Barium fluoride Barium fluoride Barium fluoride (BaF) is a chemical compound of barium and fluorine and is a salt. It is a solid which can be a transparent crystal. It occurs in nature as the mineral frankdicksonite. The solid adopts the fluorite structure and at high pressure the PbCl structure. In the vapor phase the BaF molecule is non-linear with an F-Ba-F angle of approximately 108°. This is an exception to VSEPR theory which would predict a linear structure. Ab initio calculations have been cited to propose that contributions from d orbitals in the shell below the valence shell are responsible. Another
Cutlery mustard spoon and lettuce fork. Steel was always used for more utilitarian knives, and pewter was used for some cheaper items, especially spoons. From the nineteenth century, electroplated nickel silver (EPNS) was used as a cheaper substitute for sterling silver. In 1913, the British metallurgist Harry Brearley discovered stainless steel by chance and this metal has come to be the predominant one used in cutlery. An alternative is melchior, corrosion-resistant nickel and copper alloy, which can also sometimes contain manganese and nickel-iron. Plastic cutlery is made for disposable use, and is frequently used outdoors for camping, excursions, and barbecues for