Luster nonmetallic

The ternary hydride was formed also at a reduced pressure and temperature of 200 psi and 200°C, respectively, after several cycles of hydriding and decomposition. Mg2NiH4, a rust-colored solid with a nonmetallic luster, reacted sluggishly with water but more vigorously with nitric acid solution, giving off hydrogen. Mg2NiH4 appeared to be unreactive to air upon short exposure. 

The luster of a mineral is the appearance of its surface when light is reflected off of it. Minerals can have metallic or nonmetallic luster. Minerals with metallic luster look shiny like a metal. Nonmetallic minerals can have various appearances, such as vitreous (glassy), greasy, silky, brilliant (like a diamond), or pearly. 

Certain physical properties also follow such trends, and some of these are easily observed, as shown in I Figure 3.13. At room temperature and ordinary atmospheric pressure, nitrogen is a colorless gas, phosphorus is a white nonmetallic solid, arsenic is a brittle gray solid with a slight metallic luster, antimony is a brittle silver-white solid with a metallic luster, and bismuth is a lustrous silver-white metal. 

Arsenic, selenium, tin, antimony, and tellurium all exist in metallic and nonmetallic forms. For example, Sn occurs as white tin which has a metallic luster and is a good conductor of heat and electricity, and gray tin in which the atoms are covalently bonded in a diamond-type lattice. Below 18 C, the crystalline white tin slowly changes to the powdery gray tin. This transformation was first observed as blistery outbreaks (called tin pest ) on the surface of tin objects such as organ... 

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