The role of silver on the stabilization of the incommensurately modulated structure in calaverite, AuTe2
نویسندگان
چکیده
Structural investigations of several minerals belonging to the calaverite group with composition Au1–xAgxTe2 (x = 0.00, 0.02, 0.05, 0.09, 0.19, and 0.33) indicate that Ag is randomly distributed on the Au sites. This suppresses the valence fluctuation of Au and, therefore, the structure modulations. The results are compared with the previously published incommensurately modulated structure of calaverite, Au0.9Ag0.1Te2, which is characterized by valence fluctuations of Au reinforced by an ordered distribution of Ag. The (3+1)-dimensional calaverite structure type is able to reproduce both (3+1)D and 3D related structures with the general formula AB2 (A = Au, Ag, Cu, Nb, Ta; B = Te).
منابع مشابه
Green Synthesis of Silver Nanoparticles and Its Effect on Total Proteins in Melia Azedarach Plant
Silver nano-particles have different biological applications due to their compatibility. Chemical methods usually result in remaining some amounts of toxic reactions on the nano-particles. For this reason, the use of plants as sustainable and accessible resources in preparation of compatible nano-particles has attracted a lot of attention in the recent years. This research investigated the gree...
متن کاملCrystallographic excursion in superspace
After studying more than 100 different samples of calaverite Au1-pAgpTe2 (p < 0.15) three famous mineralogists declared in a well documented 1931 publication the invalidity of the law of rational indices. What could lead them to draw such an extreme conclusion from the observation law of Hauÿ dating from more than two centuries? Their observations remained unexplained for the next forty years. ...
متن کاملAperiodic mineral structures
The three-dimensional periodic nature of crystalline structures was so strongly anchored in the minds of scientists that the numerous indications that seemed to question this model struggled to acquire the status of validity. The discovery of aperiodic crystals, a generic term including modulated, composite and quasicrystal structures, started in the 1970s with the discovery of incommensurately...
متن کاملEvaluating the Role of antioxidants in the stabilization of hydroxypropyl cellulose by ATR-FTIR Spectroscopy
This study is aimed at evaluating the performance of tetrakismethylene-3-3,5-di-tert-butyl-4-hydroxyphenyl propionate methane S1010, tris2,4-di-tert-butylphenyl phosphite S1680 and ascorbic acid AA antioxidants in stabilization of hydroxypropyl cellulose HPC. For this purpose, a number of films with weight percent ratios of 0.4 w/w were prepared in a 1 isopropanol solution w/v. Then, the films ...
متن کاملA unique distortion in K1/3Ba2/3AgTe2: X-ray diffraction determination and electronic band structure analysis of its incommensurately modulated structure.
The incommensurately modulated structure of a square Te-net, namely that of K1/3Ba2/3AgTe2, is determined from single-crystal X-ray diffraction data within a (3+1)D higher dimension formalism. The phase is shown to crystallize in the monoclinic symmetry, P2(1)(alpha 0 gamma) superspace group with the following lattice parameters: a = 4.6441(10) A, b = 4.6292(12) A, c = 23.765(9) A, and beta = 1...
متن کامل