Novel nitrogen and phosphorus-containing salts

Modified ammonium polyphosphates having the formula

• H.sub.h (NH.sub.4).sub.n O (PO.sub.3).sub.p (PO.sub.2 NH).sub.q (BO.sub.2).sub.b (X).sub.x . (H.sub.2 O).sub.y, wherein X is at least one divalent group selected from --SO.sub.3 --, --SO.sub.2 -- and --HPO.sub.2 -- , and h, n, p, q, b, x and y are all numbers from 0 to 20 which also comply with the following criteria:
• p>2;
• p>q;
• (h+n) = (p+q+b+2);
• (p+q)/( b+x) is from 1 to 100;
• and n>o;
• and n>h which are water-soluble and contain at least one radical selected from the group consisting of borate, sulphate, sulphite, and phosphite produced by admixing
• component (i) an organic ammoniating and condensing agent,
• component (ii) a phosphoric acid, the molar proportion of said component (i) to said component (ii) based on the P.sub.2 O.sub.5 content in said component (ii), being from 1.3:1 to 3:1, and
• component (iii) a compound selected from sulphuric acid, boric acid, boric oxide, phosphorous acid, sulphurous acid and the sodium potassium, calcium, urea and ammonium salts of said compound, the proportion of said component (iii) being from 2 to 1/10 moles per mole of P.sub.2 O.sub.5 in the admixture;
• and heating until a self-sustaining exothermic reaction occurs whereby said three components react and form said water-soluble modified ammonium polyphosphates.