Diborane, B2H6 (B) and methylethyl ether (A), form a compound that melts congruently at the 133 K. The system exhibits two eutectics, one at 25 mol per cent B and 123 K and a second at 90 mol per cent B and 104 K. Outline the phase diagram for this system. Assume negligible solid-solid solubility. The melting points of pure A and B are 131 K and 110 K, respectively.