Investigation of the Ho_2Se_3-Cu_2Se-PbSe and Er_2Se_3-Cu_2Se-PbSe systems at 870 K

摘要

The interactions between the components in the Ho_2Se_3-Cu_2Se-PbSe and Er_2Se_3-Cu_2Se-PbSe systems at 870 K were determined using X-ray single crystal and powder diffraction. The existence of the compounds with compositions RcuSe_2-R_(2/3)Cu_2Se_2 (Er_(2/3)Cu_2S_2 structure type, space group P3, a = 0.40563(1) nm, c = 0.64542(3) nm, R_I = 0.0737 for HoCuSe, and a=0.40407(l)nm, c = 0.64420(3) nm, R_I = 0.0660 for ErCuSe_2) and Rcu_5Se_4 (unknown structure) was confirmed in the R_2Se_3-Cu_2Se (R=Ho, Er) sections. The existence of the compounds Ho_6Pb_2Se_(11) (Y_6Pb_2Se_(11) structure type, space group Cmcm, a = 0.40561(2)nm, b= 1.34018(6)nm, c = 3.7525(1)nm) and Er_2PbSe_4 (CaFe_2O_4 structure type, space group Pnma, a = 1.2554(2) nm, b = 0.40778(5) nm, c= 1.4885(2) nm, R_I =0.0914) was confirmed in the R_2Se_3-PbSe (R = Ho, Er) sections. The existence of the compounds Ho_(3.33)CuPb_(1.5)Se_7 (Lu_(3.33)CuPb_(1.5)Se_7 structure type, space group Cm, a= 1.35314(8)nm, b = 0.40819(2)nm, c = 1.25609(7)nm, beta = 104.577(3) deg) and HoCuPbSe_3 O-BaLaCuSe3 structure type, space group Pnma, a= 1.0516(2)nm, b = 0.40470(8)nm, c=1.3410(3)nm, R_I =0.0541) in the Ho_2Se_3-Cu_2Se-PbSe system was confirmed. The formation of the compounds Er_5CuPb_3Se_(11) (Er_5CuPb_3Se_(11) structure type, space group Cmcm, a = 0.40688(2)nm, b= 1.34607(7)nm, c = 3.8040(2)nm), Er_(3.33)CuPb_(1.5)Se_7 (Lu_(3.33)CuPb_(1.5)Se_7 structure type, space group Cm, a = 1.35018(7) nm, b = 0.40693(2) nm, c = 1.25433(6) nm, beta = 104.492(2) deg) and ErCuPbSe_3 (beta-BaLaCuSe_3 structure type, space group Pnma, a = 1.04846(8) nm, b = 0.40424(3) nm, c= 1.34143(7) nm) in the Er_2Se_3-Cu_2Se-PbSe system was confirmed.