Single crystals of Ba3B6Si2O16 were obtained by cooling a melt of stoichiometric composition. The crystalstructure was determined by direct methods from X-ray single crystal diffractometry data and refined to R1 = 0.066. It is triclinic, P1, a = 5.038(1), b = 7.657(1), c = 8.526(1)Å , a = 77.68(1), β = 77.88(1), γ = 86.32(1)°. The structure consists of a layered silicoborate anion formed by four crystallographically independent polyhedra with boron and silicon distributed in different proportion over the polyhedra. Ideally, there are one BO3 triangle, two BO4 tetrahedra and one SiO4 tetrahedron forming the independent anionic unit. Silicoborate layers are located parallel to the (010) plane. The Ba(1) and Ba(2) atoms are located in two non-equivalent sites with 8-fold and 12-fold coordination, respectively. The Ba(2) atoms form Ba-O layers parallel to (010) interchanged with anionic layers. Ba-O layers are connected via Ba-O columns build up by Ba(1)O8 polyhedra along [100]. Formation of the compound is studied by heat treatments in the range 800-970°C. According to high-temperature X-ray diffraction data the thermal expansion of the compound is anisotropic and relatively low in comparison with other borates.