23^xi	107 (3)	O9—Si12—O19^xvi	99 (4)
O9^xii—Si3—O23^xi	115 (4)	O15^xii—Si12—O18^xvi	91 (3)
O2^v—Si4—O3	140 (4)	O15^xii—Si12—O19^xvi	96 (3)
O2^v—Si4—O12^iv	104 (4)	O18^xvi—Si12—O19^xvi	117 (3)
O2^v—Si4—O20^iii	112 (4)	Si2^iv—O1—Si3^iii	153 (2)
O3—Si4—O12^iv	96 (4)	Si1^xii—O2—Si4^xx	136 (2)
O3—Si4—O20^iii	107 (3)	Si4—O3—Fe6^xviii	126 (2)
O12^iv—Si4—O20^iii	78 (3)	Si3—O4—Fe5^xi	120.2 (18)
O4^iii—Fe5—O5^xvii	126 (2)	Si2^vi—O5—Fe5^iv	119.2 (17)
O4^iii—Fe5—O10^xvii	120 (3)	Si1^vi—O6—Fe6^xii	123 (2)
O4^iii—Fe5—O24^vi	101 (3)	Fe6^xii—O7—Si7^xii	115 (2)
O5^xvii—Fe5—O10^xvii	101 (3)	Si2—O8—Si11^xvii	131 (2)
O5^xvii—Fe5—O24^vi	96 (2)	Si3^x—O9—Si12	129 (2)
O10^xvii—Fe5—O24^vi	109 (2)	Fe5^iv—O10—Si10^iv	122 (2)
O3^xvi—Fe6—O6^x	110 (3)	Si1—O11—Si8^x	123 (2)
O3^xvi—Fe6—O7^x	85 (2)	Si4^xvii—O12—Si9	159 (2)
O3^xvi—Fe6—O21^vi	120 (3)	Si4^xvii—O12—O20^vi	52 (2)
O6^x—Fe6—O7^x	134 (3)	Si9—O12—O20^vi	143 (4)
O6^x—Fe6—O21^vi	94 (2)	Si8^xxi—O13—Si10^xvi	129 (2)
O7^x—Fe6—O21^vi	116 (3)	Si8^xxi—O13—O21^xiv	51 (2)
O7^x—Si7—O14^xvi	89 (3)	Si10^xvi—O13—O21^xiv	175 (4)
O7^x—Si7—O18^xiii	124 (4)	Si7^xviii—O14—Si11^xvii	159 (3)
O7^x—Si7—O23^vi	124 (4)	Si11^vi—O15—Si12^x	138 (2)
O14^xvi—Si7—O18^xiii	107 (5)	Si8^vi—O16—Si9^iv	154 (2)
O14^xvi—Si7—O23^vi	92 (4)	Si9^xviii—O17—Si10	152 (2)
O18^xiii—Si7—O23^vi	109 (4)	Si7^ix—O18—Si12^xviii	124 (2)
O11^xii—Si8—O13^xix	124 (4)	Si1^xviii—O19—Si12^xviii	156 (2)
O11^xii—Si8—O16^vi	115 (3)	Si4^xi—O20—Si10^vi	138 (2)
O11^xii—Si8—O21^xi	117 (4)	Si4^xi—O20—O12^vi	51 (2)
O13^xix—Si8—O16^vi	115 (4)	Si10^vi—O20—O12^vi	156 (4)
O13^xix—Si8—O21^xi	75 (3)	Fe6^vi—O21—Si8^iii	149 (2)
O16^vi—Si8—O21^xi	101 (3)	Fe6^vi—O21—O13^xiv	132 (3)
O12—Si9—O16^xvii	117 (4)	Si8^iii—O21—O13^xiv	54 (2)
O12—Si9—O17^xvi	128 (3)	Si2^xvi—O22—Si9^xvi	130 (2)
O12—Si9—O22^xviii	98 (4)	Si3^iii—O23—Si7^vi	162 (2)
O16^xvii—Si9—O17^xvi	104 (4)	Fe5^vi—O24—Si11^xi	121.4 (18)

Symmetry codes: (i) x−1, y, z−1; (ii) −x+1, −y, −z+1; (iii) x, −y+1/2, z−1/2; (iv) −x+1, y−1/2, −z+1/2; (v) x−1, −y+1/2, z−1/2; (vi) −x+1, −y+1, −z+1; (vii) −x+1, −y+1, −z; (viii) x, y−1, z; (ix) x, y, z−1; (x) −x+1, y+1/2, −z+3/2; (xi) x, −y+1/2, z+1/2; (xii) −x+1, y−1/2, −z+3/2; (xiii) x, y, z+1; (xiv) −x+2, −y+1, −z+1; (xv) −x+2, y−1/2, −z+1/2; (xvi) x, −y+3/2, z+1/2; (xvii) −x+1, y+1/2, −z+1/2; (xviii) x, −y+3/2, z−1/2; (xix) −x+2, y−1/2, −z+3/2; (xx) x+1, −y+1/2, z+1/2; (xxi) −x+2, y+1/2, −z+3/2.

(IV)

Crystal data

K2ZnSi5O12	V = 2334.98 (6) Å^3
Mr = 476.00	Z = 8
Monoclinic, P21/c	Dx = 2.708 (1) Mg m^−3
Hall symbol: -P 2ybc	Cu Kα radiation, λ = 1.540560 Å
a = 13.1773 (2) Å	T = 293 K
b = 13.6106 (2) Å	white
c = 13.0248 (2) Å	irregular, 10 × 5 mm
β = 91.6981 (9)°	Specimen preparation: Prepared at 843 K and 50000 kPa

Data collection

PANalytical Empyrean diffractometer	Data collection mode: reflection
Radiation source: X-ray tube	Scan method: continuous
Specimen mounting: flat plate	2θmin = 4.961°, 2θmax = 99.952°, 2θstep = 0.013°

Refinement

Rp = 0.702	Profile function: T-C-H Pseudo-Voigt
Rwp = 1.114	179 parameters
Rexp = 0.272	48 restraints
RBragg = 3.385	Background function: linear interpolation
7308 data points

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

	x	y	z	Uiso*/Ueq
K1	0.1179 (9)	0.1077 (10)	0.1014 (10)	0.1190 (19)*
K2	0.6290 (9)	0.3971 (9)	0.8479 (9)	0.1190 (19)*
K3	0.3779 (9)	0.3604 (9)	0.3824 (8)	0.1190 (19)*
K4	0.8487 (9)	0.1401 (10)	0.6518 (9)	0.1190 (19)*
Si1	0.1109 (9)	0.6737 (8)	0.5664 (8)	0.0656 (16)*
Si2	0.6418 (8)	0.8239 (8)	0.3969 (8)	0.0656 (16)*
Si3	0.5743 (9)	0.1338 (8)	0.6237 (8)	0.0656 (16)*
Si4	0.0933 (9)	0.3516 (8)	0.3182 (8)	0.0656 (16)*
Zn5	0.6462 (4)	0.5719 (4)	0.1097 (5)	0.0678 (16)*
Zn6	0.1856 (5)	0.9336 (4)	0.8692 (5)	0.0678 (16)*
Si7	0.4043 (8)	0.8568 (8)	0.9484 (8)	0.0656 (16)*
Si8	0.9006 (9)	0.3869 (8)	0.8594 (8)	0.0656 (16)*
Si9	0.8430 (9)	0.9052 (9)	0.4030 (9)	0.0656 (16)*
Si10	0.8673 (8)	0.6399 (8)	0.1196 (8)	0.0656 (16)*
Si11	0.3905 (8)	0.1085 (9)	0.1619 (8)	0.0656 (16)*
Si12	0.3235 (9)	0.5989 (8)	0.6521 (8)	0.0656 (16)*
O1	0.4612 (10)	0.3463 (16)	0.1628 (16)	0.0418 (18)*
O2	0.9766 (11)	0.1570 (15)	0.8494 (14)	0.0418 (18)*
O3	0.1595 (15)	0.4318 (11)	0.3864 (15)	0.0418 (18)*
O4	0.6082 (18)	0.0493 (11)	0.5480 (13)	0.0418 (18)*
O5	0.3524 (17)	0.1832 (13)	0.4839 (10)	0.0418 (18)*
O6	0.9131 (14)	0.3679 (14)	0.5548 (12)	0.0418 (18)*
O7	0.6757 (11)	0.4285 (15)	0.6001 (16)	0.0418 (18)*
O8	0.6697 (14)	0.7096 (10)	0.3674 (16)	0.0418 (18)*
O9	0.3682 (16)	0.6278 (15)	0.7650 (11)	0.0418 (18)*
O10	0.2124 (11)	0.0562 (13)	0.3502 (16)	0.0418 (18)*
O11	0.1086 (17)	0.7900 (10)	0.5687 (15)	0.0418 (18)*
O12	0.9034 (14)	0.8814 (15)	0.3040 (10)	0.0418 (18)*
O13	0.9790 (10)	0.8916 (16)	0.6593 (17)	0.0418 (18)*
O14	0.5251 (11)	0.6209 (15)	0.4223 (13)	0.0418 (18)*
O15	0.6836 (14)	0.9802 (10)	0.861 (2)	0.0418 (18)*
O16	0.1285 (19)	0.5193 (11)	0.0771 (15)	0.0418 (18)*
O17	0.8889 (15)	0.6595 (14)	−0.0006 (10)	0.0418 (18)*
O18	0.3884 (16)	0.8546 (15)	0.0712 (11)	0.0418 (18)*
O19	0.2137 (12)	0.8653 (15)	0.1166 (19)	0.0418 (18)*
O20	0.1554 (15)	0.2518 (11)	0.8280 (17)	0.0418 (18)*
O21	0.8489 (16)	0.1185 (14)	0.2551 (11)	0.0418 (18)*
O22	0.7327 (11)	0.6057 (13)	0.8663 (16)	0.0418 (18)*
O23	0.6121 (17)	0.2617 (10)	0.0819 (18)	0.0418 (18)*
O24	0.4427 (13)	0.4025 (15)	0.7776 (10)	0.0418 (18)*

Geometric parameters (Å, º)

K1—O2^i	3.79 (2)	K4—O19^vi	3.15 (3)
K1—O2^ii	3.87 (2)	K4—O21^x	3.55 (2)
K1—O3^iii	2.92 (2)	K4—O23^x	3.49 (2)
K1—O6^iv	3.86 (2)	Si1—O2^ix	1.63 (2)
K1—O6^v	2.77 (2)	Si1—O6^vi	1.698 (19)
K1—O8^iv	3.14 (2)	Si1—O11	1.584 (17)
K1—O10	3.51 (2)	Si1—O19^xv	1.58 (2)
K1—O12^iv	3.94 (2)	Si2—O1^xvi	1.574 (19)
K1—O13^vi	3.40 (2)	Si2—O5^vi	1.555 (17)
K1—O15^vi	2.90 (2)	Si2—O8	1.647 (18)
K1—O17^vii	3.43 (2)	Si2—O22^xvii	1.59 (2)
K1—O19^viii	3.54 (2)	Si3—O1^x	1.612 (19)
K1—O20^iii	3.54 (2)	Si3—O4	1.59 (2)
K2—O1^vi	3.69 (2)	Si3—O9^xi	1.618 (19)
K2—O4^ix	4.02 (2)	Si3—O23^x	1.61 (2)
K2—O4^x	2.73 (2)	Si4—O2^v	1.606 (19)
K2—O7	3.33 (2)	Si4—O3	1.64 (2)
K2—O9^xi	3.95 (2)	Si4—O12^iv	1.644 (17)
K2—O11^xi	3.88 (2)	Si4—O20^iii	1.63 (2)
K2—O14^vi	4.02 (2)	Zn5—O4^iii	1.896 (17)
K2—O16^vi	3.50 (3)	Zn5—O5^xvi	1.945 (17)
K2—O18^vi	3.59 (2)	Zn5—O10^xvi	1.932 (16)
K2—O21^x	3.18 (2)	Zn5—O24^vi	1.937 (16)
K2—O22	3.16 (2)	Zn6—O3^xv	1.879 (16)
K2—O23^xii	3.57 (2)	Zn6—O6^ix	1.883 (19)
K2—O23^x	4.08 (2)	Zn6—O7^ix	1.861 (16)
K2—O24	2.60 (2)	Zn6—O21^vi	1.813 (17)
K3—O1	3.10 (2)	Si7—O7^ix	1.56 (2)
K3—O3	3.04 (2)	Si7—O14^xv	1.665 (18)
K3—O5	2.78 (2)	Si7—O18^xii	1.620 (18)
K3—O7^vi	2.97 (2)	Si7—O23^vi	1.673 (18)
K3—O8^iv	3.88 (2)	Si8—O11^xi	1.624 (19)
K3—O8^vi	3.47 (2)	Si8—O13^xviii	1.614 (18)
K3—O9^vi	3.91 (2)	Si8—O16^vi	1.57 (2)
K3—O14	4.07 (2)	Si8—O21^x	1.503 (19)
K3—O14^vi	2.824 (19)	Si9—O12	1.569 (19)
K3—O15^xi	3.83 (3)	Si9—O16^xvi	1.62 (2)
K3—O18^iv	3.12 (2)	Si9—O17^xv	1.64 (2)
K3—O20^iii	3.36 (2)	Si9—O22^xvii	1.524 (19)
K3—O22^vi	3.54 (2)	Si10—O10^xvi	1.61 (2)
K3—O24^iii	3.93 (2)	Si10—O13^xvii	1.604 (18)
K4—O2	3.04 (2)	Si10—O17	1.622 (17)
K4—O4	3.63 (2)	Si10—O20^vi	1.66 (2)
K4—O6	3.46 (2)	Si11—O8^iv	1.628 (19)
K4—O9^xi	3.09 (2)	Si11—O14^iv	1.594 (19)
K4—O10^ii	2.79 (2)	Si11—O15^vi	1.58 (2)
K4—O11^vi	3.09 (2)	Si11—O24^iii	1.645 (17)
K4—O12^xiii	3.31 (2)	Si12—O9	1.616 (19)
K4—O13^viii	3.79 (2)	Si12—O15^xi	1.627 (18)
K4—O16^iv	3.43 (2)	Si12—O18^xv	1.52 (2)
K4—O17^xiv	4.04 (2)	Si12—O19^xv	1.58 (2)
O2^ix—Si1—O6^vi	117.6 (17)	O12—Si9—O16^xvi	102.1 (17)
O2^ix—Si1—O11	96.4 (17)	O12—Si9—O17^xv	109.6 (15)
O2^ix—Si1—O19^xv	106.8 (16)	O12—Si9—O22^xvii	103.0 (17)
O6^vi—Si1—O11	110.4 (16)	O16^xvi—Si9—O17^xv	108.4 (17)
O6^vi—Si1—O19^xv	114.0 (19)	O16^xvi—Si9—O22^xvii	111.0 (19)
O11—Si1—O19^xv	110.2 (18)	O17^xv—Si9—O22^xvii	121.1 (18)
O1^xvi—Si2—O5^vi	121.4 (18)	O10^xvi—Si10—O13^xvii	109.4 (15)
O1^xvi—Si2—O8	105.2 (17)	O10^xvi—Si10—O17	119.2 (18)
O1^xvi—Si2—O22^xvii	113.8 (16)	O10^xvi—Si10—O20^vi	113.8 (17)
O5^vi—Si2—O8	99.8 (16)	O13^xvii—Si10—O17	99.8 (16)
O5^vi—Si2—O22^xvii	105.8 (17)	O13^xvii—Si10—O20^vi	106.3 (17)
O8—Si2—O22^xvii	109.6 (16)	O17—Si10—O20^vi	106.9 (17)
O1^x—Si3—O4	127 (2)	O8^iv—Si11—O14^iv	95.4 (16)
O1^x—Si3—O9^xi	97.9 (16)	O8^iv—Si11—O15^vi	108.0 (15)
O1^x—Si3—O23^x	104.9 (18)	O8^iv—Si11—O24^iii	118.6 (17)
O4—Si3—O9^xi	112.8 (17)	O14^iv—Si11—O15^vi	113.1 (18)
O4—Si3—O23^x	109.6 (16)	O14^iv—Si11—O24^iii	111.0 (16)
O9^xi—Si3—O23^x	101.9 (18)	O15^vi—Si11—O24^iii	110.1 (18)
O2^v—Si4—O3	114.1 (18)	O9—Si12—O15^xi	110.8 (18)
O2^v—Si4—O12^iv	108.4 (16)	O9—Si12—O18^xv	109.5 (16)
O2^v—Si4—O20^iii	113.5 (18)	O9—Si12—O19^xv	119.7 (19)
O3—Si4—O12^iv	109.3 (16)	O15^xi—Si12—O18^xv	111.9 (19)
O3—Si4—O20^iii	105.9 (16)	O15^xi—Si12—O19^xv	103.1 (17)
O12^iv—Si4—O20^iii	105.1 (17)	O18^xv—Si12—O19^xv	101.4 (19)
O4^iii—Zn5—O5^xvi	114.8 (14)	Si2^iv—O1—Si3^iii	131.9 (14)
O4^iii—Zn5—O10^xvi	105.0 (14)	Si1^xi—O2—Si4^xix	151.8 (15)
O4^iii—Zn5—O24^vi	108.6 (13)	Si4—O3—Zn6^xvii	132.8 (11)
O5^xvi—Zn5—O10^xvi	103.2 (14)	Si3—O4—Zn5^x	116.3 (11)
O5^xvi—Zn5—O24^vi	110.6 (13)	Si2^vi—O5—Zn5^iv	125.2 (11)
O10^xvi—Zn5—O24^vi	114.5 (13)	Si1^vi—O6—Zn6^xi	122.3 (11)
O3^xv—Zn6—O6^ix	105.6 (14)	Zn6^xi—O7—Si7^xi	139.4 (12)
O3^xv—Zn6—O7^ix	101.1 (14)	Si2—O8—Si11^xvi	138.0 (14)
O3^xv—Zn6—O21^vi	116.5 (15)	Si3^ix—O9—Si12	167.4 (14)
O6^ix—Zn6—O7^ix	124.0 (15)	Zn5^iv—O10—Si10^iv	119.2 (11)
O6^ix—Zn6—O21^vi	97.2 (13)	Si1—O11—Si8^ix	145.5 (14)
O7^ix—Zn6—O21^vi	113.3 (15)	Si4^xvi—O12—Si9	151.0 (14)
O7^ix—Si7—O14^xv	116.3 (16)	Si8^xx—O13—Si10^xv	146.9 (14)
O7^ix—Si7—O18^xii	107.8 (18)	Si7^xvii—O14—Si11^xvi	148.3 (14)
O7^ix—Si7—O23^vi	115.3 (18)	Si11^vi—O15—Si12^ix	135.0 (14)
O14^xv—Si7—O18^xii	110.9 (17)	Si8^vi—O16—Si9^iv	138.9 (15)
O14^xv—Si7—O23^vi	104.2 (16)	Si9^xvii—O17—Si10	125.5 (13)
O18^xii—Si7—O23^vi	101.3 (17)	Si7^xxi—O18—Si12^xvii	140.5 (15)
O11^xi—Si8—O13^xviii	102.1 (18)	Si1^xvii—O19—Si12^xvii	172.0 (16)
O11^xi—Si8—O16^vi	109.4 (16)	Si4^x—O20—Si10^vi	134.8 (14)
O11^xi—Si8—O21^x	116.2 (18)	Zn6^vi—O21—Si8^iii	152.0 (12)
O13^xviii—Si8—O16^vi	107.6 (19)	Si2^xv—O22—Si9^xv	134.2 (15)
O13^xviii—Si8—O21^x	106.7 (18)	Si3^iii—O23—Si7^vi	153.4 (14)
O16^vi—Si8—O21^x	113.8 (18)	Zn5^vi—O24—Si11^x	117.7 (10)

Symmetry codes: (i) x−1, y, z−1; (ii) −x+1, −y, −z+1; (iii) x, −y+1/2, z−1/2; (iv) −x+1, y−1/2, −z+1/2; (v) x−1, −y+1/2, z−1/2; (vi) −x+1, −y+1, −z+1; (vii) −x+1, −y+1, −z; (viii) x, y−1, z; (ix) −x+1, y+1/2, −z+3/2; (x) x, −y+1/2, z+1/2; (xi) −x+1, y−1/2, −z+3/2; (xii) x, y, z+1; (xiii) −x+2, −y+1, −z+1; (xiv) −x+2, y−1/2, −z+1/2; (xv) x, −y+3/2, z+1/2; (xvi) −x+1, y+1/2, −z+1/2; (xvii) x, −y+3/2, z−1/2; (xviii) −x+2, y−1/2, −z+3/2; (xix) x+1, −y+1/2, z+1/2; (xx) −x+2, y+1/2, −z+3/2; (xxi) x, y, z−1.

(V)

Crystal data

K2CoSi5O12	V = 2333.96 (4) Å^3
Mr = 469.55	Z = 8
Monoclinic, P21/c	Dx = 2.673 Mg m^−3
Hall symbol: -P 2ybc	Co Kα radiation, λ = 1.789190 Å
a = 13.18783 (14) Å	T = 293 K
b = 13.63495 (16) Å	dark blue
c = 12.98764 (14) Å	irregular, 10 × 10 mm
β = 91.9994 (8)°	Specimen preparation: Prepared at 948 K and 50000 kPa

Data collection

PANalytical Empyrean diffractometer	Data collection mode: reflection
Radiation source: X-ray tube	Scan method: continuous
Specimen mounting: flat plate	2θmin = 8.281°, 2θmax = 100.272°, 2θstep = 0.013°

Refinement

Rp = 1.447	Profile function: T-C-H Pseudo-Voigt
Rwp = 2.223	169 parameters
Rexp = 0.847	48 restraints
RBragg = 6.691	Background function: linear interpolation
7007 data points

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

	x	y	z	Uiso*/Ueq
K1	0.1202 (10)	0.1048 (11)	0.0947 (9)	0.065 (2)*
K2	0.6260 (10)	0.3947 (10)	0.8520 (10)	0.065 (2)*
K3	0.3723 (10)	0.3547 (10)	0.3745 (9)	0.065 (2)*
K4	0.8486 (10)	0.1389 (10)	0.6509 (10)	0.065 (2)*
Si1	0.1103 (9)	0.6811 (8)	0.5645 (9)	0.0275 (17)*
Si2	0.6401 (9)	0.8239 (9)	0.3970 (9)	0.0275 (17)*
Si3	0.5833 (9)	0.1435 (9)	0.6287 (9)	0.0275 (17)*
Si4	0.0973 (9)	0.3489 (8)	0.3170 (9)	0.0275 (17)*
Co5	0.6434 (6)	0.5681 (6)	0.1113 (6)	0.031 (2)*
Co6	0.1881 (6)	0.9334 (6)	0.8702 (6)	0.031 (2)*
Si7	0.4043 (9)	0.8646 (8)	0.9474 (9)	0.0275 (17)*
Si8	0.9008 (9)	0.3880 (9)	0.8554 (9)	0.0275 (17)*
Si9	0.8432 (9)	0.9064 (9)	0.4051 (9)	0.0275 (17)*
Si10	0.8704 (8)	0.6372 (9)	0.1245 (9)	0.0275 (17)*
Si11	0.3931 (9)	0.1139 (9)	0.1648 (9)	0.0275 (17)*
Si12	0.3271 (9)	0.5996 (8)	0.6495 (9)	0.0275 (17)*
O1	0.4605 (11)	0.359 (2)	0.1620 (18)	0.011 (2)*
O2	0.9759 (13)	0.1412 (17)	0.8511 (17)	0.011 (2)*
O3	0.1640 (19)	0.4263 (12)	0.3888 (17)	0.011 (2)*
O4	0.610 (2)	0.0580 (12)	0.5425 (14)	0.011 (2)*
O5	0.3724 (19)	0.1800 (14)	0.4820 (11)	0.011 (2)*
O6	0.9103 (15)	0.3668 (16)	0.5498 (13)	0.011 (2)*
O7	0.6681 (12)	0.4331 (17)	0.6135 (19)	0.011 (2)*
O8	0.6754 (16)	0.7097 (11)	0.3715 (19)	0.011 (2)*
O9	0.3622 (19)	0.6503 (16)	0.7565 (12)	0.011 (2)*
O10	0.2162 (12)	0.0589 (16)	0.3429 (19)	0.011 (2)*
O11	0.115 (2)	0.8029 (11)	0.5594 (16)	0.011 (2)*
O12	0.9117 (16)	0.8623 (19)	0.3095 (11)	0.011 (2)*
O13	0.9833 (10)	0.9029 (18)	0.6659 (18)	0.011 (2)*
O14	0.5258 (12)	0.6232 (19)	0.4323 (15)	0.011 (2)*
O15	0.6756 (19)	0.9798 (11)	0.870 (2)	0.011 (2)*
O16	0.127 (2)	0.5204 (12)	0.0732 (16)	0.011 (2)*
O17	0.8832 (18)	0.6575 (16)	−0.0016 (11)	0.011 (2)*
O18	0.4073 (17)	0.8573 (19)	0.0723 (12)	0.011 (2)*
O19	0.2098 (12)	0.8626 (16)	0.1290 (19)	0.011 (2)*
O20	0.1490 (17)	0.2557 (11)	0.8155 (18)	0.011 (2)*
O21	0.8300 (17)	0.1187 (17)	0.2614 (12)	0.011 (2)*
O22	0.7310 (12)	0.6041 (16)	0.8628 (18)	0.011 (2)*
O23	0.6160 (19)	0.2484 (11)	0.0896 (19)	0.011 (2)*
O24	0.4418 (15)	0.3993 (18)	0.7774 (11)	0.011 (2)*

Geometric parameters (Å, º)

K1—O2^i	3.67 (2)	K4—O23^ix	3.50 (3)
K1—O2^ii	3.66 (3)	Si1—O2^xiii	1.70 (2)
K1—O3^iii	2.79 (3)	Si1—O6^vi	1.64 (2)
K1—O6^iv	3.76 (3)	Si1—O11	1.663 (19)
K1—O6^v	2.84 (2)	Si1—O19^xiv	1.64 (2)
K1—O8^iv	3.07 (2)	Si2—O1^xv	1.58 (2)
K1—O10	3.48 (3)	Si2—O5^vi	1.587 (19)
K1—O12^iv	3.75 (3)	Si2—O8	1.66 (2)
K1—O13^vi	3.44 (3)	Si2—O22^xvi	1.62 (2)
K1—O15^vi	2.95 (3)	Si3—O1^ix	1.69 (2)
K1—O17^vii	3.46 (3)	Si3—O4	1.66 (2)
K1—O19^viii	3.53 (3)	Si3—O9^x	1.64 (2)
K1—O20^iii	3.45 (2)	Si3—O23^ix	1.62 (2)
K2—O1^vi	3.56 (3)	Si4—O2^v	1.68 (2)
K2—O4^ix	2.57 (2)	Si4—O3	1.64 (2)
K2—O5^ix	3.93 (3)	Si4—O12^iv	1.653 (19)
K2—O7	3.21 (3)	Si4—O20^iii	1.58 (2)
K2—O9^x	3.62 (3)	Co5—O4^iii	1.980 (19)
K2—O11^x	3.78 (3)	Co5—O5^xv	1.955 (19)
K2—O16^vi	3.56 (3)	Co5—O10^xv	1.929 (18)
K2—O18^vi	3.60 (3)	Co5—O24^vi	1.914 (19)
K2—O21^ix	2.98 (3)	Co6—O3^xiv	1.956 (19)
K2—O22	3.17 (2)	Co6—O6^xiii	1.92 (2)
K2—O23^xi	3.68 (3)	Co6—O7^xiii	1.901 (18)
K2—O23^ix	3.93 (3)	Co6—O21^vi	1.859 (19)
K2—O24	2.58 (2)	Si7—O7^xiii	1.54 (2)
K3—O1	3.03 (3)	Si7—O14^xiv	1.63 (2)
K3—O3	2.93 (3)	Si7—O18^xi	1.62 (2)
K3—O5	2.76 (2)	Si7—O23^vi	1.63 (2)
K3—O7^vi	2.95 (3)	Si8—O11^x	1.62 (2)
K3—O8^iv	3.79 (3)	Si8—O13^xvii	1.576 (19)
K3—O8^vi	3.49 (3)	Si8—O16^vi	1.61 (2)
K3—O9^vi	3.95 (3)	Si8—O21^ix	1.51 (2)
K3—O14^vi	2.82 (2)	Si9—O12	1.67 (2)
K3—O15^x	3.80 (3)	Si9—O16^xv	1.63 (2)
K3—O18^iv	2.96 (3)	Si9—O17^xiv	1.57 (2)
K3—O20^iii	3.37 (2)	Si9—O22^xvi	1.57 (2)
K3—O22^vi	3.37 (3)	Si10—O10^xv	1.63 (2)
K3—O24^iii	3.81 (3)	Si10—O13^xvi	1.658 (19)
K4—O2	3.05 (2)	Si10—O17	1.675 (19)
K4—O4	3.58 (3)	Si10—O20^vi	1.68 (2)
K4—O6	3.48 (3)	Si11—O8^iv	1.65 (2)
K4—O9^x	3.07 (3)	Si11—O14^iv	1.69 (2)
K4—O10^ii	2.83 (3)	Si11—O15^vi	1.62 (2)
K4—O11^vi	2.90 (2)	Si11—O24^iii	1.587 (19)
K4—O12^xii	3.18 (2)	Si12—O9	1.61 (2)
K4—O13^viii	3.68 (3)	Si12—O15^x	1.653 (19)
K4—O16^iv	3.35 (2)	Si12—O18^xiv	1.59 (2)
K4—O19^vi	2.99 (3)	Si12—O19^xiv	1.64 (2)
K4—O21^ix	3.61 (3)
O2^xiii—Si1—O6^vi	111.4 (19)	O12—Si9—O16^xv	110 (2)
O2^xiii—Si1—O11	111.9 (19)	O12—Si9—O17^xiv	101.4 (16)
O2^xiii—Si1—O19^xiv	95.5 (16)	O12—Si9—O22^xvi	103.6 (18)
O6^vi—Si1—O11	111.6 (18)	O16^xv—Si9—O17^xiv	108.9 (19)
O6^vi—Si1—O19^xiv	115 (2)	O16^xv—Si9—O22^xvi	112 (2)
O11—Si1—O19^xiv	110.6 (19)	O17^xiv—Si9—O22^xvi	121 (2)
O1^xv—Si2—O5^vi	112.1 (19)	O10^xv—Si10—O13^xvi	109.2 (16)
O1^xv—Si2—O8	115 (2)	O10^xv—Si10—O17	117 (2)
O1^xv—Si2—O22^xvi	107.6 (17)	O10^xv—Si10—O20^vi	109.2 (19)
O5^vi—Si2—O8	101.9 (18)	O13^xvi—Si10—O17	104.6 (18)
O5^vi—Si2—O22^xvi	113 (2)	O13^xvi—Si10—O20^vi	106.6 (18)
O8—Si2—O22^xvi	107.3 (18)	O17—Si10—O20^vi	109.4 (18)
O1^ix—Si3—O4	113 (2)	O8^iv—Si11—O14^iv	94.7 (18)
O1^ix—Si3—O9^x	99.3 (18)	O8^iv—Si11—O15^vi	104.4 (16)
O1^ix—Si3—O23^ix	111 (2)	O8^iv—Si11—O24^iii	124 (2)
O4—Si3—O9^x	123.9 (18)	O14^iv—Si11—O15^vi	102 (2)
O4—Si3—O23^ix	111.2 (17)	O14^iv—Si11—O24^iii	116.8 (18)
O9^x—Si3—O23^ix	96.9 (18)	O15^vi—Si11—O24^iii	112 (2)
O2^v—Si4—O3	107 (2)	O9—Si12—O15^x	124 (2)
O2^v—Si4—O12^iv	102.5 (17)	O9—Si12—O18^xiv	102.0 (17)
O2^v—Si4—O20^iii	119 (2)	O9—Si12—O19^xiv	104.3 (19)
O3—Si4—O12^iv	120.8 (19)	O15^x—Si12—O18^xiv	106 (2)
O3—Si4—O20^iii	111.3 (18)	O15^x—Si12—O19^xiv	105.7 (18)
O12^iv—Si4—O20^iii	95.9 (18)	O18^xiv—Si12—O19^xiv	115 (2)
O4^iii—Co5—O5^xv	112.4 (15)	Si2^iv—O1—Si3^iii	131.8 (15)
O4^iii—Co5—O10^xv	106.2 (16)	Si1^x—O2—Si4^xviii	144.1 (15)
O4^iii—Co5—O24^vi	114.5 (15)	Si4—O3—Co6^xvi	130.1 (13)
O5^xv—Co5—O10^xv	108.8 (16)	Si3—O4—Co5^ix	110.7 (12)
O5^xv—Co5—O24^vi	103.5 (14)	Si2^vi—O5—Co5^iv	125.1 (12)
O10^xv—Co5—O24^vi	111.4 (15)	Si1^vi—O6—Co6^x	125.9 (13)
O3^xiv—Co6—O6^xiii	106.3 (16)	Co6^x—O7—Si7^x	131.2 (13)
O3^xiv—Co6—O7^xiii	98.9 (15)	Si2—O8—Si11^xv	130.2 (15)
O3^xiv—Co6—O21^vi	118.1 (16)	Si3^xiii—O9—Si12	150.3 (15)
O6^xiii—Co6—O7^xiii	129.0 (17)	Co5^iv—O10—Si10^iv	123.4 (12)
O6^xiii—Co6—O21^vi	104.4 (15)	Si1—O11—Si8^xiii	132.9 (15)
O7^xiii—Co6—O21^vi	101.4 (15)	Si4^xv—O12—Si9	139.1 (15)
O7^xiii—Si7—O14^xiv	118.2 (19)	Si8^xix—O13—Si10^xiv	140.0 (14)
O7^xiii—Si7—O18^xi	123 (2)	Si7^xvi—O14—Si11^xv	138.5 (15)
O7^xiii—Si7—O23^vi	109 (2)	Si11^vi—O15—Si12^xiii	136.6 (15)
O14^xiv—Si7—O18^xi	97.9 (17)	Si8^vi—O16—Si9^iv	134.6 (16)
O14^xiv—Si7—O23^vi	102.3 (19)	Si9^xvi—O17—Si10	128.4 (15)
O18^xi—Si7—O23^vi	103.5 (19)	Si7^xx—O18—Si12^xvi	127.7 (15)
O11^x—Si8—O13^xvii	111 (2)	Si1^xvi—O19—Si12^xvi	157.9 (15)
O11^x—Si8—O16^vi	97.2 (16)	Si4^ix—O20—Si10^vi	134.9 (15)
O11^x—Si8—O21^ix	115 (2)	Co6^vi—O21—Si8^iii	140.8 (13)
O13^xvii—Si8—O16^vi	104 (2)	Si2^xiv—O22—Si9^xiv	131.0 (16)
O13^xvii—Si8—O21^ix	116 (2)	Si3^iii—O23—Si7^vi	155.0 (15)
O16^vi—Si8—O21^ix	112 (2)	Co5^vi—O24—Si11^ix	119.5 (12)

Symmetry codes: (i) x−1, y, z−1; (ii) −x+1, −y, −z+1; (iii) x, −y+1/2, z−1/2; (iv) −x+1, y−1/2, −z+1/2; (v) x−1, −y+1/2, z−1/2; (vi) −x+1, −y+1, −z+1; (vii) −x+1, −y+1, −z; (viii) x, y−1, z; (ix) x, −y+1/2, z+1/2; (x) −x+1, y−1/2, −z+3/2; (xi) x, y, z+1; (xii) −x+2, −y+1, −z+1; (xiii) −x+1, y+1/2, −z+3/2; (xiv) x, −y+3/2, z+1/2; (xv) −x+1, y+1/2, −z+1/2; (xvi) x, −y+3/2, z−1/2; (xvii) −x+2, y−1/2, −z+3/2; (xviii) x+1, −y+1/2, z+1/2; (xix) −x+2, y+1/2, −z+3/2; (xx) x, y, z−1.

(VI)

Crystal data

K2CoSi5O12	Dx = 2.606 Mg m^−3
Mr = 469.55	Co Kα radiation, λ = 1.789190 Å
Cubic, Ia3d	T = 293 K
Hall symbol: -I 4bd 2c 3	dark blue
a = 13.3767 (3) Å	irregular, 10 × 5 mm
V = 2393.57 (10) Å^3	Specimen preparation: Prepared at 873 K and 100 kPa
Z = 8

Data collection

PANalytical Empyrean diffractometer	Data collection mode: reflection
Radiation source: X-ray tube	Scan method: continuous
Specimen mounting: flat plate	2θmin = 18.277°, 2θmax = 100.263°, 2θstep = 0.013°

Refinement

Rp = 0.644	Profile function: T-C-H Pseudo-Voigt
Rwp = 0.834	57 parameters
Rexp = 0.722	0 restraints
RBragg = 8.158	Background function: linear interpolation
6245 data points

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

	x	y	z	Uiso*/Ueq	Occ. (<1)
K1	0.12500	0.12500	0.12500	0.112 (7)*
Si1	0.12500	0.6649 (8)	0.5851 (8)	0.079 (4)*	0.83328
Co1	0.12500	0.6649 (8)	0.5851 (8)	0.079 (4)*	0.16670
O1	0.4616 (14)	0.3934 (9)	0.1450 (11)	0.141 (9)*	0.99998

Geometric parameters (Å, º)

K1—O1^i	3.318 (18)	K1—O1^xi	3.297 (12)
K1—O1^ii	3.318 (12)	K1—O1^xii	3.297 (18)
K1—O1^iii	3.318 (15)	Si1—O1^xiii	1.610 (18)
K1—O1^iv	3.318 (13)	Si1—O1^xiv	1.691 (16)
K1—O1^v	3.318 (18)	Si1—O1^xv	1.691 (18)
K1—O1^vi	3.318 (14)	Si1—O1^xvi	1.610 (18)
K1—O1^vii	3.297 (14)	Co1—O1^xiii	1.610 (18)
K1—O1^viii	3.297 (18)	Co1—O1^xiv	1.691 (16)
K1—O1^ix	3.297 (13)	Co1—O1^xv	1.691 (18)
K1—O1^x	3.297 (15)	Co1—O1^xvi	1.610 (18)
O1^xiii—Si1—O1^xiv	120.0 (15)	O1^xiii—Co1—O1^xvi	92.0 (16)
O1^xiii—Si1—O1^xv	107.8 (15)	O1^xiv—Co1—O1^xv	109.2 (13)
O1^xiii—Si1—O1^xvi	92.0 (16)	O1^xiv—Co1—O1^xvi	107.8 (13)
O1^xiv—Si1—O1^xv	109.2 (13)	O1^xv—Co1—O1^xvi	120.0 (16)
O1^xiv—Si1—O1^xvi	107.8 (13)	Si1^xvii—O1—Si1^vi	135.3 (10)
O1^xv—Si1—O1^xvi	120.0 (16)	Si1^xvii—O1—Co1^vi	135.3 (10)
O1^xiii—Co1—O1^xiv	120.0 (15)	Si1^vi—O1—Co1^xvii	135.3 (10)
O1^xiii—Co1—O1^xv	107.8 (15)	Co1^xvii—O1—Co1^vi	135.3 (10)

Symmetry codes: (i) −y+3/4, x−1/4, −z+1/4; (ii) −z+1/4, −y+3/4, x−1/4; (iii) x−1/4, −z+1/4, −y+3/4; (iv) −x+1/2, y−1/2, z; (v) y−1/2, z, −x+1/2; (vi) z, −x+1/2, y−1/2; (vii) y−1/4, x−1/4, z−1/4; (viii) z−1/4, y−1/4, x−1/4; (ix) x−1/4, z−1/4, y−1/4; (x) −x+1/2, −y+1/2, −z+1/2; (xi) −y+1/2, −z+1/2, −x+1/2; (xii) −z+1/2, −x+1/2, −y+1/2; (xiii) −x+1/2, −y+1, z+1/2; (xiv) y−1/4, −x+5/4, −z+3/4; (xv) −y+1/2, z+1/2, x; (xvi) x−1/4, −z+3/4, y+1/4; (xvii) −x+1/2, −y+1, z−1/2.