What made you want to look up negative valence? Please tell us where you read or heard it (including the quote, if possible).
WBS is nothing but Work Breakdown Structure. It is mainly used in Project System (PS) module. Tcode: CJ20N. For any project defined we must have atleast one WBS. Within this WBS we can have networks. Networks are nothing but the series of activities. Material are used to perform the activities.
Sulfates, also spelled sulphates, are used in a variety of common products and processes. Sodium lauryl sulfate is a strong detergent used for removing oils and grease and is found in household cleaning products, face and body washes and shampoos. Sodium sulfate is used in the manufacturing of glass and paper. Zinc sulfate is used to preserve wood. Sulfides, also spelled sulphides, come in three classes: organic sulfides, inorganic sulfides and phosphine sulfides. Organic sulfides are compounds in which sulfur is bonded to two organic groups.