Determining the melting point of a sample of the highest oxide of phosphorus
1. M1: Sample in suitable melting point apparatus (e.g. capillary in oil bath/Thiele tube / melting point apparatus)
2. M2: Heat slowly/gradually/gently to establish melting point range
3. M3: Lower melting point / (broad) range of melting point indicates presence of impurities
4. OR: Melting point agrees with/close to data book value / melts sharply/over narrow range / melting point exactly 573K indicates purity