  The central strong activities in core-collapse supernovae expect to produce
the overturning of the Fe- and Si/O-rich ejecta during the supernova explosion
based on multi-dimensional simulations. X-ray observations of the supernova
remnant Cassiopeia A have indicated that the Fe-rich ejecta lies outside the
Si-rich materials in the southeastern region, which is consistent with the
hypothesis on the inversion of the ejecta. We investigate the kinematic and
nucleosynthetic properties of the inverted ejecta layers in detail to
understand its formation process using the data taken by the Chandra X-ray
Observatory. Three-dimensional velocities of Fe- and Si/O-rich ejecta are
obtained as $>$4,500 km s$^{-1}$ and $\sim$2,000--3,000 km s$^{-1}$,
respectively, by combining proper motion and line-of-sight velocities,
indicating that the velocity of the Si/O-rich ejecta is slower than that of the
Fe-rich ejecta since the early stage of the explosion. To constrain their
burning regime, the Cr/Fe mass ratios are evaluated as $0.51_{-0.10}^{+0.11}$%
in the outermost Fe-rich region and $1.24 ^{+0.19}_{-0.20}$% in the inner
Fe/Si-rich region, suggesting that the complete Si burning layer is invertedly
located to the incomplete Si burning layer. All the results support the ejecta
overturning at the early stages of the remnant's evolution or during the
supernova explosion of Cassiopeia A.
