Some metals at interaction with hydrogen form hydrides. Sorption and десорбция hydrogen represents reversible chemical reaction. Return reaction proceeds under other conditions (pressure, temperature) and causes a process hysteresis. Metals have various structural defects; they change кинетику absorptions of hydrogen and its maintenance in volume unit. Therefore limiting possibilities of metals on reversible sorption hydrogen should be considered taking into account fields of pressure of structural defects. The most important among them are regional dispositions, tops of micro cracks and wedge disclamations. Atoms of hydrogen co-operate with fields of pressure of the listed defects. It leads to formation segregation from atoms of hydrogen. The hydrogen maintenance in unit of volume of metal increases. The comparative analysis of hydrogen capacity of structural defects is considered for stationary process. In a vicinity of each structural defect it is formed equilibrium hydrogen segregation. Superfluous concentration of atoms of hydrogen in relation to average value is defined from expression:formulaFor a regional disposition the number of atoms of hydrogen on unit of length is by integration of parity (1):formulaLet's spread out exponential function abreast. Even members of decomposition are responsible for hydrogen capacity only. Being limited to the first of them, we will receive:formulaLet's execute corresponding estimations for system Ni - B-H. Alloys on the basis of the nickel, alloyed by a pine forest, use as materials of the radio-electronic industry. From calculations under the formula (3) for the basic defects following results are received. For regional dispositions at concentrationformulaon unit of length of a line of a disposition 2,5·109 superfluous atoms of hydrogen (less than one atom on a nuclear plane) are necessary. For micro crack top at concentrationformulaon unit of length of a line of a disposition 2,5·109 superfluous atoms of hydrogen (less than one atom on a nuclear plane) are necessary. For micro crack top at concentrationformulaon unit of length 2·1010 superfluous atoms of hydrogen (two atoms on one nuclear plane) are necessary. At same concentrationformulaon unit of length of a line declination 5·1011 superfluous atoms of hydrogen (fifty atoms on a nuclear plane) are necessary. Thus, the basic structural defects for atoms of hydrogen are regional dispositions. It is caused by their high density in comparison with tops of micro cracks and wedge disclamations.