“…(a = 5.65/~,) (Efendiev, Nuriev & Safizade, 1969;Constantinescu, 1976a,b), tetragonal (a = 7.06, c = 4.98 A) (Boettcher, Haase & Treupel, 1955;Junod, 1959), orthorhombic (a = 7.05, b = 7.82, c = 4.32,~) (Zorll, 1955;Conn& Taylor, 1960;Ching-Liang & Pinsker, 1962;Sharma, 1969), monoclinic [a = 6.91, b = 7.87, c = 4.23 ,~, o~ = 99 ° 35', although the lattice parameters have been wrongly cited from the values for Ag2S (Frueh, 1958)] (De Ridder & Amelinckx, 1973;Saito, Sato & Shiojiri, 1981) and sometimes triclinic (pseudo-orthorhombic, a = 7.0, b = 7.8, c = 4.3/~,, c~ = 92, fl = 91, 3, = 92 ° ) (De Ridder & Amelinckx, 1973). Saito et al (1981) have claimed, by using films produced by the reaction of vacuum-deposited silver films with amorphous selenium films, the existence of tetragonal, orthorhombic and triclinic modifications as low-temperature phases and monoclinic and f.c.c. modifications as metastable phases and also suggested that the orthorhombic modification is the stoichiometric Ag2Se compound while the tetragonal and triclinic modifications are non-stoichiometric compounds containing excess silver and excess selenium, respectively.…”