The crystal structures of jagueite, Cu2Pd3Se4, and chrisstanleyite, Ag2Pd3Se4

The crystal structure of jagueite, ideally Cu2Pd3Se4, monoclinic, a 5.672(5), b 9.909(9), c 6.264(6) angstrom, beta 115.40(2)degrees, space group P2(1)/c, has been solved by direct methods and refined to an R-1 index of 5.52% for 956 unique reflections measured with MoK alpha X-radiation on a P-4 Bruker diffractometer equipped with a CCD area-detector. The crystal structure of chrisstanleyite, ideally Ag2Pd3Se4, monoclinic a 5.676(2), b 10.342(4), c 6.341(2) angstrom, beta 114.996(4)degrees, space group P2(1)/c, has been solved by direct methods and refined to an R-1 index of 8.3% for 1203 unique reflections measured with MoK alpha X-radiation. There are two unique Pd sites, one Cu (or Ag) and two Se sites in the unit cell. Atom Pd1 forms isolated square arrangements PdSe4, whereas the adjacent arrangements involving Pd2 are paired via a common edge. The (Cu,Ag) coordination tetrahedra form (100) layers which, together with the Pd2-Cu(Ag)-Pd1-Cu(Ag)-Pd2 system of metal-metal bonds, help to stabilize the open-work structure composed of PdSe4 squares.