The crystal structure of ZnAs₂

Abstract

ZnAs2 is monoclinic with a = 9.287 (1), b = 7691 (2), c = 8.010(1) Å, β = 102°28 (1)′, space group P21/c (C52h), Z = 8. The crystal structure was indicated by Patterson synthesis using preliminary intensity data for a pseudo‐orthorhombic unit cell and refined to a weighted residual index of 0 050 using 2031 reflexions collected on a single‐crystal diffractometer with Mo Kα (λ = 0.7107 Å) radiation. The two non‐equivalent Zn sites and four non‐equivalent As sites are each coordinated tetrahedrally, the Zn sites to four As and the As sites to two Zn and two As. The As atoms are arranged in semi‐spiral chains parallel to c. The structure of ZnAs2 differs from that previously assumed for it, the moncclinic black ZnP2 structure, in that it does not contain Zn‐Zn bonds. The marked resistivity anisotropy of ZnAs2 may be a consequence of the arrangement of the Zn(1) and Zn(2) sites in layers parallel to (100).

Crystal structure of tetrapotassium diarsenidozincate, K4ZnAs2

“…The interatomic distances of 2.2931(6) Å within [As-Zn-As] 4-units is significantly shorter than the sum of single bond radii of 2.46 Å (r(As) = 1.21 Å, r(Zn) = 1.25 Å [10]). Similarly, it is also shorter then the closest Zn-As contacts of 2.44 Å and 2.42 Å in KZnAs (Ni 2In type) [3] and ZnAs2 (ZnP2 type) [11] with trigonal planar and tetrahedral coordination of Zn (or As) atoms, respectively. …”

Crystal Growth and Structure of the Zn0.97Cd0.03As2 Solid Solution

“…Observed reflections ( I > 2 σ ( I )) 802 R 0.0264 R w 0.0756 ∆ρ max and ∆ρ min , e/Å 3 1.041 and -1.535…”

“…For seeding, we used single-crystal ZnAs 2 . (2) b , Å 7.675 (2) c , Å 7.992(2) β , deg 102.41 (3) V , Å 3 556.0 (2) F (000) 576 ρ , g/cm 3 3.913 µ , mm -1 19.768 θ max , deg 28.00…”

“…Zinc and cadmium diarsenides crystallize in the monoclinic and tetragonal systems, respectively [1][2][3]. Perfect single crystals of these II-V semiconductors offer high IR transmission in a broad spectral range and a sharp fundamental absorption edge, which makes them attractive materials for cutoff filters and immersion lenses.…”

FIR Absorption in Monoclinic ZnAs2

“…The primitive unit cell of the monoclinic ZnAs, crystal has the symmetry of C:, space group and contains as many as eight formula units [7]. A characteristic element of its crystal I) UI.…”