Ternary Early-Transition-Metal Palladium Pnictides Zr₃Pd₄P₃, Hf₃Pd₄P₃, HfPdSb, and Nb₅Pd₄P₄

Abstract

Several ternary palladium pnictides of the early transition metals have been prepared by arc-melting of the elemental metals and the binary pnictides ZrP, HfP, HfSb2, or NbP, and their structures have been determined by X-ray diffraction methods. The phosphides M3Pd4P3 (M = Zr, Hf) adopt a new structure type (Pearson symbol oP40), crystallizing in the orthorhombic space group Pnma with Z = 4 and unit cell parameters of a = 16.387(2), b = 3.8258(5), and c = 9.979(1) A for Zr3Pd4P3 and a = 16.340(2), b = 3.7867(3), and c = 9.954(1) A for Hf3Pd4P3. The antimonide HfPdSb was identified by powder X-ray diffraction (orthorhombic, Pnma, Z = 4, a = 6.754(1) A, b = 4.204(1) A, and c = 7.701(2) A) and confirmed to be isostructural to ZrPdSb, which adopts the TiNiSi-type structure. The phosphide Nb5Pd4P4 adopts the Nb5Cu4Si4-type structure, crystallizing in the tetragonal space group I4/m with Z = 2, a = 10.306(1) A, and c = 3.6372(5) A. Coordination geometries of pentacapped pentagonal prisms for the early transition metal, tetracapped distorted tetragonal prisms for Pd, and tricapped trigonal prisms for the pnicogen are found in the three structures; tetracapped tetragonal prisms for Nb are also found in Nb5-Pd4P4. In common with many metal-rich compounds whose metal-to-nonmetal ratio is equal or close to 2:1, the variety of structures formed by these ternary palladium pnictides arises from the differing connectivity of pnicogen-filled trigonal prisms. Pnicogen-pnicogen bonds are absent in these structures, but metal-metal bonds (in addition to metal-pnicogen bonds) are important interactions, as verified by extended Hückel band structure calculations on Zr3Pd4P3.

Nb4Pd0.5ZSb2 (Z = Cr, Fe, Co, Ni, Si): The First Ordered Quaternary Variants of the W5Si3-Type Structure

“…Extending our systematic studies of ternary transition metal rich pnictides, in which we have discovered the compounds M 3 Pd 4 P 3 (M = Zr, Hf), Nb 5 Pd 4 P 4 , M 3 Ni 3 Sb 4 (M = Zr, Hf), Zr 3 Pt 3 Sb 4 , and Nb 28 Ni 33.5 Sb 12.5 , we report here several members of a new family of quaternary (or pseudoquaternary) transition metal rich antimonides Nb 4 Pd 0.5 ZSb 2 (Z = Cr, Fe, Co, Ni, Si). They represent the first examples of a filled V 4 SiSb 2 -type structure, or a quaternary ordered substitutional variant of the W 5 Si 3 -type structure …”

Low-Temperature Synthesis of Amorphous FeP2 and Its Use as Anodes for Li Ion Batteries

“…Current methods of preparing nanosized particles of TMPs typically employ arrested precipitation or solvothermal routes, both of which require relatively high temperatures. For the late transition metals, pioneering studies by Brock and Schaak on the synthesis of nanosized TMPs have been focused on the use of trioctylphosphine (TOP) and trioctylphosphine oxide (TOPO) at temperatures generally in the range 200–300 °C. − In addition, Brock has also demonstrated that desilylation could be used to produce FeP nanoparticles at 240–300 °C. These high-temperature routes to TMPs in most cases provide the most thermodynamically stable, well-known crystalline phase of the material.…”

Reactivity of (Ferrocenylmethyl)phosphine toward Palladium and Platinum Chlorides. X-ray Structure of [Pd(PH2CH2Fc)Cl(μ-PHCH2Fc)]4(Fc = Ferrocenyl), a Unique Complex Containing a Pd4P4Cycle

“…48 No similar palladium polyhydrido cluster has been reported so that a Pd 4 P 4 moiety may be recognized only in the ternary palladium phosphide Nb 5 Pd 4 P 4 prepared by arc-melting of metallic palladium with NbP. 49 Therefore, the peculiar arrangement of four metals and four phosphorus donor atoms ascertained for 2 and 3 in both the solid and solution states has no precedent in eight-membered M 4 P 4 rings and cages, and likely its formation stands on steric reasons favored by the relatively small encumbrance exerted by the (ferrocenylmethyl)phosphine coligands.…”

“…Tetranuclear platinum compounds featuring a Pt 4 P 4 motif are extremely rare, being represented only by the spheroidal polyhydridotetraplatinum clusters [Pt 4 H 2 (P t Bu 3 ) 4 ] and Pt 4 H 8 [PPh i Pr 2 ] 4 . No similar palladium polyhydrido cluster has been reported so that a Pd 4 P 4 moiety may be recognized only in the ternary palladium phosphide Nb 5 Pd 4 P 4 prepared by arc-melting of metallic palladium with NbP …”

“…Distorted tetraphosphatetrametalla cubanes involving transition metals are much more rare and, to the best of our knowledge, are limited to the two derivatives [{Cp*M(µ 3 -P)} 4 ] (M ) Co, Ni) prepared by Dahl and co-workers by thermal reaction of white phosphorus with appropriate metal cyclopentadienyl precursors 46 and to the heterotetranuclear cluster [{Cp′′Ru} 3 {Cp*Fe}(µ 3 -P)} 4 ] obtained by co-thermolysis of [Cp*Fe(η 5 -P 5 48 No similar palladium polyhydrido cluster has been reported so that a Pd 4 P 4 moiety may be recognized only in the ternary palladium phosphide Nb 5 Pd 4 P 4 prepared by arc-melting of metallic palladium with NbP. 49 Therefore, the peculiar arrangement of four metals and four phosphorus donor atoms ascertained for 2 and 3 in both the solid and solution states has no precedent in eight-membered M 4 P 4 rings and cages, and likely its formation stands on steric reasons favored by the relatively small encumbrance exerted by the (ferrocenylmethyl)phosphine coligands.…”