Single crystals of six new alkali lanthanide silicates and germanates were synthesized via the flux growth method. A₂CeSi₃O₉ (A = Rb, Cs) and Cs₂CeGe₃O₉ crystallize in the Wadeite structure with space group P6₃/m and lattice parameters a = 7.1950(2) Å and c = 10.5109(3) Å for the Rb analogue. K₂CeSi₃O₉ crystallizes in a previously unobserved monoclinic distortion of the Wadeite structure with space group P2₁/n and lattice parameters a = 7.0801(2) Å, b = 10.458(2) Å, c = 12.238(2) Å and β = 90.07(3)°. Finally, Cs₈Dy₂Ge₁₆O₃₉ and Cs₈Dy₂Ge₁₆O₃₈F₂ crystallize in two new structure types that are related to each other and to the Wadeite structure. Cs₈Dy₂Ge₁₆O₃₉ crystallizes in the monoclinic space group P2/c with lattice parameters a = 12.4054(3) Å, b = 7.4310(2) Å, c = 24.5761(6) Å, and β = 90.8849(16)° and Cs₈Dy₂Ge₁₆O₃₈F₂ crystallizes in the orthorhombic space group Pnn2 with lattice parameters a = 12.3489(4) Å, b = 12.4805(5) Å, and c = 7.3802(3) Å. The synthesis and structure of the six compounds are reported and the crystallochemical reasons for the formation of each structure are discussed.

通过助熔剂生长法合成了六种新的碱金属镧系硅酸盐和锗酸盐的单晶。A ₂ CeSi ₃ O ₉（A = Rb，Cs）和Cs ₂ CeGe ₃ O ₉在Wadeite结构中以空间群P 6 ₃ / m和晶格参数a = 7.1950（2）Å和c = 10.5109（3）结晶。 Å为Rb类似物。K ₂ CeSi ₃ O ₉在空间群为P 2 ₁ / n的Wadeite结构的先前未观察到的单斜应变中结晶。和晶格参数a = 7.0801（2）Å，b = 10.458（2）Å，c = 12.238（2）Å和β = 90.07（3）°。最后，Cs ₈ Dy ₂ Ge ₁₆ O ₃₉和Cs ₈ Dy ₂ Ge ₁₆ O ₃₈ F ₂结晶为两种彼此相关且与韦氏结构相关的新结构类型。Cs ₈ Dy ₂ Ge ₁₆ O ₃₉在晶格参数为a的单斜空间群P 2 / c中结晶。= 12.4054（3）Å，b = 7.4310（2）Å，c = 24.5761（6）Å，β= 90.8849（16）°，Cs ₈ Dy ₂ Ge ₁₆ O ₃₈ F ₂在正交晶空间群Pnn 2中结晶。晶格参数a = 12.3489（4）Å，b = 12.4805（5）Å，c = 7.3802（3）Å。报告了这六种化合物的合成和结构，并讨论了形成每种结构的晶体化学原因。