Styx rule

The styx rule, also known as Lipscomb's styx rule, can be used to calculate the structures of boranes.

[1] The rule defines boranes to have four types of bonds besides the terminal B-H bonds:[2] Where: The bonding structure deduced by the styx rule doesn't reflect the true symmetry of boranes.

[2] More modern methods that more accurately reflect the bonding nature of boranes like Wade's rules have been developed.

[3] When given the chemical formula of a borane (BmHn), one can deduce its styx numbers by first separating the formula into (BH)mHn-m. Then, one can make use of three equations:[2][4] With these, one can come up with several integer combinations of styx.

However, some are ruled out because styx are non-negative.