To convert a signed binary int to a decimal number, use the following algorithm. We illustrate the algorithm on two four-bit examples: 1110 and 0101. If the leftmost bit is a 1, the number is negative. Do the following... (1110 starts with a 1.
Copper pyrites is a common name for the mineral chalcopyrite, which has a formula CuFeS2. It can be considered to be made up of Cu+ Fe3+ S2- ions but there is covalent character.
On exposure to air, chalcopyrite oxidises to a variety of oxides, hydroxides and sulfates. Associated copper minerals include the sulfides bornite (Cu 5 FeS 4), chalcocite (Cu 2 S), covellite (CuS), digenite (Cu 9 S 5); carbonates such as malachite and azurite, and rarely oxides such as cuprite (Cu 2 O). Chalcopyrite is rarely found in association with native copper.