ERTH 2102 Study Guide - Midterm Guide: Tetragonal Crystal System, Monoclinic Crystal System, Orthorhombic Crystal System
4 Jan 2016
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From naturally somewhere on earth or in the universe: stable at room temperature. Crystalline material must be stable or metastable at 25c ( exceptions: liquid mercury, water ice: typically inorganic organic. Mineral does not have c-c double bonds or contains c-h are: can be represented by a chemical formula, has an ordered atomic arrangement. Atoms are arranged in a repeating pattern in 3 dimensions. Crystallography: the way nature has put these elements together to form minerals. 8 compose over 98% pf the earths crust by weight. Coordination number gets bigger: cations get bigger because need larger sites to fit into, so charge decreases the size increases. Kyanite: high pressure, low temperature , all al3+ is most comfortable. Andalusite: very low temperatures and pressure , half is al3+ cations. Sillimanite: low pressure, high temperature , high temperature the. Each axis is at right angles to both the other axes, and one unit length on.
