Results for “Ca(CdP)2”

DOE OSTI2020

Materials Data on Ca(CdP)2 by Materials Project

CaCd2P2 crystallizes in the trigonal P-3m1 space group. The structure is three-dimensional. Ca2+ is bonded to six equivalent P3- atoms to form CaP6 octahedra that share corners with twelve equivalent CdP4 tetrahedra, edges with six equivalent CaP6 octahedra, and edges with six equivalent CdP4 tetrahedra. All Ca–P bond lengths are 3.01 Å. Cd2+ is bonded to four equivalent P3- atoms to form CdP4 tetrahedra that share corners with six equivalent CaP6 octahedra, corners with six equivalent CdP4 tetrahedra, edges with three equivalent CaP6 octahedra, and edges with three equivalent CdP4 tetrahedra. The corner-sharing octahedra tilt angles range from 15–56°. There are three shorter (2.64 Å) and one longer (2.83 Å) Cd–P bond lengths. P3- is bonded to three equivalent Ca2+ and four equivalent Cd2+ atoms to form a mixture of distorted corner and edge-sharing PCa3Cd4 pentagonal bipyramids.

36 MATERIALS SCIENCE↗

DOE OSTI2025

SnO 2 modified CsH 2 PO 4 (CDP) protonic electrolyte for an electrochemical hydrogen pump

Hydrophilic SnO 2 is introduced into CsH 2 PO 4 (CDP) to mitigate CDP's dehydration at lower partial pressure of steam, thus retaining proton conductivity.

Gupta, Minal [Department of Mechanical Engineering↗

DOE OSTI2020

Synthesis and structural characterization of the new Zintl phases Ba 3 Cd 2 P 4 and Ba 2 Cd 2 P 3 . Rare example of small gap semiconducting behavior with negative thermopower within the range 300 K-700 K

The new Zintl phases Ba 3 Cd 2 P 4 and Ba 2 Cd 2 P 3 have been synthesized using Pb flux, which allowed for the growth of 4-5 mm large crystals. The structures were determined utilizing single-crystal X-ray diffraction methods. Both compounds crystalize in the monoclinic crystal system (space group C2/m (No. 12)) and their structures are closely related. The structure of Ba 3 Cd 2 P 4 can be seen as being comprised of divalent Ba atoms and conjoined CdP 4 tetrahedra in the form of [Cd 2 P 4 ] 6- layers. Within the layers, homoatomic P–P bonds are present, which if cleaved, leave two infinite [CdP 3 ] 7- chains running along the crystallographic b-axis. The other structure, that of Ba 2 Cd 2 P 3 , can be rationalized as also having divalent Ba atoms and conjoined CdP4 tetrahedra in the form of [Cd 2 P 3 ] 6- layers. These layers, again, can be visualized as chains that run down the crystallographic b-axis, which are further connected by P-P dimers. Electronic band structure calculations show that each structure has an optimal number of valence electrons, and therefore conform to the Zintl-Klemm concept. Accordingly, the two compounds can be considered small band gap semiconductors, with band gaps of ca. 0.1 eV and 0.6 eV for Ba3Cd2P4 and Ba 2 Cd 2 P 3 , respectively. Electrical resistivity measurements show that Ba3Cd2P4 displays a large resistivity value at room temperature and an experimental band gap of ca. 0.05 eV, which fits reasonably well with the theoretical predictions. Thermopower measurements show that throughout the temperature range 300 K-700 K, Ba 3 Cd 2 P 4 displays a negative Seebeck coefficient. Here, the extremum value of -84 μV is reached at 630 K, suggestive of an n-type semiconductor, a rarity among Zintl phases.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗