Synthesis, structural characterization, and electronic structure of the novel Zintl phase Ba₂ZnP₂

The novel Zintl phase dibarium zinc diphosphide (Ba₂ZnP₂) was synthesized for the first time. This was accom­plished using the Pb flux technique, which allowed for the growth of crystals of adequate size for structural determination via single-crystal X-ray diffraction methods. The Ba₂ZnP₂ com­pound was determined to crystallize in a body-centered ortho­rhom­bic space group, Ibam (No. 72). Formally, this crystallographic arrangement belongs to the K₂SiP₂ structure type. Therefore, the structure can be best described as infinite [ZnP₂]⁴⁻ polyanionic chains with divalent Ba²⁺ cations located between the chains. All valence electrons are partitioned, which conforms to the Zintl–Klemm concept and suggests that Ba₂ZnP₂ is a valence-precise com­position. The electronic band structure of this new com­pound, com­puted with the aid of the TB–LMTO–ASA code, shows that Ba₂ZnP₂ is an intrinsic semiconductor with a band gap of ca 0.6 eV.

Computing details

Data collection: SMART (Bruker, 2014); cell refinement: SAINT (Bruker, 2014); data reduction: SAINT (Bruker, 2014); program(s) used to solve structure: SHELXT (Sheldrick, 2015a); program(s) used to refine structure: SHELXL2018 (Sheldrick, 2015b); molecular graphics: DIAMOND (Brandenburg, 2014) and OLEX2 (Dolomanov et al., 2009); software used to prepare material for publication: publCIF (Westrip, 2010).

Dibarium zinc diphosphide

Crystal data

Ba2ZnP2	Dx = 4.722 Mg m^−3
Mr = 401.99	Mo Kα radiation, λ = 0.71073 Å
Orthorhombic, Ibam	Cell parameters from 995 reflections
a = 6.756 (4) Å	θ = 3.1–29.2°
b = 13.108 (8) Å	µ = 18.38 mm^−1
c = 6.385 (4) Å	T = 200 K
V = 565.4 (6) Å^3	Block, black
Z = 4	0.05 × 0.04 × 0.03 mm
F(000) = 688

Data collection

Bruker APEXII CCD diffractometer	396 reflections with I > 2σ(I)
φ and ω scans	Rint = 0.046
Absorption correction: multi-scan (SADABS; Bruker, 2014)	θmax = 29.6°, θmin = 3.1°
Tmin = 0.249, Tmax = 0.336	h = −9→9
3529 measured reflections	k = −18→18
437 independent reflections	l = −8→8

Refinement

Refinement on F^2	Primary atom site location: dual
Least-squares matrix: full	w = 1/[σ^2(Fo^2) + (0.0163P)^2] where P = (Fo^2 + 2Fc^2)/3
R[F^2 > 2σ(F^2)] = 0.018	(Δ/σ)max < 0.001
wR(F^2) = 0.037	Δρmax = 1.12 e Å^−3
S = 1.04	Δρmin = −0.86 e Å^−3
437 reflections	Extinction correction: SHELXL2018 (Sheldrick 2015b), Fc^*=kFc[1+0.001xFc^2λ^3/sin(2θ)]^-1/4
17 parameters	Extinction coefficient: 0.00142 (12)
0 restraints

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. The collected data were integrated with the Bruker-supplied software (Bruker, 2014), and absorption correction was applied using the SADABS software (Bruker, 2014). The crystal structure was solved using the ShelXT code (Sheldrick, 2015a), using Olex2 as the graphical interface (Dolomanov et al., 2009). Structural parameters were refined using the full-matrix least squares method on F² with SHELXL (Sheldrick 2015b).

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

	x	y	z	Uiso*/Ueq
Ba	0.19118 (4)	0.35970 (2)	0.000000	0.01146 (12)
Zn	0.000000	0.000000	0.250000	0.01103 (19)
P	0.20008 (18)	0.10649 (10)	0.000000	0.0107 (3)

Atomic displacement parameters (Ų)

	U^11	U^22	U^33	U^12	U^13	U^23
Ba	0.01154 (17)	0.01068 (17)	0.01215 (17)	−0.00097 (11)	0.000	0.000
Zn	0.0105 (4)	0.0117 (4)	0.0109 (4)	0.000	0.000	0.000
P	0.0117 (6)	0.0100 (6)	0.0105 (6)	−0.0018 (5)	0.000	0.000

Geometric parameters (Å, º)

Ba—Ba^i	4.1067 (19)	Ba—P	3.320 (2)
Ba—Ba^ii	4.370 (2)	Ba—P^iii	3.306 (2)
Ba—Ba^iii	4.3698 (19)	Ba—P^viii	3.317 (2)
Ba—Ba^iv	4.1067 (19)	Ba—P^ii	3.306 (2)
Ba—Zn^v	3.2066 (12)	Zn—P	2.5147 (14)
Ba—Zn^iii	3.2066 (12)	Zn—P^i	2.5147 (14)
Ba—P^vi	3.347 (2)	Zn—P^ix	2.5147 (14)
Ba—P^vii	3.466 (2)	Zn—P^x	2.5147 (14)
Ba^iv—Ba—Ba^iii	133.03 (3)	P—Ba—P^vi	98.64 (3)
Ba^i—Ba—Ba^iii	63.03 (3)	P^iii—Ba—P^vii	76.26 (2)
Ba^ii—Ba—Ba^iii	93.87 (5)	P^ii—Ba—P^viii	79.64 (3)
Ba^i—Ba—Ba^ii	133.03 (3)	P^ii—Ba—P	97.47 (3)
Ba^iv—Ba—Ba^ii	63.03 (3)	P^viii—Ba—P^vii	69.86 (4)
Ba^iv—Ba—Ba^i	102.05 (5)	Ba^iii—Zn—Ba^vi	110.01 (4)
Zn^iii—Ba—Ba^i	91.28 (4)	Ba^iii—Zn—Ba^xi	98.82 (4)
Zn^iii—Ba—Ba^iii	84.00 (4)	Ba^vi—Zn—Ba^xi	120.29 (4)
Zn^v—Ba—Ba^ii	84.00 (4)	Ba^iii—Zn—Ba^xii	120.29 (4)
Zn^v—Ba—Ba^iv	91.28 (4)	Ba^xii—Zn—Ba^xi	110.01 (4)
Zn^v—Ba—Ba^i	142.77 (2)	Ba^xii—Zn—Ba^vi	98.82 (4)
Zn^iii—Ba—Ba^iv	142.77 (2)	P^i—Zn—Ba^xi	169.75 (2)
Zn^v—Ba—Ba^iii	128.52 (3)	P^i—Zn—Ba^vi	69.39 (5)
Zn^iii—Ba—Ba^ii	128.52 (3)	P^x—Zn—Ba^xii	73.46 (5)
Zn^iii—Ba—Zn^v	59.71 (4)	P—Zn—Ba^xii	169.75 (2)
Zn^iii—Ba—P^viii	45.31 (2)	P^x—Zn—Ba^iii	69.67 (5)
Zn^v—Ba—P^vii	44.06 (2)	P^ix—Zn—Ba^xii	69.39 (4)
Zn^iii—Ba—P^iii	45.40 (2)	P^ix—Zn—Ba^vi	69.67 (5)
Zn^v—Ba—P^ii	45.40 (2)	P—Zn—Ba^iii	69.39 (5)
Zn^v—Ba—P^vi	124.68 (3)	P—Zn—Ba^xi	69.67 (5)
Zn^v—Ba—P^iii	105.03 (4)	P—Zn—Ba^vi	73.46 (5)
Zn^iii—Ba—P^vi	124.68 (3)	P^x—Zn—Ba^xi	69.39 (5)
Zn^iii—Ba—P^ii	105.03 (4)	P^ix—Zn—Ba^xi	73.46 (5)
Zn^iii—Ba—P	124.17 (3)	P^i—Zn—Ba^xii	69.67 (5)
Zn^v—Ba—P^viii	45.31 (2)	P^ix—Zn—Ba^iii	169.75 (2)
Zn^iii—Ba—P^vii	44.06 (2)	P^x—Zn—Ba^vi	169.75 (2)
Zn^v—Ba—P	124.17 (3)	P^i—Zn—Ba^iii	73.46 (5)
P^ii—Ba—Ba^iv	52.34 (4)	P^x—Zn—P^i	101.19 (6)
P^vi—Ba—Ba^iii	105.509 (19)	P—Zn—P^x	114.97 (7)
P^iii—Ba—Ba^iii	48.87 (4)	P—Zn—P^ix	101.19 (6)
P—Ba—Ba^ii	48.60 (3)	P—Zn—P^i	112.56 (7)
P^vi—Ba—Ba^ii	105.509 (19)	P^ix—Zn—P^x	112.56 (7)
P^viii—Ba—Ba^iii	126.98 (3)	P^ix—Zn—P^i	114.97 (7)
P^ii—Ba—Ba^iii	138.88 (3)	Ba^xi—P—Ba	168.24 (4)
P^viii—Ba—Ba^iv	98.006 (17)	Ba^xi—P—Ba^vii	84.81 (4)
P^viii—Ba—Ba^ii	126.98 (3)	Ba^xi—P—Ba^vi	110.14 (4)
P^iii—Ba—Ba^iv	152.94 (3)	Ba^iii—P—Ba	82.53 (2)
P—Ba—Ba^iii	48.60 (3)	Ba^iii—P—Ba^vi	101.73 (3)
P^vii—Ba—Ba^iii	84.48 (2)	Ba^ii—P—Ba^vi	101.73 (3)
P^vi—Ba—Ba^i	51.43 (3)	Ba^iii—P—Ba^ii	149.92 (5)
P^vii—Ba—Ba^ii	84.48 (2)	Ba^ii—P—Ba^vii	76.23 (2)
P^vii—Ba—Ba^i	128.60 (3)	Ba^iii—P—Ba^xi	94.67 (3)
P^viii—Ba—Ba^i	98.006 (17)	Ba^ii—P—Ba	82.53 (3)
P^ii—Ba—Ba^ii	48.87 (4)	Ba^ii—P—Ba^xi	94.67 (3)
P^vi—Ba—Ba^iv	51.43 (3)	Ba—P—Ba^vii	83.43 (3)
P^iii—Ba—Ba^i	52.34 (4)	Ba^vii—P—Ba^vi	165.05 (5)
P^iii—Ba—Ba^ii	138.88 (3)	Ba^iii—P—Ba^vii	76.23 (2)
P^ii—Ba—Ba^i	152.94 (3)	Ba—P—Ba^vi	81.62 (3)
P^vii—Ba—Ba^iv	128.60 (3)	Zn—P—Ba^vii	127.32 (4)
P—Ba—Ba^i	90.653 (14)	Zn—P—Ba	123.04 (4)
P—Ba—Ba^iv	90.653 (14)	Zn—P—Ba^ii	143.79 (4)
P^iii—Ba—P^viii	79.64 (3)	Zn^ix—P—Ba^xi	65.02 (4)
P^iii—Ba—P^ii	149.92 (5)	Zn^ix—P—Ba	123.04 (4)
P^vi—Ba—P^vii	165.05 (5)	Zn—P—Ba^vi	62.47 (3)
P^viii—Ba—P	166.169 (16)	Zn—P—Ba^xi	65.02 (4)
P—Ba—P^vii	96.31 (3)	Zn—P—Ba^iii	65.22 (3)
P^viii—Ba—P^vi	95.19 (4)	Zn^ix—P—Ba^vi	62.47 (3)
P^ii—Ba—P^vii	76.26 (2)	Zn^ix—P—Ba^vii	127.32 (4)
P^iii—Ba—P	97.47 (3)	Zn^ix—P—Ba^ii	65.22 (3)
P^ii—Ba—P^vi	101.68 (3)	Zn^ix—P—Ba^iii	143.79 (4)
P^iii—Ba—P^vi	101.68 (3)	Zn^ix—P—Zn	78.81 (6)

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