Note: the use of the name nováčekite is inconsistent in the literature. There are two differently hydrated species (Walenta, 1964), one with 12 water molecules (nováčekite =
nováčekite-I), the other with 10 water molecules (
nováčekite-II). A further, still less hydrated species is
metanováčekite.
Both nováčekite-I and nováčekite-II are grandfathered species.
Their crystal structures have been solved by Locock et al. (2004); nováčekite-I is triclinic (P-1), with a 7.1594(5) Å, b 7.1610(5) Å, c 11.3146(7) Å, α 81.391(2)°, β 81.177(1)°, γ 88.884(1)°, while nováčekite-II is monoclinic (P21/n), with a 7.1328(11) Å, b 20.085(3) Å, c 7.1569(11) Å, β 90.585(3)°.
Most "nováčekite" specimens in collections seem to be either nováčekite-II or metanováčekite.
