To date, uranyl silicates are mostly represented by minerals in nature. However, their synthetic counterparts can be used as ion exchange materials. A new approach for the synthesis of framework uranyl silicates is reported. The new compounds Rb2[(UO2)2(Si8O19)](H2O)2.5(1), (K,Rb)2[(UO2)(Si10O22)] (2), [Rb3Cl][(UO2)(Si4O10)] (3) and [Cs3Cl][(UO2)(Si4O10)] (4) were prepared at harsh conditions in “activated” silica tubes at 900 °C. The activation of silica was performed using 40% hydrofluoric acid and lead oxide. Crystal structures of new uranyl silicates were solved by direct methods and refined:1is orthorhombic,Cmce,a= 14.5795(2) Å,b= 14.2083(2) Å,c= 23.1412(4) Å,V= 4793.70(13) Å3,R1 = 0.023;2is monoclinic,C2/m,a= 23.0027(8) Å,b= 8.0983(3) Å,c= 11.9736(4) Å,β= 90.372(3) °,V= 2230.43(14) Å3,R1 = 0.034;3is orthorhombic,Imma,a= 15.2712(12) Å,b= 7.9647(8) Å,c= 12.4607(9) Å,V= 1515.6(2) Å3,R1 = 0.035,4is orthorhombic,Imma,a= 15.4148(8) Å,b= 7.9229(4) Å,c= 13.0214(7) Å,V= 1590.30(14) Å3,R1 = 0.020. Their framework crystal structures contain channels up to 11.62 × 10.54 Å filled by various alkali metals.