Four novel alkaline earth metal uranyl borates, namely, A[(UO 2 ) 5 (BO 3 ) 2 O 2 (OH) 2 ]•5H 2 O (SrUBO-1, BaUBO-1) and A[(UO 2 ) 2 (B 2 O 5 )O] (SrUBO-2, BaUBO-2) (A = Sr, Ba), have been prepared; SrUBO-1, BaUBO-1, and BaUBO-2 were synthesized using hydrothermal methods, whereas SrUBO-2 was prepared by a traditional hightemperature solid-state method. The compounds SrUBO-1 and BaUBO-1 were found to be iso-structural and crystallized in the centrosymmetric group C2/c. Their structure features t w o -d i m e n s i o n a l a n i o n i c l a y e r s {[(UO 2 ) 5 (BO 3 ) 2 O 2 (OH) 2 ] 2− } n that are composed of [(UO 2 ) 5 O 2 (OH) 2 ] 4+ clusters and [BO 3 ] 3− polyanions. From a topological point of view, this two-dimensional anionic layer can be described as a new 4-nodal net topological type with a point symbol of {3 5 .4 5 } 2 {3 6 .4 6 .5 3 } 3 {3 7 .4 7 .5 7 } 2 . SrUBO-2 and BaUBO-2 are iso-structural and crystallized in space group C2/m. Their structures are based on a three-dimensional framework {[(UO 2 ) 2 (B 2 O 5 )O] 2− } n . Within the three-dimensional framework, two-dimensional U(2)−U(1) = U(3) layers (L 1 ) with cation to cation interactions between [U(3)O 2 ] 2+ groups and one-dimensional edge sharing U(1)−U(2) chains are present. The B 2 O 5 dimers corner sharing with U(1)-U2 chains and U(3)O 6 tetragonal bipyramids forming two-dimensional layers (L 2 ). L 1 further vertically interconnect with L 2 through bridging B 2 O 5 dimers, forming a threedimensional framework [(UO 2 ) 2 (B 2 O 5 )O] 2− . The synthetic conditions, structural characterization, thermal stability, as well as spectroscopic properties of the alkaline earth metal uranyl borates are reported and discussed.

Two new alkaline-earth strontium borogermanates, namely, SrGe2B2O8 and Sr3Ge2B6O16, have been successfully synthesized through high-temperature solid state reactions. They represent the first examples of strontium borogermanates. SrGe2B2O8 crystallized in space group Pnma, and its structure features a novel three-dimensional [Ge2B2O8](2-) framework composed of alternative linkages of the B2O7 and Ge2O7 dimeric units with one-dimensional (1D) tunnels of eight-membered rings (MRs) along the b axis that are filled by the Sr(2+) cations. Sr3Ge2B6O16 is isostructural with Ba3Ge2B6O16 and crystallizes in centrosymmetric space group P1. Its structure features a two-dimensional layer that is composed of circular B6O16 clusters and GeO4 tetrahedra that are interconnected via corner sharing, forming 1D four- and six-MR tunnels along a axis. Sr(1) cations are located in the six-MR tunnels, whereas Sr(2) cations are located in the interlayer space. Studies of their optical properties and thermal stability as well as band structure calculations based on density functional theory methods have been also performed.