You're thinking of chlorine trifluoride [1]. But red fuming nitric acid is also hypergolic with many fuels. [1] https://www.science.org/content/blog-post/sand-

You're thinking of chlorine trifluoride [1]. But red fuming nitric acid is also hypergolic with many fuels. [1] https://www.science.org/content/blog-post/sand-won-t-save-you-time https://www.science.org/content/blog-post/sand-won-t-save-yo...