Radiation-disordered crystals of phenakite Be_2SiO_4 (at fast neutron fluences of (0.75, 1.0, 1.2, 6.6, 8.5) × 10~(18) cm~(-2)) have been investigated using EPR spectroscopy. It has been established that the main radiation damages predominantly occur in the silicon-oxygen sublattice of the crystal. Vacancy centers (E′ centers, g = 2. 0015), defects of the displaced oxygen type, and O~- hole-type centers have been revealed. The paramagnetic absorption signal with the parameters g_x = 2.0218, g_y = 2.0124, and g_z = 2.0027 has been identified with the [SiO_4]~(3-) complex (a variety of O~- centers). The intense EPR signals with the parameters g_x = 2.0526, g_y = 2.0020, g_z = 2.0066 and g_x = 2.0290, g_y = 2.0030, g_z = 2.0099 have been assigned to two types of O_2~- molecular ions with different local environments. The theoretical models of radiation-induced centers have been discussed by comparing the EPR and optical spectroscopic data.
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