  Linear complementary dual codes were defined by Massey in 1992, and were used
to give an optimum linear coding solution for the two user binary adder
channel. In this paper, we define the analog of LCD codes over fields in the
ambient space with mixed binary and quaternary alphabets. These codes are
additive, in the sense that they are additive subgroups, rather than linear as
they are not vector spaces over some finite field. We study the structure of
these codes and we use the canonical Gray map from this space to the Hamming
space to construct binary LCD codes in certain cases.
