Weak temperature-independent paramagnetism

In contrast to chloride compounds, niobium oxides have a VEC of 14 electrons, due to an overall anti-bonding character of the a2u state, caused by a stronger Nb-O anti-bonding contribution. In some cases, the VEC cannot be determined unambiguously due to the uncertainty in the electron distribution between the clusters and additional niobium atoms present in the majority of the structures. The 14-electron compounds exhibit semiconducting properties and weak temperature-independent paramagnetism. Unlike niobium chlorides, the oxides do not exhibit a correlation between the electronic configuration and intra-cluster bond distances. 

Two other actinyl ions, UO (5/°) and NpO (5/ ), are worth mentioning here. Although the uranyl ion contains no unpaired/electrons, its complexes may display a weak temperature-independent paramagnetism because of... 

A series of AgF+ salts (AgFMF4 with M = B, Au and AgFMF6 with M = As, Au, Ir, Ru, Sb, Bi) have been prepared. The first was AgFAsF6 [9] made by the interaction of AgF2 with AsF5 in aHF. They all have the weak, temperature independent paramagnetism indicative of a partially filled band and suggestive of metallic character [12]. In no case however has electrical conductivity of metallic type been demonstrated in any one of these solids. A wide variety of synthetic routes have been demonstrated for the preparation of (Ag—F)]]+ salts. 

By sintering powder mixtures of NaH and Os (Ru) at temperatures of up to 870 K and H2 pressures of up to 1500 (Os) and 6000 (Ru)bar. ordered stmcture (Figure 43) by npd on deuteride of Os compounds at room temperature PAilmnm, Z = 4 contains isolated distorted pentagonal bipyramid [OsHy] 18-electron units having Os site symmetry m.2m surrounded by eight Na+ (from two Na sites) forming a distorted cube four D sites transforms into a HT modification at 459 K lif 3Na+ [TH7] , T, d (supported by experimentally measured weak temperature independent paramagnetism on Os compound). Diffraction evidence for the existence of cubic phases M3 THy- (M = K, Rb, Cs T = Ru, Os 5 0.12 for the K-Ru compound). 

A variety of AgF salts have now been prepared and structurally characterized. They all have the weak, temperature-independent paramagnetism indicative of a partially filled band. This and other properties are in conformity with the metallic nature of the chain (Ag-F). ... 

The permanganates exhibit weak temperature-independent paramagnetism though Mn has no unpaired electrons. 

---