  The topology of the magnetic interactions of the copper spins in the
nitrosonium nitratocuprate (NO)[Cu(NO3)3] suggests that it could be a
realization of the Nersesyan-Tsvelik model, whose ground state was argued to be
either a resonating valence bond (RVB) state or a valence bond crystal (VBC).
The measurement of thermodynamic and resonant properties reveals a behavior
inherent to low dimensional spin S = 1/2 systems and provides indeed no
evidence for the formation of long-range magnetic order down to 1.8 K.
