Designing proper energetic and reactive precursor combinations to produce a desired inorganic material is a function of many factors, such as thermal and chemical stability of the precursors and products, potential for undesirable side reactions, and ease of product isolation.  Solvent-free energetic and exothermic solid-state metathesis (SSM) reactions can form a variety of crystalline metal oxide, nitride, sulfide, and phosphide materials in seconds.  Our previous work on “cooling down” exothermic SSM reactions using superheated solvents opened access to thermally metastable metal nitrides (e.g., Cu₃N and InN) and oxides (e.g. anatase TiO₂).  This presentation will detail a serendipitous discovery of “salt unbalanced” SSM reactions that rapidly forms layered metal oxyhalide structures and solid-solution oxyhalides in seconds (e.g., BiOCl, LaOCl, and GdOCl).  Recent advances with solvothermally moderated materials synthesis will also be described where reactive molecular white P₄ successfully produces nanoscale phosphorus-rich metal phosphides (e.g., CuP₂ and CoP₃).  The key component for success in the phosphide reactions is the use of a rigorously anhydrous reaction environment.