The LaNiAl type structure has been previously described in details in numerous reports, here we want to focus on the peculiarities of the quaternary derivative with special emphasis on the structural relation to the parent structures and the crystal chemistry aspects that are related to the pronounced Mn/Cd crystallographic site preferences. Hence, as depicted in Figure compound exhibits the characteristic of both the TiNiSi (or anti-PbCl2) type and the ZrNiAl type parent structures, and this can be expressed in the idealized formula as (EuCdPt)(EuMnPt), when neglecting the partial Cd/Mn mixing at first, so that each of the mixed atomic site is assigned to the main occupying element Cd2 (89%) or Mn1 (78 %). Thus, the TiNiSi related slabs has the idealized composition "EuMnPt" in which Pt1 is nine-coordinated to three closest Mn1 atoms with Pt1-Mn1 distances of 2.709(1) and 2.723(1) Å, to two Cd2 atoms with Pt1-Cd2 distance of 2.837(1) Å, and finally to four Eu atoms at longer distances of 3.012(1) to 3.212(1) Å, resulting in Pt1@Mn3Cd2Eu4 coordination environment. The coordination geometry here is similar to the Si@Ni4Ti5 coordination observed in the TiNiSi prototype, with the five Ti-type positions that are shared by four Eu and one Cd atoms. In turn, the Mn1 position is found in a distorted tetrahedra geometry Mn1@Pt3Pt with three Pt1 and one Pt2, and Mn1-Pt2 distance of 2.755(1) Å. Slightly shorter Mn-Pt bond lengths of 2.71 Å are reported in binary MnPt tetragonal phase, which are closed to the sum of covalent radii of Mn (1.37 Å), and Pt (1.37 Å). Non-negligeable Mn1-Mn1 distances of 3.084(1) Å between the centres of the edge-sharing MnPt4 tetrahedra, generate Mn zigzag chains running along the b-direction. The second coordination sphere of Mn1 include one Cd2 (Mn1-Cd2 = 3.080(1) Å), two alike Mn1 within the zigzag chain, and five Eu atoms, resulting in Mn1@Pt4Cd1Mn2Eu5, which is similar to the Ni@Si4Ni2Ti6 in the TiNiSi prototype in which one Cd2 position at the interface shares the Ti role with five Eu atoms. The Mn1-Eu distances are longest between 3.335(1) and 3.448(1) Å, but close to the sum of atomic radii, given Mn (1.37 Å), and Eu (2.00 Å). In the ZrNiAl related slabs with the idealized composition "EuCdPt", Pt2 positions are in the typical tri-capped trigonal prism coordination geometry of the prototype as Pt2@MnCd2Eu6 with Pt2-Cd2 distances that are close to the sum of atomic radii, given Cd (1.49 Å), while Cd2 positions at the interface are coordinated by four closest Pt atoms in tetrahedral geometry, and six Eu atoms in the second coordination sphere, in a wedge shape coordination polyhedron, leading to Cd2@Pt4Eu6. Here, Cd2-Pt1 distances are between 2.838(1) and 2.956(1) Å, also close to the sum of atomic radii. The tetrahedral coordination geometry of Cd2 is rather typical of the TiNiSi type, as Cd2 is located at the interface of the two different slabs. The Cd2-Eu distances are between 3.345(1) and 3.453(1) Å, in the same range as Mn1-Eu. Here the Pt2-Eu distances (3.094(1) to 3.141(1) Å) are in the same range as Pt1-Eu distances. In turn, the Eu substructure consists of Pt2 centered trigonal prismatic motives and, they share edges in the ac plane and faces in the b-direction to form 2D sheets that are stacked along the c-direction. The minimum distance between these triangular sheets corresponds to Eu-Eu distance of 3.771(1) Å, which is shorter than similar Eu-Eu distances within the triangular motives between 3.854(1) and 3.921(1) Å.