Abstract. Let E be a central extension of the form 0 → V → G → W → 0 where V and W are elementary abelian 2-groups. Associated to E there is a quadratic map Q : W → V , given by the 2-power map, which uniquely determines the extension. This quadratic map also determines the extension class q of the extension in H 2 (W, V ) and an ideal I(q) in H 2 (G, Z/2) which is generated by the components of q. We say that E is Bockstein closed if I(q) is an ideal closed under the Bockstein operator.We find a direct condition on the quadratic map Q that characterizes when the extension is Bockstein closed. Using this characterization, we show for example that quadratic maps induced from the fundamental quadratic mapOn the other hand, it is well known that an extension is Bockstein closed if and only if it lifts to an extension 0In this situation, one may write β(q) = Lq for a "binding matrix" L with entries in H 1 (W, Z/2). We find a direct way to calculate the module structure of M in terms of L. Using this, we study extensions where the lattice M is diagonalizable/triangulable and find interesting equivalent conditions to these properties.