One example of a binary chemical weapon is the United States Army M687. In the M687, methylphosphonyl difluoride (military name: DF, a Schedule 1 chemical) and a mixture of two agents are held in chambers within the munition, separated by a partition.  When the weapon is fired, acceleration causes the partition to break, and the precursors are mixed by the rotation of the munition in flight, producing sarin nerve agent.
The Soviet Union and later Russian Federation experimented with binary munitions capable of mixing and distributing two agents that would work together in worsening the weapon's effects, an example of which would be the combination of nerve agents with blister agents.
The director of a non-proliferation research program of the Middlebury Institute of International Studies at Monterey has stated that the assassination of Kim Jong-nam due to poisoning with VX was likely carried out with a binary version of the agent, since VX fumes would otherwise have killed the suspected attackers.