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A nonstoichiometric line phase, Rh 3 Cd 5−δ (δ ∼ 0.56), is found in close vicinity to RhCd and structurally characterized by single-crystal X-ray diffraction and energy-dispersive X-ray spectroscopy. The compound crystallizes in the cubic space group Im3m (No. 229) with lattice constant a = 6.3859(9) Å and represents a 2 × 2 × 2 superstructure of RhCd, which accommodates a vacancy concentration of nearly 6% in its crystal structure. The first-principles electronic structure calculation on a hypothetical ordered configuration of Rh 3 Cd 5−δ reveals that Rh−Cd heteroatomic interaction plays a major role in the stability of the compound. A combination of the total energy, formation energy, and crystal orbital Hamilton population calculations on hypothetical model configurations establishes that the compound upholds an optimum vacancy concentration in the Cd2a (Cd1) site for the stability of the phase.

Single crystalline titled phase is synthesized by conventional high-temperature solid-state synthesis. Crystal structure of Ni 3 GaSb is re-investigated by single-crystal X-ray diffraction and energy dispersive X-ray analysis. The compound crystallizes in P6 3 /mmc space group, the structure can be described as an intermediate of NiSb and Ni 2 In structures, similar to Ni 3 GaAs. Electronic structure of the compound is investigated by firstprinciples electronic structure calculations on the ordered model of Ni 3 GaSb. Stability and bond analysis was done by COHP calculations. Hetero-atomic NiÀ Sb and NiÀ Ga interactions play a major role towards to stability of the compound, these interactions are also responsible to modify the electronic structure of the titled compound. It was tested for catalytic activity and selectivity for acetylene hydrogenation reaction. Ni 3 GaSb was found to be a selective catalyst with 95.53 % C 2 H 2 conversion giving 60 % selectivity towards C 2 H 4 at 550°C.

InPd 3-x Cu x (x = 0-1) were prepared by high temperature synthesis starting from the highly pure constituent elements. The crystal structures were determined by X-ray diffraction. In the structure of InPd 3-x Cu x (x = 0-1), Cu stabilizes the TiAl 3 -type InPd 3 and selectively substitutes one of the two Pd positions and at the limiting composition ordered InPd 2 Cu is formed where Cu completely occupies that position. The intriguing selective substitution was investigated by first-principles total energy calculations followed by electronic structure and chemical bonding analysis.

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