The single crystla of K2CaB8O26H24 has been determined by X-ray diffraction. Crystal data:orthorhombic, P212121,a=1.1550(2)nm,b=1. 2484(2)nm,c=1.6580(2)nm。 V=2.3906(6)nm^3,Z=4,Dc=1.792g·cm^-3,μ=0. 720mm^-1, F=(000)=1320. Its vibrational spectra are recorded. The observed frequencies and their assignments are given. The dissolution of K2CaB8O26H24 was incongruous and its production is X-ray amorphis. This amorphism would transform to crystal. The mechanism of dissolution was suggested.

Key words: DOUBLE SALTS, VIBRATIONAL SPECTRUM, DISSOLUTION, CRYSTAL STRUCTURE, X-RAY DIFFRACTION ANALYSIS