The hexagonal hydrogen insertion compound, hexH(x)MoO(3), with the tunnel structure was obtained from sodium decamolybdate, Na-deca. A maximum amount of inserted hydrogen was x = 1.5. Hydrogen insertion accompanied the insertion of hydrate water. NMR results prove the presence of the paired protons and the isolated protons fixed in the position. When the protons were inserted, they were distributed into the paired protons and the isolated ones. The model of hydrogen insertion was proposed.