ðɪ ˈælkəlˌaɪ mˈɛɾəl bˈoːɹaɪdz tˈɛnd təbi bˈoːɹɑːnɹˈɪtʃ, ɪnvˈɑːlvɪŋ ɐpɹˈiːʃiəbəl bˈoːɹɑːn bˈoːɹɑːn bˈɑːndɪŋ ɪnvˈɑːlvɪŋ dˌɛltɐhˈiːdɹəl stɹˈʌktʃɚz, ænd ɑːɹ θˈɜːməli ʌnstˈeɪbəl dˈuː tə ðɪ ˈælkəlˌaɪ mˈɛɾəlz hˌævɪŋ ɐ vˈɛɹi hˈaɪ vˈeɪpɚ pɹˈɛʃɚɹ æɾ ˈɛlɪvˌeɪɾᵻd tˈɛmpɹɪtʃɚz.
The alkali metal borides tend to be boron-rich, involving appreciable boron–boron bonding involving deltahedral structures, and are thermally unstable due to the alkali metals having a very high vapour pressure at elevated temperatures.