One of relatively few reactions that takes place directly between two solids at room temperature is ba(oh)2 · 8h2o + ammonium thiocyanate --> barium thiocyanate + water + ammonia in this equation, the · 8h2o in ba(oh)2 · 8h2o indicates the presence of eight water molecules. this compound is called barium hydroxide octahydrate. what mass of ammonium thiocyanate must be used if it is to react completely with 6.5 g barium hydroxide octahydrate?