Quasi-solvothennal syntheses and X-ray crystal structures of two germanates (H_3O)_4Ge_7O_(16)'3Hk_2O and K_4Ce_9O_(20) are presented. Although both structures are built up from the same rock-like secondary building units (SBUs) Ge_(10)O_(28), the frameworks are different because of the different connect manners of SBUs. Crystal data for H_4Ge_7H_2O: M_r = 894.27, space group P-43m, a=0.77309(18) ran, V = 0.46205(19) nm~3, Z = l, Mo Ka, λ=0.071073 nm, R(F) =3.48%, wR(F~2) =8.39% for 20 parameters and 228 reflections with I>2a(l). Crystal data for K_4Ce_9O_(20),: M_r = 1129.71, space group 14(l)/a, a = 1.5002(3) nm, c= 0.7383(2) nm, V= 1.6618(7) nm~3, Z = 4, MoKa, R(F) =3.92%, wR(F~2} = 11.97% for 75 parameters and 922 reflections with I>2a(I).

Key words: GERMANATE, MOLECULAR SIEVE, SINGLE CRYSTALS, CRYSTAL STRUCTURE