Interconnected silica spheres (155) with hexagonally ordered mesopores have been synthesized with only a quarter of the total amount of surfactant used in the most surfactant-effective synthesis reported to date, i.e. a surfactant/silica molar ratio of 0.03. A MCM-41-type silica material with spherical core/shell morphology and an average particle size of ca. 250 nm was produced using a simple one-pot hydrothermal step. The shape of the spheres as well as their properties was found to be dependent on the synthesis parameters such as the ammonia and surfactant concentration, being the optimum ammonia/surfactant molar ratio ca. 2000. The samples prepared under these conditions have specific areas of 400-450 m(2) g(-1) and mesopore volumes up to 0.5 cm(3) g(-1). (C) 2011 Elsevier B.V. All rights reserved.