New alkali borosulfates were obtained by precipitation from oleum, solid-state reactions, or thermal decomposition. The crystal structures were characterized with single-crystal data. They are all based on corner-linked BO4 and SO4 tetrahedra with varying coordination of the alkali cations. According to the ratio of BO4 and SO4 tetrahedra, different frameworks are observed, i.e., noncondensed complex anions (1:4), one-dimensional chains (1:3), or three-dimensional (3D) networks (1:2). This is in analogy to silicates, where the ratio Si/O relates to the dimensionality also. For Na-5[B(SO4)(4)], which exists in two different polymorphs, there are noncondensed pentameric units. Na-5[B(SO4)(4)]-I: space group Pca2(1), a = 10.730(2) angstrom, b = 13.891(3) angstrom, c = 18.197(4) angstrom. Na-5[B(SO4)(4)]-II: space group P2(1)2(1)2(1), a = 8.624(2) angstrom, b = 9.275(2) angstrom, c = 16.671(3) angstrom. A(3)[B(SO4)(3)] (A = K, Rb) are isotypic with Ba-3[B(PO4)(3)] adopting space group Ibca [K-3[B(SO4)(3)], a = 7.074(4) angstrom, b = 14.266(9) angstrom, c = 22.578(14) angstrom; Rb-3[B(SO4)(3)], a = 7.2759(5) angstrom, b = 14.7936(11) angstrom, c = 22.637(2) angstrom] with vierer chains of BO4 tetrahedra based on two bridging and two terminal SO4 tetrahedra. Li[B(SO4)(2)] [space group Pc, a = 7.6353(15) angstrom, b = 9.342(2) angstrom, c = 8.432(2) angstrom, and beta = 92.55(2)degrees] comprises a 3D network that is closely related to beta-tridymite. Li[B(S2O7)(2)] [space group P2(1)2(1)2(1), a = 10.862(2) angstrom, b = 10.877(2) angstrom, c = 17.769(4) angstrom] represents the first example of a disulfate complex with noncondensed [B(S2O7)(2)](-) units. Vibrational spectra were recorded from all compounds, and the thermal behavior was also investigated.