▎ 摘　　要

The porous structure of graphene-like boron nitride t-BNg powders is qualified. The material is homogenous and micro-mesoporous, with pores being distributed in the range 3.53-4.12 nm corresponding to 55% volume and 60% specific surface area of mesopores. The specific surface area of micropores calculated with the Dubinin-Kadlets method (t-method) is 28.3 m(2)/g and the specific surface area of mesopores calculated with the Barrett-Joyner-Halenda method is 141 m(2)/g. Powders of graphene-like t-BNg synthesized from carbamide contain impurities of polycondensed flat particles of boron oxonitride. Impurities as a refined sublimate (white powder) are separated out of the washed and dried t-BNg powder by subsequent vacuum heat treatment at 540 K and pressure to ae1.0 Pa. The sublimate is identified as a heterocyclic six-membered dimer with molecular formula H(OH)[(BON)(2)](OH)H.