K₂LaCl₅

The ternary title compound, dipotassium lanthanum penta­chloride, K₂LaCl₅, is isotypic with Y₂HfS₅ and various ternary rare-earth metal(III) halides with the general formula A₂MX₅ (A = NH₄, In^I, Na-Cs; M = La-Dy; X = Cl-I). The La³⁺ cations and three of the four symmetry-independent chloride anions are located on a crystallographic mirror plane. The La³⁺ cations are surrounded by seven chloride anions, each in the shape of a monocapped trigonal prism, whereas the coordination spheres of the K⁺ cations exhibit one more cap. Three of the four independent chloride anions reside in a fivefold cationic coordination, leading to distorted square pyramids. The fourth chloride anion has only four cationic neighbours, forming no specific polyhedron.

Key indicators

• Single-crystal X-ray study
• T = 293 K
• Mean [sigma](La-Cl) = 0.003 Å
• R factor = 0.059
• wR factor = 0.142
• Data-to-parameter ratio = 37.5

checkCIF/PLATON results

No syntax errors found



Alert level A
PLAT029_ALERT_3_A _diffrn_measured_fraction_theta_full Low .......       0.92

Alert level B
PLAT774_ALERT_1_B Suspect X-Y Bond in CIF:   K      --  K       ..       4.34 Ang.
PLAT774_ALERT_1_B Suspect X-Y Bond in CIF:   K      --  LA      ..       4.39 Ang.
PLAT774_ALERT_1_B Suspect X-Y Bond in CIF:   K      --  K       ..       4.43 Ang.
PLAT774_ALERT_1_B Suspect X-Y Bond in CIF:   K      --  K       ..       4.48 Ang.
PLAT774_ALERT_1_B Suspect X-Y Bond in CIF:   LA     --  K       ..       4.39 Ang.
PLAT774_ALERT_1_B Suspect X-Y Bond in CIF:   LA     --  K       ..       4.39 Ang.

Alert level C
REFLT03_ALERT_3_C  Reflection count < 95% complete
           From the CIF: _diffrn_reflns_theta_max           32.98
           From the CIF: _diffrn_reflns_theta_full          32.93
           From the CIF: _reflns_number_total               1650
           TEST2: Reflns within _diffrn_reflns_theta_max
           Count of symmetry unique reflns         1796
           Completeness (_total/calc)             91.87%
RINTA01_ALERT_3_C  The value of Rint is greater than 0.12
            Rint given   0.139
PLAT910_ALERT_3_C Missing # of FCF Reflections Below Th(Min) .....          2
PLAT911_ALERT_3_C Missing # FCF Refl Between THmin & STh/L=  0.600         35
PLAT913_ALERT_3_C Missing # of Very Strong Reflections in FCF ....          1
PLAT048_ALERT_1_C MoietyFormula Not Given ........................          ?
PLAT194_ALERT_1_C Missing _cell_measurement_reflns_used datum ....          ?
PLAT912_ALERT_4_C Missing # of FCF Reflections Above STh/L=  0.600         49
PLAT922_ALERT_1_C wR2 * 100.0 in the CIF and FCF Differ by .......      -0.42
PLAT923_ALERT_1_C S    values in the CIF and FCF Differ by .......       0.02
PLAT927_ALERT_1_C Reported and Calculated  wR2 * 100.0 Differ by .      -0.43
PLAT951_ALERT_1_C Reported and Calculated Kmax Values Differ by ..          2

Alert level G
REFLT03_ALERT_1_G ALERT: Expected hkl max differ from CIF values
           From the CIF: _diffrn_reflns_theta_max           32.98
           From the CIF: _reflns_number_total               1650
           From the CIF: _diffrn_reflns_limit_ max hkl   19.   11.   12.
           From the CIF: _diffrn_reflns_limit_ min hkl  -19.  -11.  -12.
           TEST1: Expected hkl limits for theta max
           Calculated maximum hkl   19.   13.   12.
           Calculated minimum hkl  -19.  -13.  -12.
PLAT199_ALERT_1_G Check the Reported _cell_measurement_temperature        293 K
PLAT200_ALERT_1_G Check the Reported   _diffrn_ambient_temperature        293 K
PLAT764_ALERT_4_G Overcomplete CIF Bond List Detected (Rep/Expd) .       5.14 Ratio
PLAT794_ALERT_5_G Note: Tentative Bond Valency for La      .......       3.02

   1 ALERT level A = In general: serious problem
   6 ALERT level B = Potentially serious problem
  12 ALERT level C = Check and explain
   5 ALERT level G = General alerts; check

  15 ALERT type 1 CIF construction/syntax error, inconsistent or missing data
   0 ALERT type 2 Indicator that the structure model may be wrong or deficient
   6 ALERT type 3 Indicator that the structure quality may be low
   2 ALERT type 4 Improvement, methodology, query or suggestion
   1 ALERT type 5 Informative message, check

# start Validation Reply Form
_vrf_PLAT029_I
;
PROBLEM: _diffrn_measured_fraction_theta_full Low .......       0.92
RESPONSE: ...
;

   1 ALERT level A = Data missing that is essential or data in wrong format
   0 ALERT level G = General alerts. Data that may be required is missing

S1. Comment

The ternary rare-earth metal(III) halide K₂LaCl₅ (Fig. 1) belongs to the A₂MX₅ series (A = NH₄, In, Na – Cs; M = La – Dy; X = Cl – I) (Meyer & Hüttl, 1983; Meyer et al., 1985; Wickleder & Meyer 1995). It can be described as ordered structural variety of U₃Ch₅ (Ch = S and Se) or the low-temperature phase of Yb₅Sb₃, respectively, as anti-isotypical arrangement. While the K⁺ cations have eight contacts to Cl^- anions (Fig. 2), the La³⁺ cations are surrounded by only seven of them. In both cases distorted mono- or bicapped trigonal prisms [LaCl₇]^4– or [KCl₈]^7– originate. For the lanthanum bearing ones they are linked via common edges and form chains, which run along [010] (Fig. 3). Together with the chloride anions (Cl1)^-, (Cl2)^– and (Cl3)^-, La³⁺ occupies the 4c position and shows the site symmetry m, while the (Cl4)^- anion and the K⁺ cation are located at the 8d position with the site symmetry 1.

Related literature

For the U₃Ch₅-type structure (Ch = S and Se) and its relationship to Y₂HfS₅, see: Moseley et al. (1972); Potel et al. (1972); Jeitschko & Donohue (1975). For the low-temperature phase of Yb₅Sb₃, see: Brunton & Steinfink (1971). For the series of the ternary rare-earth metal(III) halides with A = NH₄, In, Na – Cs; M = La – Dy; X = Cl – I, see: Meyer & Hüttl (1983); Meyer et al. (1985); Wickleder & Meyer (1995).

S2. Experimental

Colourless, transparent, brick-shaped single crystals of K₂LaCl₅ were obtained as by-product from the reaction of potassium azide (KN₃), lanthanum (La), the corresponding sesquioxide (La₂O₃) and trichloride (LaCl₃) in the presence of KCl as flux with the purpose to synthesize K₂La₄ONCl₉. The mixture was transferred into a torch-sealed, evacuated, fused silica vessel, heated at 1123 K for seven days, followed by cooling to room temperature within 24 h.

Computing details

Data collection: DIF4 (Stoe & Cie, 1992); cell refinement: DIF4 (Stoe & Cie, 1992); data reduction: REDU4 (Stoe & Cie, 1992); program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: DIAMOND (Brandenburg, 2006); software used to prepare material for publication: SHELXL97 (Sheldrick, 2008).

Figures

	Fig. 1. Crystal structure of K2LaCl5 as viewed along [010].
	Fig. 2. Coordination sphere of the K^+ cations with the shape of a bicapped trigonal prism. [Symmetry codes: (i) –x+^1/2, –y + 1, z–^1/2; (ii) x+^1/2, y, –z+^3/2; (iii) –x+^3/2, –y + 1, z+^1/2; (iv) –x+^3/2, –y + 1, z–^1/2.]
	Fig. 3. View at the chain formed by edge-sharing monocapped trigonal prisms [LaCl7]^4– with its contacts to the K^+ cations. Displacement ellipsoids are drawn at 90% probability level.

dipotassium lanthanum pentachloride

Crystal data

K2LaCl5	F(000) = 720
Mr = 394.36	Dx = 2.893 Mg m^−3
Orthorhombic, Pnma	Mo Kα radiation, λ = 0.71073 Å
Hall symbol: -P 2ac 2n	θ = 3.4–33.0°
a = 12.7402 (8) Å	µ = 7.02 mm^−1
b = 8.8635 (6) Å	T = 293 K
c = 8.0174 (5) Å	Bricks, colourless
V = 905.35 (10) Å^3	0.33 × 0.28 × 0.24 mm
Z = 4

Data collection

Stoe IPDS-I diffractometer	1650 independent reflections
Radiation source: fine-focus sealed tube	872 reflections with I > 2σ(I)
Graphite monochromator	Rint = 0.139
imaging plate detector system scans	θmax = 33.0°, θmin = 3.4°
Absorption correction: numerical (X-SHAPE; Stoe & Cie, 1999)	h = −19→19
Tmin = 0.106, Tmax = 0.185	k = −11→11
12421 measured reflections	l = −12→12

Refinement

Refinement on F^2	Primary atom site location: structure-invariant direct methods
Least-squares matrix: full	Secondary atom site location: difference Fourier map
R[F^2 > 2σ(F^2)] = 0.059	w = 1/[σ^2(Fo^2) + (0.0799P)^2] where P = (Fo^2 + 2Fc^2)/3
wR(F^2) = 0.142	(Δ/σ)max = 0.004
S = 0.90	Δρmax = 1.58 e Å^−3
1650 reflections	Δρmin = −2.64 e Å^−3
44 parameters	Extinction correction: SHELXL97 (Sheldrick, 2008), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
0 restraints	Extinction coefficient: 0.0094 (12)

Special details

Geometry. All e.s.d.'s (except the e.s.d. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell e.s.d.'s are taken into account individually in the estimation of e.s.d.'s in distances, angles and torsion angles; correlations between e.s.d.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell e.s.d.'s is used for estimating e.s.d.'s involving l.s. planes.

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 > σ(F²) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F² are statistically about twice as large as those based on F, and R- factors based on ALL data will be even larger.

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

	x	y	z	Uiso*/Ueq
K	0.67125 (15)	0.4946 (3)	0.5481 (3)	0.0379 (5)
La	0.50680 (5)	0.2500	0.07776 (8)	0.0248 (2)
Cl1	−0.0065 (2)	0.7500	0.9311 (4)	0.0310 (6)
Cl2	0.7911 (2)	0.2500	0.3299 (4)	0.0333 (7)
Cl3	0.6828 (2)	0.2500	0.8662 (4)	0.0374 (8)
Cl4	0.57990 (17)	0.5441 (3)	0.1663 (3)	0.0342 (5)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
K	0.0381 (10)	0.0363 (14)	0.0393 (11)	0.0014 (8)	−0.0014 (7)	−0.0070 (9)
La	0.0286 (3)	0.0234 (4)	0.0222 (3)	0.000	0.0022 (3)	0.000
Cl1	0.0347 (13)	0.0354 (17)	0.0228 (11)	0.000	0.0016 (12)	0.000
Cl2	0.0282 (13)	0.039 (2)	0.0322 (15)	0.000	0.0006 (11)	0.000
Cl3	0.0368 (15)	0.045 (2)	0.0308 (15)	0.000	0.0088 (12)	0.000
Cl4	0.0460 (12)	0.0267 (13)	0.0301 (10)	−0.0030 (9)	−0.0102 (8)	0.0025 (8)

Geometric parameters (Å, º)

K—Cl1^i	3.160 (3)	La—Cl4^x	2.895 (2)
K—Cl2	3.177 (3)	La—K^vi	4.389 (2)
K—Cl1^ii	3.206 (3)	La—K^xi	4.389 (2)
K—Cl2^iii	3.234 (3)	Cl1—La^xii	2.833 (3)
K—Cl3^iv	3.272 (4)	Cl1—K^xii	3.160 (3)
K—Cl4	3.304 (3)	Cl1—K^xiii	3.160 (3)
K—Cl4^iii	3.327 (3)	Cl1—K^xiv	3.206 (3)
K—Cl3	3.351 (4)	Cl1—K^xv	3.206 (3)
K—K^v	4.336 (5)	Cl2—La^xvi	2.845 (3)
K—La^vi	4.389 (2)	Cl2—K^v	3.177 (3)
K—K^vi	4.432 (4)	Cl2—K^xvii	3.234 (3)
K—K^iii	4.4838 (18)	Cl2—K^iv	3.234 (3)
La—Cl3^vii	2.812 (3)	Cl3—La^xviii	2.812 (3)
La—Cl1^i	2.833 (3)	Cl3—K^iii	3.272 (4)
La—Cl2^viii	2.845 (3)	Cl3—K^xix	3.272 (3)
La—Cl4	2.858 (2)	Cl3—K^v	3.351 (4)
La—Cl4^v	2.858 (2)	Cl4—La^x	2.895 (2)
La—Cl4^ix	2.895 (2)	Cl4—K^iv	3.327 (3)
Cl1^i—K—Cl2	71.80 (8)	Cl3^vii—La—Cl4	83.68 (6)
Cl1^i—K—Cl1^ii	91.76 (5)	Cl1^i—La—Cl4	75.64 (5)
Cl2—K—Cl1^ii	148.21 (10)	Cl2^viii—La—Cl4	104.48 (5)
Cl1^i—K—Cl2^iii	141.81 (10)	Cl3^vii—La—Cl4^v	83.68 (6)
Cl2—K—Cl2^iii	142.29 (7)	Cl1^i—La—Cl4^v	75.64 (5)
Cl1^ii—K—Cl2^iii	64.80 (8)	Cl2^viii—La—Cl4^v	104.48 (5)
Cl1^i—K—Cl3^iv	136.03 (10)	Cl4—La—Cl4^v	131.62 (9)
Cl2—K—Cl3^iv	87.34 (7)	Cl3^vii—La—Cl4^ix	84.06 (7)
Cl1^ii—K—Cl3^iv	86.34 (8)	Cl1^i—La—Cl4^ix	132.50 (6)
Cl2^iii—K—Cl3^iv	75.11 (8)	Cl2^viii—La—Cl4^ix	78.89 (7)
Cl1^i—K—Cl4	65.30 (7)	Cl4—La—Cl4^ix	150.15 (6)
Cl2—K—Cl4	75.52 (8)	Cl4^v—La—Cl4^ix	73.58 (7)
Cl1^ii—K—Cl4	72.88 (8)	Cl3^vii—La—Cl4^x	84.06 (7)
Cl2^iii—K—Cl4	127.34 (10)	Cl1^i—La—Cl4^x	132.50 (6)
Cl3^iv—K—Cl4	72.27 (8)	Cl2^viii—La—Cl4^x	78.89 (7)
Cl1^i—K—Cl4^iii	130.30 (10)	Cl4—La—Cl4^x	73.58 (7)
Cl2—K—Cl4^iii	68.18 (8)	Cl4^v—La—Cl4^x	150.15 (6)
Cl1^ii—K—Cl4^iii	136.98 (9)	Cl4^ix—La—Cl4^x	78.15 (9)
Cl2^iii—K—Cl4^iii	74.46 (8)	Cl3^vii—La—K^vi	145.53 (4)
Cl3^iv—K—Cl4^iii	69.93 (8)	Cl1^i—La—K^vi	46.84 (5)
Cl4—K—Cl4^iii	127.83 (9)	Cl2^viii—La—K^vi	47.41 (5)
Cl1^i—K—Cl3	79.12 (8)	Cl4—La—K^vi	61.85 (6)
Cl2—K—Cl3	87.50 (8)	Cl4^v—La—K^vi	117.97 (6)
Cl1^ii—K—Cl3	116.64 (9)	Cl4^ix—La—K^vi	126.15 (5)
Cl2^iii—K—Cl3	85.10 (7)	Cl4^x—La—K^vi	86.55 (6)
Cl3^iv—K—Cl3	139.63 (8)	Cl3^vii—La—K^xi	145.53 (4)
Cl4—K—Cl3	143.76 (10)	Cl1^i—La—K^xi	46.84 (5)
Cl4^iii—K—Cl3	71.00 (8)	Cl2^viii—La—K^xi	47.41 (5)
Cl1^i—K—K^v	46.68 (5)	Cl4—La—K^xi	117.97 (6)
Cl2—K—K^v	46.96 (6)	Cl4^v—La—K^xi	61.85 (6)
Cl1^ii—K—K^v	134.91 (5)	Cl4^ix—La—K^xi	86.55 (6)
Cl2^iii—K—K^v	134.42 (6)	Cl4^x—La—K^xi	126.15 (6)
Cl3^iv—K—K^v	133.77 (6)	K^vi—La—K^xi	62.09 (7)
Cl4—K—K^v	97.63 (6)	La^xii—Cl1—K^xii	107.21 (8)
Cl4^iii—K—K^v	84.07 (6)	La^xii—Cl1—K^xiii	107.21 (8)
Cl3—K—K^v	49.68 (5)	K^xii—Cl1—K^xiii	86.64 (11)
Cl1^i—K—La^vi	102.32 (7)	La^xii—Cl1—K^xiv	93.04 (7)
Cl2—K—La^vi	167.59 (9)	K^xii—Cl1—K^xiv	159.73 (10)
Cl1^ii—K—La^vi	40.13 (5)	K^xiii—Cl1—K^xiv	88.24 (5)
Cl2^iii—K—La^vi	40.37 (6)	La^xii—Cl1—K^xv	93.04 (7)
Cl3^iv—K—La^vi	103.97 (7)	K^xii—Cl1—K^xv	88.24 (5)
Cl4—K—La^vi	112.49 (7)	K^xiii—Cl1—K^xv	159.73 (10)
Cl4^iii—K—La^vi	110.55 (6)	K^xiv—Cl1—K^xv	89.82 (11)
Cl3—K—La^vi	80.57 (6)	La^xvi—Cl2—K^v	108.72 (9)
K^v—K—La^vi	121.04 (3)	La^xvi—Cl2—K	108.72 (9)
Cl1^i—K—K^vi	46.30 (6)	K^v—Cl2—K	86.07 (11)
Cl2—K—K^vi	113.09 (10)	La^xvi—Cl2—K^xvii	92.22 (8)
Cl1^ii—K—K^vi	45.45 (6)	K^v—Cl2—K^xvii	88.75 (3)
Cl2^iii—K—K^vi	104.62 (9)	K—Cl2—K^xvii	159.00 (11)
Cl3^iv—K—K^vi	117.84 (10)	La^xvi—Cl2—K^iv	92.22 (8)
Cl4—K—K^vi	59.28 (6)	K^v—Cl2—K^iv	159.00 (11)
Cl4^iii—K—K^vi	171.90 (11)	K—Cl2—K^iv	88.75 (3)
Cl3—K—K^vi	100.93 (9)	K^xvii—Cl2—K^iv	88.84 (11)
K^v—K—K^vi	91.23 (7)	La^xviii—Cl3—K^iii	100.62 (8)
La^vi—K—K^vi	66.36 (5)	La^xviii—Cl3—K^xix	100.62 (8)
Cl1^i—K—K^iii	125.25 (10)	K^iii—Cl3—K^xix	87.54 (11)
Cl2—K—K^iii	106.95 (10)	La^xviii—Cl3—K	115.09 (9)
Cl1^ii—K—K^iii	104.75 (8)	K^iii—Cl3—K	85.21 (4)
Cl2^iii—K—K^iii	45.10 (6)	K^xix—Cl3—K	144.27 (10)
Cl3^iv—K—K^iii	97.44 (9)	La^xviii—Cl3—K^v	115.10 (9)
Cl4—K—K^iii	169.44 (11)	K^iii—Cl3—K^v	144.27 (10)
Cl4^iii—K—K^iii	47.24 (6)	K^xix—Cl3—K^v	85.21 (4)
Cl3—K—K^iii	46.65 (6)	K—Cl3—K^v	80.64 (10)
K^v—K—K^iii	91.22 (6)	La—Cl4—La^x	106.42 (7)
La^vi—K—K^iii	67.00 (4)	La—Cl4—K	102.93 (8)
K^vi—K—K^iii	126.56 (8)	La^x—Cl4—K	147.62 (10)
Cl3^vii—La—Cl1^i	127.18 (9)	La—Cl4—K^iv	98.37 (8)
Cl3^vii—La—Cl2^viii	157.97 (10)	La^x—Cl4—K^iv	103.65 (8)
Cl1^i—La—Cl2^viii	74.85 (9)	K—Cl4—K^iv	85.10 (6)

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