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ZnO2 is Calaverite structured and crystallizes in the trigonal P-3m1 space group. The structure is two-dimensional and consists of one ZnO2 sheet oriented in the (0, 0, 1) direction. Zn is bonded to six equivalent O atoms to form edge-sharing ZnO6 octahedra. All Zn–O bond lengths are 2.04 Å. O is bonded in a distorted trigonal non-coplanar geometry to three equivalent Zn atoms.
ZnO2 crystallizes in the orthorhombic Imm2 space group. The structure is two-dimensional and consists of two ZnO2 sheets oriented in the (0, 0, 1) direction. there are two inequivalent Zn sites. In the first Zn site, Zn is bonded to four O atoms to form corner-sharing ZnO4 tetrahedra. There are a spread of Zn–O bond distances ranging from 1.87–2.03 Å. In the second Zn site, Zn is bonded to four O atoms to form corner-sharing ZnO4 tetrahedra. There is two shorter (1.96 Å) and two longer (2.01 Å) Zn–O bond length. There are four inequivalent O sites. In the first O site, O is bonded in a distorted bent 150 degrees geometry to two Zn atoms. In the second O site, O is bonded in a distorted trigonal planar geometry to two equivalent Zn and one O atom. The O–O bond length is 1.41 Å. In the third O site, O is bonded in a distorted water-like geometry to two equivalent Zn atoms. In the fourth O site, O is bonded in a distorted trigonal planar geometry to two equivalent Zn and one O atom. The O–O bond length is 1.47 Å.
ZnO2 is Pyrite-like structured and crystallizes in the cubic Pa-3 space group. The structure is three-dimensional. Zn is bonded to six equivalent O atoms to form ZnO6 octahedra that share corners with twelve equivalent ZnO6 octahedra and corners with six equivalent OZn3O tetrahedra. The corner-sharing octahedral tilt angles are 70°. All Zn–O bond lengths are 2.14 Å. O is bonded to three equivalent Zn and one O atom to form OZn3O tetrahedra that share corners with three equivalent ZnO6 octahedra and corners with fifteen equivalent OZn3O tetrahedra. The corner-sharing octahedral tilt angles are 71°. The O–O bond length is 1.50 Å.
ZnO2 is Pyrite-like structured and crystallizes in the orthorhombic P2_12_12_1 space group. The structure is three-dimensional. Zn is bonded to six O atoms to form ZnO6 octahedra that share corners with four equivalent ZnO6 octahedra, corners with six OZn3O tetrahedra, and edges with four equivalent ZnO6 octahedra. The corner-sharing octahedra tilt angles range from 67–69°. There are a spread of Zn–O bond distances ranging from 2.11–2.15 Å. There are two inequivalent O sites. In the first O site, O is bonded to three equivalent Zn and one O atom to form distorted OZn3O tetrahedra that share corners with three equivalent ZnO6 octahedra, corners with nine OZn3O tetrahedra, and edges with three OZn3O tetrahedra. The corner-sharing octahedra tilt angles range from 66–74°. The O–O bond length is 1.50 Å. In the second O site, O is bonded to three equivalent Zn and one O atom to form OZn3O tetrahedra that share corners with three equivalent ZnO6 octahedra, corners with thirteen OZn3O tetrahedra, and an edgeedge with one OZn3O tetrahedra. The corner-sharing octahedra tilt angles range from 57–65°.
ZnO2 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Zn sites. In the first Zn site, Zn is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Zn–O bond distances ranging from 1.99–2.41 Å. In the second Zn site, Zn is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Zn–O bond distances ranging from 1.98–2.40 Å. In the third Zn site, Zn is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Zn–O bond distances ranging from 1.98–2.40 Å. In the fourth Zn site, Zn is bonded in a 6-coordinate geometry to six O atoms. There are a spread of Zn–O bond distances ranging from 1.98–2.38 Å. There are eight inequivalent O sites. In the first O site, O is bonded in a trigonal non-coplanar geometry to two Zn and one O atom. The O–O bond length is 1.28 Å. In the second O site, O is bonded in a trigonal non-coplanar geometry to two Zn and one O atom. The O–O bond length is 1.27 Å. In the third O site, O is bonded in a trigonal non-coplanar geometry to two Zn and one O atom. In the fourth O site, O is bonded in a trigonal non-coplanar geometry to two Zn and one O atom. In the fifth O site, O is bonded to four Zn atoms to form a mixture of edge and corner-sharing OZn4 tetrahedra. In the sixth O site, O is bonded to four Zn atoms to form a mixture of edge and corner-sharing OZn4 tetrahedra. In the seventh O site, O is bonded to four Zn atoms to form a mixture of edge and corner-sharing OZn4 tetrahedra. In the eighth O site, O is bonded to four Zn atoms to form a mixture of edge and corner-sharing OZn4 tetrahedra.
Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations
(ZnO2)5(NO3)2 crystallizes in the monoclinic C2/m space group. The structure is two-dimensional and consists of four nitric acid molecules and two ZnO2 sheets oriented in the (1, 0, 0) direction. In each ZnO2 sheet, there are three inequivalent Zn sites. In the first Zn site, Zn is bonded to six O atoms to form ZnO6 octahedra that share corners with four equivalent ZnO4 tetrahedra and edges with four equivalent ZnO6 octahedra. There are two shorter (2.01 Å) and four longer (2.05 Å) Zn–O bond lengths. In the second Zn site, Zn is bonded to six O atoms to form ZnO6 octahedra that share corners with four equivalent ZnO4 tetrahedra and edges with four ZnO6 octahedra. There are a spread of Zn–O bond distances ranging from 2.01–2.07 Å. In the third Zn site, Zn is bonded to four O atoms to form corner-sharing ZnO4 tetrahedra. The corner-sharing octahedra tilt angles range from 54–55°. There are a spread of Zn–O bond distances ranging from 1.89–1.96 Å. There are four inequivalent O sites. In the first O site, O is bonded in a trigonal planar geometry to three Zn atoms. In the second O site, O is bonded in a trigonal planar geometry to three Zn atoms. In the third O site, O is bonded in a trigonal non-coplanar geometry to three Zn atoms. In the fourth O site, O is bonded in a single-bond geometry to one Zn atom.
0.970(0.95(K{sub 0.485}Na{sub 0.515})NbO{sub 3}–0.05LiSbO{sub 3})–0.015CuO–0.015Al{sub 2}O{sub 3} (KNNLS–CA) ceramic powder obtained through the conventional solid state reaction. The ZnO nanoparticles (denoted as ZnO1) and poly (vinylidene fluoride) (PVDF) were supplied from commercial companies. The self-synthesized ZnO powder (denoted as ZnO2) were prepared by hydrothermal method using Zn (CH{sub 3}COO){sub 2}·2H{sub 2}O and NaOH. Subsequently, the two kinds of composites were fabricated by hot-pressing process using KNNLS–CA ceramic powder, two kinds of ZnO powder and PVDF polymer. The effects of the ZnO on the crystalline structures, morphology, thermal stability, densities and electric properties of composites were studied systemically. The KNNLS–CA ceramic possesses a perovskite phase with orthorhombic symmetry and peaks from the second phase of K{sub 3}Li{sub 2}Nb{sub 5}O{sub 15} (PDF#52-0157) are detected by X-ray diffraction. PVDF polymer mainly possesses α, β and γ phases. Two kinds of ZnO all possess hexagonal wurtzite structures without any impurity phase. It is worth noting that the ZnO particles have great impacts on lattice constants, strain and crystallinity. In addition, the ZnO particles can enhance the relative fraction of β phase in PVDF and improve the thermal stability of the composite. Interestingly, the dielectric and piezoelectric properties are also found to be improved with the increase of ZnO content. Especially, when 10 wt.% ZnO2 is doped, the dielectric permittivity reaches the value of 586.4 (100 Hz) at room temperature and the piezoelectric constant is 64 pC/N. After 30 days of aging test, it is obvious that all the composites present a good stability of piezoelectric property.