Supposedly it is an amalgam of the crystalline powdered form of
Mercuric Pyro-antimonate, Hg2Sb2O7. However, the description of the
method of production and the density attributed to it, 20.20 g/cc,
thought to be achieved by applying a pressure of 5 atmospheres(maybe)
to it, is not consistent with mercury's compressibility factor. It is
therefore probably best to consider the compound as a separate issue
from the amalgam, for now at least.
Refer to the Chemical Abstracts Service's Number
Section for 1965-1971:-
20720-76-7 Antimonic acid (H4Sb2O7), mercury(2+)salt(1:2)
H4O7Sb2.2Hg
The CAS Subject Index for 1967-1971 has (page 2785s):-
mercury(2+) salt (1:2)[20720-76-7], crystal structure of, 69: 71239v
whilst the Chemical Abstracts themselves include an entry in volume
69,
for 1968, on page 6661 beginning:-
71239v New ternary oxides of mercury with the pyrochlore
structure. Sleight, A.W. (E.I. du Pont de Nemours and Co.,
Wilmington, Del.) Inorg. Chem. 1968, 7(9), 1704-8 (Eng). Three new
ternary oxides of Hg- Hg2Nb2O7, Hg2Ta2O7 and Hg2S2O7 (sic) - have
been
prepd. and characterized.......
An enquiry sent to CAS drew a response stating that:-
'....."Hg2S2O7" appeared as a typographical error for "Hg2SbO7"'(!)
Steve Shires.