pr ism ▁is ▁the ▁second ▁in ▁an ▁infinite ▁set ▁of ▁anti pr isms ▁formed ▁by ▁an ▁even - number ed ▁sequence ▁of ▁triangle ▁sides ▁closed ▁by ▁two ▁polygon ▁caps . ▁It ▁is ▁also ▁known ▁as ▁an ▁ant ic ube . ▁ ▁If ▁all ▁its ▁faces ▁are ▁regular , ▁it ▁is ▁a ▁sem ire g ular ▁poly hed ron ▁or ▁uniform ▁poly hed ron . ▁ ▁Point s ▁on ▁a ▁sphere ▁When ▁eight ▁points ▁are ▁distributed ▁on ▁the ▁surface ▁of ▁a ▁sphere ▁with ▁the ▁aim ▁of ▁maxim ising ▁the ▁distance ▁between ▁them ▁in ▁some ▁sense , ▁the ▁resulting ▁shape ▁corresponds ▁to ▁a ▁square ▁anti pr ism ▁rather ▁than ▁a ▁cube . ▁Specific ▁methods ▁of ▁distrib uting ▁the ▁points ▁include , ▁for ▁example , ▁the ▁Thom son ▁problem ▁( min im izing ▁the ▁sum ▁of ▁all ▁the ▁reci pro cal s ▁of ▁distances ▁between ▁points ), ▁maxim ising ▁the ▁distance ▁of ▁each ▁point ▁to ▁the ▁nearest ▁point , ▁or ▁minim ising ▁the ▁sum ▁of ▁all ▁reci pro cal s ▁of ▁squares ▁of ▁distances ▁between ▁points . ▁ ▁M ole cules ▁with ▁square ▁anti pr ism atic ▁geometry ▁ ▁According ▁to ▁the ▁V SE PR ▁theory ▁of ▁mole cular ▁geometry ▁in ▁chem istry , ▁which ▁is ▁based ▁on ▁the ▁general ▁principle ▁of ▁maxim izing ▁the ▁distances ▁between ▁points , ▁a ▁square ▁anti pr ism ▁is ▁the ▁fav oured ▁geometry ▁when ▁eight ▁pairs ▁of ▁electrons ▁surr ound ▁a ▁central ▁atom . ▁One ▁mole c ule ▁with ▁this ▁geometry ▁is ▁the ▁oct a flu or ox en ate