Stuck in Our Teeth? Crystal Structure of a New Copper Amalgam, Cu3Hg

Abstract

Abstract:We have synthesized a new Cu amalgam, the Cu-rich phase Cu 3 Hg. It crystallizes with the Ni 3 Sn structure type with a hexagonal unit cell (space group P6 3 /mmc , a = 5.408(4) Å, c = 4.390(3) Å) and shows some mixed occupancy of Cu on the Hg site, resulting in a refined composition of Cu 3.11 Hg 0.89 . This is the first example of an amalgam with the Ni 3 Sn structure type where Hg is located mainly on the Sn site. Cu 3 Hg might be one of the phases constituting dental amalgams and therefore has major relevance, as well as the only Cu amalgam phase described so far, Cu 7 Hg 6 with the γ-brass structure. It occurs as a biphase in our samples. Thermal decomposition of Cu amalgam samples in a dynamic vacuum yields nanostructured copper networks, possibly suitable for catalytic applications.

Superconductivity in Crystallographically Disordered LaHg6.4

“… 48 − 54 Moreover, peculiar magnetic correlations, brought on by the mixing of d and f orbitals, have been observed in several solid-state compounds. 23 , 51 − 60 Additionally, the application potential of some mercury-based materials has been discussed. 23 , 61 However, it is well-known that much care must be taken during the synthesis, handling, and characterization of mercury-based compounds, in particular rare earth metals’ mercurides—from toxicity concerns to their high chemical reactivity—as these systems pose several experimental challenges.…”

“… 23 , 51 − 60 Additionally, the application potential of some mercury-based materials has been discussed. 23 , 61 However, it is well-known that much care must be taken during the synthesis, handling, and characterization of mercury-based compounds, in particular rare earth metals’ mercurides—from toxicity concerns to their high chemical reactivity—as these systems pose several experimental challenges. 27 , 62 − 64 The complexity of work on mercury-based materials is reflected in a low number of systems that have been discovered so far.…”

“…Mercury-based compounds (amalgams) have received a considerable amount of attention in the chemical communitythese materials often host complex crystallographic arrangements − and display peculiar bonding features. ,− As a result, some of these materials show peculiar superconducting characteristics, ,,− including high critical temperatures, which can be enhanced even further by the application of pressure. Some mercury-containing materials were even suggested to exhibit topologically nontrivial states. − Moreover, peculiar magnetic correlations, brought on by the mixing of d and f orbitals, have been observed in several solid-state compounds. ,− Additionally, the application potential of some mercury-based materials has been discussed. , However, it is well-known that much care must be taken during the synthesis, handling, and characterization of mercury-based compounds, in particular rare earth metals’ mercuridesfrom toxicity concerns to their high chemical reactivityas these systems pose several experimental challenges. ,− The complexity of work on mercury-based materials is reflected in a low number of systems that have been discovered so far. Furthermore, detailed investigations of chemical and physical properties are often missing even for binary and ternary compounds that are already known.…”

Chemical and Physical Properties of YHg3 and LuHg3

“…It has been suggested that the Lu–Hg system would likely look similar to that of Er–Hg and Ho–Hg . The Y–Hg phase diagram remains partially unknown. − Among the Y–Hg and Lu–Hg phases, three compounds have been reported to exist: Y/LuHg (structure type CsCl), ,, Y/LuHg 2 (structure type UHg 2 ), ,, and Y/LuHg 3 (structure type Mg 3 Cd). ,, The latter structure type, with the P 6 3 /mmc space group, ,− is the most common among all compounds with the 1:3 and 3:1 stoichiometry, − ,− ,− as summarized in Figure . The atomic positions are reversed in the latter case, which results in Na 3 Hg, Mg 3 Hg, and Cu 3 Hg compounds (elements marked with stars). ,, …”

“…Space groups of binary mercury-based compounds with 1:3 and 3:1 (elements marked by stars) stoichiometries. Majority of compounds crystallize with the P 6 3 / mmc space group. ,− The inset shows the Mg 3 Cd-type crystal structure of Y/LuHg 3 ( P 6 3 / mmc space group) with gray and green spheres representing Hg and Y/Lu, respectively.…”