It has been shown that to define the order of Lewis acid strength at least two properties must be considered.
ɪt hˈæzbiːn ʃˈoʊn ðæt tə dᵻfˈaɪn ðɪ ˈɔːɹdɚɹ ʌv lˈuːɪs ˈæsɪd stɹˈɛŋθ æt lˈiːst tˈuː pɹˈɑːpɚɾiz mˈʌst biː kənsˈɪdɚd.