The crystal structure of braggite, (Pt, Pd, Ni)S

Abstract

The determination of the crystal structure of braggite by Patterson methods confirms the proposal of Gaskell [Z. Kristallogr. (1935) 96, 203-213], that braggite is isostructural with PdS. The cell dimensions are a= 6.380(1), e= 6.570(1) A, Z= 8 and the space group is P42/m. Full-matrix least-squares procedures were used with two sets of merged 4-circle diffractometer data to refine the atomic parameters to an R value of 0.068. Generalized absorption corrections were applied. Several different configurations of metal ordering were tested for the stoichiometric composition PtsPdzNiSs. It is proposed that the two Pd atoms preferentially occupy the site 2(d),(0,~-,1-), in the structure and that this is the minimum requirement in the formation of the PdS (braggite or vysotskite) structure rather than the PtS (cooperite) structure.

Raman Spectroscopic Identification of Synthetic “Braggite” (Pt, Pd, Ni)S Samples in Comparison with Synthetic “Cooperite”

“…Nickel in vysotskite is not considered an essential constituent, 4 and com positional changes of braggite/vysotskite are not associated with structural changes. 11 The variation of nickel in our samples, therefore, does not seem to have an in¯uence on the spectrum . Therefore the Ram an spectrum of sample SV304 should not show any obvious differences w ith respect to the other samples.…”

“…Structures of the synthetic``cooperites' ' and``braggites' ' are currently being determined, and these shall be published elsewhere.``Braggite' ' (Pt, Pd, Ni)S has been reported as being isom orphous with the structure of palladium sul® de, 10 and the cr ystal structure of naturally occurring``braggite'' has been shown by Childs and Hall 11 to have the space group P4 2 /m(C ) and Z 5 8. The m etal…”

Raman Spectra of Synthetic ‘Braggite’, (Pd,Pt,Ni)S

“…2). Factor group analysis (De Angelis et al, 1972) performed by means of the correlation method (Fateley et al, 1971) resulted for 'vysotskite' as ideal PdS with space group P42/m and Z -8 (Childs and Hall, 1973) in 14 modes (2 A2g , 3 Big , 2 t~2g , 7 Eg). With the incorporation of Pt into the crystalline unit, the environment and interaction of the ions can be expected to change.…”

Exciton‐Like and Mid‐Gap Absorption Dynamics of PtS in Resonant and Transparent Regions

“…A and B are the rate constants for electrons and holes trapped by defects via an Auger process, respectively. Choosing A, B, and n d as the fitting parameters, we can simulate the temporal evolution of △A by combining Equations ( 5) and ( 7)- (9). Figure 4a shows our experimental data (dots) and the fitting curve.…”

“…[7] Unexpected electronic field shift was recently noted by Harms et al when they employed a high resolution intracavity laser spectroscopy. [8] Although efforts and progress on comprehending the properties of PtS have been ongoing, they thus far mainly concentrated upon the structure and synthesis, [5][6][7][9][10][11] the electrical properties, [11][12][13][14][15] and a few on the optical properties including our latest work on optical nonlinearity and ultrafast optics aspects from the bulk to their 2D form. [16][17][18][19] The global optical property of PtS, however, is still suffering a significant knowledge gap.…”