  Venus' mass and radius are similar to those of Earth. However,
dissimilarities in atmospheric properties, geophysical activity and magnetic
field generation could hint towards significant differences in the chemical
composition and interior evolution of the two planets. Although various
explanations for the differences between Venus and Earth have been proposed,
the currently available data are insufficient to discriminate among the
different solutions. Here we investigate the possible range of Venus structure
models. We assume that core segregation happened as a single-stage event. The
mantle composition is inferred from the core composition using a prescription
for metal-silicate partitioning. We consider three different cases for the
composition of Venus defined via the bulk Si and Mg content, and the core's S
content. Permissible ranges for the core size, mantle and core composition as
well as the normalized moment of inertia (MoI) are presented for these
compositions. A solid inner core could exist for all compositions. We estimate
that Venus' MoI is 0.317-0.351 and its core size 2930-4350 km for all assumed
compositions. Higher MoI values correspond to more oxidizing conditions during
core segregation. A determination of the abundance of FeO in Venus' mantle by
future missions could further constrain its composition and internal structure.
This can reveal important information on Venus' formation and evolution, and
possibly, the reasons for the differences between Venus and our home planet.
